Sample records for identified homozygous mutations

  1. Spectrum of mutations in homozygous familial hypercholesterolemia in India, with four novel mutations.

    PubMed

    Setia, Nitika; Saxena, Renu; Arora, Anjali; Verma, Ishwar C

    2016-12-01

    Homozygous familial hypercholesterolemia (FH) is a rare but serious, inherited disorder of lipid metabolism characterized by very high total and LDL cholesterol levels from birth. It presents as cutaneous and tendon xanthomas since childhood, with or without cardiac involvement. FH is commonly caused by mutations in three genes, i.e. LDL receptor (LDLR), apolipoprotein B (ApoB) and PCSK9. We aimed to determine the spectrum of mutations in cases of homozygous FH in Asian Indians and evaluate if there was any similarity to the mutations observed in Caucasians. Sixteen homozygous FH subjects from eleven families were analyzed for mutations by Sanger sequencing. Large rearrangements in LDLR gene were evaluated by multiplex ligation probe dependent amplification (MLPA) technique. Ten mutations were observed in LDLR gene, of which four mutations were novel. No mutation was detected in ApoB gene and common PCSK9 mutation (p.D374Y). Fourteen cases had homozygous mutations; one had compound heterozygous mutation, while no mutation was detected in one clinically homozygous case. We report an interesting "Triple hit" case with features of homozygous FH. The spectrum of mutations in the Asian Indian population is quite heterogeneous. Of the mutations identified, 40% were novel. No mutation was observed in exons 3, 9 and 14 of LDLR gene, which are considered to be hot spots in studies done on Asian Indians in South Africa. Early detection followed by aggressive therapy, and cascade screening of extended families has been initiated to reduce the morbidity and mortality in these patients. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  2. Whole-exome sequencing identifies novel homozygous mutation in NPAS2 in family with nonobstructive azoospermia.

    PubMed

    Ramasamy, Ranjith; Bakırcıoğlu, M Emre; Cengiz, Cenk; Karaca, Ender; Scovell, Jason; Jhangiani, Shalini N; Akdemir, Zeynep C; Bainbridge, Matthew; Yu, Yao; Huff, Chad; Gibbs, Richard A; Lupski, James R; Lamb, Dolores J

    2015-08-01

    To investigate the genetic cause of nonobstructive azoospermia (NOA) in a consanguineous Turkish family through homozygosity mapping followed by targeted exon/whole-exome sequencing to identify genetic variations. Whole-exome sequencing (WES). Research laboratory. Two siblings in a consanguineous family with NOA. Validating all variants passing filter criteria with Sanger sequencing to confirm familial segregation and absence in the control population. Discovery of a mutation that could potentially cause NOA. A novel nonsynonymous mutation in the neuronal PAS-2 domain (NPAS2) was identified in a consanguineous family from Turkey. This mutation in exon 14 (chr2: 101592000 C>G) of NPAS2 is likely a disease-causing mutation as it is predicted to be damaging, it is a novel variant, and it segregates with the disease. Family segregation of the variants showed the presence of the homozygous mutation in the three brothers with NOA and a heterozygous mutation in the mother as well as one brother and one sister who were both fertile. The mutation is not found in the single-nucleotide polymorphism database, the 1000 Genomes Project, the Baylor College of Medicine cohort of 500 Turkish patients (not a population-specific polymorphism), or the matching 50 fertile controls. With the use of WES we identified a novel homozygous mutation in NPAS2 as a likely disease-causing variant in a Turkish family diagnosed with NOA. Our data reinforce the clinical role of WES in the molecular diagnosis of highly heterogeneous genetic diseases for which conventional genetic approaches have previously failed to find a molecular diagnosis. Copyright © 2015 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  3. Exome sequencing identifies a novel homozygous mutation in the phosphate transporter SLC34A1 in hypophosphatemia and nephrocalcinosis.

    PubMed

    Rajagopal, Abbhirami; Braslavsky, Débora; Lu, James T; Kleppe, Soledad; Clément, Florencia; Cassinelli, Hamilton; Liu, David S; Liern, Jose Miguel; Vallejo, Graciela; Bergadá, Ignacio; Gibbs, Richard A; Campeau, Phillipe M; Lee, Brendan H

    2014-11-01

    Two Argentinean siblings (a boy and a girl) from a nonconsanguineous family presented with hypercalcemia, hypercalciuria, hypophosphatemia, low parathyroid hormone (PTH), and nephrocalcinosis. The goal of this study was to identify genetic causes of the clinical findings in the two siblings. Whole exome sequencing was performed to identify disease-causing mutations in the youngest sibling, and a candidate variant was screened in other family members by Sanger sequencing. In vitro experiments were conducted to determine the effects of the mutation that was identified. Affected siblings (2 y.o. female and 10 y.o male) and their parents were included in the study. Informed consent was obtained for genetic studies. A novel homozygous mutation in the gene encoding the renal sodium-dependent phosphate transporter SLC34A1 was identified in both siblings (c.1484G>A, p.Arg495His). In vitro studies showed that the p.Arg495His mutation resulted in decreased phosphate uptake when compared to wild-type SLC34A1. The homozygous G>A transition that results in the substitution of histidine for arginine at position 495 of the renal sodium-dependent phosphate transporter, SLC34A1, is involved in disease pathogenesis in these patients. Our report of the second family with two mutated SLC34A1 alleles expands the known phenotype of this rare condition.

  4. Exome Sequencing Identifies a Novel Homozygous Mutation in the Phosphate Transporter SLC34A1 in Hypophosphatemia and Nephrocalcinosis

    PubMed Central

    Rajagopal, Abbhirami; Braslavsky, Débora; Lu, James T.; Kleppe, Soledad; Clément, Florencia; Cassinelli, Hamilton; Liu, David S.; Liern, Jose Miguel; Vallejo, Graciela; Bergadá, Ignacio; Gibbs, Richard A.; Campeau, Phillipe M.

    2014-01-01

    Context: Two Argentinean siblings (a boy and a girl) from a nonconsanguineous family presented with hypercalcemia, hypercalciuria, hypophosphatemia, low parathyroid hormone (PTH), and nephrocalcinosis. Objective: The goal of this study was to identify genetic causes of the clinical findings in the two siblings. Design: Whole exome sequencing was performed to identify disease-causing mutations in the youngest sibling, and a candidate variant was screened in other family members by Sanger sequencing. In vitro experiments were conducted to determine the effects of the mutation that was identified. Patients and Other Participants: Affected siblings (2 y.o. female and 10 y.o male) and their parents were included in the study. Informed consent was obtained for genetic studies. Results: A novel homozygous mutation in the gene encoding the renal sodium-dependent phosphate transporter SLC34A1 was identified in both siblings (c.1484G>A, p.Arg495His). In vitro studies showed that the p.Arg495His mutation resulted in decreased phosphate uptake when compared to wild-type SLC34A1. Conclusions: The homozygous G>A transition that results in the substitution of histidine for arginine at position 495 of the renal sodium-dependent phosphate transporter, SLC34A1, is involved in disease pathogenesis in these patients. Our report of the second family with two mutated SLC34A1 alleles expands the known phenotype of this rare condition. PMID:25050900

  5. Homozygous SLC2A9 Mutations Cause Severe Renal Hypouricemia

    PubMed Central

    Gray, Nicola K.; Campbell, Susan; Shu, Xinhua; Sawyer, Lindsay; Richardson, William; Rechavi, Gideon; Amariglio, Ninette; Ganon, Liat; Sela, Ben-Ami; Bahat, Hilla; Goldman, Michael; Weissgarten, Joshua; Millar, Michael R.; Wright, Alan F.; Holtzman, Eliezer J.

    2010-01-01

    Hereditary hypouricemia may result from mutations in the renal tubular uric acid transporter URAT1. Whether mutation of other uric acid transporters produces a similar phenotype is unknown. We studied two families who had severe hereditary hypouricemia and did not have a URAT1 defect. We performed a genome-wide homozygosity screen and linkage analysis and identified the candidate gene SLC2A9, which encodes the glucose transporter 9 (GLUT9). Both families had homozygous SLC2A9 mutations: A missense mutation (L75R) in six affected members of one family and a 36-kb deletion, resulting in a truncated protein, in the other. In vitro, the L75R mutation dramatically impaired transport of uric acid. The mean concentration of serum uric acid of seven homozygous individuals was 0.17 ± 0.2 mg/dl, and all had a fractional excretion of uric acid >150%. Three individuals had nephrolithiasis, and three had a history of exercise-induced acute renal failure. In conclusion, homozygous loss-of-function mutations of GLUT9 cause a total defect of uric acid absorption, leading to severe renal hypouricemia complicated by nephrolithiasis and exercise-induced acute renal failure. In addition to clarifying renal handling of uric acid, our findings may provide a better understanding of the pathophysiology of acute renal failure, nephrolithiasis, hyperuricemia, and gout. PMID:19926891

  6. Homozygous STIL Mutation Causes Holoprosencephaly and Microcephaly in Two Siblings

    PubMed Central

    Mouden, Charlotte; de Tayrac, Marie; Dubourg, Christèle; Rose, Sophie; Carré, Wilfrid; Hamdi-Rozé, Houda; Babron, Marie-Claude; Akloul, Linda; Héron-Longe, Bénédicte; Odent, Sylvie; Dupé, Valérie; Giet, Régis; David, Véronique

    2015-01-01

    Holoprosencephaly (HPE) is a frequent congenital malformation of the brain characterized by impaired forebrain cleavage and midline facial anomalies. Heterozygous mutations in 14 genes have been identified in HPE patients that account for only 30% of HPE cases, suggesting the existence of other HPE genes. Data from homozygosity mapping and whole-exome sequencing in a consanguineous Turkish family were combined to identify a homozygous missense mutation (c.2150G>A; p.Gly717Glu) in STIL, common to the two affected children. STIL has a role in centriole formation and has previously been described in rare cases of microcephaly. Rescue experiments in U2OS cells showed that the STIL p.Gly717Glu mutation was not able to fully restore the centriole duplication failure following depletion of endogenous STIL protein indicating the deleterious role of the mutation. In situ hybridization experiments using chick embryos demonstrated that expression of Stil was in accordance with a function during early patterning of the forebrain. It is only the second time that a STIL homozygous mutation causing a recessive form of HPE was reported. This result also supports the genetic heterogeneity of HPE and increases the panel of genes to be tested for HPE diagnosis. PMID:25658757

  7. Mutational Profile of Homozygous β-Thalassemia in Rio de Janeiro, Brazil.

    PubMed

    Carrocini, Gisele C S; Venancio, Larissa P R; Pessoa, Viviani L R; Lobo, Clarisse L C; Bonini-Domingos, Claudia R

    2017-01-01

    β-Thalassemia (β-thal) is a hemolytic anemia that is caused by point mutations in most cases. The Brazilian population is highly heterogeneous and knowledge of the mutations that make up the genotypic profile of individuals can contribute information about the formation of the population and clinical condition of patients. In this study, we evaluated the mutations present in homozygous β-thal patients from Rio de Janeiro, Brazil. We analyzed 24 samples of peripheral blood of patients with homozygous β-thal. To identify the mutations, we carried out allele-specific-polymerase chain reaction (AS-PCR) and DNA sequencing. We found 11 different mutations on the β-globin gene. Among the most frequent mutations observed were HBB: c.92 + 6T>C, followed by HBB: c.93-21G>A, HBB: c.118C>T and HBB: c.92 + 1G>A. We also identified the rare mutation HBB: c.75T>A that was reported in an individual carrying Hb S (HBB: c.20A>T)/β-thal (HBB: c.75T>A) but not in Brazilian thalassemic patients, thus, this is the first report of this mutation in Brazilian β-thal patients. For its multiethnic character, Brazil has different mutations that cause β-thal and that are distributed with different frequencies according to the regions of the country. Our findings contribute to the description of the mutational profile of Brazilian thalassemic patients, showing wide heterogeneity and genetic variability.

  8. Diploid yeast cells yield homozygous spontaneous mutations

    NASA Technical Reports Server (NTRS)

    Esposito, M. S.; Bruschi, C. V.; Brushi, C. V. (Principal Investigator)

    1993-01-01

    A leucine-requiring hybrid of Saccharomyces cerevisiae, homoallelic at the LEU1 locus (leu1-12/leu1-12) and heterozygous for three chromosome-VII genetic markers distal to the LEU1 locus, was employed to inquire: (1) whether spontaneous gene mutation and mitotic segregation of heterozygous markers occur in positive nonrandom association and (2) whether homozygous LEU1/LEU1 mutant diploids are generated. The results demonstrate that gene mutation of leu1-12 to LEU1 and mitotic segregation of heterozygous chromosome-VII markers occur in strong positive nonrandom association, suggesting that the stimulatory DNA lesion is both mutagenic and recombinogenic. In addition, genetic analysis of diploid Leu+ revertants revealed that approximately 3% of mutations of leu1-12 to LEU1 result in LEU1/LEU1 homozygotes. Red-white sectored Leu+ colonies exhibit genotypes that implicate post-replicational chromatid breakage and exchange near the site of leu1-12 reversion, chromosome loss, and subsequent restitution of diploidy, in the sequence of events leading to mutational homozygosis. By analogy, diploid cell populations can yield variants homozygous for novel recessive gene mutations at biologically significant rates. Mutational homozygosis may be relevant to both carcinogenesis and the evolution of asexual diploid organisms.

  9. Homozygous null mutations in ZMPSTE24 in restrictive dermopathy: evidence of genetic heterogeneity.

    PubMed

    Ahmad, Z; Phadke, S R; Arch, E; Glass, J; Agarwal, A K; Garg, A

    2012-02-01

    Restrictive dermopathy (RD) results in stillbirth or early neonatal death. RD is characterized by prematurity, intrauterine growth retardation, fixed facial expression, micrognathia, mouth in the 'o' position, rigid and tense skin with erosions and denudations and multiple joint contractures. Nearly all 25 previously reported neonates with RD had homozygous or compound heterozygous null mutations in the ZMPSTE24 gene. Here, we report three new cases of RD; all died within 3 weeks of birth. One of them had a previously reported homozygous c.1085dupT (p.Leu362PhefsX19) mutation, the second case had a novel homozygous c.1020G>A (p.Trp340X) null mutation in ZMPSTE24, but the third case, a stillborn with features of RD except for the presence of tapering rather than rounded, bulbous digits, harbored no disease-causing mutations in LMNA or ZMPSTE24. In the newborn with a novel ZMPSTE24 mutation, unique features included butterfly-shaped thoracic 5 vertebra and the bulbous appearance of the distal clavicles. Skin biopsies from both the stillborn fetus and the newborn with c.1020G>A ZMPSTE24 mutation showed absence of elastic fibers throughout the dermis. This report provides evidence of genetic heterogeneity among RD and concludes that there may be an additional locus for RD which remains to be identified. © 2010 John Wiley & Sons A/S.

  10. HomSI: a homozygous stretch identifier from next-generation sequencing data.

    PubMed

    Görmez, Zeliha; Bakir-Gungor, Burcu; Sagiroglu, Mahmut Samil

    2014-02-01

    In consanguineous families, as a result of inheriting the same genomic segments through both parents, the individuals have stretches of their genomes that are homozygous. This situation leads to the prevalence of recessive diseases among the members of these families. Homozygosity mapping is based on this observation, and in consanguineous families, several recessive disease genes have been discovered with the help of this technique. The researchers typically use single nucleotide polymorphism arrays to determine the homozygous regions and then search for the disease gene by sequencing the genes within this candidate disease loci. Recently, the advent of next-generation sequencing enables the concurrent identification of homozygous regions and the detection of mutations relevant for diagnosis, using data from a single sequencing experiment. In this respect, we have developed a novel tool that identifies homozygous regions using deep sequence data. Using *.vcf (variant call format) files as an input file, our program identifies the majority of homozygous regions found by microarray single nucleotide polymorphism genotype data. HomSI software is freely available at www.igbam.bilgem.tubitak.gov.tr/softwares/HomSI, with an online manual.

  11. Phenotypes of Recessive Pediatric Cataract in a Cohort of Children with Identified Homozygous Gene Mutations (An American Ophthalmological Society Thesis)

    PubMed Central

    Khan, Arif O.; Aldahmesh, Mohammed A.; Alkuraya, Fowzan S.

    2015-01-01

    Purpose: To assess for phenotype-genotype correlations in families with recessive pediatric cataract and identified gene mutations. Methods: Retrospective review (2004 through 2013) of 26 Saudi Arabian apparently nonsyndromic pediatric cataract families referred to one of the authors (A.O.K.) and for which recessive gene mutations were identified. Results: Fifteen different homozygous recessive gene mutations were identified in the 26 consanguineous families; two genes and five families are novel to this study. Ten families had a founder CRYBB1 deletion (all with bilateral central pulverulent cataract), two had the same missense mutation in CRYAB (both with bilateral juvenile cataract with marked variable expressivity), and two had different mutations in FYCO1 (both with bilateral posterior capsular abnormality). The remaining 12 families each had mutations in 12 different genes (CRYAA, CRYBA1, AKR1E2, AGK, BFSP2, CYP27A1, CYP51A1, EPHA2, GCNT2, LONP1, RNLS, WDR87) with unique phenotypes noted for CYP27A1 (bilateral juvenile fleck with anterior and/or posterior capsular cataract and later cerebrotendinous xanthomatosis), EPHA2 (bilateral anterior persistent fetal vasculature), and BFSP2 (bilateral flecklike with cloudy cortex). Potential carrier signs were documented for several families. Conclusions: In this recessive pediatric cataract case series most identified genes are noncrystallin. Recessive pediatric cataract phenotypes are generally nonspecific, but some notable phenotypes are distinct and associated with specific gene mutations. Marked variable expressivity can occur from a recessive missense CRYAB mutation. Genetic analysis of apparently isolated pediatric cataract can sometimes uncover mutations in a syndromic gene. Some gene mutations seem to be associated with apparent heterozygous carrier signs. PMID:26622071

  12. Homozygous Mutations in WEE2 Cause Fertilization Failure and Female Infertility.

    PubMed

    Sang, Qing; Li, Bin; Kuang, Yanping; Wang, Xueqian; Zhang, Zhihua; Chen, Biaobang; Wu, Ling; Lyu, Qifeng; Fu, Yonglun; Yan, Zheng; Mao, Xiaoyan; Xu, Yao; Mu, Jian; Li, Qiaoli; Jin, Li; He, Lin; Wang, Lei

    2018-04-05

    Fertilization is a fundamental process of development and is a prerequisite for successful human reproduction. In mice, although several receptor proteins have been shown to play important roles in the process of fertilization, only three genes have been shown to cause fertilization failure and infertility when deleted in vivo. In clinical practice, some infertility case subjects suffer from recurrent failure of in vitro fertilization and intracytoplasmic sperm injection attempts due to fertilization failure, but the genetic basis of fertilization failure in humans remains largely unknown. Wee2 is a key oocyte-specific kinase involved in the control of meiotic arrest in mice, but WEE2 has not been associated with any diseases in humans. In this study, we identified homozygous mutations in WEE2 that are responsible for fertilization failure in humans. All four independent affected individuals had homozygous loss-of-function missense mutations or homozygous frameshift protein-truncating mutations, and the phenotype of fertilization failure was shown to follow a Mendelian recessive inheritance pattern. All four mutations significantly decreased the amount of WEE2 protein in vitro and in affected individuals' oocytes in vivo, and they all led to abnormal serine phosphorylation of WEE2 and reduced tyrosine 15 phosphorylation of Cdc2 in vitro. In addition, injection of WEE2 cRNA into affected individuals' oocytes rescued the fertilization failure phenotype and led to the formation of blastocysts in vitro. This work presents a novel gene responsible for human fertilization failure and has implications for future therapeutic treatments for infertility cases. Copyright © 2018 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  13. [Breeding of transgenic mice expressing human tau isoform with P301L mutation and identification of homozygous transgenic mice].

    PubMed

    Wang, Yan-yan; Chen, Ru-zhui; Zhu, Xiao-nani; Liu, Jing; Li, Zhi-hui; Liu, Xiu-juan; Li, Zhi-hui; Na, Xin; Liang, Shan-shan; Qiu, Guo-guang; Zhang, Wei; Wang, Hai; Wang, Xue-lan

    2012-05-01

    To establish homozygous transgenic mouse strain expressing human tau isoform with P301L mutation. Five transgenic mice expressing human tau isoform with P301L mutation were obtained by microinjection into male nuclei. Homozygote and hemizygote were identified by PCR and real-time fluorescent quantitative PCR. Ninety five homozygous transgenic mice were selected, and the results indicated that homozygous transgenic mice were superior to hemizygote in simulating the changes of biological characteristics. Exogenous gene tau is able to stably transmit to next generation and the combination of SYBR Green real-time fluorescent quantitative PCR with the traditional mating is a fast, reliable and economical way to screen homozygous and hemizygous transgenic mice.

  14. Homozygous TREM2 mutation in a family with atypical frontotemporal dementia.

    PubMed

    Le Ber, Isabelle; De Septenville, Anne; Guerreiro, Rita; Bras, José; Camuzat, Agnès; Caroppo, Paola; Lattante, Serena; Couarch, Philippe; Kabashi, Edor; Bouya-Ahmed, Kawtar; Dubois, Bruno; Brice, Alexis

    2014-10-01

    TREM2 mutations were first identified in Nasu-Hakola disease, a rare autosomal recessive disease characterized by recurrent fractures because of bone cysts and presenile dementia. Recently, homozygous and compound heterozygous TREM2 mutations were identified in rare families with frontotemporal lobar degeneration (FTLD) but without bone involvement. We identified a p.Thr66Met heterozygous mutation in a new consanguineous Italian family. Two sibs had early onset autosomal recessive FTLD without severe bone disorders. Atypical signs were present in this family: early parietal and hippocampus involvement, parkinsonism, epilepsy, and corpus callosum thickness on brain magnetic resonance imaging. This study further demonstrates the implication of TREM2 mutations in FTLD phenotypes. It illustrates the variability of bone phenotype and underlines the frequency of atypical signs in TREM2 carriers. This and previous studies evidence that TREM2 mutation screening should be limited to autosomal recessive FTLD with atypical phenotypes characterized by: (1) a very young age at onset (20-50 years); (2) early parietal and hippocampal deficits; (3) the presence of seizures and parkinsonism; (4) suggestive extensive white matter lesions and corpus callosum thickness on brain magnetic resonance imaging. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Homozygous TREM2 mutation in a family with atypical frontotemporal dementia

    PubMed Central

    Bras, José; Camuzat, Agnès; Caroppo, Paola; Lattante, Serena; Couarch, Philippe; Kabashi, Edor; Bouya-Ahmed, Kawtar; Dubois, Bruno; Brice, Alexis

    2014-01-01

    TREM2 mutations were first identified in Nasu-Hakola disease, a rare autosomal recessive disease characterized by recurrent fractures because of bone cysts and presenile dementia. Recently, homozygous and compound heterozygous TREM2 mutations were identified in rare families with frontotemporal lobar degeneration (FTLD) but without bone involvement. We identified a p.Thr66Met heterozygous mutation in a new consanguineous Italian family. Two sibs had early onset autosomal recessive FTLD without severe bone disorders. Atypical signs were present in this family: early parietal and hippocampus involvement, parkinsonism, epilepsy, and corpus callosum thickness on brain magnetic resonance imaging. This study further demonstrates the implication of TREM2 mutations in FTLD phenotypes. It illustrates the variability of bone phenotype and underlines the frequency of atypical signs in TREM2 carriers. This and previous studies evidence that TREM2 mutation screening should be limited to autosomal recessive FTLD with atypical phenotypes characterized by: (1) a very young age at onset (20–50 years); (2) early parietal and hippocampal deficits; (3) the presence of seizures and parkinsonism; (4) suggestive extensive white matter lesions and corpus callosum thickness on brain magnetic resonance imaging. PMID:24910390

  16. A syndrome of microcephaly, short stature, polysyndactyly, and dental anomalies caused by a homozygous KATNB1 mutation.

    PubMed

    Yigit, Gökhan; Wieczorek, Dagmar; Bögershausen, Nina; Beleggia, Filippo; Möller-Hartmann, Claudia; Altmüller, Janine; Thiele, Holger; Nürnberg, Peter; Wollnik, Bernd

    2016-03-01

    Using whole-exome sequencing, we identified a homozygous acceptor splice-site mutation in intron 6 of the KATNB1 gene in a patient from a consanguineous Turkish family who presented with congenital microcephaly, lissencephaly, short stature, polysyndactyly, and dental abnormalities. cDNA analysis revealed complete loss of the natural acceptor splice-site resulting either in the usage of an alternative, exonic acceptor splice-site inducing a frame-shift and premature protein truncation or, to a minor extent, in complete skipping of exon 7. Both effects most likely lead to complete loss of KATNB1 function. Homozygous and compound heterozygous mutations in KATNB1 have very recently been described as a cause of microcephaly with brain malformations and seizures. We extend the KATNB1 associated phenotype by describing a syndrome characterized by primordial dwarfism, lissencephaly, polysyndactyly, and dental anomalies, which is caused by a homozygous truncating KATNB1 mutation. © 2015 Wiley Periodicals, Inc.

  17. Krüppel-like factor 1 mutations and expression of hemoglobins F and A2 in homozygous hemoglobin E syndrome.

    PubMed

    Tepakhan, Wanicha; Yamsri, Supawadee; Fucharoen, Goonnapa; Sanchaisuriya, Kanokwan; Fucharoen, Supan

    2015-07-01

    The basis for variability of hemoglobin (Hb) F in homozygous Hb E disease is not well understood. We have examined multiple mutations of the Krüppel-like factor 1 (KLF1) gene; an erythroid specific transcription factor and determined their associations with Hbs F and A2 expression in homozygous Hb E. Four KLF1 mutations including G176AfsX179, T334R, R238H, and -154 (C-T) were screened using specific PCR assays on 461 subjects with homozygous Hb E and 100 normal controls. None of these four mutations were observed in 100 normal controls. Among 461 subjects with homozygous Hb E, 306 had high (≥5 %) and 155 had low (<5 %) Hb F. DNA analysis identified the KLF1 mutations in 35 cases of the former group with high Hb F, including the G176AfsX179 mutation (17/306 = 5.6 %), T334R mutation (9/306 = 2.9 %), -154 (C-T) mutation (7/306 = 2.3 %), and R328H mutation (2/306 = 0.7 %). Only two subjects in the latter group with low Hb F carried the G176AfsX179 and -154 (C-T) mutations. Significant higher Hb A2 level was observed in those of homozygous Hb E with the G176AfsX179 mutation as compared to those without KLF1 mutations. These results indicate that KLF1 is among the genetic factors associated with increased Hbs F and A2, and in combination with other factors could explain the variabilities of these Hb expression in Hb E syndrome.

  18. Homozygous YME1L1 mutation causes mitochondriopathy with optic atrophy and mitochondrial network fragmentation.

    PubMed

    Hartmann, Bianca; Wai, Timothy; Hu, Hao; MacVicar, Thomas; Musante, Luciana; Fischer-Zirnsak, Björn; Stenzel, Werner; Gräf, Ralph; van den Heuvel, Lambert; Ropers, Hans-Hilger; Wienker, Thomas F; Hübner, Christoph; Langer, Thomas; Kaindl, Angela M

    2016-08-06

    Mitochondriopathies often present clinically as multisystemic disorders of primarily high-energy consuming organs. Assembly, turnover, and surveillance of mitochondrial proteins are essential for mitochondrial function and a key task of AAA family members of metalloproteases. We identified a homozygous mutation in the nuclear encoded mitochondrial escape 1-like 1 gene YME1L1, member of the AAA protease family, as a cause of a novel mitochondriopathy in a consanguineous pedigree of Saudi Arabian descent. The homozygous missense mutation, located in a highly conserved region in the mitochondrial pre-sequence, inhibits cleavage of YME1L1 by the mitochondrial processing peptidase, which culminates in the rapid degradation of YME1L1 precursor protein. Impaired YME1L1 function causes a proliferation defect and mitochondrial network fragmentation due to abnormal processing of OPA1. Our results identify mutations in YME1L1 as a cause of a mitochondriopathy with optic nerve atrophy highlighting the importance of YME1L1 for mitochondrial functionality in humans.

  19. Homozygous YME1L1 mutation causes mitochondriopathy with optic atrophy and mitochondrial network fragmentation

    PubMed Central

    Hartmann, Bianca; Wai, Timothy; Hu, Hao; MacVicar, Thomas; Musante, Luciana; Fischer-Zirnsak, Björn; Stenzel, Werner; Gräf, Ralph; van den Heuvel, Lambert; Ropers, Hans-Hilger; Wienker, Thomas F; Hübner, Christoph; Langer, Thomas; Kaindl, Angela M

    2016-01-01

    Mitochondriopathies often present clinically as multisystemic disorders of primarily high-energy consuming organs. Assembly, turnover, and surveillance of mitochondrial proteins are essential for mitochondrial function and a key task of AAA family members of metalloproteases. We identified a homozygous mutation in the nuclear encoded mitochondrial escape 1-like 1 gene YME1L1, member of the AAA protease family, as a cause of a novel mitochondriopathy in a consanguineous pedigree of Saudi Arabian descent. The homozygous missense mutation, located in a highly conserved region in the mitochondrial pre-sequence, inhibits cleavage of YME1L1 by the mitochondrial processing peptidase, which culminates in the rapid degradation of YME1L1 precursor protein. Impaired YME1L1 function causes a proliferation defect and mitochondrial network fragmentation due to abnormal processing of OPA1. Our results identify mutations in YME1L1 as a cause of a mitochondriopathy with optic nerve atrophy highlighting the importance of YME1L1 for mitochondrial functionality in humans. DOI: http://dx.doi.org/10.7554/eLife.16078.001 PMID:27495975

  20. An homozygous mutation in KCNK3 is associated with an aggressive form of hereditary pulmonary arterial hypertension.

    PubMed

    Navas Tejedor, P; Tenorio Castaño, J; Palomino Doza, J; Arias Lajara, P; Gordo Trujillo, G; López Meseguer, M; Román Broto, A; Lapunzina Abadía, P; Escribano Subía, P

    2017-03-01

    Pulmonary arterial hypertension (PAH) is a rare devastating disease characterized by a high genetic heterogeneity with several related genes recently described, including BMPR2,TBX4 and KCNK3. The association between KCNK3 and PAH has been recently identified, but the prognosis and phenotype associated with these mutations have been poorly described. We studied a series of 136 idiopathic and hereditary PAH Spanish patients for BMPR2, TBX4 and KCNK3 mutations. We report the results of KCNK3 in which we were able to describe two new mutations (p.Gly106Arg and p.Leu214Arg) in three patients. The first one was found in a patient belonging to a consanguineous Romani family, who carried a homozygous mutation in KCNK3 and developed a severe and early form of the disease. To the best of our knowledge, this is the first time that a homozygous mutation in KCNK3 is reported in a PAH patient. The second one was found in a patient who presented at the young adult age a severe form of the disease. The present report supports the contribution of KCNK3 mutations to the genetic etiology of PAH and strongly suggests that mutations in KCNK3 follow incomplete dominance with worsening of the clinical features in homozygous patients. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  1. Somatic overgrowth associated with homozygous mutations in both MAN1B1 and SEC23A

    PubMed Central

    Gupta, Swati; Fahiminiya, Somayyeh; Wang, Tracy; Dempsey Nunez, Laura; Rosenblatt, David S.; Gibson, William T.; Gilfix, Brian; Bergeron, John J. M.; Jerome-Majewska, Loydie A.

    2016-01-01

    Using whole-exome sequencing, we identified homozygous mutations in two unlinked genes, SEC23A c.1200G>C (p.M400I) and MAN1B1 c.1000C>T (p.R334C), associated with congenital birth defects in two patients from a consanguineous family. Patients presented with carbohydrate-deficient transferrin, tall stature, obesity, macrocephaly, and maloccluded teeth. The parents were healthy heterozygous carriers for both mutations and an unaffected sibling with tall stature carried the heterozygous mutation in SEC23A only. Mutations in SEC23A are responsible for craniolenticosultura dysplasia (CLSD). CLSD patients are short, have late-closing fontanels, and have reduced procollagen (pro-COL1A1) secretion because of abnormal pro-COL1A1 retention in the endoplasmic reticulum (ER). The mutation we identified in MAN1B1 was previously associated with reduced MAN1B1 protein and congenital disorders of glycosylation (CDG). CDG patients are also short, are obese, and have abnormal glycan remodeling. Molecular analysis of fibroblasts from the family revealed normal levels of SEC23A in all cells and reduced levels of MAN1B1 in cells with heterozygous or homozygous mutations in SEC23A and MAN1B1. Secretion of pro-COL1A1 was increased in fibroblasts from the siblings and patients, and pro-COL1A1 was retained in Golgi of heterozygous and homozygous mutant cells, although intracellular pro-COL1A1 was increased in patient fibroblasts only. We postulate that increased pro-COL1A1 secretion is responsible for tall stature in these patients and an unaffected sibling, and not previously discovered in patients with mutations in either SEC23A or MAN1B1. The patients in this study share biochemical and cellular characteristics consistent with mutations in MAN1B1 and SEC23A, indicating a digenic disease. PMID:27148587

  2. [Cytochrome c oxydase-deficient Leigh syndrome with homozygous mutation in SURF1 gene].

    PubMed

    Monnot, S; Chabrol, B; Cano, A; Pellissier, J F; Collignon, P; Montfort, M F; Paquis-Flucklinger, V

    2005-05-01

    Leigh syndrome is a heterogeneous disorder, usually due to a defect in oxidative metabolism. Mutations in SURF1 gene have been identified in patients with cytochrome c oxidase deficiency. We report a homozygous splice site deletion [516-2_516-1delAG] in a young girl presenting with cytochrome c oxidase-deficient Leigh syndrome. Identification of molecular defect is indispensable for genetic counselling and prenatal diagnosis.

  3. Homozygous ARHGEF2 mutation causes intellectual disability and midbrain-hindbrain malformation.

    PubMed

    Ravindran, Ethiraj; Hu, Hao; Yuzwa, Scott A; Hernandez-Miranda, Luis R; Kraemer, Nadine; Ninnemann, Olaf; Musante, Luciana; Boltshauser, Eugen; Schindler, Detlev; Hübner, Angela; Reinecker, Hans-Christian; Ropers, Hans-Hilger; Birchmeier, Carmen; Miller, Freda D; Wienker, Thomas F; Hübner, Christoph; Kaindl, Angela M

    2017-04-01

    Mid-hindbrain malformations can occur during embryogenesis through a disturbance of transient and localized gene expression patterns within these distinct brain structures. Rho guanine nucleotide exchange factor (ARHGEF) family members are key for controlling the spatiotemporal activation of Rho GTPase, to modulate cytoskeleton dynamics, cell division, and cell migration. We identified, by means of whole exome sequencing, a homozygous frameshift mutation in the ARHGEF2 as a cause of intellectual disability, a midbrain-hindbrain malformation, and mild microcephaly in a consanguineous pedigree of Kurdish-Turkish descent. We show that loss of ARHGEF2 perturbs progenitor cell differentiation and that this is associated with a shift of mitotic spindle plane orientation, putatively favoring more symmetric divisions. The ARHGEF2 mutation leads to reduction in the activation of the RhoA/ROCK/MLC pathway crucial for cell migration. We demonstrate that the human brain malformation is recapitulated in Arhgef2 mutant mice and identify an aberrant migration of distinct components of the precerebellar system as a pathomechanism underlying the midbrain-hindbrain phenotype. Our results highlight the crucial function of ARHGEF2 in human brain development and identify a mutation in ARHGEF2 as novel cause of a neurodevelopmental disorder.

  4. Homozygous ARHGEF2 mutation causes intellectual disability and midbrain-hindbrain malformation

    PubMed Central

    Yuzwa, Scott A.; Hernandez-Miranda, Luis R.; Musante, Luciana; Boltshauser, Eugen; Schindler, Detlev; Hübner, Angela; Reinecker, Hans-Christian; Ropers, Hans-Hilger; Miller, Freda D.; Hübner, Christoph; Kaindl, Angela M.

    2017-01-01

    Mid-hindbrain malformations can occur during embryogenesis through a disturbance of transient and localized gene expression patterns within these distinct brain structures. Rho guanine nucleotide exchange factor (ARHGEF) family members are key for controlling the spatiotemporal activation of Rho GTPase, to modulate cytoskeleton dynamics, cell division, and cell migration. We identified, by means of whole exome sequencing, a homozygous frameshift mutation in the ARHGEF2 as a cause of intellectual disability, a midbrain-hindbrain malformation, and mild microcephaly in a consanguineous pedigree of Kurdish-Turkish descent. We show that loss of ARHGEF2 perturbs progenitor cell differentiation and that this is associated with a shift of mitotic spindle plane orientation, putatively favoring more symmetric divisions. The ARHGEF2 mutation leads to reduction in the activation of the RhoA/ROCK/MLC pathway crucial for cell migration. We demonstrate that the human brain malformation is recapitulated in Arhgef2 mutant mice and identify an aberrant migration of distinct components of the precerebellar system as a pathomechanism underlying the midbrain-hindbrain phenotype. Our results highlight the crucial function of ARHGEF2 in human brain development and identify a mutation in ARHGEF2 as novel cause of a neurodevelopmental disorder. PMID:28453519

  5. Neurologic syndrome associated with homozygous mutation at MAG sialic acid binding site.

    PubMed

    Roda, Ricardo H; FitzGibbon, Edmond J; Boucekkine, Houda; Schindler, Alice B; Blackstone, Craig

    2016-08-01

    The MAG gene encodes myelin-associated glycoprotein (MAG), an abundant protein involved in axon-glial interactions and myelination during nerve regeneration. Several members of a consanguineous family with a clinical syndrome reminiscent of Pelizaeus-Merzbacher disease and demyelinating leukodystrophy on brain MRI were recently found to harbor a homozygous missense p.Ser133Arg MAG mutation. Here, we report two brothers from a nonconsanguineous family afflicted with progressive cognitive impairment, neuropathy, ataxia, nystagmus, and gait disorder. Exome sequencing revealed the homozygous missense mutation p.Arg118His in MAG. This Arg118 residue in immunoglobulin domain 1 is critical for sialic acid binding, providing a compelling mechanistic basis for disease pathogenesis.

  6. Homozygous mutation of VPS16 gene is responsible for an autosomal recessive adolescent-onset primary dystonia.

    PubMed

    Cai, Xiaodong; Chen, Xin; Wu, Song; Liu, Wenlan; Zhang, Xiejun; Zhang, Doudou; He, Sijie; Wang, Bo; Zhang, Mali; Zhang, Yuan; Li, Zongyang; Luo, Kun; Cai, Zhiming; Li, Weiping

    2016-05-12

    Dystonia is a neurological movement disorder that is clinically and genetically heterogeneous. Herein, we report the identification a novel homozygous missense mutation, c.156 C > A in VPS16, co-segregating with disease status in a Chinese consanguineous family with adolescent-onset primary dystonia by whole exome sequencing and homozygosity mapping. To assess the biological role of c.156 C > A homozygous mutation of VPS16, we generated mice with targeted mutation site of Vps16 through CRISPR-Cas9 genome-editing approach. Vps16 c.156 C > A homozygous mutant mice exhibited significantly impaired motor function, suggesting that VPS16 is a new causative gene for adolescent-onset primary dystonia.

  7. Homozygous and compound heterozygous mutations in the FBN1 gene: unexpected findings in molecular diagnosis of Marfan syndrome.

    PubMed

    Arnaud, Pauline; Hanna, Nadine; Aubart, Mélodie; Leheup, Bruno; Dupuis-Girod, Sophie; Naudion, Sophie; Lacombe, Didier; Milleron, Olivier; Odent, Sylvie; Faivre, Laurence; Bal, Laurence; Edouard, Thomas; Collod-Beroud, Gwenaëlle; Langeois, Maud; Spentchian, Myrtille; Gouya, Laurent; Jondeau, Guillaume; Boileau, Catherine

    2017-02-01

    Marfan syndrome (MFS) is an autosomal-dominant connective tissue disorder usually associated with heterozygous mutations in the gene encoding fibrillin-1 (FBN1). Homozygous and compound heterozygous cases are rare events and have been associated with a clinical severe presentation. Report unexpected findings of homozygosity and compound heterozygosity in the course of molecular diagnosis of heterozygous MFS and compare the findings with published cases. In the context of molecular diagnosis of heterozygous MFS, systematic sequencing of the FBN1 gene was performed in 2500 probands referred nationwide. 1400 probands carried a heterozygous mutation in this gene. Unexpectedly, among them four homozygous cases (0.29%) and five compound heterozygous cases (0.36%) were identified (total: 0.64%). Interestingly, none of these cases carried two premature termination codon mutations in the FBN1 gene. Clinical features for these carriers and their families were gathered and compared. There was a large spectrum of severity of the disease in probands carrying two mutated FBN1 alleles, but none of them presented extremely severe manifestations of MFS in any system compared with carriers of only one mutated FBN1 allele. This observation is not in line with the severe clinical features reported in the literature for four homozygous and three compound heterozygous probands. Homozygotes and compound heterozygotes were unexpectedly identified in the course of molecular diagnosis of MFS. Contrary to previous reports, the presence of two mutated alleles was not associated with severe forms of MFS. Although homozygosity and compound heterozygosity are rarely found in molecular diagnosis, they should not be overlooked, especially among consanguineous families. However, no predictive evaluation of severity should be provided. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  8. Widespread correlations between dominance and homozygous effects of mutations: implications for theories of dominance.

    PubMed

    Phadnis, Nitin; Fry, James D

    2005-09-01

    The dominance of deleterious mutations has important consequences for phenomena such as inbreeding depression, the evolution of diploidy, and levels of natural genetic variation. Kacser and Burns' metabolic theory provides a paradigmatic explanation for why most large-effect mutations are recessive. According to the metabolic theory, the recessivity of large-effect mutations is a consequence of a diminishing-returns relationship between flux through a metabolic pathway and enzymatic activity at any step in the pathway, which in turn is an inevitable consequence of long metabolic pathways. A major line of support for this theory was the demonstration of a negative correlation between homozygous effects and dominance of mutations in Drosophila, consistent with a central prediction of the metabolic theory. Using data on gene deletions in yeast, we show that a negative correlation between homozygous effects and dominance of mutations exists for all major categories of genes analyzed, not just those encoding enzymes. The relationship between dominance and homozygous effects is similar for duplicated and single-copy genes and for genes whose products are members of protein complexes and those that are not. A complete explanation of dominance therefore requires either a generalization of Kacser and Burns' theory to nonenzyme genes or a new theory.

  9. Phenotypic comparison of individuals with homozygous or heterozygous mutation of NOTCH3 in a large CADASIL family.

    PubMed

    Abou Al-Shaar, Hussam; Qadi, Najeeb; Al-Hamed, Mohamed H; Meyer, Brian F; Bohlega, Saeed

    2016-08-15

    Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary microangiopathy caused by mutations in NOTCH3, very rarely homoallelic. To describe the clinical, radiological, and neuropsychological features in an extended CADASIL family including members with either a homozygous or heterozygous NOTCH3 R1231C mutation. The pedigree included 3 generations of a family with 13 affected individuals. The patients were examined clinically and radiologically. Neuropsychological testing was performed on the proband. Sequencing of the entire coding DNA sequence (CDS) and flanking regions of NOTCH3 was undertaken using PCR amplification and direct Sanger sequencing. Homozygous C3769T mutation, predicting R1231C in exon 22 of NOTCH3 was found in 7 family members. Six other family members harbored the same in the heterozygous state. Homozygous individuals showed a slightly more severe clinical and radiological phenotype of earlier onset compared to their heterozygous counterparts. This study reports the largest number of patients with homozygous NOTCH3 mutation. The phenotype and imaging features of homozygous individuals is within the spectrum of CADASIL, although slightly at the severe end when compared to heterozygotes carrying the same mutation. Both genetic modifiers and environmental factors may play an essential role in modification and alteration of the clinical phenotype and white matter changes among CADASIL patients. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. A novel homozygous HOXB1 mutation in a Turkish family with hereditary congenital facial paresis.

    PubMed

    Sahin, Yavuz; Güngör, Olcay; Ayaz, Akif; Güngör, Gülay; Sahin, Bedia; Yaykasli, Kursad; Ceylaner, Serdar

    2017-02-01

    Hereditary congenital facial paresis (HCFP) is characterized by isolated dysfunction of the facial nerve (CN VII) due to congenital cranial dysinnervation disorders. HCFP has genetic heterogeneity and HOXB1 is the first identified gene. We report the clinical, radiologic and molecular investigations of three patients admitted for HCFP in a large consanguineous Turkish family. High-throughput sequencing and Sanger sequencing of all patients revealed a novel homozygous mutation p.Arg230Trp (c.688C>T) within the HOXB1 gene. The report of the mutation brings the total number of HOXB1 mutations identified in HCFP to four. The results of this study emphasize that in individuals with congenital facial palsy accompanied by hearing loss and dysmorphic facial features, HOXB1 mutation causing HCFP should be kept in mind. Copyright © 2016 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

  11. Identification of a novel homozygous mutation in MYO3A in a Chinese family with DFNB30 non-syndromic hearing impairment.

    PubMed

    Qu, Ronggui; Sang, Qing; Xu, Yao; Feng, Ruizhi; Jin, Li; He, Lin; Wang, Lei

    2016-05-01

    Hearing loss is a common sensory impairment. Several genetic loci or genes responsible for non-syndrome hearing loss have been identified, including the well-known deafness genes GJB2, MT-RNR1 and SLC26A4. MYO3A belongs to the myosin superfamily. Previously only three mutations in this gene have been found in an Isreali family with DFNB30, in which patients demonstrated progressive hearing loss. In this study, we characterized a consanguineous Kazakh family with congenital hearing loss. By targeted sequence capture and next-generation sequencing, we identified a homozygous mutation and did bioinformatics analysis to this mutation. A homozygous mutation, MYO3A:c.1841C>T (p.S614F), was identified to be responsible for the disease. Ser614 is located in the motor domain of MYO3A that is highly conserved among different species. Molecular modeling predicts that the conserved Ser614 may play an important role in maintaining the stability of β-sheet and the interaction between neighboring β-strand. This is the second report on MYO3A mutations in deafness and the first report in China. The finding help facilitate establishing a better relationship between MYO3A mutation and hearing phenotypes. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  12. Spinal motor neuron involvement in a patient with homozygous PRUNE mutation.

    PubMed

    Iacomino, Michele; Fiorillo, Chiara; Torella, Annalaura; Severino, Mariasavina; Broda, Paolo; Romano, Catia; Falsaperla, Raffaele; Pozzolini, Giulia; Minetti, Carlo; Striano, Pasquale; Nigro, Vincenzo; Zara, Federico

    2018-05-01

    In the last few years, whole exome sequencing (WES) allowed the identification of PRUNE mutations in patients featuring a complex neurological phenotype characterized by severe neurodevelopmental delay, microcephaly, epilepsy, optic atrophy, and brain or cerebellar atrophy. We describe an additional patient with homozygous PRUNE mutation who presented with spinal muscular atrophy phenotype, in addition to the already known brain developmental disorder. This novel feature expands the clinical consequences of PRUNE mutations and allow to converge PRUNE syndrome with previous descriptions of neurodevelopmental/neurodegenerative disorders linked to altered microtubule dynamics. Copyright © 2017 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

  13. A Homozygous Nme7 Mutation Is Associated with Situs Inversus Totalis.

    PubMed

    Reish, Orit; Aspit, Liam; Zouella, Arielle; Roth, Yehudah; Polak-Charcon, Sylvie; Baboushkin, Tatiana; Benyamini, Lilach; Scheetz, Todd E; Mussaffi, Huda; Sheffield, Val C; Parvari, Ruti

    2016-08-01

    We investigated the cause of situs inversus totalis (SIT) in two siblings from a consanguineous family. Genotyping and whole-exome analysis revealed a homozygous change in NME7, resulting in deletion of an exon causing an in-frame deletion of 34 amino acids located in the second NDK domain of the protein and segregated with the defective lateralization in the family. NME7 is an important developmental gene, and NME7 protein is a component of the γ-tubulin ring complex. This mutation is predicted to affect the interaction of NME7 protein with this complex as it deletes the amino acids crucial for the binding. SIT associated with homozygous deletion in our patients is in line with Nme7(-/-) mutant mice phenotypes consisting of congenital hydrocephalus and SIT, indicating a novel human laterality patterning role for NME7. Further cases are required to elaborate the full human phenotype associated with NME7 mutations. © 2016 WILEY PERIODICALS, INC.

  14. Targeted next-generation sequencing identifies a homozygous nonsense mutation in ABHD12, the gene underlying PHARC, in a family clinically diagnosed with Usher syndrome type 3.

    PubMed

    Eisenberger, Tobias; Slim, Rima; Mansour, Ahmad; Nauck, Markus; Nürnberg, Gudrun; Nürnberg, Peter; Decker, Christian; Dafinger, Claudia; Ebermann, Inga; Bergmann, Carsten; Bolz, Hanno Jörn

    2012-09-02

    Usher syndrome (USH) is an autosomal recessive genetically heterogeneous disorder with congenital sensorineural hearing impairment and retinitis pigmentosa (RP). We have identified a consanguineous Lebanese family with two affected members displaying progressive hearing loss, RP and cataracts, therefore clinically diagnosed as USH type 3 (USH3). Our study was aimed at the identification of the causative mutation in this USH3-like family. Candidate loci were identified using genomewide SNP-array-based homozygosity mapping followed by targeted enrichment and next-generation sequencing. Using a capture array targeting the three identified homozygosity-by-descent regions on chromosomes 1q43-q44, 20p13-p12.2 and 20p11.23-q12, we identified a homozygous nonsense mutation, p.Arg65X, in ABHD12 segregating with the phenotype. Mutations of ABHD12, an enzyme hydrolyzing an endocannabinoid lipid transmitter, cause PHARC (polyneuropathy, hearing loss, ataxia, retinitis pigmentosa, and early-onset cataract). After the identification of the ABHD12 mutation in this family, one patient underwent neurological examination which revealed ataxia, but no polyneuropathy. ABHD12 is not known to be related to the USH protein interactome. The phenotype of our patient represents a variant of PHARC, an entity that should be taken into account as differential diagnosis for USH3. Our study demonstrates the potential of comprehensive genetic analysis for improving the clinical diagnosis.

  15. Acral peeling skin syndrome resulting from a homozygous nonsense mutation in the CSTA gene encoding cystatin A.

    PubMed

    Krunic, Aleksandar L; Stone, Kristina L; Simpson, Michael A; McGrath, John A

    2013-01-01

    Acral peeling skin syndrome (APSS) is a clinically and genetically heterogeneous disorder. We used whole-exome sequencing to identify the molecular basis of APSS in a consanguineous Jordanian-American pedigree. We identified a homozygous nonsense mutation (p.Lys22X) in the CSTA gene, encoding cystatin A, that was confirmed using Sanger sequencing. Cystatin A is a protease inhibitor found in the cornified cell envelope, and loss-of-function mutations have previously been reported in two cases of exfoliative ichthyosis. Our study expands the molecular pathology of APSS and demonstrates the value of next-generation sequencing in the genetic characterization of inherited skin diseases. © 2013 Wiley Periodicals, Inc.

  16. Elevated heart rate triggers action potential alternans and sudden death. translational study of a homozygous KCNH2 mutation.

    PubMed

    Schweigmann, Ulrich; Biliczki, Peter; Ramirez, Rafael J; Marschall, Christoph; Takac, Ina; Brandes, Ralf P; Kotzot, Dieter; Girmatsion, Zenawit; Hohnloser, Stefan H; Ehrlich, Joachim R

    2014-01-01

    Long QT syndrome (LQTS) leads to arrhythmic events and increased risk for sudden cardiac death (SCD). Homozygous KCNH2 mutations underlying LQTS-2 have previously been termed "human HERG knockout" and typically express severe phenotypes. We studied genotype-phenotype correlations of an LQTS type 2 mutation identified in the homozygous index patient from a consanguineous Turkish family after his brother died suddenly during febrile illness. Clinical work-up, DNA sequencing, mutagenesis, cell culture, patch-clamp, in silico mathematical modelling, protein biochemistry, confocal microscopy were performed. Genetic analysis revealed a homozygous C-terminal KCNH2 mutation (p.R835Q) in the index patient (QTc ∼506 ms with notched T waves). Parents were I° cousins - both heterozygous for the mutation and clinically unremarkable (QTc ∼447 ms, father and ∼396 ms, mother). Heterologous expression of KCNH2-R835Q showed mildly reduced current amplitudes. Biophysical properties of ionic currents were also only nominally changed with slight acceleration of deactivation and more negative V50 in R835Q-currents. Protein biochemistry and confocal microscopy revealed similar expression patterns and trafficking of WT and R835Q, even at elevated temperature. In silico analysis demonstrated mildly prolonged ventricular action potential duration (APD) compared to WT at a cycle length of 1000 ms. At a cycle length of 350 ms M-cell APD remained stable in WT, but displayed APD alternans in R835Q. Kv11.1 channels affected by the C-terminal R835Q mutation display mildly modified biophysical properties, but leads to M-cell APD alternans with elevated heart rate and could precipitate SCD under specific clinical circumstances associated with high heart rates.

  17. Identifying mutations in Tunisian families with retinal dystrophy.

    PubMed

    Habibi, Imen; Chebil, Ahmed; Falfoul, Yosra; Allaman-Pillet, Nathalie; Kort, Fedra; Schorderet, Daniel F; El Matri, Leila

    2016-11-22

    Retinal dystrophies (RD) are a rare genetic disorder with high genetic heterogeneity. This study aimed at identifying disease-causing variants in fifteen consanguineous Tunisian families. Full ophthalmic examination was performed. Index patients were subjected to IROme analysis or whole exome sequencing followed by homozygosity mapping. All detected variations were confirmed by direct Sanger sequencing. Mutation analysis in our patients revealed two compound heterozygous mutations p.(R91W);(V172D) in RPE65, and five novel homozygous mutations: p.R765C in CNGB1, p.H337R in PDE6B, splice site variant c.1129-2A > G and c.678_681delGAAG in FAM161A and c.1133 + 3_1133 + 6delAAGT in CERKL. The latter mutation impacts pre-mRNA splicing of CERKL. The other changes detected were six previously reported mutations in CNGB3 (p.R203*), ABCA4 (p.W782*), NR2E3 (p.R311Q), RPE65 (p.H182Y), PROM1 (c.1354dupT) and EYS (c.5928-2A > G). Segregation analysis in each family showed that all affected individuals were homozygotes and unaffected individuals were either heterozygote carriers or homozygous wild type allele. These results confirm the involvement of a large number of genes in RD in the Tunisian population.

  18. Neonatal-Onset Chronic Diarrhea Caused by Homozygous Nonsense WNT2B Mutations.

    PubMed

    O'Connell, Amy E; Zhou, Fanny; Shah, Manasvi S; Murphy, Quinn; Rickner, Hannah; Kelsen, Judith; Boyle, John; Doyle, Jefferson J; Gangwani, Bharti; Thiagarajah, Jay R; Kamin, Daniel S; Goldsmith, Jeffrey D; Richmond, Camilla; Breault, David T; Agrawal, Pankaj B

    2018-06-04

    Homozygous nonsense mutations in WNT2B were identified in three individuals from two unrelated families with severe, neonatal-onset osmotic diarrhea after whole-exome sequencing was performed on trios from the two families. Intestinal biopsy samples from affected individuals were used for histology and immunofluorescence and to generate enteroids ex vivo. Histopathologic evaluation demonstrated chronic inflammatory changes in the stomach, duodenum, and colon. Immunofluorescence demonstrated diminished staining for OLFM4, a marker for intestinal stem cells (ISCs). The enteroids generated from WNT2B-deficient intestinal epithelium could not be expanded and did not survive passage. Addition of CHIR-99021 (a GSK3A and GSK3B inhibitor and activator of canonical WNT/β-CATENIN signaling) could not rescue WNT2B-deficient enteroids. Addition of supplemental recombinant murine WNT2B was able to perpetuate small enteroids for multiple passages but failed to expand their number. Enteroids showed a 10-fold increase in the expression of LEF1 mRNA and a 100-fold reduction in TLR4 expression, compared with controls by quantitative RT-PCR, indicating alterations in canonical WNT and microbial pattern-recognition signaling. In summary, individuals with homozygous nonsense mutations in WNT2B demonstrate severe intestinal dysregulation associated with decreased ISC number and function, likely explaining their diarrheal phenotype. WNT2B deficiency should be considered for individuals with neonatal-onset diarrhea. Copyright © 2018 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  19. Report of Chinese family with severe dermatitis, multiple allergies and metabolic wasting syndrome caused by novel homozygous desmoglein-1 gene mutation.

    PubMed

    Cheng, Ruhong; Yan, Ming; Ni, Cheng; Zhang, Jia; Li, Ming; Yao, Zhirong

    2016-10-01

    Recently, homozygous mutations in the desmoglein-1 (DSG1) gene and heterozygous mutation in the desmoplakin (DSP) gene have been demonstrated to be associated with severe dermatitis, multiple allergies and metabolic wasting (SAM) syndrome (Mendelian Inheritance in Man no. 615508). We aim to identify the molecular basis for a Chinese pedigree of SAM syndrome. A Chinese pedigree of SAM syndrome was subjected to mutation detection in the DSG1 gene. Sequence analysis of the DSG1 gene and quantitative reverse transcriptase polymerase chain reaction analysis for gene expression of DSG1 using cDNA derived from the epidermis of patients and controls were both performed. Skin biopsies were also taken from patients for pathological study and transmission electron microscopy observation. Novel homozygous splicing mutation c.1892-1delG in the exon-intron border of the DSG1 gene has been demonstrated to be associated with SAM syndrome. We report a new family of SAM syndrome of Asian decent and expand the spectrum of mutations in the DSG1 gene. © 2016 Japanese Dermatological Association.

  20. Rare intracranial cholesterol deposition and a homozygous mutation of LDLR in a familial hypercholesterolemia patient.

    PubMed

    Li, Haoxian; Zhang, Yanghui; Wei, Xianda; Peng, Ying; Yang, Pu; Tan, Hu; Chen, Chen; Pan, Qian; Liang, Desheng; Wu, Lingqian

    2015-09-15

    Familial hypercholesterolemia (FH MIM# 143890) is one of the most common autosomal inherited diseases. FH is characterized by elevated plasma levels of total cholesterol and low-density lipoprotein-cholesterol. Mutation in the LDLR gene, which encodes the LDL receptor protein, is responsible for most of the morbidity of FH. The incidence of heterozygous FH is about 1/500, whereas the incidence of homozygous FH is only 1/1,000,000 in Caucasian population. In this study, we report a homozygous LDLR mutation (c.298G>A) in a familial hypercholesterolemia patient, who exhibited intracranial cholesterol deposition, which is a rare addition to the common FH phenotypes. The proband's consanguineous parents have the same heterozygous mutation with elevated concentrations of LDL-C but no xanthoma. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Targeted next-generation sequencing identifies a homozygous nonsense mutation in ABHD12, the gene underlying PHARC, in a family clinically diagnosed with Usher syndrome type 3

    PubMed Central

    2012-01-01

    Background Usher syndrome (USH) is an autosomal recessive genetically heterogeneous disorder with congenital sensorineural hearing impairment and retinitis pigmentosa (RP). We have identified a consanguineous Lebanese family with two affected members displaying progressive hearing loss, RP and cataracts, therefore clinically diagnosed as USH type 3 (USH3). Our study was aimed at the identification of the causative mutation in this USH3-like family. Methods Candidate loci were identified using genomewide SNP-array-based homozygosity mapping followed by targeted enrichment and next-generation sequencing. Results Using a capture array targeting the three identified homozygosity-by-descent regions on chromosomes 1q43-q44, 20p13-p12.2 and 20p11.23-q12, we identified a homozygous nonsense mutation, p.Arg65X, in ABHD12 segregating with the phenotype. Conclusion Mutations of ABHD12, an enzyme hydrolyzing an endocannabinoid lipid transmitter, cause PHARC (polyneuropathy, hearing loss, ataxia, retinitis pigmentosa, and early-onset cataract). After the identification of the ABHD12 mutation in this family, one patient underwent neurological examination which revealed ataxia, but no polyneuropathy. ABHD12 is not known to be related to the USH protein interactome. The phenotype of our patient represents a variant of PHARC, an entity that should be taken into account as differential diagnosis for USH3. Our study demonstrates the potential of comprehensive genetic analysis for improving the clinical diagnosis. PMID:22938382

  2. Homozygous Mutations in NEUROD1 Are Responsible for a Novel Syndrome of Permanent Neonatal Diabetes and Neurological Abnormalities

    PubMed Central

    Rubio-Cabezas, Oscar; Minton, Jayne A.L.; Kantor, Iren; Williams, Denise; Ellard, Sian; Hattersley, Andrew T.

    2010-01-01

    OBJECTIVE NEUROD1 is expressed in both developing and mature β-cells. Studies in mice suggest that this basic helix-loop-helix transcription factor is critical in the development of endocrine cell lineage. Heterozygous mutations have previously been identified as a rare cause of maturity-onset diabetes of the young (MODY). We aimed to explore the potential contribution of NEUROD1 mutations in patients with permanent neonatal diabetes. RESEARCH DESIGN AND METHODS We sequenced the NEUROD1 gene in 44 unrelated patients with permanent neonatal diabetes of unknown genetic etiology. RESULTS Two homozygous mutations in NEUROD1 (c.427_ 428del and c.364dupG) were identified in two patients. Both mutations introduced a frameshift that would be predicted to generate a truncated protein completely lacking the activating domain. Both patients had permanent diabetes diagnosed in the first 2 months of life with no evidence of exocrine pancreatic dysfunction and a morphologically normal pancreas on abdominal imaging. In addition to diabetes, they had learning difficulties, severe cerebellar hypoplasia, profound sensorineural deafness, and visual impairment due to severe myopia and retinal dystrophy. CONCLUSIONS We describe a novel clinical syndrome that results from homozygous loss of function mutations in NEUROD1. It is characterized by permanent neonatal diabetes and a consistent pattern of neurological abnormalities including cerebellar hypoplasia, learning difficulties, sensorineural deafness, and visual impairment. This syndrome highlights the critical role of NEUROD1 in both the development of the endocrine pancreas and the central nervous system in humans. PMID:20573748

  3. A homozygous nonsense CEP250 mutation combined with a heterozygous nonsense C2orf71 mutation is associated with atypical Usher syndrome.

    PubMed

    Khateb, Samer; Zelinger, Lina; Mizrahi-Meissonnier, Liliana; Ayuso, Carmen; Koenekoop, Robert K; Laxer, Uri; Gross, Menachem; Banin, Eyal; Sharon, Dror

    2014-07-01

    Usher syndrome (USH) is a heterogeneous group of inherited retinitis pigmentosa (RP) and sensorineural hearing loss (SNHL) caused by mutations in at least 12 genes. Our aim is to identify additional USH-related genes. Clinical examination included visual acuity test, funduscopy and electroretinography. Genetic analysis included homozygosity mapping and whole exome sequencing (WES). A combination of homozygosity mapping and WES in a large consanguineous family of Iranian Jewish origin revealed nonsense mutations in two ciliary genes: c.3289C>T (p.Q1097*) in C2orf71 and c.3463C>T (p.R1155*) in centrosome-associated protein CEP250 (C-Nap1). The latter has not been associated with any inherited disease and the c.3463C>T mutation was absent in control chromosomes. Patients who were double homozygotes had SNHL accompanied by early-onset and severe RP, while patients who were homozygous for the CEP250 mutation and carried a single mutant C2orf71 allele had SNHL with mild retinal degeneration. No ciliary structural abnormalities in the respiratory system were evident by electron microscopy analysis. CEP250 expression analysis of the mutant allele revealed the generation of a truncated protein lacking the NEK2-phosphorylation region. A homozygous nonsense CEP250 mutation, in combination with a heterozygous C2orf71 nonsense mutation, causes an atypical form of USH, characterised by early-onset SNHL and a relatively mild RP. The severe retinal involvement in the double homozygotes indicates an additive effect caused by nonsense mutations in genes encoding ciliary proteins. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  4. Efficient introduction of specific homozygous and heterozygous mutations using CRISPR/Cas9.

    PubMed

    Paquet, Dominik; Kwart, Dylan; Chen, Antonia; Sproul, Andrew; Jacob, Samson; Teo, Shaun; Olsen, Kimberly Moore; Gregg, Andrew; Noggle, Scott; Tessier-Lavigne, Marc

    2016-05-05

    The bacterial CRISPR/Cas9 system allows sequence-specific gene editing in many organisms and holds promise as a tool to generate models of human diseases, for example, in human pluripotent stem cells. CRISPR/Cas9 introduces targeted double-stranded breaks (DSBs) with high efficiency, which are typically repaired by non-homologous end-joining (NHEJ) resulting in nonspecific insertions, deletions or other mutations (indels). DSBs may also be repaired by homology-directed repair (HDR) using a DNA repair template, such as an introduced single-stranded oligo DNA nucleotide (ssODN), allowing knock-in of specific mutations. Although CRISPR/Cas9 is used extensively to engineer gene knockouts through NHEJ, editing by HDR remains inefficient and can be corrupted by additional indels, preventing its widespread use for modelling genetic disorders through introducing disease-associated mutations. Furthermore, targeted mutational knock-in at single alleles to model diseases caused by heterozygous mutations has not been reported. Here we describe a CRISPR/Cas9-based genome-editing framework that allows selective introduction of mono- and bi-allelic sequence changes with high efficiency and accuracy. We show that HDR accuracy is increased dramatically by incorporating silent CRISPR/Cas-blocking mutations along with pathogenic mutations, and establish a method termed 'CORRECT' for scarless genome editing. By characterizing and exploiting a stereotyped inverse relationship between a mutation's incorporation rate and its distance to the DSB, we achieve predictable control of zygosity. Homozygous introduction requires a guide RNA targeting close to the intended mutation, whereas heterozygous introduction can be accomplished by distance-dependent suboptimal mutation incorporation or by use of mixed repair templates. Using this approach, we generated human induced pluripotent stem cells with heterozygous and homozygous dominant early onset Alzheimer's disease-causing mutations in

  5. Mutation screening of the HGD gene identifies a novel alkaptonuria mutation with significant founder effect and high prevalence.

    PubMed

    Sakthivel, Srinivasan; Zatkova, Andrea; Nemethova, Martina; Surovy, Milan; Kadasi, Ludevit; Saravanan, Madurai P

    2014-05-01

    Alkaptonuria (AKU) is an autosomal recessive disorder; caused by the mutations in the homogentisate 1, 2-dioxygenase (HGD) gene located on Chromosome 3q13.33. AKU is a rare disorder with an incidence of 1: 250,000 to 1: 1,000,000, but Slovakia and the Dominican Republic have a relatively higher incidence of 1: 19,000. Our study focused on studying the frequency of AKU and identification of HGD gene mutations in nomads. HGD gene sequencing was used to identify the mutations in alkaptonurics. For the past four years, from subjects suspected to be clinically affected, we found 16 positive cases among a randomly selected cohort of 41 Indian nomads (Narikuravar) settled in the specific area of Tamil Nadu, India. HGD gene mutation analysis showed that 11 of these patients carry the same homozygous splicing mutation c.87 + 1G > A; in five cases, this mutation was found to be heterozygous, while the second AKU-causing mutation was not identified in these patients. This result indicates that the founder effect and high degree of consanguineous marriages have contributed to AKU among nomads. Eleven positive samples were homozygous for a novel mutation c.87 + 1G > A, that abolishes an intron 2 donor splice site and most likely causes skipping of exon 2. The prevalence of AKU observed earlier seems to be highly increased in people of nomadic origin. © 2014 John Wiley & Sons Ltd/University College London.

  6. Homozygous SALL1 Mutation Causes a Novel Multiple Congenital Anomaly—Mental Retardation Syndrome

    PubMed Central

    Vodopiutz, Julia; Zoller, Heinz; Fenwick, Aimée L.; Arnhold, Richard; Schmid, Max; Prayer, Daniela; Müller, Thomas; Repa, Andreas; Pollak, Arnold; Aufricht, Christoph; Wilkie, Andrew O.M.; Janecke, Andreas R.

    2013-01-01

    Objective To delineate a novel autosomal recessive multiple congenital anomaly-mental retardation (MCA-MR) syndrome in 2 female siblings of a consanguineous pedigree and to identify the disease-causing mutation. Study design Both siblings were clinically characterized and homozygosity mapping and sequencing of candidate genes were applied. The contribution of nonsense-mediated messenger RNA (mRNA) decay to the expression of mutant mRNA in fibroblasts of a healthy carrier and a control was studied by pyrosequencing. Results We identified the first homozygous SALL1 mutation, c.3160C > T (p.R1054*), in 2 female siblings presenting with multiple congenital anomalies, central nervous system defects, cortical blindness, and absence of psychomotor development (ie, a novel recognizable, autosomal recessive MCA-MR). The mutant SALL1 transcript partially undergoes nonsense-mediated mRNA decay and is present at 43% of the normal transcript level in the fibroblasts of a healthy carrier. Conclusion Previously heterozygous SALL1 mutations and deletions have been associated with dominantly inherited anal-renal-radial-ear developmental anomalies. We identified an allelic recessive SALL1-related MCA-MR. Our findings imply that quantity and quality of SALL1 transcript are important for SALL1 function and determine phenotype, and mode of inheritance, of allelic SALL1-related disorders. This novel MCA-MR emphasizes SALL1 function as critical for normal central nervous system development and warrants a detailed neurologic investigation in all individuals with SALL1 mutations. PMID:23069192

  7. A novel homozygous truncating GNAT1 mutation implicated in retinal degeneration.

    PubMed

    Carrigan, Matthew; Duignan, Emma; Humphries, Pete; Palfi, Arpad; Kenna, Paul F; Farrar, G Jane

    2016-04-01

    The GNAT1 gene encodes the α subunit of the rod transducin protein, a key element in the rod phototransduction cascade. Variants in GNAT1 have been implicated in stationary night-blindness in the past, but unlike other proteins in the same pathway, it has not previously been implicated in retinitis pigmentosa. A panel of 182 retinopathy-associated genes was sequenced to locate disease-causing mutations in patients with inherited retinopathies. Sequencing revealed a novel homozygous truncating mutation in the GNAT1 gene in a patient with significant pigmentary disturbance and constriction of visual fields, a presentation consistent with retinitis pigmentosa. This is the first report of a patient homozygous for a complete loss-of-function GNAT1 mutation. The clinical data from this patient provide definitive evidence of retinitis pigmentosa with late onset in addition to the lifelong night-blindness that would be expected from a lack of transducin function. These data suggest that some truncating GNAT1 variants can indeed cause a recessive, mild, late-onset retinal degeneration in human beings rather than just stationary night-blindness as reported previously, with notable similarities to the phenotype of the Gnat1 knockout mouse. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  8. Novel homozygous mutations in the osteoprotegerin gene TNFRSF11B in two unrelated patients with juvenile Paget's disease.

    PubMed

    Naot, Dorit; Choi, Ally; Musson, David Shaun; Simsek Kiper, Pelin Özlem; Utine, Gulen Eda; Boduroglu, Koray; Peacock, Munro; DiMeglio, Linda A; Cundy, Tim

    2014-11-01

    Most patients with juvenile Paget's disease (JPD) are homozygous for mutations in the gene TNFRSF11B that result in deficiency of osteoprotegerin (OPG) - a key regulator of bone turnover. So far, about 10 different OPG mutations have been described. The current study presents two novel OPG mutations in JPD patients. Patient 1 was diagnosed at the age of 9months when he presented with inability to sit up, slow growth, marked bone pain and very high levels of serum alkaline phosphatase. Patient 2 presented a milder phenotype. He was initially diagnosed with osteogenesis imperfecta, and although he had numerous fractures and bone deformity, he was still independently mobile at the age of 19years, when a diagnosis of JPD was confirmed. Sequence analysis of DNA samples from the patients determined two novel homozygous mutations in TNFSRF11B. Patient 1 (severe phenotype) had a large (245-251kbp) homozygous deletion beginning in intron 1 that resulted in loss of 4 of the 5 exons of TNFSRF11B, including the whole ligand-binding domain. Patient 2 had a homozygous missense mutation resulting in a Thr>Pro change in exon 2 of TNFSRF11B that is predicted to disrupt the OPG ligand-binding domain. Taken in conjunction with other published cases, these results are consistent with the hypothesis that the most severe phenotypes in JPD are seen in patients with major gene deletions or mutations affecting cysteine residues in the ligand-binding domain. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. A novel homozygous mutation in the FSHR gene is causative for primary ovarian insufficiency.

    PubMed

    Liu, Hongli; Xu, Xiaofei; Han, Ting; Yan, Lei; Cheng, Lei; Qin, Yingying; Liu, Wen; Zhao, Shidou; Chen, Zi-Jiang

    2017-12-01

    To identify the potential FSHR mutation in a Chinese woman with primary ovarian insufficiency (POI). Genetic and functional studies. University-based reproductive medicine center. A POI patient, her family members, and another 192 control women with regular menstruation. Ovarian biopsy was performed in the patient. Sanger sequencing was carried out for the patient, her sister, and parents. The novel variant identified was further confirmed with the use of control subjects. Sanger sequencing and genotype analysis to identify the potential variant of the FSHR gene; hematoxylin and eosin staining of the ovarian section to observe the follicular development; Western blotting and immunofluorescence to detect FSH receptor (FSHR) expression; and cyclic adenosine monophosphate (cAMP) assay to monitor FSH-induced signaling. Histologic examination of the ovaries in the patient revealed follicular development up to the early antral stage. Mutational screening and genotype analysis of the FSHR gene identified a novel homozygous mutation c.175C>T (p.R59X) in exon 2, which was inherited in the autosomal recessive mode from her heterozygous parents but was absent in her sister and the 192 control women. Functional studies demonstrated that in vitro the nonsense mutation caused the loss of full-length FSHR expression and that p.R59X mutant showed no response to FSH stimulation in the cAMP level. The mutation p.R59X in FSHR is causative for POI by means of arresting folliculogenesis. Copyright © 2017 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  10. Two homozygous mutations in the exon 5 of BCKDHB gene that may cause the classic form of maple syrup urine disease.

    PubMed

    Su, Ling; Lu, Zhikun; Li, Fatao; Shao, Yongxian; Sheng, Huiying; Cai, Yanna; Liu, Li

    2017-06-01

    Maple syrup urine disease (MSUD) is a rare autosomal recessive genetic disorder caused by defects in the catabolism of the branched-chain amino acids (BCAAs). Classic form of MSUD (CMSUD) is caused by mutations in BCKDHA, BCKDHB, DBT genes mostly. In this study, we analyzed the clinical and genetic characteristics of two patients with CMSUD. Two homozygous mutations, c.517G > T (p.Asp173Tyr) and c.503G > A (p.Arg168His), both in the exon 5 of BCKDHB were detected respectively. The novel mutation p.Asp173Tyr of patient A, inherited from his parents, is predicted to affect conformation of protein by computer analysis. The reported mutation p.Arg168His observed in patient B seemed to occur in a maternal uniparental disomy inheritance manner. Review of related literature revealed that most missense mutations in exon 5 of BCKDHB in homozygous genotype often result in CMSUD because of its incorrect conformation, and exon 5 of BCKDHB might be a susceptible region. Thus the novel homozygous mutation p.Asp173Tyr and the founder homozygous mutation p.Arg168His may be responsible for the clinical presentation of the two CMSUD patients, facilitating the future genetic counselling and prenatal diagnosis.

  11. Deficiency in GnRH receptor trafficking due to a novel homozygous mutation causes idiopathic hypogonadotropic hypogonadism in three prepubertal siblings.

    PubMed

    Zhang, Rui; Linpeng, Siyuan; Li, Zhuo; Cao, Yingxi; Tan, Hu; Liang, Desheng; Wu, Lingqian

    2018-08-30

    Idiopathic hypogonadotropic hypogonadism (IHH) is characterized by low levels of gonadotropins and delayed or absent sexual development. Most of the patients are diagnosed in late adolescence or early adulthood. Determining the diagnosis of IHH in prepubertal patients can be challenging. Making a timely, correct diagnosis has important clinical implications. Here we aimed to identify the genetic cause of IHH in three prepubertal siblings from a Chinese Han family and give appropriate treatment advice. Using whole exome sequencing (WES), we identified a novel homozygous GNRHR mutation (NM_000406; c.364C>T, p.L122F) in two prepubertal boys with cryptorchidism and micropenis. Sanger sequencing showed that their younger asymptomatic sister also had the homozygous GNRHR mutation. This mutation was inherited from the father and the mother. Immunofluorescence analysis showed that in permeabilized cells, expression of the mutant receptor on the cell membrane was significantly lower than that of wild-type. Calcium mobilization assays demonstrated that c.364C>T in the GNRHR gene is a complete loss-of-function mutation that caused IHH. These results may contribute to the genetic diagnosis of the three prepubertal siblings with IHH. According to this diagnosis, timely hormonal treatment can be given for the three prepubertal patients to induce pubertal development, especially for the asymptomatic female. Copyright © 2018 Elsevier B.V. All rights reserved.

  12. Phenotypic variability in patients with ADA2 deficiency due to identical homozygous R169Q mutations.

    PubMed

    Van Montfrans, Joris M; Hartman, Esther A R; Braun, Kees P J; Hennekam, Eric A M; Hak, Elisabeth A; Nederkoorn, Paul J; Westendorp, Willeke F; Bredius, Robbert G M; Kollen, Wouter J W; Schölvinck, Elisabeth H; Legger, G Elizabeth; Meyts, Isabelle; Liston, Adrian; Lichtenbelt, Klaske D; Giltay, Jacques C; Van Haaften, Gijs; De Vries Simons, Gaby M; Leavis, Helen; Sanders, Cornelis J G; Bierings, Marc B; Nierkens, Stefan; Van Gijn, Marielle E

    2016-05-01

    To determine the genotype-phenotype association in patients with adenosine deaminase-2 (ADA2) deficiency due to identical homozygous R169Q mutations inCECR1 METHODS: We present a case series of nine ADA2-deficient patients with an identical homozygous R169Q mutation. Clinical and diagnostic data were collected and available MRI studies were reviewed. We performed genealogy and haplotype analyses and measured serum ADA2 activity. ADA2 activity values were correlated to clinical symptoms. Age of presentation differed widely between the nine presented patients (range: 0 months to 8 years). The main clinical manifestations were (hepato)splenomegaly (8/9), skin involvement (8/9) and neurological involvement (8/9, of whom 6 encountered stroke). Considerable variation was seen in type, frequency and intensity of other symptoms, which included aplastic anaemia, acute myeloid leukaemia and cutaneous ulcers. Common laboratory abnormalities included cytopenias and hypogammaglobulinaemia. ADA2 enzyme activity in patients was significantly decreased compared with healthy controls. ADA2 activity levels tended to be lower in patients with stroke compared with patients without stroke. Genealogical studies did not identify a common ancestor; however, based on allele frequency, a North-West European founder effect can be noted. Three patients underwent haematopoietic cell transplantation, after which ADA2 activity was restored and clinical symptoms resolved. This case series revealed large phenotypic variability in patients with ADA2 deficiency though they were homozygous for the same R169Q mutation inCECR1 Disease modifiers, including epigenetic and environmental factors, thus seem important in determining the phenotype. Furthermore, haematopoietic cell transplantation appears promising for those patients with a severe clinical phenotype. © The Author 2016. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions

  13. Vincristine-induced central neurotoxicity in a collie homozygous for the ABCB1Δ mutation.

    PubMed

    Krugman, L; Bryan, J N; Mealey, K L; Chen, A

    2012-03-01

    A six-year-old, neutered, female collie was presented to an oncology specialty service after developing tetraparesis and self-mutilation that progressively worsened while receiving chemotherapy for lymphoma. Neurologic examination revealed ataxia, paresis and diminished conscious proprioception in all limbs with entire spinal reflexes. Magnetic resonance imaging of the brain and spinal cord was normal. Electromyography of the limbs ruled out a vincristine-induced peripheral neuropathy. Cerebrospinal fluid analysis and cerebrospinal fluid and serum testing for Neospora and Toxoplasma were normal. Results of MDR1 genotyping revealed that the dog was homozygous for the ABCB1-1Δ (MDR1) mutation. This clinical presentation strongly resembled the effects seen from inadvertent intrathecal administration of vincristine in humans. Dogs that are homozygous for the ABCB1-1Δ (MDR1) mutation should not receive standard dosages of chemotherapy drugs known to be eliminated by P-glycoprotein, the gene product of ABCB1. Testing for this mutation is strongly recommended before chemotherapy initiation for at-risk breeds. © 2011 British Small Animal Veterinary Association.

  14. A cystic fibrosis patient who is homozygous for the A559T mutation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    McDowell, T.; Shackleton, S.; Dear, S.

    1995-09-01

    We have recently defined a cystic fibrosis (CF) patient who is homozygous for the A559T mutation in exon 11 of the cystic fibrosis transmembrane conductance regulator (CFTR) gene. This mutation was detected by direct sequence analysis and confirmed to be carried by both parents (of West Indian origin) of the index case. The A559T mutation has not been detected in any Caucasian CF patients. The presence of this mutation in North American black CF patients and a British CF patient of West Indian origin is clearly of interest in designing CF screening tests that are tailored to specific ethnic groups.more » 1 ref.« less

  15. Neonatal diabetes caused by a homozygous KCNJ11 mutation demonstrates that tiny changes in ATP sensitivity markedly affect diabetes risk.

    PubMed

    Vedovato, Natascia; Cliff, Edward; Proks, Peter; Poovazhagi, Varadarajan; Flanagan, Sarah E; Ellard, Sian; Hattersley, Andrew T; Ashcroft, Frances M

    2016-07-01

    The pancreatic ATP-sensitive potassium (KATP) channel plays a pivotal role in linking beta cell metabolism to insulin secretion. Mutations in KATP channel genes can result in hypo- or hypersecretion of insulin, as in neonatal diabetes mellitus and congenital hyperinsulinism, respectively. To date, all patients affected by neonatal diabetes due to a mutation in the pore-forming subunit of the channel (Kir6.2, KCNJ11) are heterozygous for the mutation. Here, we report the first clinical case of neonatal diabetes caused by a homozygous KCNJ11 mutation. A male patient was diagnosed with diabetes shortly after birth. At 5 months of age, genetic testing revealed he carried a homozygous KCNJ11 mutation, G324R, (Kir6.2-G324R) and he was successfully transferred to sulfonylurea therapy (0.2 mg kg(-1) day(-1)). Neither heterozygous parent was affected. Functional properties of wild-type, heterozygous and homozygous mutant KATP channels were examined after heterologous expression in Xenopus oocytes. Functional studies indicated that the Kir6.2-G324R mutation reduces the channel ATP sensitivity but that the difference in ATP inhibition between homozygous and heterozygous channels is remarkably small. Nevertheless, the homozygous patient developed neonatal diabetes, whereas the heterozygous parents were, and remain, unaffected. Kir6.2-G324R channels were fully shut by the sulfonylurea tolbutamide, which explains why the patient's diabetes was well controlled by sulfonylurea therapy. The data demonstrate that tiny changes in KATP channel activity can alter beta cell electrical activity and insulin secretion sufficiently to cause diabetes. They also aid our understanding of how the Kir6.2-E23K variant predisposes to type 2 diabetes.

  16. Differential functional readthrough over homozygous nonsense mutations contributes to the bleeding phenotype in coagulation factor VII deficiency.

    PubMed

    Branchini, A; Ferrarese, M; Lombardi, S; Mari, R; Bernardi, F; Pinotti, M

    2016-10-01

    Essentials Potentially null homozygous Factor(F)7 nonsense mutations are associated to variable bleeding symptoms. Readthrough of p.Ser112X (life-threatening) and p.Cys132X (moderate) stop codons was investigated. Readthrough-mediated insertion of wild-type or tolerated residues produce functional proteins. Functional readthrough over homozygous F7 nonsense mutations contributes to the bleeding phenotype. Background Whereas the rare homozygous nonsense mutations causing factor (F)VII deficiency may predict null conditions that are almost completely incompatible with life, they are associated with appreciable differences in hemorrhagic symptoms. The misrecognition of premature stop codons (readthrough) may account for variable levels of functional full-length proteins. Objectives To experimentally evaluate the basal and drug-induced levels of FVII resulting from the homozygous p.Cys132X and p.Ser112X nonsense mutations that are associated with moderate (132X) or life-threatening (112X) symptoms, and that are predicted to undergo readthrough with (132X) or without (112X) production of wild-type FVII. Methods We transiently expressed recombinant FVII (rFVII) nonsense and missense variants in human embryonic kidney 293 cells, and evaluated secreted FVII protein and functional levels by ELISA, activated FX generation, and coagulation assays. Results The levels of functional FVII produced by p.Cys132X and p.Ser112X mutants (rFVII-132X, 1.1% ± 0.2% of wild-type rFVII; rFVII-112X, 0.5% ± 0.1% of wild-type rFVII) were compatible with the occurrence of spontaneous readthrough, which was magnified by the addition of G418 - up to 12% of the wild-type value for the rFVII-132X nonsense variant. The predicted missense variants arising from readthrough abolished (rFVII-132Trp/Arg) or reduced (rFVII-112Trp/Cys/Arg, 22-45% of wild-type levels) secretion and function. These data suggest that the appreciable rescue of p.Cys132X function was driven by reinsertion of the wild

  17. Whole-Exome Sequencing Identifies Homozygous AFG3L2 Mutations in a Spastic Ataxia-Neuropathy Syndrome Linked to Mitochondrial m-AAA Proteases

    PubMed Central

    Martinelli, Paola; Cherukuri, Praveen F.; Teer, Jamie K.; Hansen, Nancy F.; Cruz, Pedro; Mullikin for the NISC Comparative Sequencing Program, James C.; Blakesley, Robert W.; Golas, Gretchen; Kwan, Justin; Sandler, Anthony; Fuentes Fajardo, Karin; Markello, Thomas; Tifft, Cynthia; Blackstone, Craig; Rugarli, Elena I.; Langer, Thomas; Gahl, William A.; Toro, Camilo

    2011-01-01

    We report an early onset spastic ataxia-neuropathy syndrome in two brothers of a consanguineous family characterized clinically by lower extremity spasticity, peripheral neuropathy, ptosis, oculomotor apraxia, dystonia, cerebellar atrophy, and progressive myoclonic epilepsy. Whole-exome sequencing identified a homozygous missense mutation (c.1847G>A; p.Y616C) in AFG3L2, encoding a subunit of an m-AAA protease. m-AAA proteases reside in the mitochondrial inner membrane and are responsible for removal of damaged or misfolded proteins and proteolytic activation of essential mitochondrial proteins. AFG3L2 forms either a homo-oligomeric isoenzyme or a hetero-oligomeric complex with paraplegin, a homologous protein mutated in hereditary spastic paraplegia type 7 (SPG7). Heterozygous loss-of-function mutations in AFG3L2 cause autosomal-dominant spinocerebellar ataxia type 28 (SCA28), a disorder whose phenotype is strikingly different from that of our patients. As defined in yeast complementation assays, the AFG3L2Y616C gene product is a hypomorphic variant that exhibited oligomerization defects in yeast as well as in patient fibroblasts. Specifically, the formation of AFG3L2Y616C complexes was impaired, both with itself and to a greater extent with paraplegin. This produced an early-onset clinical syndrome that combines the severe phenotypes of SPG7 and SCA28, in additional to other “mitochondrial” features such as oculomotor apraxia, extrapyramidal dysfunction, and myoclonic epilepsy. These findings expand the phenotype associated with AFG3L2 mutations and suggest that AFG3L2-related disease should be considered in the differential diagnosis of spastic ataxias. PMID:22022284

  18. Mutations in HAMP and HJV genes and their impact on expression of clinical hemochromatosis in a cohort of 100 Spanish patients homozygous for the C282Y mutation of HFE gene.

    PubMed

    Altès, Albert; Bach, Vanessa; Ruiz, Angels; Esteve, Anna; Felez, Jordi; Remacha, Angel F; Sardà, M Pilar; Baiget, Montserrat

    2009-10-01

    Most hereditary hemochromatosis (HH) patients are homozygous for the C282Y mutation of the HFE gene. Nevertheless, penetrance of the disease is very variable. In some patients, penetrance can be mediated by concomitant mutations in other iron master genes. We evaluated the clinical impact of hepcidin (HAMP) and hemojuvelin mutations in a cohort of 100 Spanish patients homozygous for the C282Y mutation of the HFE gene. HAMP and hemojuvelin mutations were evaluated in all patients by bidirectional direct cycle sequencing. Phenotype-genotype interactions were evaluated. A heterozygous mutation of the HAMP gene (G71D) was found in only one out of 100 cases. Following, we performed a study of several members of that family, and we observed several members had a digenic inheritance of the C282Y mutation of the HFE gene and the G71D mutation of the HAMP gene. This mutation in the HAMP gene did not modify the phenotype of the individuals who were homozygous for the C282Y mutation. One other patient presented a new polymorphism in the hemojuvelin gene, without consequences in iron load or clinical course of the disease. In conclusion, HAMP and hemojuvelin mutations are rare among Spanish HH patients, and their impact in this population is not significant.

  19. Exome Sequencing Identifies Truncating Mutations in Human SERPINF1 in Autosomal-Recessive Osteogenesis Imperfecta

    PubMed Central

    Becker, Jutta; Semler, Oliver; Gilissen, Christian; Li, Yun; Bolz, Hanno Jörn; Giunta, Cecilia; Bergmann, Carsten; Rohrbach, Marianne; Koerber, Friederike; Zimmermann, Katharina; de Vries, Petra; Wirth, Brunhilde; Schoenau, Eckhard; Wollnik, Bernd; Veltman, Joris A.; Hoischen, Alexander; Netzer, Christian

    2011-01-01

    Osteogenesis imperfecta (OI) is a heterogeneous genetic disorder characterized by bone fragility and susceptibility to fractures after minimal trauma. After mutations in all known OI genes had been excluded by Sanger sequencing, we applied next-generation sequencing to analyze the exome of a single individual who has a severe form of the disease and whose parents are second cousins. A total of 26,922 variations from the human reference genome sequence were subjected to several filtering steps. In addition, we extracted the genotypes of all dbSNP130-annotated SNPs from the exome sequencing data and used these 299,494 genotypes as markers for the genome-wide identification of homozygous regions. A single homozygous truncating mutation, affecting SERPINF1 on chromosome 17p13.3, that was embedded into a homozygous stretch of 2.99 Mb remained. The mutation was also homozygous in the affected brother of the index patient. Subsequently, we identified homozygosity for two different truncating SERPINF1 mutations in two unrelated patients with OI and parental consanguinity. All four individuals with SERPINF1 mutations have severe OI. Fractures of long bones and severe vertebral compression fractures with resulting deformities were observed as early as the first year of life in these individuals. Collagen analyses with cultured dermal fibroblasts displayed no evidence for impaired collagen folding, posttranslational modification, or secretion. SERPINF1 encodes pigment epithelium-derived factor (PEDF), a secreted glycoprotein of the serpin superfamily. PEDF is a multifunctional protein and one of the strongest inhibitors of angiogenesis currently known in humans. Our data provide genetic evidence for PEDF involvement in human bone homeostasis. PMID:21353196

  20. A Novel Homozygous Missense Mutation in HOXC13 Leads to Autosomal Recessive Pure Hair and Nail Ectodermal Dysplasia.

    PubMed

    Li, Xiaoxiao; Orseth, Meredith Lee; Smith, J Michael; Brehm, Mary Abigail; Agim, Nnenna Gebechi; Glass, Donald Alexander

    2017-03-01

    Pure hair and nail ectodermal dysplasia (PHNED) is a rare disorder that presents with hypotrichosis and nail dystrophy while sparing other ectodermal structures such as teeth and sweat glands. We describe a homozygous novel missense mutation in the HOXC13 gene that resulted in autosomal recessive PHNED in a Hispanic child. The mutation c.812A>G (p.Gln271Arg) is located within the DNA-binding domain of the HOXC13 gene, cosegregates within the family, and is predicted to be maximally damaging. This is the first reported case of a missense HOXC13 mutation resulting in PHNED and the first reported case of PHNED identified in a North American family. Our findings illustrate the critical role of HOXC13 in human hair and nail development. © 2017 Wiley Periodicals, Inc.

  1. Homozygous p.V116* mutation in C12orf65 results in Leigh syndrome.

    PubMed

    Imagawa, Eri; Fattal-Valevski, Aviva; Eyal, Ori; Miyatake, Satoko; Saada, Ann; Nakashima, Mitsuko; Tsurusaki, Yoshinori; Saitsu, Hirotomo; Miyake, Noriko; Matsumoto, Naomichi

    2016-02-01

    Leigh syndrome (LS) is an early-onset progressive neurodegenerative disorder associated with mitochondrial dysfunction. LS is characterised by elevated lactate and pyruvate and bilateral symmetric hyperintense lesions in the basal ganglia, thalamus, brainstem, cerebral white matter or spinal cord on T2-weighted MRI. LS is a genetically heterogeneous disease, and to date mutations in approximately 40 genes related to mitochondrial function have been linked to the disorder. We investigated a pair of female monozygotic twins diagnosed with LS from consanguineous healthy parents of Indian origin. Their common clinical features included optic atrophy, ophthalmoplegia, spastic paraparesis and mild intellectual disability. High-blood lactate and high-intensity signal in the brainstem on T2-weighted MRI were consistent with a clinical diagnosis of LS. To identify the genetic cause of their condition, we performed whole exome sequencing. We identified a homozygous nonsense mutation in C12orf65 (NM_001143905; c.346delG, p.V116*) in the affected twins. Interestingly, the identical mutation was previously reported in an Indian family with Charcot-Marie Tooth disease type 6, which displayed some overlapping clinical features with the twins. We demonstrate that the identical nonsense mutation in C12orf65 can result in different clinical features, suggesting the involvement of unknown modifiers. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  2. dRTA and hemolytic anemia: first detailed description of SLC4A1 A858D mutation in homozygous state.

    PubMed

    Fawaz, Naglaa A; Beshlawi, Ismail O; Al Zadjali, Shoaib; Al Ghaithi, Hamed K; Elnaggari, Mohamed A; Elnour, Ibtisam; Wali, Yasser A; Al-Said, Bushra B; Rehman, Jalil U; Pathare, Anil V; Knox-Macaulay, Huxley; Alkindi, Salam S

    2012-04-01

    Mutations in the anion exchanger 1 (AE1) gene encoding the erythroid and kidney anion (chloride-bicarbonate) exchanger 1 may result in familial distal renal tubular acidosis (dRTA) in association with membrane defect hemolytic anemia. Seven children presenting with hyperchloremic normal anion gap metabolic acidosis, failure to thrive, and compensated hemolytic anemia were studied. Analysis of red cell AE1/Band 3 surface expression by Eosin 5'-maleimide (E5M) was performed in patients and their family members using flow cytometry. Genetic studies showed that all patients carried a common SLC4A1 mutation, c.2573C>A; p.Ala858Asp in exon 19, found as homozygous (A858D/A858D) mutation in the patients and heterozygous (A858D/N) in the parents. Analysis by flowcytometry revealed a single uniform fluorescence peak, with the mean channel fluorescence (MCF) markedly reduced in cases with homozygous mutation, along with a left shift of fluorescence signal but was only mildly reduced in the heterozygous state. Red cell morphology showed striking acanthocytosis in the homozygous state [patients] and only a mild acanthocytosis in heterozygous state [parents]. In conclusion, this is the first description of a series of homozygous cases with the A858D mutation. The E5M flowcytometry test is specific for reduction in the Band 3 membrane protein and was useful in conjunction with a careful morphological examination of peripheral blood smears in our patient cohort. © 2012 John Wiley & Sons A/S.

  3. A syndrome of congenital microcephaly, intellectual disability and dysmorphism with a homozygous mutation in FRMD4A.

    PubMed

    Fine, Dina; Flusser, Hagit; Markus, Barak; Shorer, Zamir; Gradstein, Libe; Khateeb, Shareef; Langer, Yshia; Narkis, Ginat; Birk, Ruth; Galil, Aharon; Shelef, Ilan; Birk, Ohad S

    2015-12-01

    A consanguineous Bedouin Israeli kindred presented with a novel autosomal recessive intellectual disability syndrome of congenital microcephaly, low anterior hairline, bitemporal narrowing, low-set protruding ears, strabismus and tented thick eyebrows with sparse hair in their medial segment. Brain imaging demonstrated various degrees of agenesis of corpus callosum and hypoplasia of the vermis and cerebellum. Genome-wide linkage analysis followed by fine mapping defined a 7.67 Mb disease-associated locus (LOD score 4.99 at θ=0 for marker D10S1653). Sequencing of the 48 genes within the locus identified a single non-synonymous homozygous duplication frameshift mutation of 13 nucleotides (c.2134_2146dup13) within the coding region of FRMD4A, that was common to all affected individuals and not found in 180 non-related Bedouin controls. Three of 50 remotely related healthy controls of the same tribe were heterozygous for the mutation. FRMD4A, member of the FERM superfamily, is involved in cell structure, transport and signaling. It regulates cell polarity by playing an important role in the activation of ARF6, mediating the interaction between Par3 and the ARF6 guanine nucleotide exchange factor. ARF6 is known to modulate cell polarity in neurons, and regulates dendritic branching in hippocampal neurons and neurite outgrowth. The FRMD4 domain that is essential for determining cell polarity through interaction with Par3 is truncated by the c.2134_2146dup13 mutation. FRMD4A polymorphisms were recently suggested to be a risk factor for Alzheimer's disease. We now show a homozygous frameshift mutation of the same gene in a severe neurologic syndrome with unique dysmorphism.

  4. ABCD syndrome is caused by a homozygous mutation in the EDNRB gene.

    PubMed

    Verheij, Joke B G M; Kunze, Jürgen; Osinga, Jan; van Essen, Anthonie J; Hofstra, Robert M W

    2002-03-15

    ABCD syndrome is an autosomal recessive syndrome characterized by albinism, black lock, cell migration disorder of the neurocytes of the gut (Hirschsprung disease [HSCR]), and deafness. This phenotype clearly overlaps with the features of the Shah-Waardenburg syndrome, comprising sensorineural deafness; hypopigmentation of skin, hair, and irides; and HSCR. Therefore, we screened DNA of the index patient of the ABCD syndrome family for mutations in the endothelin B receptor (EDNRB) gene, a gene known to be involved in Shah-Waardenburg syndrome. A homozygous nonsense mutation in exon 3 (R201X) of the EDNRB gene was found. We therefore suggest that ABCD syndrome is not a separate entity, but an expression of Shah-Waardenburg syndrome.

  5. Identification of a novel homozygous TRAPPC9 gene mutation causing non-syndromic intellectual disability, speech disorder, and secondary microcephaly.

    PubMed

    Abbasi, Ansar A; Blaesius, Kathrin; Hu, Hao; Latif, Zahid; Picker-Minh, Sylvie; Khan, Muhammad N; Farooq, Sundas; Khan, Muzammil A; Kaindl, Angela M

    2017-12-01

    TRAPPC9 gene mutations have been linked recently to autosomal recessive mental retardation 13 (MRT13; MIM#613192) with only eight families reported world-wide. We assessed patients from two consanguineous pedigrees of Pakistani descent with non-syndromic intellectual disability and postnatal microcephaly through whole exome sequencing (WES) and cosegregation analysis. Here we report six further patients from two pedigrees with homozygous TRAPPC9 gene mutations, the novel nonsense mutation c.2065G>T (p.E689*) and the previously identified nonsense mutation c.1423C>T (p.R475*). We provide an overview of previously reported clinical features and highlight common symptoms and variability of MRT13. Common findings are intellectual disability and absent speech, and frequently microcephaly, motor delay and pathological findings on MRI including diminished cerebral white matter volume are present. Mutations in TRAPPC9 should be considered in non-syndromic autosomal recessive intellectual disability with severe speech disorder. © 2017 Wiley Periodicals, Inc.

  6. A Novel Homozygous Mutation in FOXC1 Causes Axenfeld Rieger Syndrome with Congenital Glaucoma

    PubMed Central

    Micheal, Shazia; Villanueva-Mendoza, Cristina; Cortés-González, Vianney; Khan, Muhammad Imran; den Hollander, Anneke I.

    2016-01-01

    Background Anterior segment dysgenesis (ASD) disorders are a group of clinically and genetically heterogeneous phenotypes in which frequently cornea, iris, and lens are affected. This study aimed to identify novel mutations in PAX6, PITX2 and FOXC1 in families with anterior segment dysgenesis disorders. Methods We studied 14 Pakistani and one Mexican family with Axenfeld Rieger syndrome (ARS; n = 10) or aniridia (n = 5). All affected and unaffected family members underwent full ophthalmologic and general examinations. Total genomic DNA was isolated from peripheral blood. PCR and Sanger sequencing were performed for the exons and intron-exon boundaries of the FOXC1, PAX6, and PITX2 genes. Results Mutations were identified in five of the 15 probands; four variants were novel and one variant was described previously. A novel de novo variant (c.225C>A; p.Tyr75*) was identified in the PAX6 gene in two unrelated probands with aniridia. In addition, a known variant (c.649C>T; p.Arg217*) in PAX6 segregated in a family with aniridia. In the FOXC1 gene, a novel heterozygous variant (c.454T>C; p.Trp152Arg) segregated with the disease in a Mexican family with ARS. A novel homozygous variant (c.92_100del; p.Ala31_Ala33del) in the FOXC1 gene segregated in a Pakistani family with ARS and congenital glaucoma. Conclusions Our study expands the mutation spectrum of the PAX6 and FOXC1 genes in individuals with anterior segment dysgenesis disorders. In addition, our study suggests that FOXC1 mutations, besides typical autosomal dominant ARS, can also cause ARS with congenital glaucoma through an autosomal recessive inheritance pattern. Our results thus expand the disease spectrum of FOXC1, and may lead to a better understanding of the role of FOXC1 in development. PMID:27463523

  7. A Novel Homozygous Mutation in FOXC1 Causes Axenfeld Rieger Syndrome with Congenital Glaucoma.

    PubMed

    Micheal, Shazia; Siddiqui, Sorath Noorani; Zafar, Saemah Nuzhat; Villanueva-Mendoza, Cristina; Cortés-González, Vianney; Khan, Muhammad Imran; den Hollander, Anneke I

    2016-01-01

    Anterior segment dysgenesis (ASD) disorders are a group of clinically and genetically heterogeneous phenotypes in which frequently cornea, iris, and lens are affected. This study aimed to identify novel mutations in PAX6, PITX2 and FOXC1 in families with anterior segment dysgenesis disorders. We studied 14 Pakistani and one Mexican family with Axenfeld Rieger syndrome (ARS; n = 10) or aniridia (n = 5). All affected and unaffected family members underwent full ophthalmologic and general examinations. Total genomic DNA was isolated from peripheral blood. PCR and Sanger sequencing were performed for the exons and intron-exon boundaries of the FOXC1, PAX6, and PITX2 genes. Mutations were identified in five of the 15 probands; four variants were novel and one variant was described previously. A novel de novo variant (c.225C>A; p.Tyr75*) was identified in the PAX6 gene in two unrelated probands with aniridia. In addition, a known variant (c.649C>T; p.Arg217*) in PAX6 segregated in a family with aniridia. In the FOXC1 gene, a novel heterozygous variant (c.454T>C; p.Trp152Arg) segregated with the disease in a Mexican family with ARS. A novel homozygous variant (c.92_100del; p.Ala31_Ala33del) in the FOXC1 gene segregated in a Pakistani family with ARS and congenital glaucoma. Our study expands the mutation spectrum of the PAX6 and FOXC1 genes in individuals with anterior segment dysgenesis disorders. In addition, our study suggests that FOXC1 mutations, besides typical autosomal dominant ARS, can also cause ARS with congenital glaucoma through an autosomal recessive inheritance pattern. Our results thus expand the disease spectrum of FOXC1, and may lead to a better understanding of the role of FOXC1 in development.

  8. A novel XPD mutation in a compound heterozygote; the mutation in the second allele is present in three homozygous patients with mild sun sensitivity.

    PubMed

    Falik-Zaccai, Tzipora C; Erel-Segal, Reut; Horev, Liran; Bitterman-Deutsch, Ora; Koka, Sivan; Chaim, Sara; Keren, Zohar; Kalfon, Limor; Gross, Bella; Segal, Zvi; Orgal, Shlomi; Shoval, Yishay; Slor, Hanoch; Spivak, Graciela; Hanawalt, Philip C

    2012-08-01

    The XPD protein plays a pivotal role in basal transcription and in nucleotide excision repair (NER) as one of the ten known components of the transcription factor TFIIH. Mutations in XPD can result in the DNA repair-deficient diseases xeroderma pigmentosum (XP), trichothiodystrophy (TTD), cerebro-oculo-facial-skeletal syndrome, and in combined phenotypes such as XP/Cockayne syndrome and XP/TTD. We describe here an 18-year-old individual with mild sun sensitivity, no neurological abnormalities and no tumors, who carries a p.R683Q mutation in one allele, and the novel p.R616Q mutation in the other allele of the XPD gene. We also describe four patients from one family, homozygous for the identical p.R683Q mutation in XPD, who exhibit mild skin pigmentation and loss of tendon reflexes. Three homozygous patients presented with late-onset skin tumors, and two with features of premature aging and moderate cognitive decline. Cells from the compound heterozygous individual and from one of the patients homozygous for p.R683Q exhibited similar responses to UV irradiation: reduced viability and defective overall removal of UV-induced cyclobutane pyrimidine dimers, implying deficient global genomic NER. Cells from the compound heterozygous subject also failed to recover RNA synthesis after UV, indicating defective transcription-coupled NER. Mutations affecting codon 616 in XPD generally result in functionally null proteins; we hypothesize that the phenotype of the heterozygous patient results solely from expression of the p.R683Q allele. This study illustrates the importance of detailed follow up with sun sensitive individuals, to ensure appropriate prophylaxis and to understand the mechanistic basis of the implicated hereditary disease. Copyright © 2012 Wiley Periodicals, Inc.

  9. Exome Sequencing Identified a Recessive RDH12 Mutation in a Family with Severe Early-Onset Retinitis Pigmentosa

    PubMed Central

    Gong, Bo; Wei, Bo; Huang, Lulin; Hao, Jilong; Li, Xiulan; Yang, Yin; Zhou, Yu; Hao, Fang; Cui, Zhihua; Zhang, Dingding; Wang, Le

    2015-01-01

    Retinitis pigmentosa (RP) is the most important hereditary retinal disease caused by progressive degeneration of the photoreceptor cells. This study is to identify gene mutations responsible for autosomal recessive retinitis pigmentosa (arRP) in a Chinese family using next-generation sequencing technology. A Chinese family with 7 members including two individuals affected with severe early-onset RP was studied. All patients underwent a complete ophthalmic examination. Exome sequencing was performed on a single RP patient (the proband of this family) and direct Sanger sequencing on other family members and normal controls was followed to confirm the causal mutations. A homozygous mutation c.437Tidentified as being related to the phenotype of this arRP family. This homozygous mutation was detected in the two affected patients, but not present in other family members and 600 normal controls. Another three normal members in the family were found to carry this heterozygous missense mutation. Our results emphasize the importance of c.437Tmutation in the pathogenesis and clinical diagnosis of RP. PMID:26124963

  10. A homozygous missense mutation in human KLOTHO causes severe tumoral calcinosis

    PubMed Central

    Ichikawa, Shoji; Imel, Erik A.; Kreiter, Mary L.; Yu, Xijie; Mackenzie, Donald S.; Sorenson, Andrea H.; Goetz, Regina; Mohammadi, Moosa; White, Kenneth E.; Econs, Michael J.

    2007-01-01

    Familial tumoral calcinosis is characterized by ectopic calcifications and hyperphosphatemia due to inactivating mutations in FGF23 or UDP-N-acetyl-α-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase 3 (GALNT3). Herein we report a homozygous missense mutation (H193R) in the KLOTHO (KL) gene of a 13-year-old girl who presented with severe tumoral calcinosis with dural and carotid artery calcifications. This patient exhibited defects in mineral ion homeostasis with marked hyperphosphatemia and hypercalcemia as well as elevated serum levels of parathyroid hormone and FGF23. Mapping of H193R mutation onto the crystal structure of myrosinase, a plant homolog of KL, revealed that this histidine residue was at the base of the deep catalytic cleft and mutation of this histidine to arginine should destabilize the putative glycosidase domain (KL1) of KL, thereby attenuating production of membrane-bound and secreted KL. Indeed, compared with wild-type KL, expression and secretion of H193R KL were markedly reduced in vitro, resulting in diminished ability of FGF23 to signal via its cognate FGF receptors. Taken together, our findings provide what we believe to be the first evidence that loss-of-function mutations in human KL impair FGF23 bioactivity, underscoring the essential role of KL in FGF23-mediated phosphate and vitamin D homeostasis in humans. PMID:17710231

  11. A homozygous CARD9 mutation in a family with susceptibility to fungal infections.

    PubMed

    Glocker, Erik-Oliver; Hennigs, Andre; Nabavi, Mohammad; Schäffer, Alejandro A; Woellner, Cristina; Salzer, Ulrich; Pfeifer, Dietmar; Veelken, Hendrik; Warnatz, Klaus; Tahami, Fariba; Jamal, Sarah; Manguiat, Annabelle; Rezaei, Nima; Amirzargar, Ali Akbar; Plebani, Alessandro; Hannesschläger, Nicole; Gross, Olaf; Ruland, Jürgen; Grimbacher, Bodo

    2009-10-29

    Chronic mucocutaneous candidiasis may be manifested as a primary immunodeficiency characterized by persistent or recurrent infections of the mucosa or the skin with candida species. Most cases are sporadic, but both autosomal dominant inheritance and autosomal recessive inheritance have been described. We performed genetic studies in 36 members of a large, consanguineous five-generation family, in which 4 members had recurrent fungal infections and an additional 3 members died during adolescence, 2 after invasive infection of the brain with candida species. All 36 family members were enrolled in the study, and 22 had blood samples taken for DNA analysis. Homozygosity mapping was used to locate the mutated gene. In the 4 affected family members (patients) and the 18 unaffected members we sequenced CARD9, the gene encoding the caspase recruitment domain-containing protein 9, carried out T-cell phenotyping, and performed functional studies, with the use of either leukocytes from the patients or a reconstituted murine model of the genetic defect. We found linkage (lod score, 3.6) to a genomic interval on chromosome 9q, including CARD9. All four patients had a homozygous point mutation in CARD9, resulting in a premature termination codon (Q295X). Healthy family members had wild-type expression of the CARD9 protein; the four patients lacked wild-type expression, which was associated with low numbers of Th17 cells (helper T cells producing interleukin-17). Functional studies based on genetic reconstitution of myeloid cells from Card9(-/-) mice showed that the Q295X mutation impairs innate signaling from the antifungal pattern-recognition receptor dectin-1. An autosomal recessive form of susceptibility to chronic mucocutaneous candidiasis is associated with homozygous mutations in CARD9. 2009 Massachusetts Medical Society

  12. Increased risk of recurrent thrombosis in patients with essential thrombocythemia carrying the homozygous JAK2 V617F mutation.

    PubMed

    De Stefano, Valerio; Za, Tommaso; Rossi, Elena; Vannucchi, Alessandro M; Ruggeri, Marco; Elli, Elena; Micò, Caterina; Tieghi, Alessia; Cacciola, Rossella R; Santoro, Cristina; Vianelli, Nicola; Guglielmelli, Paola; Pieri, Lisa; Scognamiglio, Francesca; Cacciola, Emma; Rodeghiero, Francesco; Pogliani, Enrico M; Finazzi, Guido; Gugliotta, Luigi; Leone, Giuseppe; Barbui, Tiziano

    2010-02-01

    Evidence suggests that the JAK2 V617F mutation is associated with an increased risk of first thrombosis in patients with essential thrombocythemia (ET). Whether this mutation is also a risk factor for recurrent thrombosis is currently unknown. To investigate the impact of the JAK2 V617F mutation on the risk of recurrent thrombosis in patients with ET, we carried out a multicentre retrospective cohort study. We recruited 143 patients with previous arterial (64.4%) or venous major thrombosis (34.8%) or both (0.8%); 98 of them (68.5%) carried the mutation. Thrombosis recurred in 43 of the patients (30%); overall, after adjustment for sex, age, presence of vascular risk factors, and treatment after the first thrombosis, the presence of the JAK2 mutation did not predict recurrence (multivariable hazard ratio, HR, 0.88, 95% CI 0.46-1.68). Indeed, the individuals homozygous for the JAK2 V617F (allele burden >50%) mutation had an increased risk of recurrence in comparison with wild-type patients (HR 6.15, 95% CI 1.51-24.92). In conclusion, a homozygous JAK2 V617F mutation is an independent risk factor for recurrent thrombosis in patients with ET.

  13. GNE Myopathy in Turkish Sisters with a Novel Homozygous Mutation

    PubMed Central

    Diniz, Gulden; Secil, Yaprak; Ceylaner, Serdar; Tokucoglu, Figen; Türe, Sabiha; Celebisoy, Mehmet; İncesu, Tülay Kurt; Akhan, Galip

    2016-01-01

    Background. Hereditary inclusion body myopathy is caused by biallelic defects in the GNE gene located on chromosome 9p13. It generally affects adults older than 20 years of age. Methods and Results. In this study, we present two Turkish sisters with progressive myopathy and describe a novel mutation in the GNE gene. Both sisters had slightly higher levels of creatine kinase (CK) and muscle weakness. The older sister presented at 38 years of age with an inability to climb steps, weakness, and a steppage gait. Her younger sister was 36 years old and had similar symptoms. The first symptoms of the disorder were seen when the sisters were 30 and 34 years old, respectively. The muscle biopsy showed primary myopathic features and presence of rimmed vacuoles. DNA analysis demonstrated the presence of previously unknown homozygous mutations [c.2152 G>A (p.A718T)] in the GNE genes. Conclusion. Based on our literature survey, we believe that ours is the first confirmed case of primary GNE myopathy with a novel missense mutation in Turkey. These patients illustrate that the muscle biopsy is still an important method for the differential diagnosis of vacuolar myopathies in that the detection of inclusions is required for the definitive diagnosis. PMID:27298745

  14. Homozygous EDNRB mutation in a patient with Waardenburg syndrome type 1.

    PubMed

    Morimoto, Noriko; Mutai, Hideki; Namba, Kazunori; Kaneko, Hiroki; Kosaki, Rika; Matsunaga, Tatsuo

    2018-04-01

    To examine and expand the genetic spectrum of Waardenburg syndrome type 1 (WS1). Clinical features related to Waardenburg syndrome (WS) were examined in a five-year old patient. Mutation analysis of genes related to WS was performed in the proband and her parents. Molecular modeling of EDNRB and the p.R319W mutant was conducted to predict the pathogenicity of the mutation. The proband showed sensorineural hearing loss, heterochromia iridis, and dystopia canthorum, fulfilling the clinical criteria of WS1. Genetic analyses revealed that the proband had no mutation in PAX3 which has been known as the cause of WS1, but had a homozygous missense mutation (p.R319W) in endothelin receptor type B (EDNRB) gene. The asymptomatic parents had the mutation in a heterozygote state. This mutation has been previously reported in a heterozygous state in a patient with Hirschsprung's disease unaccompanied by WS, but the patient and her parents did not show any symptoms in gastrointestinal tract. Molecular modeling of EDNRB with the p.R319W mutation demonstrated reduction of the positively charged surface area in this region, which might reduce binding ability of EDNRB to G protein and lead to abnormal signal transduction underlying the WS phenotype. Our findings suggested that autosomal recessive mutation in EDNRB may underlie a part of WS1 with the current diagnostic criteria, and supported that Hirschsprung's disease is a multifactorial genetic disease which requires additional factors. Further molecular analysis is necessary to elucidate the gene interaction and to reappraise the current WS classification. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. First description of phosphofructokinase deficiency in spain: identification of a novel homozygous missense mutation in the PFKM gene

    PubMed Central

    Vives-Corrons, Joan-Lluis; Koralkova, Pavla; Grau, Josep M.; Mañú Pereira, Maria del Mar; Van Wijk, Richard

    2013-01-01

    Phosphofructokinase deficiency is a very rare autosomal recessive disorder, which belongs to group of rare inborn errors of metabolism called glycogen storage disease. Here we report on a new mutation in the phosphofructokinase (PFK) gene PFKM identified in a 65-years-old woman who suffered from lifelong intermittent muscle weakness and painful spasms of random occurrence, episodic dark urines, and slight haemolytic anemia. After ruling out the most common causes of chronic haemolytic anemia, the study of a panel of 24 enzyme activities showed a markedly decreased PFK activity in red blood cells (RBCs) from the patient. DNA sequence analysis of the PFKM gene subsequently revealed a novel homozygous mutation: c.926A>G; p.Asp309Gly. This mutation is predicted to severely affect enzyme catalysis thereby accounting for the observed enzyme deficiency. This case represents a prime example of classical PFK deficiency and is the first reported case of this very rare red blood cell disorder in Spain. PMID:24427140

  16. Homozygous SLC6A17 Mutations Cause Autosomal-Recessive Intellectual Disability with Progressive Tremor, Speech Impairment, and Behavioral Problems

    PubMed Central

    Iqbal, Zafar; Willemsen, Marjolein H.; Papon, Marie-Amélie; Musante, Luciana; Benevento, Marco; Hu, Hao; Venselaar, Hanka; Wissink-Lindhout, Willemijn M.; Vulto-van Silfhout, Anneke T.; Vissers, Lisenka E.L.M.; de Brouwer, Arjan P.M.; Marouillat, Sylviane; Wienker, Thomas F.; Ropers, Hans Hilger; Kahrizi, Kimia; Nadif Kasri, Nael; Najmabadi, Hossein; Laumonnier, Frédéric; Kleefstra, Tjitske; van Bokhoven, Hans

    2015-01-01

    We report on Dutch and Iranian families with affected individuals who present with moderate to severe intellectual disability and additional phenotypes including progressive tremor, speech impairment, and behavioral problems in certain individuals. A combination of exome sequencing and homozygosity mapping revealed homozygous mutations c.484G>A (p.Gly162Arg) and c.1898C>G (p.Pro633Arg) in SLC6A17. SLC6A17 is predominantly expressed in the brain, encodes a synaptic vesicular transporter of neutral amino acids and glutamate, and plays an important role in the regulation of glutamatergic synapses. Prediction programs and 3D modeling suggest that the identified mutations are deleterious to protein function. To directly test the functional consequences, we investigated the neuronal subcellular localization of overexpressed wild-type and mutant variants in mouse primary hippocampal neuronal cells. Wild-type protein was present in soma, axons, dendrites, and dendritic spines. p.Pro633Arg altered SLC6A17 was found in soma and proximal dendrites but did not reach spines. p.Gly162Arg altered SLC6A17 showed a normal subcellular distribution but was associated with an abnormal neuronal morphology mainly characterized by the loss of dendritic spines. In summary, our genetic findings implicate homozygous SLC6A17 mutations in autosomal-recessive intellectual disability, and their pathogenic role is strengthened by genetic evidence and in silico and in vitro functional analyses. PMID:25704603

  17. Homozygous Loss-of-function Mutations in SOHLH1 in Patients With Nonsyndromic Hypergonadotropic Hypogonadism

    PubMed Central

    Bayram, Yavuz; Gulsuner, Suleyman; Guran, Tulay; Abaci, Ayhan; Yesil, Gozde; Gulsuner, Hilal Unal; Atay, Zeynep; Pierce, Sarah B.; Gambin, Tomasz; Lee, Ming; Turan, Serap; Bober, Ece; Atik, Mehmed M.; Walsh, Tom; Karaca, Ender; Pehlivan, Davut; Jhangiani, Shalini N.; Muzny, Donna; Bereket, Abdullah; Buyukgebiz, Atilla; Boerwinkle, Eric; Gibbs, Richard A.

    2015-01-01

    Context: Hypergonadotropic hypogonadism presents in females with delayed or arrested puberty, primary or secondary amenorrhea due to gonadal dysfunction, and is further characterized by elevated gonadotropins and low sex steroids. Chromosomal aberrations and various specific gene defects can lead to hypergonadotropic hypogonadism. Responsible genes include those with roles in gonadal development or maintenance, sex steroid synthesis, or end-organ resistance to gonadotropins. Identification of novel causative genes in this disorder will contribute to our understanding of the regulation of human reproductive function. Objectives: The aim of this study was to identify and report the gene responsible for autosomal-recessive hypergonadotropic hypogonadism in two unrelated families. Design and Participants: Clinical evaluation and whole-exome sequencing were performed in two pairs of sisters with nonsyndromic hypergonadotropic hypogonadism from two unrelated families. Results: Exome sequencing analysis revealed two different truncating mutations in the same gene: SOHLH1 c.705delT (p.Pro235fs*4) and SOHLH1 c.27C>G (p.Tyr9stop). Both mutations were unique to the families and segregation was consistent with Mendelian expectations for an autosomal-recessive mode of inheritance. Conclusions: Sohlh1 was known from previous mouse studies to be a transcriptional regulator that functions in the maintenance and survival of primordial ovarian follicles, but loss-of-function mutations in human females have not been reported. Our results provide evidence that homozygous-truncating mutations in SOHLH1 cause female nonsyndromic hypergonadotropic hypogonadism. PMID:25774885

  18. Homozygous MYH7 R1820W mutation results in recessive myosin storage myopathy: scapuloperoneal and respiratory weakness with dilated cardiomyopathy.

    PubMed

    Yüceyar, Nur; Ayhan, Özgecan; Karasoy, Hatice; Tolun, Aslıhan

    2015-04-01

    Myosin storage myopathy (MSM) is a protein aggregate myopathy caused by the accumulation of myosin in muscle fibres and results from MYH7 mutation. Although MYH7 mutation is also an established cause of variable cardiomyopathy with or without skeletal myopathy, cardiomyopathy with MSM is a rare combination. Here, we update the clinical findings in the two brothers that we previously reported as having recessively inherited MSM characterized by scapuloperoneal distribution of weakness and typical hyaline-like bodies in type 1 muscle fibres. One of the patients, weak from childhood but not severely symptomatic until 28 years of age, had an unusual combination of MSM, severe dilated cardiomyopathy, and respiratory impairment at the age of 44 years. We identified homozygous missense mutation c.5458C>T (p.R1820W) in exon 37 in these patients as the second recessive MYH7 mutation reported to date. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Identification of a novel homozygous mutation Arg459Pro in SYNJ1 gene of an Indian family with autosomal recessive juvenile Parkinsonism.

    PubMed

    Kirola, Laxmi; Behari, Madhuri; Shishir, Chandan; Thelma, B K

    2016-10-01

    A novel homozygous missense mutation (c.773G > A, p.Arg258Gln) in Synaptojanin 1 (SYNJ1, 21q22.2) has recently been reported in two Italian and one Iranian consanguineous families with autosomal recessive juvenile Parkinsonism (ARJP). Contribution of this synaptic gene related to Parkinsonism phenotypes in other populations still remains unidentified. An ARJP family with two affected siblings characterized by frequent tremor with bradykinesia and rigidity was recruited in this study. Both siblings showed intense dyskinesia and dystonia on administration of Syndopa. The family was analyzed for both mutations and exon dosage variations in PARKIN, PINK1 and DJ1. Further, whole exome sequencing was performed in two affected and one unaffected sibling in the family. We identified a novel homozygous mutation (c.1376C > G, p.Arg459Pro) in SYNJ1 segregating in this family. This p.Arg459Pro mutation was not observed in 285 additional Parkinson disease (PD) samples (32 familial, 81 early onset and 172 late onset) screened by PCR-Sanger-sequencing. It was also absent in dbSNP, 1000 Genomes, ExAC, NHLBI-ESP database and in >250 ethnically matched exomes available in our laboratory. The arginine residue is highly conserved across species and predicted to be damaging by several in silico tools. As with the previous mutation p.Arg258Gln, p.Arg459Pro is also present in Sac 1 domain of SYNJ1 wherein p.Arg258Gln mutation has already been described to impair the phosphatase activity. We report another novel mutation in SYNJ1 of an Indian consanguineous ARJP family. Finding an additional mutation in this gene further supports the involvement of SYNJ1 in PD pathogenesis across different ethnicities. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. A homozygous FANCM mutation underlies a familial case of non-syndromic primary ovarian insufficiency

    PubMed Central

    Caburet, Sandrine; Guigon, Celine; Mäkinen, Marika; Tanner, Laura; Hietala, Marja; Urbanska, Kaja; Bellutti, Laura; Legois, Bérangère; Bessieres, Bettina; Gougeon, Alain; Benachi, Alexandra; Livera, Gabriel; Rosselli, Filippo

    2017-01-01

    Primary Ovarian Insufficiency (POI) affects ~1% of women under forty. Exome sequencing of two Finnish sisters with non-syndromic POI revealed a homozygous mutation in FANCM, leading to a truncated protein (p.Gln1701*). FANCM is a DNA-damage response gene whose heterozygous mutations predispose to breast cancer. Compared to the mother's cells, the patients’ lymphocytes displayed higher levels of basal and mitomycin C (MMC)-induced chromosomal abnormalities. Their lymphoblasts were hypersensitive to MMC and MMC-induced monoubiquitination of FANCD2 was impaired. Genetic complementation of patient's cells with wild-type FANCM improved their resistance to MMC re-establishing FANCD2 monoubiquitination. FANCM was more strongly expressed in human fetal germ cells than in somatic cells. FANCM protein was preferentially expressed along the chromosomes in pachytene cells, which undergo meiotic recombination. This mutation may provoke meiotic defects leading to a depleted follicular stock, as in Fancm-/- mice. Our findings document the first Mendelian phenotype due to a biallelic FANCM mutation. PMID:29231814

  1. Adult siblings with homozygous G6PC3 mutations expand our understanding of the severe congenital neutropenia type 4 (SCN4) phenotype.

    PubMed

    Fernandez, Bridget A; Green, Jane S; Bursey, Ford; Barrett, Brendan; MacMillan, Andrée; McColl, Sarah; Fernandez, Sara; Rahman, Proton; Mahoney, Krista; Pereira, Sergio L; Scherer, Stephen W; Boycott, Kym M; Woods, Michael O

    2012-11-21

    Severe congenital neutropenia type 4 (SCN4) is an autosomal recessive disorder caused by mutations in the third subunit of the enzyme glucose-6-phosphatase (G6PC3). Its core features are congenital neutropenia and a prominent venous skin pattern, and affected individuals have variable birth defects. Oculocutaneous albinism type 4 (OCA4) is caused by autosomal recessive mutations in SLC45A2. We report a sister and brother from Newfoundland, Canada with complex phenotypes. The sister was previously reported by Cullinane et al., 2011. We performed homozygosity mapping, next generation sequencing and conventional Sanger sequencing to identify mutations that cause the phenotype in this family. We have also summarized clinical data from 49 previously reported SCN4 cases with overlapping phenotypes and interpret the medical histories of these siblings in the context of the literature. The siblings' phenotype is due in part to a homozygous mutation in G6PC3, [c.829C > T, p.Gln277X]. Their ages are 38 and 37 years respectively and they are the oldest SCN4 patients published to date. Both presented with congenital neutropenia and later developed Crohn disease. We suggest that the latter is a previously unrecognized SCN4 manifestation and that not all affected individuals have an intellectual disability. The sister also has a homozygous mutation in SLC45A2, which explains her severe oculocutaneous hypopigmentation. Her brother carried one SLC45A2 mutation and was diagnosed with "partial OCA" in childhood. This family highlights that apparently novel syndromes can in fact be caused by two known autosomal recessive disorders.

  2. Novel homozygous FANCL mutation and somatic heterozygous SETBP1 mutation in a Chinese girl with Fanconi Anemia.

    PubMed

    Wu, Weiqing; Liu, Yang; Zhou, Qinghua; Wang, Qin; Luo, Fuwei; Xu, Zhiyong; Geng, Qian; Li, Peining; Zhang, Hui Z; Xie, Jiansheng

    2017-07-01

    Fanconi Anemia (FA) is a rare genetically heterogeneous disorder with 17 known complement groups caused by mutations in different genes. FA complementation group L (FA-L, OMIM #608111) occurred in 0.2% of all FA and only eight mutant variants in the FANCL gene were documented. Phenotype and genotype correlation in FANCL associated FA is still obscure. Here we describe a Chinese girl with FA-L caused by a novel homozygous mutation c.822_823insCTTTCAGG (p.Asp275LeufsX13) in the FANCL gene. The patient's clinical course was typical for FA with progression to bone marrow failure, and death from acute myelomonocytic leukemia (AML-M4) at 9 years of age. Mutation analysis also detected a likely somatic c.2608G > A (p.Gly870Ser) in the SETBP1 gene. Consistent copy number losses of 7q and 18p and gains of 3q and 21q and accumulated non-clonal single cell chromosomal abnormalities were detected in blood leukocytes as her FA progressed. This is the first Chinese FA-L case caused by a novel FANCL mutation. The somatic gene mutation and copy number aberrations could be used to monitor disease progression and the clinical findings provide further information for genotype-phenotype correlation for FA-L. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  3. Homozygous SLC6A17 mutations cause autosomal-recessive intellectual disability with progressive tremor, speech impairment, and behavioral problems.

    PubMed

    Iqbal, Zafar; Willemsen, Marjolein H; Papon, Marie-Amélie; Musante, Luciana; Benevento, Marco; Hu, Hao; Venselaar, Hanka; Wissink-Lindhout, Willemijn M; Vulto-van Silfhout, Anneke T; Vissers, Lisenka E L M; de Brouwer, Arjan P M; Marouillat, Sylviane; Wienker, Thomas F; Ropers, Hans Hilger; Kahrizi, Kimia; Nadif Kasri, Nael; Najmabadi, Hossein; Laumonnier, Frédéric; Kleefstra, Tjitske; van Bokhoven, Hans

    2015-03-05

    We report on Dutch and Iranian families with affected individuals who present with moderate to severe intellectual disability and additional phenotypes including progressive tremor, speech impairment, and behavioral problems in certain individuals. A combination of exome sequencing and homozygosity mapping revealed homozygous mutations c.484G>A (p.Gly162Arg) and c.1898C>G (p.Pro633Arg) in SLC6A17. SLC6A17 is predominantly expressed in the brain, encodes a synaptic vesicular transporter of neutral amino acids and glutamate, and plays an important role in the regulation of glutamatergic synapses. Prediction programs and 3D modeling suggest that the identified mutations are deleterious to protein function. To directly test the functional consequences, we investigated the neuronal subcellular localization of overexpressed wild-type and mutant variants in mouse primary hippocampal neuronal cells. Wild-type protein was present in soma, axons, dendrites, and dendritic spines. p.Pro633Arg altered SLC6A17 was found in soma and proximal dendrites but did not reach spines. p.Gly162Arg altered SLC6A17 showed a normal subcellular distribution but was associated with an abnormal neuronal morphology mainly characterized by the loss of dendritic spines. In summary, our genetic findings implicate homozygous SLC6A17 mutations in autosomal-recessive intellectual disability, and their pathogenic role is strengthened by genetic evidence and in silico and in vitro functional analyses. Copyright © 2015 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  4. A homozygous PMS2 founder mutation with an attenuated constitutional mismatch repair deficiency phenotype.

    PubMed

    Li, Lili; Hamel, Nancy; Baker, Kristi; McGuffin, Michael J; Couillard, Martin; Gologan, Adrian; Marcus, Victoria A; Chodirker, Bernard; Chudley, Albert; Stefanovici, Camelia; Durandy, Anne; Hegele, Robert A; Feng, Bing-Jian; Goldgar, David E; Zhu, Jun; De Rosa, Marina; Gruber, Stephen B; Wimmer, Katharina; Young, Barbara; Chong, George; Tischkowitz, Marc D; Foulkes, William D

    2015-05-01

    Inherited mutations in DNA mismatch repair genes predispose to different cancer syndromes depending on whether they are mono-allelic or bi-allelic. This supports a causal relationship between expression level in the germline and phenotype variation. As a model to study this relationship, our study aimed to define the pathogenic characteristics of a recurrent homozygous coding variant in PMS2 displaying an attenuated phenotype identified by clinical genetic testing in seven Inuit families from Northern Quebec. Pathogenic characteristics of the PMS2 mutation NM_000535.5:c.2002A>G were studied using genotype-phenotype correlation, single-molecule expression detection and single genome microsatellite instability analysis. This PMS2 mutation generates a de novo splice site that competes with the authentic site. In homozygotes, expression of the full-length protein is reduced to a level barely detectable by conventional diagnostics. Median age at primary cancer diagnosis is 22 years among 13 NM_000535.5:c.2002A>G homozygotes, versus 8 years in individuals carrying bi-allelic truncating mutations. Residual expression of full-length PMS2 transcript was detected in normal tissues from homozygotes with cancers in their 20s. Our genotype-phenotype study of c.2002A>G illustrates that an extremely low level of PMS2 expression likely delays cancer onset, a feature that could be exploited in cancer preventive intervention. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  5. Homozygous/Compound Heterozygous Triadin Mutations Associated With Autosomal-Recessive Long-QT Syndrome and Pediatric Sudden Cardiac Arrest: Elucidation of the Triadin Knockout Syndrome.

    PubMed

    Altmann, Helene M; Tester, David J; Will, Melissa L; Middha, Sumit; Evans, Jared M; Eckloff, Bruce W; Ackerman, Michael J

    2015-06-09

    Long-QT syndrome (LQTS) may result in syncope, seizures, or sudden cardiac arrest. Although 16 LQTS-susceptibility genes have been discovered, 20% to 25% of LQTS remains genetically elusive. We performed whole-exome sequencing child-parent trio analysis followed by recessive and sporadic inheritance modeling and disease-network candidate analysis gene ranking to identify a novel underlying genetic mechanism for LQTS. Subsequent mutational analysis of the candidate gene was performed with polymerase chain reaction, denaturing high-performance liquid chromatography, and DNA sequencing on a cohort of 33 additional unrelated patients with genetically elusive LQTS. After whole-exome sequencing and variant filtration, a homozygous p.D18fs*13 TRDN-encoded triadin frameshift mutation was discovered in a 10-year-old female patient with LQTS with a QTc of 500 milliseconds who experienced recurrent exertion-induced syncope/cardiac arrest beginning at 1 year of age. Subsequent mutational analysis of TRDN revealed either homozygous or compound heterozygous frameshift mutations in 4 of 33 unrelated cases of LQTS (12%). All 5 TRDN-null patients displayed extensive T-wave inversions in precordial leads V1 through V4, with either persistent or transient QT prolongation and severe disease expression of exercise-induced cardiac arrest in early childhood (≤3 years of age) and required aggressive therapy. The overall yield of TRDN mutations was significantly greater in patients ≤10 years of age (5 of 10, 50%) compared with older patients (0 of 24, 0%; P=0.0009). We identified TRDN as a novel underlying genetic basis for recessively inherited LQTS. All TRDN-null patients had strikingly similar phenotypes. Given the recurrent nature of potential lethal arrhythmias, patients fitting this phenotypic profile should undergo cardiac TRDN genetic testing. © 2015 American Heart Association, Inc.

  6. Identification and molecular characterisation of a homozygous missense mutation in the ADAMTS10 gene in a patient with Weill-Marchesani syndrome.

    PubMed

    Steinkellner, Hannes; Etzler, Julia; Gogoll, Laura; Neesen, Jürgen; Stifter, Eva; Brandau, Oliver; Laccone, Franco

    2015-09-01

    Weill-Marchesani syndrome is a rare disorder of the connective tissue. Functional variants in ADAMTS10 are associated with Weill-Marchesani syndrome-1. We identified a homozygous missense mutation, c.41T>A, of the ADAMTS10 gene in a 19-year-old female with typical symptoms of WMS1: proportionate short stature, brachydactyly, joint stiffness, and microspherophakia. The ADAMTS10 missense mutation was analysed in silico, with conflicting results as to its effects on protein function, but it was predicted to affect the leader sequence. Molecular characterisation in HEK293 Ebna cells revealed an intracellular mis-targeting of the ADAMTS10 protein with a reduced concentration of the polypeptide in the endoplasmic reticulum. A large reduction in glycosylation of the cytoplasmic fraction of the mutant ADAMTS10 protein versus the wild-type protein and a lack of secretion of the mutant protein are also evident in our results.In conclusion, we identified a novel missense mutation of the ADAMTS10 gene and confirmed the functional consequences suggested by the in silico analysis by conducting molecular studies.

  7. Phenotypic Variation in Patients with Homozygous c.1678G>T Mutation in EVC Gene: Report of Two Mexican Families with Ellis-van Creveld Syndrome

    PubMed Central

    Ibarra-Ramirez, Marisol; Campos-Acevedo, Luis Daniel; Lugo-Trampe, Jose; Martínez-Garza, Laura E.; Martinez-Glez, Víctor; Valencia-Benitez, María; Lapunzina, Pablo; Ruiz-Peréz, Víctor

    2017-01-01

    Case series Patient: — Final Diagnosis: Ellis van Creveld syndrome Symptoms: Conical teeth • polydactyly • short stature Medication: — Clinical Procedure: — Specialty: Pediatrics and Neonatology Objective: Rare disease Background: Ellis-van Creveld syndrome is an autosomal recessive chondro-ectodermal dysplasia characterized by disproportionate short stature, limb shortening, narrow chest, postaxial polydactyly and dysplastic nails and teeth. In addition, 60% of cases present congenital heart defects. Ellis-van Creveld syndrome is predominantly caused by mutations in the EVC or EVC2 (4p16) genes, with only a few cases caused by mutations in WDR35. Case Report: Here, we report on two Mexican families with patients diagnosed with Ellis-van Creveld syndrome. Family 1 includes four patients: three females of 15, 18, and 23 years of age and a 7-year old male. Family 2 has only one affected newborn male. All patients exhibited multiple features including hypodontia, dysplastic teeth, extra frenula, mild short stature, distal limb shortening, postaxial polydactyly of hands and feet, nail dystrophy, and knee joint abnormalities. Only two patients had an atrial septal defect. In all cases, molecular analysis by Sanger sequencing identified the same homozygous mutation in exon 12 of EVC, c.1678G>T, which leads to a premature stop codon. Conclusions: The mutation c.1678G>T has been previously reported in another Mexican patient and it appears to be a recurrent mutation in Mexico which could represent a founder mutation. The large number of patients in this case allows the clinical variability and spectrum of manifestations present in individuals with Ellis-van Creveld syndrome even if they carry the same homozygous mutation in a same family. PMID:29229899

  8. Plasma lipoprotein(a) levels in patients with homozygous autosomal dominant hypercholesterolemia.

    PubMed

    Sjouke, Barbara; Yahya, Reyhana; Tanck, Michael W T; Defesche, Joep C; de Graaf, Jacqueline; Wiegman, Albert; Kastelein, John J P; Mulder, Monique T; Hovingh, G Kees; Roeters van Lennep, Jeanine E

    Patients with autosomal dominant hypercholesterolemia (ADH), caused by mutations in either low-density lipoprotein receptor (LDLR), apolipoprotein B (APOB), or proprotein convertase subtilisin-kexin type 9 (PCSK9) are characterized by high low-density lipoprotein cholesterol levels and in some studies also high lipoprotein(a) (Lp(a)) levels were observed. The question remains whether this effect on Lp(a) levels is gene-dose-dependent in individuals with either 0, 1, or 2 LDLR or APOB mutations. We set out to study whether Lp(a) levels differ among bi-allelic ADH mutation carriers, and their relatives, in the Netherlands. Bi-allelic ADH mutation carriers were identified in the database of the national referral laboratory for DNA diagnostics of inherited dyslipidemias. Family members were invited by the index cases to participate. Clinical parameters and Lp(a) levels were measured in bi-allelic ADH mutation carriers and their heterozygous and unaffected relatives. We included a total of 119 individuals; 34 bi-allelic ADH mutation carriers (20 homozygous/compound heterozygous LDLR mutation carriers (HoFH), 2 homozygous APOB mutation carriers (HoFDB), and 12 double heterozygotes for an LDLR and APOB mutation), 63 mono-allelic ADH mutation carriers (50 heterozygous LDLR [HeFH], 13 heterozygous APOB [HeFDB] mutation carriers), and 22 unaffected family members. Median Lp(a) levels in unaffected relatives, HeFH, and HoFH patients were 19.9 (11.1-41.5), 24.4 (5.9-70.6), and 47.3 (14.9-111.7) mg/dL, respectively (P = .150 for gene-dose dependency). Median Lp(a) levels in HeFDB and HoFDB patients were 50.3 (18.7-120.9) and 205.5 (no interquartile range calculated), respectively (P = .012 for gene-dose-dependency). Double heterozygous carriers of LDLR and APOB mutations had median Lp(a) levels of 27.0 (23.5-45.0), which did not significantly differ from HoFH and HoFDB patients (P = .730 and .340, respectively). A (trend toward) increased plasma Lp(a) levels in homozygous

  9. Homozygous HAX1 mutations in severe congenital neutropenia patients with sporadic disease: a novel mutation in two unrelated British kindreds.

    PubMed

    Smith, Bradley N; Ancliff, Phil J; Pizzey, Arnold; Khwaja, Asim; Linch, David C; Gale, Rosemary E

    2009-03-01

    Patients with autosomal dominant (AD), sporadic and X-linked severe congenital neutropenia (SCN) may have mutations in the elastase 2 (ELA2) or Wiskott-Aldrich syndrome (WAS) genes. Homozygous mutations in the HAX1 gene have recently been reported in autosomal recessive (AR) cases of primarily Middle-Eastern descent and the original Kostmann family. We screened 109 predominantly Caucasian SCN kindreds for mutations in these genes; 33 (30%) had 24 different ELA2 mutations, five of them novel, two kindreds (2%) had WAS mutations and four kindreds (4%) had three different HAX1 mutations, two of them novel. One HAX1 mutation (p.Ser43LeufsX11) was found in an AR Ashkenazi Jewish kindred, the other (p.Glu31LysfsX54) in two unrelated British patients with sporadic disease. Microsatellite analysis of the HAX1 locus revealed a common haplotype (maximum distance 4.1 Megabases) for the p.Glu31LysfsX54 patients, suggesting a possible ancestral founder. In functional assays, the level of spontaneous and staurosporine-induced apoptosis was increased in neutrophils from both p.Ser43LeufsX11 patients but not a p.Glu31LysfsX54 patient, suggesting the possible presence of modifying factors. The low incidence of HAX1 mutations in our study suggests that the frequency may vary between racial groups but suggests that irrespective of inheritance or racial origin, SCN patients should be screened for HAX1 mutations.

  10. Permanent neonatal diabetes caused by a homozygous nonsense mutation in the glucokinase gene.

    PubMed

    Rubio-Cabezas, O; Díaz González, F; Aragonés, A; Argente, J; Campos-Barros, A

    2008-06-01

    Glucokinase deficiency is an unfrequent cause of permanent neonatal diabetes (PND), as only seven patients have been reported, either homozygous for a missense or frameshift mutation or compound heterozygous for both of them. We report here the first known case caused by a homozygous nonsense mutation (Y61X) in the glucokinase gene (GCK) that introduces a premature stop codon, generating a truncated protein that is predicted to be completely inactive as it lacks both the glucose- and the adenosine triphosphate-binding sites. The proband, born to consanguineous parents, was a full-term, intra-uterine growth-retarded male newborn who presented with a glycaemia of 129 mg/dL (7.16 mmol/L) on his second day of life, increasing thereafter up to 288 mg/dL (15.98 mmol/L) and 530 mg/dL (29.41 mmol/L) over the next 24 h, in the face of low serum insulin (<3 muIU/mL; <20.83 pmol/L). He was put on insulin on the third day of life. Insulin has never been discontinued since then. The patient was tested negative for anti-insulin and islet cell antibodies at age 5 months. His father had non-progressive, impaired fasting glucose for several years. The mother was found to be mildly hyperglycaemic only when her glucose was checked after the child was diagnosed. In conclusion, biallelic GCK loss should be considered as a potential cause of PND in children born to consanguineous parents, even if they are not known to be diabetic at the time of PND presentation.

  11. Primary Ciliary Dyskinesia Caused by Homozygous Mutation in DNAL1, Encoding Dynein Light Chain 1

    PubMed Central

    Mazor, Masha; Alkrinawi, Soliman; Chalifa-Caspi, Vered; Manor, Esther; Sheffield, Val C.; Aviram, Micha; Parvari, Ruti

    2011-01-01

    In primary ciliary dyskinesia (PCD), genetic defects affecting motility of cilia and flagella cause chronic destructive airway disease, randomization of left-right body asymmetry, and, frequently, male infertility. The most frequent defects involve outer and inner dynein arms (ODAs and IDAs) that are large multiprotein complexes responsible for cilia-beat generation and regulation, respectively. Although it has long been suspected that mutations in DNAL1 encoding the ODA light chain1 might cause PCD such mutations were not found. We demonstrate here that a homozygous point mutation in this gene is associated with PCD with absent or markedly shortened ODA. The mutation (NM_031427.3: c.449A>G; p.Asn150Ser) changes the Asn at position150, which is critical for the proper tight turn between the β strand and the α helix of the leucine-rich repeat in the hydrophobic face that connects to the dynein heavy chain. The mutation reduces the stability of the axonemal dynein light chain 1 and damages its interactions with dynein heavy chain and with tubulin. This study adds another important component to understanding the types of mutations that cause PCD and provides clinical information regarding a specific mutation in a gene not yet known to be associated with PCD. PMID:21496787

  12. A homozygous mutation in the stem II domain of RNU4ATAC causes typical Roifman syndrome.

    PubMed

    Dinur Schejter, Yael; Ovadia, Adi; Alexandrova, Roumiana; Thiruvahindrapuram, Bhooma; Pereira, Sergio L; Manson, David E; Vincent, Ajoy; Merico, Daniele; Roifman, Chaim M

    2017-01-01

    Roifman syndrome (OMIM# 616651) is a complex syndrome encompassing skeletal dysplasia, immunodeficiency, retinal dystrophy and developmental delay, and is caused by compound heterozygous mutations involving the Stem II region and one of the other domains of the RNU4ATAC gene. This small nuclear RNA gene is essential for minor intron splicing. The Canadian Centre for Primary Immunodeficiency Registry and Repository were used to derive patient information as well as tissues. Utilising RNA sequencing methodologies, we analysed samples from patients with Roifman syndrome and assessed intron retention. We demonstrate that a homozygous mutation in Stem II is sufficient to cause the full spectrum of features associated with typical Roifman syndrome. Further, we demonstrate the same pattern of aberration in minor intron retention as found in cases with compound heterozygous mutations.

  13. CRISPR Correction of a Homozygous Low-Density Lipoprotein Receptor Mutation in Familial Hypercholesterolemia Induced Pluripotent Stem Cells.

    PubMed

    Omer, Linda; Hudson, Elizabeth A; Zheng, Shirong; Hoying, James B; Shan, Yuan; Boyd, Nolan L

    2017-11-01

    Familial hypercholesterolemia (FH) is a hereditary disease primarily due to mutations in the low-density lipoprotein receptor (LDLR) that lead to elevated cholesterol and premature development of cardiovascular disease. Homozygous FH patients (HoFH) with two dysfunctional LDLR alleles are not as successfully treated with standard hypercholesterol therapies, and more aggressive therapeutic approaches to control cholesterol levels must be considered. Liver transplant can resolve HoFH, and hepatocyte transplantation has shown promising results in animals and humans. However, demand for donated livers and high-quality hepatocytes overwhelm the supply. Human pluripotent stem cells can differentiate to hepatocyte-like cells (HLCs) with the potential for experimental and clinical use. To be of future clinical use as autologous cells, LDLR genetic mutations in derived FH-HLCs need to be corrected. Genome editing technology clustered-regularly-interspaced-short-palindromic-repeats/CRISPR-associated 9 (CRISPR/Cas9) can repair pathologic genetic mutations in human induced pluripotent stem cells. We used CRISPR/Cas9 genome editing to permanently correct a 3-base pair homozygous deletion in LDLR exon 4 of patient-derived HoFH induced pluripotent stem cells. The genetic correction restored LDLR-mediated endocytosis in FH-HLCs and demonstrates the proof-of-principle that CRISPR-mediated genetic modification can be successfully used to normalize HoFH cholesterol metabolism deficiency at the cellular level.

  14. Association of a homozygous nonsense mutation in the ABCA4 (ABCR) gene with cone-rod dystrophy phenotype in an Italian family.

    PubMed

    Simonelli, Francesca; Testa, Francesco; Zernant, Jana; Nesti, Anna; Rossi, Settimio; Rinaldi, Ernesto; Allikmets, Rando

    2004-01-01

    Genetic variation in the ABCA4 (ABCR) gene has been associated with several distinct retinal phenotypes, including Stargardt disease/fundus flavimaculatus (STGD/FFM), cone-rod dystrophy (CRD), retinitis pigmentosa (RP) and age-related macular degeneration. The current model of genotype/phenotype association suggests that patients harboring deleterious mutations in both ABCR alleles would develop RP-like retinal pathology. Here we describe ABCA4-associated phenotypes, including a proband with a homozygous nonsense mutation in a family from Southern Italy. The proband had been originally diagnosed with STGD. Ophthalmologic examination included kinetic perimetry, electrophysiological studies and fluorescein angiography. DNA of the affected individual and family members was analyzed for variants in all 50 exons of the ABCA4 gene by screening on the ABCR400 microarray. A homozygous nonsense mutation 2971G>T (G991X) was detected in a patient initially diagnosed with STGD based on funduscopic evidence, including bull's eye depigmentation of the fovea and flecks at the posterior pole extending to the mid-peripheral retina. Since this novel nucleotide substitution results in a truncated, nonfunctional, ABCA4 protein, the patient was examined in-depth for the severity of the disease phenotype. Indeed, subsequent electrophysiological studies determined severely reduced cone amplitude as compared to the rod amplitude, suggesting the diagnosis of CRD. ABCR400 microarray is an efficient tool for determining causal genetic variation, including new mutations. A homozygous protein-truncating mutation in ABCA4 can cause a phenotype ranging from STGD to CRD as diagnosed at an early stage of the disease. Only a combination of comprehensive genotype/phenotype correlation studies will determine the proper diagnosis and prognosis of ABCA4-associated pathology. Copyright 2004 S. Karger AG, Basel

  15. Normosmic idiopathic hypogonadotropic hypogonadism due to a novel homozygous nonsense c.C969A (p.Y323X) mutation in the KISS1R gene in three unrelated families.

    PubMed

    Demirbilek, Huseyin; Ozbek, M Nuri; Demir, Korcan; Kotan, L Damla; Cesur, Yasar; Dogan, Murat; Temiz, Fatih; Mengen, Eda; Gurbuz, Fatih; Yuksel, Bilgin; Topaloglu, A Kemal

    2015-03-01

    The spectrum of genetic alterations in cases of hypogonadotropic hypogonadism continue to expand. However, KISS1R mutations remain rare. The aim of this study was to understand the molecular basis of normosmic idiopathic hypogonadotropic hypogonadism. Clinical characteristics, hormonal studies and genetic analyses of seven cases with idiopathic normosmic hypogonadotropic hypogonadism (nIHH) from three unrelated consanguineous families are presented. One male presented with absence of pubertal onset and required surgery for severe penoscrotal hypospadias and cryptorchidism, while other two males had absence of pubertal onset. Two of four female cases required replacement therapy for pubertal onset and maintenance, whereas the other two had spontaneous pubertal onset but incomplete maturation. In sequence analysis, we identified a novel homozygous nonsense (p.Y323X) mutation (c.C969A) in the last exon of the KISS1R gene in all clinically affected cases. We identified a homozygous nonsense mutation in the KISS1R gene in three unrelated families with nIHH, which enabled us to observe the phenotypic consequences of this rare condition. Escape from nonsense-mediated decay, and thus production of abnormal proteins, may account for the variable severity of the phenotype. Although KISS1R mutations are extremely rare and can cause a heterogeneous phenotype, analysis of the KISS1R gene should be a part of genetic analysis of patients with nIHH, to allow better understanding of phenotype-genotype relationship of KISS1R mutations and the underlying genetic basis of patients with nIHH. © 2014 John Wiley & Sons Ltd.

  16. Variable presentation of primary hyperoxaluria type 1 in 2 patients homozygous for a novel combined deletion and insertion mutation in exon 8 of the AGXT gene.

    PubMed

    von Schnakenburg, C; Hulton, S A; Milford, D V; Roper, H P; Rumsby, G

    1998-01-01

    Two unrelated patients of Pakistani origin presented with primary hyperoxaluria type 1 (PH1) at 4 months and 3 years of age, respectively. While the younger patient failed to thrive and suffered from early renal failure, the older one showed a relatively benign history with urolithiasis as the main feature of the disease. In both patients the diagnosis was confirmed by assessment of alanine:glyoxylate aminotransferase catalytic and immunoreactivity in liver biopsy specimens. The underlying genetic defect was found to be a combined deletion and insertion in exon 8 which alters the reading frame of the protein. The nucleotide change introduces a Stu1 restriction site which facilitated typing of additional family members. Both patients and a further affected brother were homozygous for this mutation, while their parents were heterozygous for it. This mutation is the first deletion/insertion identified in PH1. Although rare in our PH1 patient cohort (2.5% of alleles), the finding of 2 homozygous apparently unrelated individuals of the same ethnic origin suggests that it may prove worthwhile to screen other Asian patients for this mutation. These PH1 cases present further evidence that factors other than genotype contribute significantly to the clinical presentation and severity of PH1.

  17. A homozygous NOP14 variant is likely to cause recurrent pregnancy loss.

    PubMed

    Suzuki, Toshifumi; Behnam, Mahdiyeh; Ronasian, Firooze; Salehi, Mansoor; Shiina, Masaaki; Koshimizu, Eriko; Fujita, Atsushi; Sekiguchi, Futoshi; Miyatake, Satoko; Mizuguchi, Takeshi; Nakashima, Mitsuko; Ogata, Kazuhiro; Takeda, Satoru; Matsumoto, Naomichi; Miyake, Noriko

    2018-04-01

    Recurrent pregnancy loss is newly defined as more than two consecutive miscarriages. Recurrent pregnancy loss occurs in <5% of total pregnancies. The cause in approximately 40-60% of recurrent pregnancy loss cases remains elusive and must be determined. We investigated two unrelated Iranian consanguineous families with recurrent pregnancy loss. We performed exome sequencing using DNA from a miscarriage tissue and identified a homozygous NOP14 missense variant (c.[136C>G];[136C>G]) in both families. NOP14 is an evolutionally conserved protein among eukaryotes and is required for 18S rRNA processing and 40S ribosome biogenesis. Interestingly, in zebrafish, homozygous mutation of nop14 (possibly loss of function) resulting from retrovirus-mediated insertional mutagenesis led to embryonic lethality at 5 days after fertilization, mimicking early pregnancy loss in humans. Similarly, it is known that the nop14-null yeast is inviable. These data suggest that the homozygous NOP14 mutation is likely to cause recurrent pregnancy loss. Furthermore, this study shows that exome sequencing is very useful to determine the etiology of unsolved recurrent pregnancy loss.

  18. Primary ciliary dyskinesia caused by homozygous mutation in DNAL1, encoding dynein light chain 1.

    PubMed

    Mazor, Masha; Alkrinawi, Soliman; Chalifa-Caspi, Vered; Manor, Esther; Sheffield, Val C; Aviram, Micha; Parvari, Ruti

    2011-05-13

    In primary ciliary dyskinesia (PCD), genetic defects affecting motility of cilia and flagella cause chronic destructive airway disease, randomization of left-right body asymmetry, and, frequently, male infertility. The most frequent defects involve outer and inner dynein arms (ODAs and IDAs) that are large multiprotein complexes responsible for cilia-beat generation and regulation, respectively. Although it has long been suspected that mutations in DNAL1 encoding the ODA light chain1 might cause PCD such mutations were not found. We demonstrate here that a homozygous point mutation in this gene is associated with PCD with absent or markedly shortened ODA. The mutation (NM_031427.3: c.449A>G; p.Asn150Ser) changes the Asn at position150, which is critical for the proper tight turn between the β strand and the α helix of the leucine-rich repeat in the hydrophobic face that connects to the dynein heavy chain. The mutation reduces the stability of the axonemal dynein light chain 1 and damages its interactions with dynein heavy chain and with tubulin. This study adds another important component to understanding the types of mutations that cause PCD and provides clinical information regarding a specific mutation in a gene not yet known to be associated with PCD. Copyright © 2011 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  19. Other autoinflammatory disease genes in an FMF-prevalent population: a homozygous MVK mutation and a novel heterozygous TNFRSF1A mutation in two different Turkish families with clinical FMF.

    PubMed

    Karacan, İlker; Uğurlu, Serdal; Tolun, Aslıhan; Tahir Turanlı, Eda; Ozdogan, Huri

    2017-01-01

    No MEFV mutations are detected in approximately 10% of the patients with clinical FMF in populations where the disease is highly prevalent. Causative mutations were searched in other genes in two such families with "MEFV negative clinical FMF". Father and daughter of family A had attacks of fever, abdominal pain and AA amyloidosis. The two sibs of family B complained of febrile episodes with abdominal pain and arthritis. The patients were clinically investigated. Exome analysis in the daughter in family A and linkage analysis and candidate gene sequencing for the members of family B were performed. All patients were re-evaluated in the light of the genetic findings. In the daughter in family A, filtering of the exome file for variants in 25 autoimmune/inflammatory disease-related genes revealed two heterozygous missense variants in TNFRSF1A, novel p.Cys72Phe and frequent p.Arg121Gln. In family B, novel, homozygous missense p.Cys161Arg in MVK was identified. A clinical re-evaluation of the patients revealed a phenotype consistent with FMF rather than TRAPS in family A and an overlap of FMF with HIDS in family B. In high risk populations of FMF a proportion of patients without MEFV mutations may carry causative mutations in other genes, and the clinical findings may not be fully consistent with the phenotype expected of the mutation identified but rather resemble FMF or an overlap syndrome.

  20. Furosemide loading test in a case of homozygous solute carrier family 12, member 1 (SLC12A1) mutation (g.62382825G>A, p.Pro372Leu) in Japanese Black cattle.

    PubMed

    Hasegawa, Kiyotoshi; Sasaki, Shinji; Sakamoto, Yoichi; Takano, Akifumi; Takayama, Megumi; Higashi, Tomoko; Sugimoto, Yoshikazu; Yasuda, Yasuaki

    2017-10-01

    Hydrallantois is the excessive accumulation of fluid in the allantoic cavity in a pregnant animal and is associated with fetal death. We recently identified a recessive missense mutation in the solute carrier family 12, member 1 (SLC12A1) gene (g.62382825G>A, p.Pro372Leu) that is associated with hydrallantois in Japanese Black cattle. Unexpectedly, we found a case of the homozygous risk-allele for SLC12A1 in a calf, using a PCR-based direct DNA sequencing test. The homozygote was outwardly healthy up to 3 months of age and the mother did not exhibit any clinical symptoms of hydrallantois. In order to validate these observations, we performed confirmation tests for the genotype and a diuretic loading test using furosemide, which inhibits the transporter activity of the SLC12A1 protein. The results showed that the calf was really homozygous for the risk-allele. In the homozygous calf, administration of furosemide did not alter urinary Na + or Cl - levels, in contrast to the heterozygote and wild-type calves in which these were significantly increased. These results demonstrate that the SLC12A1 (g.62382825G>A, p.Pro372Leu) is a hypomorphic or loss-of-function mutation and the hydrallantois with this mutation shows incomplete penetrance in Japanese Black cattle. © 2017 Japanese Society of Animal Science.

  1. Phenotypes in siblings with homozygous mutations of TRAPPC9 and/or MCPH1 support a bifunctional model of MCPH1.

    PubMed

    Duerinckx, Sarah; Meuwissen, Marije; Perazzolo, Camille; Desmyter, Laurence; Pirson, Isabelle; Abramowicz, Marc

    2018-04-24

    Autosomal recessive intellectual disability (ARID) is vastly heterogeneous. Truncating mutations of TRAPPC9 were reported in 8 ARID families. Autosomal recessive primary microcephaly (MCPH) represents another subgroup of ARID, itself very heterogeneous, where the size of the brain is very small since birth. MCPH1 plays a role at the centrosome via a BRCT1 domain, and in DNA Damage Repair (DDR) via BRCT2 and BRCT3, and it is not clear which of these two mechanisms causes MCPH in man. We studied the phenotype and sequenced the exome in two siblings with MCPH and their unaffected sister. Homozygous mutations of TRAPPC9 (p.Leu178Pro) and of MCPH1 (p.Arg741X) were found in both affected siblings. Brain MRI showed anomalies previously associated with TRAPPC9 defects, supporting the implication of TRAPPC9 in the phenotype. Importantly, the asymptomatic sister with normal head size was homozygous for the MCPH1 truncating mutation and heterozygous for the TRAPPC9 mutation. The affected siblings represent the first ARID cases with a TRAPPC9 missense mutation and with microcephaly of prenatal onset of. Furthermore, their unaffected sister represents strong evidence that the lack of MCPH1 BRCT3 domain does not cause MCPH in man, supporting a bifunctional model of MCPH1 where the centrosomal function is involved in brain volumic development and not the DDR function. © 2018 The Authors. Molecular Genetics & Genomic Medicine published by Wiley Periodicals, Inc.

  2. Novel homozygous mutation, c.400C>T (p.Arg134*), in the PVRL1 gene underlies cleft lip/palate-ectodermal dysplasia syndrome in an Asian patient.

    PubMed

    Yoshida, Kazue; Hayashi, Ryota; Fujita, Hideki; Kubota, Masaya; Kondo, Mai; Shimomura, Yutaka; Niizeki, Hironori

    2015-07-01

    Cleft lip/palate-ectodermal dysplasia syndrome is a rare, autosomal recessive disorder caused by homozygous loss-of-function mutations of the poliovirus receptor-like 1 (PVRL1) gene encoding nectin-1. Nectin-1 is a cell-cell adhesion molecule that is important for the initial step in the formation of adherens junctions and tight junctions; it is expressed in keratinocytes, neurons, and the developing face and palate. Clinical manifestations comprise a unique facial appearance with cleft lip/palate, ectodermal dysplasia, cutaneous syndactyly of the fingers and/or toes, and in some cases, mental retardation. We present the first report, to our knowledge, of an Asian individual with cleft lip/palate-ectodermal dysplasia syndrome with a novel PVRL1 mutation. A 7-year-old Japanese boy, the first child of a consanguineous marriage, showed hypohidrotic ectodermal dysplasia with sparse, brittle, fine, dry hair and hypodontia, the unique facial appearance with cleft lip/palate, cutaneous syndactyly of the fingers and mild mental retardation. Scanning electron microscopic examination of the hair demonstrated pili torti and pili trianguli et canaliculi. Mutation analysis of exon 2 of PVRL1 revealed a novel homozygous nonsense mutation, c.400C>T (p.Arg134*). His parents were heterozygous for the mutant alleles. All four PVRL1 mutations identified in cleft lip/palate-ectodermal dysplasia syndrome to date, including this study, resulted in truncated proteins that lack the transmembrane domain and intracellular domain of nectin-1, which is necessary to initiate the cell-cell adhesion process. © 2015 Japanese Dermatological Association.

  3. Microcephaly-capillary malformation syndrome: Brothers with a homozygous STAMBP mutation, uncovered by exome sequencing.

    PubMed

    Naseer, Muhammad Imran; Sogaty, Sameera; Rasool, Mahmood; Chaudhary, Adeel G; Abutalib, Yousif Ahmed; Walker, Susan; Marshall, Christian R; Merico, Daniele; Carter, Melissa T; Scherer, Stephen W; Al-Qahtani, Mohammad H; Zarrei, Mehdi

    2016-11-01

    We describe two brothers from a consanguineous family of Egyptian ancestry, presenting with microcephaly, apparent global developmental delay, seizures, spasticity, congenital blindness, and multiple cutaneous capillary malformations. Through exome sequencing, we uncovered a homozygous missense variant in STAMBP (p.K303R) in the two siblings, inherited from heterozygous carrier parents. Mutations in STAMBP are known to cause microcephaly-capillary malformation syndrome (MIC-CAP) and the phenotype in this family is consistent with this diagnosis. We compared the findings in the present brothers with those of earlier reported patients. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  4. A homozygous mutation in HESX1 is associated with evolving hypopituitarism due to impaired repressor-corepressor interaction

    PubMed Central

    Carvalho, Luciani R.; Woods, Kathryn S.; Mendonca, Berenice B.; Marcal, Nathalie; Zamparini, Andrea L.; Stifani, Stefano; Brickman, Joshua M.; Arnhold, Ivo J.P.; Dattani, Mehul T.

    2003-01-01

    The paired-like homeobox gene expressed in embryonic stem cells Hesx1/HESX1 encodes a developmental repressor and is expressed in early development in a region fated to form the forebrain, with subsequent localization to Rathke’s pouch, the primordium of the anterior pituitary gland. Mutations within the gene have been associated with septo-optic dysplasia, a constellation of phenotypes including eye, forebrain, and pituitary abnormalities, or milder degrees of hypopituitarism. We identified a novel homozygous nonconservative missense mutation (I26T) in the critical Engrailed homology repressor domain (eh1) of HESX1, the first, to our knowledge, to be described in humans, in a girl with evolving combined pituitary hormone deficiency born to consanguineous parents. Neuroimaging revealed a thin pituitary stalk with anterior pituitary hypoplasia and an ectopic posterior pituitary, but no midline or optic nerve abnormalities. This I26T mutation did not affect the DNA-binding ability of HESX1 but led to an impaired ability to recruit the mammalian Groucho homolog/Transducin-like enhancer of split-1 (Gro/TLE1), a crucial corepressor for HESX1, thereby leading to partial loss of repression. Thus, the novel pituitary phenotype highlighted here appears to be a specific consequence of the inability of HESX1 to recruit Groucho-related corepressors, suggesting that other molecular mechanisms govern HESX1 function in the forebrain. PMID:14561704

  5. Homozygous G320V mutation in the HJV gene causing juvenile hereditary haemochromatosis type A. A case report.

    PubMed

    Militaru, Mariela S; Popp, Radu A; Trifa, Adrian P

    2010-06-01

    While classical hereditary haemochromatosis, usually associated with mutations in the HFE gene, has an adult age onset and a long, progressive evolution, juvenile haemochromatosis, most often associated with mutations in the HJV gene, is a more severe, rapidly progressive condition and has an onset before the age of 30. We report a 26-year old woman with a severe iron overload, affected by hypogonadotropic hypogonadism and moderate dilative cardiomyopathy, in whom the molecular analysis revealed a homozygous genotype for G320V mutation in the HJV gene. As juvenile haemochromatosis is a severe disease, death usually occurring from cardiac involvement, an efficient iron removal from the body strategy should be started as soon as possible, in order to prevent irreversible damage.

  6. Hypophosphatemic osteomalacia and bone sclerosis caused by a novel homozygous mutation of the FAM20C gene in an elderly man with a mild variant of Raine syndrome.

    PubMed

    Takeyari, Shinji; Yamamoto, Takehisa; Kinoshita, Yuka; Fukumoto, Seiji; Glorieux, Francis H; Michigami, Toshimi; Hasegawa, Kosei; Kitaoka, Taichi; Kubota, Takuo; Imanishi, Yasuo; Shimotsuji, Tsunesuke; Ozono, Keiichi

    2014-10-01

    Hypophosphatemia and increased serum fibroblast growth factor 23 (FGF23) levels have been reported in young brothers with compound heterozygous mutations for the FAM20C gene; however, rickets was not observed in these cases. We report an adult case of Raine syndrome accompanying hypophosphatemic osteomalacia with a homozygous FAM20C mutation (R408W) associated with increased periosteal bone formation in the long bones and an increase in bone mineral density in the femoral neck. The patient, a 61-year-old man, was born from a cousin-to-cousin marriage. A short stature and severe dental demineralization were reported at an elementary school age. Hypophosphatemia was noted inadvertently at 27years old, at which time he started to take an active vitamin D metabolite (alphacalcidol) and phosphate. He also manifested ossification of the posterior longitudinal ligament. On bone biopsy performed at the age of 41years, we found severe osteomalacia surrounding osteocytes, which appeared to be an advanced form of periosteocytic hypomineralized lesions compared to those reported in patients with X-linked hypophosphatemic rickets. Laboratory data at 61years of age revealed markedly increased serum intact-FGF23 levels, which were likely to be the cause of hypophosphatemia and the decreased level of 1,25(OH)2D. We recently identified a homozygous FAM20C mutation, which was R408W, in this patient. When expressed in HEK293 cells, the R408W mutant protein exhibited impaired kinase activity and secretion. Our findings suggest that certain homozygous FAM20C mutations can cause FGF23-related hypophosphatemic osteomalacia and indicate the multiple roles of FAM20C in bone. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. A homozygous MYO7A mutation associated to Usher syndrome and unilateral auditory neuropathy spectrum disorder.

    PubMed

    Xia, Hong; Hu, Pengzhi; Yuan, Lamei; Xiong, Wei; Xu, Hongbo; Yi, Junhui; Yang, Zhijian; Deng, Xiong; Guo, Yi; Deng, Hao

    2017-10-01

    Usher syndrome (USH) is an autosomal recessive disorder characterized by sensorineural hearing loss, progressive visual loss and night blindness due to retinitis pigmentosa (RP), with or without vestibular dysfunction. The purpose of this study was to detect the causative gene in a consanguineous Chinese family with USH. A c.3696_3706del (p.R1232Sfs*72) variant in the myosin VIIa gene (MYO7A) was identified in the homozygous state by exome sequencing. The co‑segregation of the MYO7A c.3696_3706del variant with the phenotype of deafness and progressive visual loss in the USH family was confirmed by Sanger sequencing. The variant was absent in 200 healthy controls. Therefore, the c.3696_3706del variant may disrupt the interaction between myosin VIIa and other USH1 proteins, and impair melanosome transport in retinal pigment epithelial cells. Notably, bilateral auditory brainstem responses were absent in two patients of the USH family, while distortion product otoacoustic emissions were elicited in the right ears of the two patients, consistent with clinical diagnosis of unilateral auditory neuropathy spectrum disorder. These data suggested that the homozygous c.3696_3706del variant in the MYO7A gene may be the disease‑causing mutation for the disorder in this family. These findings broaden the phenotype spectrum of the MYO7A gene, and may facilitate understanding of the molecular pathogenesis of the disease, and genetic counseling for the family.

  8. Novel mutations in the GPIHBP1 gene identified in 2 patients with recurrent acute pancreatitis.

    PubMed

    Ariza, María José; Martínez-Hernández, Pedro Luis; Ibarretxe, Daiana; Rabacchi, Claudio; Rioja, José; Grande-Aragón, Cristina; Plana, Nuria; Tarugi, Patrizia; Olivecrona, Gunilla; Calandra, Sebastiano; Valdivielso, Pedro

    2016-01-01

    Glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1 (GPIHBP1) has been demonstrated to be essential for the in vivo function of lipoprotein lipase (LPL), the major triglyceride (TG)-hydrolyzing enzyme involved in the intravascular lipolysis of TG-rich lipoproteins. Recently, loss-of-function mutations of GPIHBP1 have been reported as the cause of type I hyperlipoproteinemia in several patients. Two unrelated patients were referred to our Lipid Units because of a severe hypertriglyceridemia and recurrent pancreatitis. We measured LPL activity in postheparin plasma and serum ApoCII and sequenced LPL, APOC2, and GPIHBP1. The 2 patients exhibited very low LPL activity not associated with mutations in LPL gene or with ApoCII deficiency. The sequence of GPIHBP1 revealed 2 novel point mutations. One patient (proband 1) was found to be homozygous for a C>A transversion in exon 3 resulting in the conversion of threonine to lysine at position 80 (p.Thr80Lys). The other patient (proband 2) was found to be homozygous for a G>T transversion in the third base of the ATG translation initiation codon in exon 1, resulting in the conversion of methionine to isoleucine (p.Met1Ile). In conclusion, we have identified 2 novel GPIHBP1 missense mutations in 2 unrelated patients as the cause of their severe hypertriglyceridemia. Copyright © 2016 National Lipid Association. Published by Elsevier Inc. All rights reserved.

  9. Minimal phenotype of mice homozygous for a null mutation in the forkhead/winged helix gene, Mf2.

    PubMed

    Kume, T; Deng, K; Hogan, B L

    2000-02-01

    Mf2 (mesoderm/mesenchyme forkhead 2) encodes a forkhead/winged helix transcription factor expressed in numerous tissues of the mouse embryo, including paraxial mesoderm, somites, branchial arches, vibrissae, developing central nervous system, and developing kidney. We have generated mice homozygous for a null mutation in the Mf2 gene (Mf2(lacZ)) to examine its role during embryonic development. The lacZ allele also allows monitoring of Mf2 gene expression. Homozygous null mutants are viable and fertile and have no major developmental defects. Some mutants show renal abnormalities, including kidney hypoplasia and hydroureter, but the penetrance of this phenotype is only 40% or lower, depending on the genetic background. These data suggest that Mf2 can play a unique role in kidney development, but there is functional redundancy in this organ and other tissues with other forkhead/winged helix genes.

  10. Homozygous PPT1 Splice Donor Mutation in a Cane Corso Dog With Neuronal Ceroid Lipofuscinosis.

    PubMed

    Kolicheski, A; Barnes Heller, H L; Arnold, S; Schnabel, R D; Taylor, J F; Knox, C A; Mhlanga-Mutangadura, T; O'Brien, D P; Johnson, G S; Dreyfus, J; Katz, M L

    2017-01-01

    A 10-month-old spayed female Cane Corso dog was evaluated after a 2-month history of progressive blindness, ataxia, and lethargy. Neurologic examination abnormalities indicated a multifocal lesion with primarily cerebral and cerebellar signs. Clinical worsening resulted in humane euthanasia. On necropsy, there was marked astrogliosis throughout white matter tracts of the cerebrum, most prominently in the corpus callosum. In the cerebral cortex and midbrain, most neurons contained large amounts of autofluorescent storage material in the perinuclear area of the cells. Cerebellar storage material was present in the Purkinje cells, granular cell layer, and perinuclear regions of neurons in the deep nuclei. Neuronal ceroid lipofuscinosis (NCL) was diagnosed. Whole genome sequencing identified a PPT1c.124 + 1G>A splice donor mutation. This nonreference assembly allele was homozygous in the affected dog, has not previously been reported in dbSNP, and was absent from the whole genome sequences of 45 control dogs and 31 unaffected Cane Corsos. Our findings indicate a novel mutation causing the CLN1 form of NCL in a previously unreported dog breed. A canine model for CLN1 disease could provide an opportunity for therapeutic advancement, benefiting both humans and dogs with this disorder. Copyright © 2016 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

  11. A homozygous FITM2 mutation causes a deafness-dystonia syndrome with motor regression and signs of ichthyosis and sensory neuropathy.

    PubMed

    Zazo Seco, Celia; Castells-Nobau, Anna; Joo, Seol-Hee; Schraders, Margit; Foo, Jia Nee; van der Voet, Monique; Velan, S Sendhil; Nijhof, Bonnie; Oostrik, Jaap; de Vrieze, Erik; Katana, Radoslaw; Mansoor, Atika; Huynen, Martijn; Szklarczyk, Radek; Oti, Martin; Tranebjærg, Lisbeth; van Wijk, Erwin; Scheffer-de Gooyert, Jolanda M; Siddique, Saadat; Baets, Jonathan; de Jonghe, Peter; Kazmi, Syed Ali Raza; Sadananthan, Suresh Anand; van de Warrenburg, Bart P; Khor, Chiea Chuen; Göpfert, Martin C; Qamar, Raheel; Schenck, Annette; Kremer, Hannie; Siddiqi, Saima

    2017-02-01

    A consanguineous family from Pakistan was ascertained to have a novel deafness-dystonia syndrome with motor regression, ichthyosis-like features and signs of sensory neuropathy. By applying a combined strategy of linkage analysis and whole-exome sequencing in the presented family, a homozygous nonsense mutation, c.4G>T (p.Glu2*), in FITM2 was identified. FITM2 and its paralog FITM1 constitute an evolutionary conserved protein family involved in partitioning of triglycerides into cellular lipid droplets. Despite the role of FITM2 in neutral lipid storage and metabolism, no indications for lipodystrophy were observed in the affected individuals. In order to obtain independent evidence for the involvement of FITM2 in the human pathology, downregulation of the single Fitm ortholog, CG10671, in Drosophila melanogaster was pursued using RNA interference. Characteristics of the syndrome, including progressive locomotor impairment, hearing loss and disturbed sensory functions, were recapitulated in Drosophila, which supports the causative nature of the FITM2 mutation. Mutation-based genetic counseling can now be provided to the family and insight is obtained into the potential impact of genetic variation in FITM2. © 2017. Published by The Company of Biologists Ltd.

  12. APOA5 Q97X mutation identified through homozygosity mapping causes severe hypertriglyceridemia in a Chilean consanguineous family.

    PubMed

    Dussaillant, Catalina; Serrano, Valentina; Maiz, Alberto; Eyheramendy, Susana; Cataldo, Luis Rodrigo; Chavez, Matías; Smalley, Susan V; Fuentes, Marcela; Rigotti, Attilio; Rubio, Lorena; Lagos, Carlos F; Martinez, José Alfredo; Santos, José Luis

    2012-11-15

    Severe hypertriglyceridemia (HTG) has been linked to defects in LPL, APOC2, APOA5, LMF1 and GBIHBP1 genes. However, a number of severe HTG cases are probably caused by as yet unidentified mutations. Very high triglyceride plasma levels (>112 mmol/L at diagnosis) were found in two sisters of a Chilean consanguineous family, which is strongly suggestive of a recessive highly penetrant mutation. The aim of this study was to determine the genetic locus responsible for the severe HTG in this family. We carried out a genome-wide linkage study with nearly 300,000 biallelic markers (Illumina Human CytoSNP-12 panel). Using the homozygosity mapping strategy, we searched for chromosome regions with excess of homozygous genotypes in the affected cases compared to non-affected relatives. A large homozygous segment was found in the long arm of chromosome 11, with more than 2,500 consecutive homozygous SNP shared by the proband with her affected sister, and containing the APOA5/A4/C3/A1 cluster. Direct sequencing of the APOA5 gene revealed a known homozygous nonsense Q97X mutation (p.Gln97Ter) found in both affected sisters but not in non-affected relatives nor in a sample of unrelated controls. The Q97X mutation of the APOA5 gene in homozygous status is responsible for the severe hypertriglyceridemia in this family. We have shown that homozygosity mapping correctly pinpointed the genomic region containing the gene responsible for severe hypertriglyceridemia in this consanguineous Chilean family.

  13. APOA5 Q97X Mutation Identified through homozygosity mapping causes severe hypertriglyceridemia in a Chilean consanguineous family

    PubMed Central

    2012-01-01

    Background Severe hypertriglyceridemia (HTG) has been linked to defects in LPL, APOC2, APOA5, LMF1 and GBIHBP1 genes. However, a number of severe HTG cases are probably caused by as yet unidentified mutations. Very high triglyceride plasma levels (>112 mmol/L at diagnosis) were found in two sisters of a Chilean consanguineous family, which is strongly suggestive of a recessive highly penetrant mutation. The aim of this study was to determine the genetic locus responsible for the severe HTG in this family. Methods We carried out a genome-wide linkage study with nearly 300,000 biallelic markers (Illumina Human CytoSNP-12 panel). Using the homozygosity mapping strategy, we searched for chromosome regions with excess of homozygous genotypes in the affected cases compared to non-affected relatives. Results A large homozygous segment was found in the long arm of chromosome 11, with more than 2,500 consecutive homozygous SNP shared by the proband with her affected sister, and containing the APOA5/A4/C3/A1 cluster. Direct sequencing of the APOA5 gene revealed a known homozygous nonsense Q97X mutation (p.Gln97Ter) found in both affected sisters but not in non-affected relatives nor in a sample of unrelated controls. Conclusion The Q97X mutation of the APOA5 gene in homozygous status is responsible for the severe hypertriglyceridemia in this family. We have shown that homozygosity mapping correctly pinpointed the genomic region containing the gene responsible for severe hypertriglyceridemia in this consanguineous Chilean family. PMID:23151256

  14. Screening of LDLR and APOB gene mutations in Mexican patients with homozygous familial hypercholesterolemia.

    PubMed

    Hernández Flores, Teresita De Jesús; González García, Juan Ramón; Colima Fausto, Ana Gabriela; Vázquez Cárdenas, Norma Alejandra; Sánchez López, Yoaly; Zarate Morales, César Augusto; Magaña Torres, María Teresa

    Familial hypercholesterolemia (FH) is an autosomal dominant disorder that causes accumulation of serum low-density lipoprotein cholesterol and premature cardiovascular disease. It is mainly related to mutations in the LDLR gene. Homozygous FH (HoFH) patients have the most severe form of the disease accounting for a worldwide prevalence of 1:1,000,000. In Mexico, at least 5 cases of HoFH have been reported. The aim of this study was to describe the clinical, biochemical, and molecular data observed in patients with HoFH phenotype. We included 13 patients, belonging to 11 families, with clinical and biochemical diagnoses suggestive of HoFH. Molecular analyses of the LDLR and APOB genes were performed by means of polymerase chain reaction followed by Sanger sequencing. The causal mutation of HoFH was found in 8 of 11 unrelated patients. Excepting 1, all were true homozygotes. Six different variants in LDLR were identified: c.-139delCTCCCCCTGC, p.Glu140Lys, p.Asp360His, p.Asn405Lys, p.Ala755Glyfs*7, and p.Leu759Serfs*6. Of these, p.Asp360His and p.Asn405Lys were detected for the first time in Mexico; p.Leu759Serfs*6 showed to be the most frequent (43.7% of the alleles 7/16), and c.-139delCTCCCCCTGC is a new variant located in the promoter region. This work increases knowledge of biochemical and genetic features in Mexican patients with HoFH. A novel mutation in the LDLR gene promoter was detected: c.-139delCTCCCCCTGC, which possibly inhibits its expression. Copyright © 2018 National Lipid Association. Published by Elsevier Inc. All rights reserved.

  15. Minimal Phenotype of Mice Homozygous for a Null Mutation in the Forkhead/Winged Helix Gene, Mf2

    PubMed Central

    Kume, Tsutomu; Deng, Keyu; Hogan, Brigid L. M.

    2000-01-01

    Mf2 (mesoderm/mesenchyme forkhead 2) encodes a forkhead/winged helix transcription factor expressed in numerous tissues of the mouse embryo, including paraxial mesoderm, somites, branchial arches, vibrissae, developing central nervous system, and developing kidney. We have generated mice homozygous for a null mutation in the Mf2 gene (Mf2lacZ) to examine its role during embryonic development. The lacZ allele also allows monitoring of Mf2 gene expression. Homozygous null mutants are viable and fertile and have no major developmental defects. Some mutants show renal abnormalities, including kidney hypoplasia and hydroureter, but the penetrance of this phenotype is only 40% or lower, depending on the genetic background. These data suggest that Mf2 can play a unique role in kidney development, but there is functional redundancy in this organ and other tissues with other forkhead/winged helix genes. PMID:10648626

  16. Severe coagulation factor VII deficiency caused by a novel homozygous mutation (p. Trp284Gly) in loop 140s.

    PubMed

    Hao, Xiuping; Cheng, XiaoLi; Ye, Jiajia; Wang, Yingyu; Yang, LiHong; Wang, Mingshan; Jin, Yanhui

    2016-06-01

    Congenital coagulation factor VII (FVII) deficiency is a rare disorder caused by mutation in F7 gene. Herein, we reported a patient who had unexplained hematuria and vertigo with consanguineous parents. He has been diagnosed as having FVII deficiency based on the results of reduced FVII activity (2.0%) and antigen (12.8%). The thrombin generation tests verified that the proband has obstacles in producing thrombin. Direct sequencing analysis revealed a novel homozygous missense mutation p.Trp284Gly. Also noteworthy is the fact that the mutational residue belongs to structurally conserved loop 140s, which majorly undergo rearrangement after FVII activation. Model analysis indicated that the substitution disrupts these native hydrophobic interactions, which are of great importance to the conformation in the activation domain of FVIIa.

  17. Novel homozygous VHL mutation in exon 2 is associated with congenital polycythemia but not with cancer.

    PubMed

    Lanikova, Lucie; Lorenzo, Felipe; Yang, Chunzhang; Vankayalapati, Hari; Drachtman, Richard; Divoky, Vladimir; Prchal, Josef T

    2013-05-09

    Germline von Hippel-Lindau (VHL) gene mutations underlie dominantly inherited familial VHL tumor syndrome comprising a predisposition for renal cell carcinoma, pheochromocytoma/paraganglioma, cerebral hemangioblastoma, and endolymphatic sac tumors. However, recessively inherited congenital polycythemia, exemplified by Chuvash polycythemia, has been associated with 2 separate 3' VHL gene mutations in exon 3. It was proposed that different positions of loss-of-function VHL mutations are associated with VHL syndrome cancer predisposition and only C-terminal domain-encoding VHL mutations would cause polycythemia. However, now we describe a new homozygous VHL exon 2 mutation of the VHL gene:(c.413C>T):P138L, which is associated in the affected homozygote with congenital polycythemia but not in her, or her-heterozygous relatives, with cancer or other VHL syndrome tumors. We show that VHL(P138L) has perturbed interaction with hypoxia-inducible transcription factor (HIF)1α. Further, VHL(P138L) protein has decreased stability in vitro. Similarly to what was reported in Chuvash polycythemia and some other instances of HIFs upregulation, VHL(P138L) erythroid progenitors are hypersensitive to erythropoietin. Interestingly, the level of RUNX1/AML1 and NF-E2 transcripts that are specifically upregulated in acquired polycythemia vera were also upregulated in VHL(P138L) granulocytes.

  18. Early Clinical Diagnosis of PC1/3 Deficiency in a Patient With a Novel Homozygous PCSK1 Splice-Site Mutation.

    PubMed

    Härter, Bettina; Fuchs, Irene; Müller, Thomas; Akbulut, Ulas Emre; Cakir, Murat; Janecke, Andreas R

    2016-04-01

    Autosomal recessive proprotein convertase 1/3 (PC1/3) deficiency, caused by mutations in the PCSK1 gene, is characterized by severe congenital malabsorptive diarrhea, early-onset obesity, and certain endocrine abnormalities. We suspected PC1/3 deficiency in a 4-month-old girl based on the presence of congenital diarrhea and polyuria. Sequencing the whole coding region and splice sites detected a novel homozygous PCSK1 splice-site mutation, c.544-2A>G, in the patient. The mutation resulted in the skipping of exon 5, the generation of a premature termination codon, and nonsense-mediated PCSK1 messenger ribonucleic acid decay, which was demonstrated in complementary DNA derived from fibroblasts.

  19. A novel homozygous variant in the SMOC1 gene underlying Waardenburg anophthalmia syndrome.

    PubMed

    Ullah, Asmat; Umair, Muhammad; Ahmad, Farooq; Muhammad, Dost; Basit, Sulman; Ahmad, Wasim

    2017-01-01

    Waardenburg anophthalmia syndrome (WAS), also known as ophthalmo-acromelic syndrome or anophthalmia-syndactyly, is a rare congenital disorder that segregates in an autosomal recessive pattern. Clinical features of the syndrome include malformation of the eyes and the skeleton. Mostly, WAS is caused by mutations in the SMOC-1 gene. The present report describes a large consanguineous family of Pakistani origin segregating Waardenburg anophthalmia syndrome in an autosomal recessive pattern. Genotyping followed by Sanger sequencing was performed to search for a candidate gene. SNP genotyping using AffymetrixGeneChip Human Mapping 250K Nsp array established a single homozygous region among affected members on chromosome 14q23.1-q24.3 harboring the SMOC1 gene. Sequencing of the gene revealed a novel homozygous missense mutation (c.812G>A; p.Cys271Tyr) in the family. This is the first report of Waardenburg anophthalmia syndrome caused by a SMOC1 variant in a Pakistani population. The mutation identified in the present investigation extends the body of evidence implicating the gene SMOC-1 in causing WAS.

  20. Maternal segmental disomy in Leigh syndrome with cytochrome c oxidase deficiency caused by homozygous SURF1 mutation.

    PubMed

    van Riesen, A K J; Antonicka, H; Ohlenbusch, A; Shoubridge, E A; Wilichowski, E K G

    2006-04-01

    Cytochrome c oxidase deficiency (COX) is the most frequent cause of Leigh syndrome (LS), a mitochondrial subacute necrotizing encephalomyelopathy. Most of these LS (COX-) patients show mutations in SURF1 on chromosome 9 (9q34), which encodes a protein essential for the assembly of the COX complex. We describe a family whose first-born boy developed characteristic features of LS. Severe COX deficiency in muscle was caused by a novel homozygous nonsense mutation in SURF1. Segregation analysis of this mutation in the family was incompatible with autosomal recessive inheritance but consistent with a maternal disomy. Haplotype analysis of microsatellite markers confirmed isodisomy involving nearly the complete long arm of chromosome 9 (9q21-9tel). No additional physical abnormalities were present in the boy, suggesting that there are no imprinted genes on the long arm of chromosome 9 which are crucial for developmental processes. This case of segmental isodisomy illustrates that genotyping of parents is crucial for correct genetic counseling.

  1. Pregnancy-associated osteoporosis with a heterozygous deactivating LDL receptor-related protein 5 (LRP5) mutation and a homozygous methylenetetrahydrofolate reductase (MTHFR) polymorphism.

    PubMed

    Cook, Fiona J; Mumm, Steven; Whyte, Michael P; Wenkert, Deborah

    2014-04-01

    Pregnancy-associated osteoporosis (PAO) is a rare, idiopathic disorder that usually presents with vertebral compression fractures (VCFs) within 6 months of a first pregnancy and delivery. Spontaneous improvement is typical. There is no known genetic basis for PAO. A 26-year-old primagravida with a neonatal history of unilateral blindness attributable to hyperplastic primary vitreous sustained postpartum VCFs consistent with PAO. Her low bone mineral density (BMD) seemed to respond to vitamin D and calcium therapy, with no fractures after her next successful pregnancy. Investigation of subsequent fetal losses revealed homozygosity for the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism associated both with fetal loss and with osteoporosis (OP). Because her neonatal unilateral blindness and OP were suggestive of loss-of-function mutation(s) in the gene that encodes LDL receptor-related protein 5 (LRP5), LRP5 exon and splice site sequencing was also performed. This revealed a unique heterozygous 12-bp deletion in exon 21 (c.4454_4465del, p.1485_1488del SSSS) in the patient, her mother and sons, but not her father or brother. Her mother had a normal BMD, no history of fractures, PAO, ophthalmopathy, or fetal loss. Her two sons had no ophthalmopathy and no skeletal issues. Her osteoporotic father (with a family history of blindness) and brother had low BMDs first documented at ages ∼40 and 32 years, respectively. Serum biochemical and bone turnover studies were unremarkable in all subjects. We postulate that our patient's heterozygous LRP5 mutation together with her homozygous MTHFR polymorphism likely predisposed her to low peak BMD. However, OP did not cosegregate in her family with the LRP5 mutation, the homozygous MTHFR polymorphism, or even the combination of the two, implicating additional genetic or nongenetic factors in her PAO. Nevertheless, exploration for potential genetic contributions to PAO may explain part of the pathogenesis of this

  2. Dihydrofolate Reductase Deficiency Due to a Homozygous DHFR Mutation Causes Megaloblastic Anemia and Cerebral Folate Deficiency Leading to Severe Neurologic Disease

    PubMed Central

    Cario, Holger; Smith, Desirée E.C.; Blom, Henk; Blau, Nenad; Bode, Harald; Holzmann, Karlheinz; Pannicke, Ulrich; Hopfner, Karl-Peter; Rump, Eva-Maria; Ayric, Zuleya; Kohne, Elisabeth; Debatin, Klaus-Michael; Smulders, Yvo; Schwarz, Klaus

    2011-01-01

    The importance of intracellular folate metabolism is illustrated by the severity of symptoms and complications caused by inborn disorders of folate metabolism or by folate deficiency. We examined three children of healthy, distantly related parents presenting with megaloblastic anemia and cerebral folate deficiency causing neurologic disease with atypical childhood absence epilepsy. Genome-wide homozygosity mapping revealed a candidate region on chromosome 5 including the dihydrofolate reductase (DHFR) locus. DHFR sequencing revealed a homozygous DHFR mutation, c.458A>T (p.Asp153Val), in all siblings. The patients' folate profile in red blood cells (RBC), plasma, and cerebrospinal fluid (CSF), analyzed by liquid chromatography tandem mass spectrometry, was compatible with DHFR deficiency. DHFR activity and fluorescein-labeled methotrexate (FMTX) binding were severely reduced in EBV-immortalized lymphoblastoid cells of all patients. Heterozygous cells displayed intermediate DHFR activity and FMTX binding. RT-PCR of DHFR mRNA revealed no differences between wild-type and DHFR mutation-carrying cells, whereas protein expression was reduced in cells with the DHFR mutation. Treatment with folinic acid resulted in the resolution of hematological abnormalities, normalization of CSF folate levels, and improvement of neurological symptoms. In conclusion, the homozygous DHFR mutation p.Asp153Val causes DHFR deficiency and leads to a complex hematological and neurological disease that can be successfully treated with folinic acid. DHFR is necessary for maintaining sufficient CSF and RBC folate levels, even in the presence of adequate nutritional folate supply and normal plasma folate. PMID:21310277

  3. RNA-based mutation analysis identifies an unusual MSH6 splicing defect and circumvents PMS2 pseudogene interference.

    PubMed

    Etzler, J; Peyrl, A; Zatkova, A; Schildhaus, H-U; Ficek, A; Merkelbach-Bruse, S; Kratz, C P; Attarbaschi, A; Hainfellner, J A; Yao, S; Messiaen, L; Slavc, I; Wimmer, K

    2008-02-01

    Heterozygous germline mutations in one of the mismatch repair (MMR) genes MLH1, MSH2, MSH6, and PMS2 cause hereditary nonpolyposis colorectal cancer (HNPCC) or Lynch syndrome, a dominantly inherited cancer susceptibility syndrome. Recent reports provide evidence for a novel recessively inherited cancer syndrome with constitutive MMR deficiency due to biallelic germline mutations in one of the MMR genes. MMR-deficiency (MMR-D) syndrome is characterized by childhood brain tumors, hematological and/or gastrointestinal malignancies, and signs of neurofibromatosis type 1 (NF1). We established an RNA-based mutation detection assay for the four MMR genes, since 1) a number of splicing defects may escape detection by the analysis of genomic DNA, and 2) DNA-based mutation detection in the PMS2 gene is severely hampered by the presence of multiple highly similar pseudogenes, including PMS2CL. Using this assay, which is based on direct cDNA sequencing of RT-PCR products, we investigated two families with children suspected to suffer from MMR-D syndrome. We identified a homozygous complex MSH6 splicing alteration in the index patients of the first family and a novel homozygous PMS2 mutation (c.182delA) in the index patient of the second family. Furthermore, we demonstrate, by the analysis of a PMS2/PMS2CL "hybrid" allele carrier, that RNA-based PMS2 testing effectively avoids the caveats of genomic DNA amplification approaches; i.e., pseudogene coamplification as well as allelic dropout, and will, thus, allow more sensitive mutation analysis in MMR deficiency and in HNPCC patients with PMS2 defects. (c) 2007 Wiley-Liss, Inc.

  4. A Homozygous Mutation in the Tight-Junction Protein JAM3 Causes Hemorrhagic Destruction of the Brain, Subependymal Calcification, and Congenital Cataracts

    PubMed Central

    Mochida, Ganeshwaran H.; Ganesh, Vijay S.; Felie, Jillian M.; Gleason, Danielle; Hill, R. Sean; Clapham, Katie Rose; Rakiec, Daniel; Tan, Wen-Hann; Akawi, Nadia; Al-Saffar, Muna; Partlow, Jennifer N.; Tinschert, Sigrid; Barkovich, A. James; Ali, Bassam; Al-Gazali, Lihadh; Walsh, Christopher A.

    2010-01-01

    The tight junction, or zonula occludens, is a specialized cell-cell junction that regulates epithelial and endothelial permeability, and it is an essential component of the blood-brain barrier in the cerebrovascular endothelium. In addition to functioning as a diffusion barrier, tight junctions are also involved in signal transduction. In this study, we identified a homozygous mutation in the tight-junction protein gene JAM3 in a large consanguineous family from the United Arab Emirates. Some members of this family had a rare autosomal-recessive syndrome characterized by severe hemorrhagic destruction of the brain, subependymal calcification, and congenital cataracts. Their clinical presentation overlaps with some reported cases of pseudo-TORCH syndrome as well as with cases involving mutations in occludin, another component of the tight-junction complex. However, massive intracranial hemorrhage distinguishes these patients from others. Homozygosity mapping identified the disease locus in this family on chromosome 11q25 with a maximum multipoint LOD score of 6.15. Sequence analysis of genes in the candidate interval uncovered a mutation in the canonical splice-donor site of intron 5 of JAM3. RT-PCR analysis of a patient lymphoblast cell line confirmed abnormal splicing, leading to a frameshift mutation with early termination. JAM3 is known to be present in vascular endothelium, although its roles in cerebral vasculature have not been implicated. Our results suggest that JAM3 is essential for maintaining the integrity of the cerebrovascular endothelium as well as for normal lens development in humans. PMID:21109224

  5. Identification of a novel homozygous mutation (S144I) in a Malay patient with maple syrup urine disease.

    PubMed

    Ali, Ernie Zuraida; Yunus, Zabedah Md; Desa, Norsiah Md; Hock, Ngu Lock

    2013-01-01

    Maple syrup urine disease (MSUD) is a rare autosomal recessive metabolic disorder of branched-chain amino acid metabolism caused by the defective function of branched-chain α-ketoacid dehydrogenase complex (BCKDH). It is characterised by increased plasma leucine, isoleucine, and valine levels, and mutations can be detected in any one of the BCKDHA, BCKDHB, and DBT genes. In this study, we describe the molecular basis of a novel mutation found in one MSUD Malay patient from consanguineous parents. A homozygous mutation has been detected in this patient whose both parents carried a heterozygous mutation at DNA coding region c.431G>T in exon 4, which resulted in a substitution of serine to isoleucine at codon 144 (p.S144I). In silico analysis predicted S144I to be potentially damaging. The mutation was located on the alpha helical region of the BCKDHA protein, and it is predicted to affect the stability of protein due to the loss of various polar interactions between local secondary structures. Homology analysis revealed that this mutation occurred in a highly conserved region (100%). This result indicates that S144I mutation is likely pathogenic and may contribute to the classic form of MSUD in this patient.

  6. Clinical implications of mutation analysis in primary hyperoxaluria type 1.

    PubMed

    van Woerden, Christiaan S; Groothoff, Jaap W; Wijburg, Frits A; Annink, Carla; Wanders, Ronald J A; Waterham, Hans R

    2004-08-01

    Primary hyperoxaluria type 1 (PH1) is an inborn error of glyoxylate metabolism with an extensive clinical and genetic heterogeneity. Although over 50 disease-causing mutations have been identified, the relationship between genotype and clinical outcome remains unclear. The aim of this study was to determine this association in order to find clues for improvement of patient care. AGXT mutation analysis and assessment of biochemical characteristics and clinical outcome were performed on patients from a Dutch PH1 cohort. Thirty-three of a cohort of 57 PH1 patients, identified in The Netherlands over a period of 30 years, were analyzed. Ten different mutations were found. The most common mutations were the Gly170Arg, Phe152Ile, and the 33insC mutations, with an allele frequency of 43%, 19%, and 15%, respectively. Homozygous Gly170Arg and Phe152Ile mutations were associated with pyridoxine responsiveness and a preserved renal function over time when treatment was timely initiated. All patients homozygous for the 33insC mutation had end-stage renal disease (ESRD) before the first year of age. In two unrelated patients, a new Val336Asp mutation was found coupled with the Gly170Arg mutation on the minor allele. We also found 3 patients homozygous for a novel Gly82Arg mutation with adverse outcome in 2 of them. Early detection of Gly170Arg and Phe152Ile mutations in PH1 has important clinical implications because of their association with pyridoxine responsiveness and clinical outcome. The association of a homozygous 33insC mutation with severe infantile ESRD, resulting in early deaths in 2 out of 3 cases, warrants a choice for prenatal diagnostics in affected families.

  7. A novel APOC2 gene mutation identified in a Chinese patient with severe hypertriglyceridemia and recurrent pancreatitis.

    PubMed

    Jiang, Jingjing; Wang, Yuhui; Ling, Yan; Kayoumu, Abudurexiti; Liu, George; Gao, Xin

    2016-01-16

    The severe forms of hypertriglyceridemia are usually caused by genetic defects. In this study, we described a Chinese female with severe hypertriglyceridemia caused by a novel homozygous mutation in the APOC2 gene. Lipid profiles of the pedigree were studied in detail. LPL and HL activity were also measured. The coding regions of 5 candidate genes (namely LPL, APOC2, APOA5, LMF1, and GPIHBP1) were sequenced using genomic DNA from peripheral leucocytes. The ApoE gene was also genotyped. Serum triglyceride level was extremely high in the proband, compared with other family members. Plasma LPL activity was also significantly reduced in the proband. Serum ApoCII was very low in the proband as well as in the heterozygous mutation carriers. A novel mutation (c.86A > CC) was identified on exon 3 [corrected] of the APOC2 gene, which converted the Asp [corrected] codon at position 29 into Ala, followed by a termination codon (TGA). This study presented the first case of ApoCII deficiency in the Chinese population, with a novel mutation c.86A > CC in the APOC2 gene identified. Serum ApoCII protein might be a useful screening test for identifying mutation carriers.

  8. Exome Sequencing Identifies Mitochondrial Alanyl-tRNA Synthetase Mutations in Infantile Mitochondrial Cardiomyopathy

    PubMed Central

    Götz, Alexandra; Tyynismaa, Henna; Euro, Liliya; Ellonen, Pekka; Hyötyläinen, Tuulia; Ojala, Tiina; Hämäläinen, Riikka H.; Tommiska, Johanna; Raivio, Taneli; Oresic, Matej; Karikoski, Riitta; Tammela, Outi; Simola, Kalle O.J.; Paetau, Anders; Tyni, Tiina; Suomalainen, Anu

    2011-01-01

    Infantile cardiomyopathies are devastating fatal disorders of the neonatal period or the first year of life. Mitochondrial dysfunction is a common cause of this group of diseases, but the underlying gene defects have been characterized in only a minority of cases, because tissue specificity of the manifestation hampers functional cloning and the heterogeneity of causative factors hinders collection of informative family materials. We sequenced the exome of a patient who died at the age of 10 months of hypertrophic mitochondrial cardiomyopathy with combined cardiac respiratory chain complex I and IV deficiency. Rigorous data analysis allowed us to identify a homozygous missense mutation in AARS2, which we showed to encode the mitochondrial alanyl-tRNA synthetase (mtAlaRS). Two siblings from another family, both of whom died perinatally of hypertrophic cardiomyopathy, had the same mutation, compound heterozygous with another missense mutation. Protein structure modeling of mtAlaRS suggested that one of the mutations affected a unique tRNA recognition site in the editing domain, leading to incorrect tRNA aminoacylation, whereas the second mutation severely disturbed the catalytic function, preventing tRNA aminoacylation. We show here that mutations in AARS2 cause perinatal or infantile cardiomyopathy with near-total combined mitochondrial respiratory chain deficiency in the heart. Our results indicate that exome sequencing is a powerful tool for identifying mutations in single patients and allows recognition of the genetic background in single-gene disorders of variable clinical manifestation and tissue-specific disease. Furthermore, we show that mitochondrial disorders extend to prenatal life and are an important cause of early infantile cardiac failure. PMID:21549344

  9. Homozygous NOTCH3 null mutation and impaired NOTCH3 signaling in recessive early-onset arteriopathy and cavitating leukoencephalopathy.

    PubMed

    Pippucci, Tommaso; Maresca, Alessandra; Magini, Pamela; Cenacchi, Giovanna; Donadio, Vincenzo; Palombo, Flavia; Papa, Valentina; Incensi, Alex; Gasparre, Giuseppe; Valentino, Maria Lucia; Preziuso, Carmela; Pisano, Annalinda; Ragno, Michele; Liguori, Rocco; Giordano, Carla; Tonon, Caterina; Lodi, Raffaele; Parmeggiani, Antonia; Carelli, Valerio; Seri, Marco

    2015-06-01

    Notch signaling is essential for vascular physiology. Neomorphic heterozygous mutations in NOTCH3, one of the four human NOTCH receptors, cause cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). Hypomorphic heterozygous alleles have been occasionally described in association with a spectrum of cerebrovascular phenotypes overlapping CADASIL, but their pathogenic potential is unclear. We describe a patient with childhood-onset arteriopathy, cavitating leukoencephalopathy with cerebral white matter abnormalities presented as diffuse cavitations, multiple lacunar infarctions and disseminated microbleeds. We identified a novel homozygous c.C2898A (p.C966*) null mutation in NOTCH3 abolishing NOTCH3 expression and causing NOTCH3 signaling impairment. NOTCH3 targets acting in the regulation of arterial tone (KCNA5) or expressed in the vasculature (CDH6) were downregulated. Patient's vessels were characterized by smooth muscle degeneration as in CADASIL, but without deposition of granular osmiophilic material (GOM), the CADASIL hallmark. The heterozygous parents displayed similar but less dramatic trends in decrease in the expression of NOTCH3 and its targets, as well as in vessel degeneration. This study suggests a functional link between NOTCH3 deficiency and pathogenesis of vascular leukoencephalopathies. © 2015 The Authors. Published under the terms of the CC BY 4.0 license.

  10. A Homozygous Missense Mutation in TGM5 Abolishes Epidermal Transglutaminase 5 Activity and Causes Acral Peeling Skin Syndrome

    PubMed Central

    Cassidy, Andrew J.; van Steensel, Maurice A. M.; Steijlen, Peter M.; van Geel, Michel; Velden, Jaap van der; Morley, Susan M.; Terrinoni, Alessandro; Melino, Gerry; Candi, Eleonora; McLean, W. H. Irwin

    2005-01-01

    Peeling skin syndrome is an autosomal recessive genodermatosis characterized by the shedding of the outer epidermis. In the acral form, the dorsa of the hands and feet are predominantly affected. Ultrastructural analysis has revealed tissue separation at the junction between the granular cells and the stratum corneum in the outer epidermis. Genomewide linkage analysis in a consanguineous Dutch kindred mapped the gene to 15q15.2 in the interval between markers D15S1040 and D15S1016. Two homozygous missense mutations, T109M and G113C, were found in TGM5, which encodes transglutaminase 5 (TG5), in all affected persons in two unrelated families. The mutation was present on the same haplotype in both kindreds, indicating a probable ancestral mutation. TG5 is strongly expressed in the epidermal granular cells, where it cross-links a variety of structural proteins in the terminal differentiation of the epidermis to form the cornified cell envelope. An established, in vitro, biochemical cross-linking assay revealed that, although T109M is not pathogenic, G113C completely abolishes TG5 activity. Three-dimensional modeling of TG5 showed that G113C lies close to the catalytic domain, and, furthermore, that this glycine residue is conserved in all known transglutaminases, which is consistent with pathogenicity. Other families with more-widespread peeling skin phenotypes lacked TGM5 mutations. This study identifies the first causative gene in this heterogeneous group of skin disorders and demonstrates that the protein cross-linking function performed by TG5 is vital for maintaining cell-cell adhesion between the outermost layers of the epidermis. PMID:16380904

  11. Heterogeneity of the cystic fibrosis phenotype in a large kindred family in Qatar with cystic fibrosis mutation (I1234V).

    PubMed

    Abdul Wahab, A; Al Thani, G; Dawod, S T; Kambouris, M; Al Hamed, M

    2001-04-01

    Twenty-nine subjects (17 families) with cystic fibrosis belonging to the same Bedouin tribe were screened for cystic fibrosis transmembrane regulator gene mutations (CFTR). Homozygous I1234V mutation in exon 19 was identified in all families with a relatively high rate of consanguinity (96.6 per cent). The homozygous I1234V mutation tended to present with a variable degree of pulmonary disease, pancreatic insufficiency and electrolyte imbalance. Homozygous I1234V was found to be a common mutation in the studied Bedouin tribe in Qatar.

  12. A novel homozygous mutation in G6PC3 presenting as cyclic neutropenia and severe congenital neutropenia in the same family.

    PubMed

    Alangari, Abdullah A; Alsultan, Abdulrahman; Osman, Mohamed Elfaki; Anazi, Shamsa; Alkuraya, Fowzan S

    2013-11-01

    Patients with autosomal recessive cyclic neutropenia have no known causative genetic defect yet. Autozygosity mapping on two branches of an extended multiplex consanguineous family presenting with cyclic neutropenia or severe congenital neutropenia to look for candidate gene, followed by candidate gene selection and sequencing. A single autozygous interval on Chr17:33,901,938-45,675,414 that is exclusively shared by the affected members was identified. This interval spans 11.8 Mb and contains 30 genes. Review of these genes highlighted G6PC3 as the most likely candidate given its known role in neutrophil biology. Direct sequencing revealed a novel homozygous mutation (NM_138387.3, c.974T > G, p.Leu325Arg). Two of our patients had associated congenital defects that are known to occur in patients with G6PC3 mutations, including congenital heart disease and intermittent thrombocytopenia. Biallelic G6PC3 defects should be considered in patients with autosomal recessive cyclic neutropenia, especially those with typical associated congenital defects.

  13. Dihydrofolate reductase deficiency due to a homozygous DHFR mutation causes megaloblastic anemia and cerebral folate deficiency leading to severe neurologic disease.

    PubMed

    Cario, Holger; Smith, Desirée E C; Blom, Henk; Blau, Nenad; Bode, Harald; Holzmann, Karlheinz; Pannicke, Ulrich; Hopfner, Karl-Peter; Rump, Eva-Maria; Ayric, Zuleya; Kohne, Elisabeth; Debatin, Klaus-Michael; Smulders, Yvo; Schwarz, Klaus

    2011-02-11

    The importance of intracellular folate metabolism is illustrated by the severity of symptoms and complications caused by inborn disorders of folate metabolism or by folate deficiency. We examined three children of healthy, distantly related parents presenting with megaloblastic anemia and cerebral folate deficiency causing neurologic disease with atypical childhood absence epilepsy. Genome-wide homozygosity mapping revealed a candidate region on chromosome 5 including the dihydrofolate reductase (DHFR) locus. DHFR sequencing revealed a homozygous DHFR mutation, c.458A>T (p.Asp153Val), in all siblings. The patients' folate profile in red blood cells (RBC), plasma, and cerebrospinal fluid (CSF), analyzed by liquid chromatography tandem mass spectrometry, was compatible with DHFR deficiency. DHFR activity and fluorescein-labeled methotrexate (FMTX) binding were severely reduced in EBV-immortalized lymphoblastoid cells of all patients. Heterozygous cells displayed intermediate DHFR activity and FMTX binding. RT-PCR of DHFR mRNA revealed no differences between wild-type and DHFR mutation-carrying cells, whereas protein expression was reduced in cells with the DHFR mutation. Treatment with folinic acid resulted in the resolution of hematological abnormalities, normalization of CSF folate levels, and improvement of neurological symptoms. In conclusion, the homozygous DHFR mutation p.Asp153Val causes DHFR deficiency and leads to a complex hematological and neurological disease that can be successfully treated with folinic acid. DHFR is necessary for maintaining sufficient CSF and RBC folate levels, even in the presence of adequate nutritional folate supply and normal plasma folate. Copyright © 2011 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  14. Exome sequencing identifies CTSK mutations in patients originally diagnosed as intermediate osteopetrosis☆

    PubMed Central

    Pangrazio, Alessandra; Puddu, Alessandro; Oppo, Manuela; Valentini, Maria; Zammataro, Luca; Vellodi, Ashok; Gener, Blanca; Llano-Rivas, Isabel; Raza, Jamal; Atta, Irum; Vezzoni, Paolo; Superti-Furga, Andrea; Villa, Anna; Sobacchi, Cristina

    2014-01-01

    Autosomal Recessive Osteopetrosis is a genetic disorder characterized by increased bone density due to lack of resorption by the osteoclasts. Genetic studies have widely unraveled the molecular basis of the most severe forms, while cases of intermediate severity are more difficult to characterize, probably because of a large heterogeneity. Here, we describe the use of exome sequencing in the molecular diagnosis of 2 siblings initially thought to be affected by “intermediate osteopetrosis”, which identified a homozygous mutation in the CTSK gene. Prompted by this finding, we tested by Sanger sequencing 25 additional patients addressed to us for recessive osteopetrosis and found CTSK mutations in 4 of them. In retrospect, their clinical and radiographic features were found to be compatible with, but not typical for, Pycnodysostosis. We sought to identify modifier genes that might have played a role in the clinical manifestation of the disease in these patients, but our results were not informative. In conclusion, we underline the difficulties of differential diagnosis in some patients whose clinical appearance does not fit the classical malignant or benign picture and recommend that CTSK gene be included in the molecular diagnosis of high bone density conditions. PMID:24269275

  15. Whole exome sequencing identifies a homozygous nonsense variation in ALMS1 gene in a patient with syndromic obesity.

    PubMed

    Das Bhowmik, Aneek; Gupta, Neerja; Dalal, Ashwin; Kabra, Madhulika

    In the present study we report on genetic analysis in a patient with developmental delay, truncal obesity and vision problem, to find the causative mutation. Whole exome sequencing was performed on genomic DNA extracted from whole blood of the patient which revealed a homozygous nonsense variant (c.2816T>A) in exon 8 of ALMS1 gene that results in a stop codon and premature truncation at codon 939 (p.L939Ter) of the protein. The mutation was confirmed by Sanger sequencing. Exome sequencing was helpful in establishing diagnosis of Alstrom syndrome in this patient. This case highlights the utility of exome sequencing in clinical practice. Copyright © 2016 Asia Oceania Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.

  16. Genetic screening for PRA-associated mutations in multiple dog breeds shows that PRA is heterogeneous within and between breeds.

    PubMed

    Downs, Louise M; Hitti, Rebekkah; Pregnolato, Silvia; Mellersh, Cathryn S

    2014-03-01

    To assess the extent of progressive retinal atrophy (PRA) genetic heterogeneity within and between domestic dog breeds. DNA from 231 dogs with PRA, representing 36 breeds, was screened for 17 mutations previously associated with PRA in at least one breed of dog. Screening methods included amplified fragment size discrimination using gel electrophoresis or detection of fluorescence, (TaqMan(®) ; Life Technologies, Carlsbad, CA, USA) allelic discrimination, and Sanger sequencing. Of the 231 dogs screened, 129 were homozygous for a PRA-associated mutation, 29 dogs were carriers, and 73 were homozygous for the wild-type allele at all loci tested. In two of the 129 dogs, homozygous mutations were identified that had not previously been observed in the respective breeds: one Chinese Crested dog was homozygous for the RCD3-associated mutation usually found in the Cardigan Welsh Corgi, and one Standard Poodle was homozygous for the RCD4-associated mutation previously reported to segregate in Gordon and Irish Setters. In the majority of the breeds (15/21) in which a PRA-associated mutation is known to segregate, cases were identified that did not carry any of the known PRA-associated mutations. Progressive retinal atrophy in the dog displays significant genetic heterogeneity within as well as between breeds. There are also several instances where PRA-associated mutations segregate among breeds with no known close ancestry. © 2013 American College of Veterinary Ophthalmologists.

  17. Novel Homozygous Missense Mutation in RYR1 Leads to Severe Congenital Ptosis, Ophthalmoplegia, and Scoliosis in the Absence of Myopathy.

    PubMed

    Dilaver, Nafi; Mazaheri, Neda; Maroofian, Reza; Zeighami, Jawaher; Seifi, Tahere; Zamani, Mina; Sedaghat, Alireza; Shariati, Gholam Reza; Galehdari, Hamid

    2017-12-01

    Ryanodine receptor 1 ( RYR1 ) is an intracellular calcium receptor primarily expressed in skeletal muscle with a role in excitation contraction. Both dominant and recessive mutations in the RYR1 gene cause a range of RYR1 -related myopathies and/or susceptibility to malignant hyperthermia (MH). Recently, an atypical manifestation of ptosis, variably presenting with ophthalmoplegia, facial paralysis, and scoliosis but without significant muscle weakness, has been reported in 9 cases from 4 families with bialleic variants in RYR1 . Two affected children from a consanguineous family with severe congenital ptosis, ophthalmoplegia, scoliosis, and distinctive long faces but without skeletal myopathy were studied. To identify the cause of the hereditary condition, DNA from the proband was subjected to whole exome sequencing (WES). WES revealed a novel homozygous missense variant in RYR1 (c.14066T>A; p.IIe4689Asn), which segregated within the family. Although the phenotype of the affected siblings in this study was similar to previously described cases, the clinical features were more severely expressed. Our findings contribute to the expansion of phenotypes related to RYR1 dysfunction. Additionally, it supports a new RYR1 -related clinical presentation without musculoskeletal involvement. It is important that individuals with RYR1 mutations are considered susceptible to MH, as 70% of the MH cases are caused by mutations in the RYR1 gene.

  18. Odonto-onycho-dermal dysplasia in a patient homozygous for a WNT10A nonsense mutation and mild manifestations of ectodermal dysplasia in carriers of the mutation.

    PubMed

    Krøigård, Anne Bruun; Clemmensen, Ole; Gjørup, Hans; Hertz, Jens Michael; Bygum, Anette

    2016-03-10

    Odonto-onycho-dermal dysplasia (OODD) is a rare form of ectodermal dysplasia characterized by severe oligodontia, onychodysplasia, palmoplantar hyperkeratosis, dry skin, hypotrichosis, and hyperhidrosis of the palms and soles. The ectodermal dysplasias resulting from biallelic mutations in the WNT10A gene result in highly variable phenotypes, ranging from isolated tooth agenesis to OODD and Schöpf-Schulz-Passarge syndrome (SSPS). We identified a female patient, with consanguineous parents, who was clinically diagnosed with OODD. Genetic testing showed that she was homozygous for a previously reported pathogenic mutation in the WNT10A gene, c.321C > A, p.Cys107*. The skin and nail abnormalities were for many years interpreted as psoriasis and treated accordingly. A thorough clinical examination revealed hypotrichosis and hyperhidrosis of the soles and dental examination revealed agenesis of permanent teeth except the two maxillary central incisors. Skin biopsies from the hyperkeratotic palms and soles showed the characteristic changes of eccrine syringofibroadenomatosis, which has been described in patients with ectodermal dysplasias. Together with a family history of tooth anomalies, this lead to the clinical suspicion of a hereditary ectodermal dysplasia. This case illustrates the challenges of diagnosing ectodermal dysplasia like OODD and highlights the relevance of interdisciplinary cooperation in the diagnosis of rare conditions.

  19. Aromatase Deficiency due to a Homozygous CYP19A1 Mutation in a 46,XX Egyptian Patient with Ambiguous Genitalia.

    PubMed

    Mazen, Inas; McElreavey, Ken; Elaidy, Aya; Kamel, Alaa K; Abdel-Hamid, Mohamed S

    2017-01-01

    Aromatase deficiency (AD) is a very rare disorder resulting from mutations in the CYP19A1 gene encoding aromatase, a cytochrome P450 enzyme that plays a pivotal role in androgen conversion to estrogens. AD is inherited in an autosomal recessive trait, and to date only 35 cases have been described in the literature. Herein, we depict a new patient reared as a male, who presented at the age of 21 years with no palpable testis, hypoplastic scrotum, penis-like phallus (3 cm), and penoscrotal hypospadias. The patient was born to consanguineous parents, his karyotype was 46,XX, and SRY was negative. Pelvic sonar showed a small hypoplastic uterus, and no testis could be identified. Serum testosterone was within the reference range of females along with high gonadotropins. Pathology of gonadal biopsy showed ovarian stroma negative for oocytic follicle consistent with streak gonads. All these data were suggestive of AD, which was subsequently confirmed by molecular investigation of the CYP19A1 gene. A homozygous splice site mutation in the donor splice site of exon 9 was identified, c.1263 + 1G>T. This is the first report of such a rare disorder in an Egyptian patient. Our results reinforce the importance of considering AD in patients with 46,XX disorders of sex development after ruling out congenital adrenal hyperplasia. © 2018 S. Karger AG, Basel.

  20. Efficacy of Rosuvastatin in Children With Homozygous Familial Hypercholesterolemia and Association With Underlying Genetic Mutations.

    PubMed

    Stein, Evan A; Dann, Eldad J; Wiegman, Albert; Skovby, Flemming; Gaudet, Daniel; Sokal, Etienne; Charng, Min-Ji; Mohamed, Mafauzy; Luirink, Ilse; Raichlen, Joel S; Sundén, Mattias; Carlsson, Stefan C; Raal, Frederick J; Kastelein, John J P

    2017-08-29

    Homozygous familial hypercholesterolemia (HoFH), a rare genetic disorder, is characterized by extremely elevated levels of low-density lipoprotein cholesterol (LDL-C) and accelerated atherosclerotic cardiovascular disease. Statin treatment starts at diagnosis, but no statin has been formally evaluated in, or approved for, HoFH children. The authors sought to assess the LDL-C efficacy of rosuvastatin versus placebo in HoFH children, and the relationship with underlying genetic mutations. This was a randomized, double-blind, 12-week, crossover study of rosuvastatin 20 mg versus placebo, followed by 12 weeks of open-label rosuvastatin. Patients discontinued all lipid-lowering treatment except ezetimibe and/or apheresis. Clinical and laboratory assessments were performed every 6 weeks. The relationship between LDL-C response and genetic mutations was assessed by adding children and adults from a prior HoFH rosuvastatin trial. Twenty patients were screened, 14 randomized, and 13 completed the study. The mean age was 10.9 years; 8 patients were on ezetimibe and 7 on apheresis. Mean LDL-C was 481 mg/dl (range: 229 to 742 mg/dl) on placebo and 396 mg/dl (range: 130 to 700 mg/dl) on rosuvastatin, producing a mean 85.4 mg/dl (22.3%) difference (p = 0.005). Efficacy was similar regardless of age or use of ezetimibe or apheresis, and was maintained for 12 weeks. Adverse events were few and not serious. Patients with 2 defective versus 2 negative LDL receptor mutations had mean LDL-C reductions of 23.5% (p = 0.0044) and 14% (p = 0.038), respectively. This first-ever pediatric HoFH statin trial demonstrated safe and effective LDL-C reduction with rosuvastatin 20 mg alone or added to ezetimibe and/or apheresis. The LDL-C response in children and adults was related to underlying genetic mutations. (A Study to Evaluate the Efficacy and Safety of Rosuvastatin in Children and Adolescents With Homozygous Familial Hypercholesterolemia [HYDRA]; NCT02226198

  1. Exome sequencing in schizophrenic patients with high levels of homozygosity identifies novel and extremely rare mutations in the GABA/glutamatergic pathways.

    PubMed

    Giacopuzzi, Edoardo; Gennarelli, Massimo; Minelli, Alessandra; Gardella, Rita; Valsecchi, Paolo; Traversa, Michele; Bonvicini, Cristian; Vita, Antonio; Sacchetti, Emilio; Magri, Chiara

    2017-01-01

    Inbreeding is a known risk factor for recessive Mendelian diseases and previous studies have suggested that it could also play a role in complex disorders, such as psychiatric diseases. Recent inbreeding results in the presence of long runs of homozygosity (ROHs) along the genome, which are also defined as autozygosity regions. Genetic variants in these regions have two alleles that are identical by descent, thus increasing the odds of bearing rare recessive deleterious mutations due to a homozygous state. A recent study showed a suggestive enrichment of long ROHs in schizophrenic patients, suggesting that recent inbreeding could play a role in the disease. To better understand the impact of autozygosity on schizophrenia risk, we selected, from a cohort of 180 Italian patients, seven subjects with extremely high numbers of large ROHs that were likely due to recent inbreeding and characterized the mutational landscape within their ROHs using Whole Exome Sequencing and, gene set enrichment analysis. We identified a significant overlap (17%; empirical p-value = 0.0171) between genes inside ROHs affected by low frequency functional homozygous variants (107 genes) and the group of most promising candidate genes mutated in schizophrenia. Moreover, in four patients, we identified novel and extremely rare damaging mutations in the genes involved in neurodevelopment (MEGF8) and in GABA/glutamatergic synaptic transmission (GAD1, FMN1, ANO2). These results provide insights into the contribution of rare recessive mutations and inbreeding as risk factors for schizophrenia. ROHs that are likely due to recent inbreeding harbor a combination of predisposing low-frequency variants and extremely rare variants that have a high impact on pivotal biological pathways implicated in the disease. In addition, this study confirms that focusing on patients with high levels of homozygosity could be a useful prioritization strategy for discovering new high-impact mutations in genetically

  2. Mutations in WNT1 Cause Different Forms of Bone Fragility

    PubMed Central

    Keupp, Katharina; Beleggia, Filippo; Kayserili, Hülya; Barnes, Aileen M.; Steiner, Magdalena; Semler, Oliver; Fischer, Björn; Yigit, Gökhan; Janda, Claudia Y.; Becker, Jutta; Breer, Stefan; Altunoglu, Umut; Grünhagen, Johannes; Krawitz, Peter; Hecht, Jochen; Schinke, Thorsten; Makareeva, Elena; Lausch, Ekkehart; Cankaya, Tufan; Caparrós-Martín, José A.; Lapunzina, Pablo; Temtamy, Samia; Aglan, Mona; Zabel, Bernhard; Eysel, Peer; Koerber, Friederike; Leikin, Sergey; Garcia, K. Christopher; Netzer, Christian; Schönau, Eckhard; Ruiz-Perez, Victor L.; Mundlos, Stefan; Amling, Michael; Kornak, Uwe; Marini, Joan; Wollnik, Bernd

    2013-01-01

    We report that hypofunctional alleles of WNT1 cause autosomal-recessive osteogenesis imperfecta, a congenital disorder characterized by reduced bone mass and recurrent fractures. In consanguineous families, we identified five homozygous mutations in WNT1: one frameshift mutation, two missense mutations, one splice-site mutation, and one nonsense mutation. In addition, in a family affected by dominantly inherited early-onset osteoporosis, a heterozygous WNT1 missense mutation was identified in affected individuals. Initial functional analysis revealed that altered WNT1 proteins fail to activate canonical LRP5-mediated WNT-regulated β-catenin signaling. Furthermore, osteoblasts cultured in vitro showed enhanced Wnt1 expression with advancing differentiation, indicating a role of WNT1 in osteoblast function and bone development. Our finding that homozygous and heterozygous variants in WNT1 predispose to low-bone-mass phenotypes might advance the development of more effective therapeutic strategies for congenital forms of bone fragility, as well as for common forms of age-related osteoporosis. PMID:23499309

  3. Homozygosity for a newly identified missense mutation in a patient with very severe combined immunodeficiency due to adenosine deaminase deficiency (ADA-SCID).

    PubMed Central

    Hirschhorn, R; Chakravarti, V; Puck, J; Douglas, S D

    1991-01-01

    We have identified a previously unrecognized missense mutation in a patient with severe combined immunodeficiency due to adenosine deaminase deficiency (ADA-SCID). The mutation is a G646-to-A transition at a CG dinucleotide and predicts a glycine-to-arginine substitution at codon 216. Computer analysis of secondary structure predicts a major alteration with loss of a beta-pleated sheet in a highly conserved region of the protein. The basepair substitution also generates a new site for the restriction enzyme BstXI in exon 7 of the genomic DNA. Digestion of genomic DNA from the patient and from his parents revealed that he was homozygous for the mutation and that his mother and father were carriers. This mutation in homozygous form appears to be associated with very severe disease, since the patient had perinatal onset of clinical manifestations of SCID, the highest concentration of the toxic metabolite deoxyATP in nine patients studied, and a relatively poor immunologic response during the initial 2 years of therapy with polyethylene glycol-adenosine deaminase. Analysis of DNA from 21 additional patients with ADA-SCID and from 19 unrelated normals revealed that, while none of the normal individuals showed the abnormal restriction fragment, two of the 21 patients studied were heterozygous for the G646-to-A mutation. Images Figure 2 PMID:1680289

  4. Uncommon runs of homozygosity disclose homozygous missense mutations in two ciliopathy-related genes (SPAG17 and WDR35) in a patient with multiple brain and skeletal anomalies.

    PubMed

    Córdova-Fletes, Carlos; Becerra-Solano, Luis E; Rangel-Sosa, Martha M; Rivas-Estilla, Ana María; Alberto Galán-Huerta, Kame; Ortiz-López, Rocío; Rojas-Martínez, Augusto; Juárez-Vázquez, Clara I; García-Ortiz, José E

    2018-03-01

    We describe a patient severely affected with multiple congenital anomalies, including brain malformations and skeletal dysplasia suggestive of cranioectodermal dysplasia (CED) ciliopathy, who unusually carries several homozygosity tracts involving homozygous missense mutations in SPAG17 (exon 8; c.1069G > C; p.Asp357His) and WDR35 (exon 13; c.1415G > A; p.Arg472Gln) as revealed by homozygosity mapping and next generation sequencing. SPAG17 is essential for the function and structure of motile cilia, while WDR35 belongs to the same intraflagellar transport (IFT) gene family whose protein products are part of functional IFT A and B complexes. Formerly, SPAG17 was related - through polymorphic variants - to an influence on individuals' height; more recently, Spag17-/- mice models were reported to present skeletal and bone defects, reduced mucociliary clearance, respiratory distress, and cerebral ventricular enlargement. Homozygous or compound heterozygous mutations in WDR35 have mainly been related to CED2 or short-rib thoracic dysplasia 7, with only three cases showing some brain anomalies. Given that our patient presents these clinical features and the close functional relationship between SPAG17 and WDR35, it is feasible that the combined effects from both mutations contribute to his phenotype. To our knowledge, this patient is the first to harbor a likely pathogenic homozygous mutation in both genes at the same time. Thus, the resulting complex phenotype of this patient illustrates the heterogeneity associated with ciliopathies and further expands the clinical and mutational spectrum of these diseases. Finally, we highlight the combined use of high-throughput tools to diagnose and support the proper handling of this and other patients. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  5. Whole-exome sequencing identified a homozygous FNBP4 mutation in a family with a condition similar to microphthalmia with limb anomalies.

    PubMed

    Kondo, Yukiko; Koshimizu, Eriko; Megarbane, Andre; Hamanoue, Haruka; Okada, Ippei; Nishiyama, Kiyomi; Kodera, Hirofumi; Miyatake, Satoko; Tsurusaki, Yoshinori; Nakashima, Mitsuko; Doi, Hiroshi; Miyake, Noriko; Saitsu, Hirotomo; Matsumoto, Naomichi

    2013-07-01

    Microphthalmia with limb anomalies (MLA), also known as Waardenburg anophthalmia syndrome or ophthalmoacromelic syndrome, is a rare autosomal recessive disorder. Recently, we and others successfully identified SMOC1 as the causative gene for MLA. However, there are several MLA families without SMOC1 abnormality, suggesting locus heterogeneity in MLA. We aimed to identify a pathogenic mutation in one Lebanese family having an MLA-like condition without SMOC1 mutation by whole-exome sequencing (WES) combined with homozygosity mapping. A c.683C>T (p.Thr228Met) in FNBP4 was found as a primary candidate, drawing the attention that FNBP4 and SMOC1 may potentially modulate BMP signaling. Copyright © 2013 Wiley Periodicals, Inc.

  6. Evolutionary Analysis Predicts Sensitive Positions of MMP20 and Validates Newly- and Previously-Identified MMP20 Mutations Causing Amelogenesis Imperfecta

    PubMed Central

    Gasse, Barbara; Prasad, Megana; Delgado, Sidney; Huckert, Mathilde; Kawczynski, Marzena; Garret-Bernardin, Annelyse; Lopez-Cazaux, Serena; Bailleul-Forestier, Isabelle; Manière, Marie-Cécile; Stoetzel, Corinne; Bloch-Zupan, Agnès; Sire, Jean-Yves

    2017-01-01

    Amelogenesis imperfecta (AI) designates a group of genetic diseases characterized by a large range of enamel disorders causing important social and health problems. These defects can result from mutations in enamel matrix proteins or protease encoding genes. A range of mutations in the enamel cleavage enzyme matrix metalloproteinase-20 gene (MMP20) produce enamel defects of varying severity. To address how various alterations produce a range of AI phenotypes, we performed a targeted analysis to find MMP20 mutations in French patients diagnosed with non-syndromic AI. Genomic DNA was isolated from saliva and MMP20 exons and exon-intron boundaries sequenced. We identified several homozygous or heterozygous mutations, putatively involved in the AI phenotypes. To validate missense mutations and predict sensitive positions in the MMP20 sequence, we evolutionarily compared 75 sequences extracted from the public databases using the Datamonkey webserver. These sequences were representative of mammalian lineages, covering more than 150 million years of evolution. This analysis allowed us to find 324 sensitive positions (out of the 483 MMP20 residues), pinpoint functionally important domains, and build an evolutionary chart of important conserved MMP20 regions. This is an efficient tool to identify new- and previously-identified mutations. We thus identified six functional MMP20 mutations in unrelated families, finding two novel mutated sites. The genotypes and phenotypes of these six mutations are described and compared. To date, 13 MMP20 mutations causing AI have been reported, making these genotypes and associated hypomature enamel phenotypes the most frequent in AI. PMID:28659819

  7. Evolutionary Analysis Predicts Sensitive Positions of MMP20 and Validates Newly- and Previously-Identified MMP20 Mutations Causing Amelogenesis Imperfecta.

    PubMed

    Gasse, Barbara; Prasad, Megana; Delgado, Sidney; Huckert, Mathilde; Kawczynski, Marzena; Garret-Bernardin, Annelyse; Lopez-Cazaux, Serena; Bailleul-Forestier, Isabelle; Manière, Marie-Cécile; Stoetzel, Corinne; Bloch-Zupan, Agnès; Sire, Jean-Yves

    2017-01-01

    Amelogenesis imperfecta (AI) designates a group of genetic diseases characterized by a large range of enamel disorders causing important social and health problems. These defects can result from mutations in enamel matrix proteins or protease encoding genes. A range of mutations in the enamel cleavage enzyme matrix metalloproteinase-20 gene ( MMP20 ) produce enamel defects of varying severity. To address how various alterations produce a range of AI phenotypes, we performed a targeted analysis to find MMP20 mutations in French patients diagnosed with non-syndromic AI. Genomic DNA was isolated from saliva and MMP20 exons and exon-intron boundaries sequenced. We identified several homozygous or heterozygous mutations, putatively involved in the AI phenotypes. To validate missense mutations and predict sensitive positions in the MMP20 sequence, we evolutionarily compared 75 sequences extracted from the public databases using the Datamonkey webserver. These sequences were representative of mammalian lineages, covering more than 150 million years of evolution. This analysis allowed us to find 324 sensitive positions (out of the 483 MMP20 residues), pinpoint functionally important domains, and build an evolutionary chart of important conserved MMP20 regions. This is an efficient tool to identify new- and previously-identified mutations. We thus identified six functional MMP20 mutations in unrelated families, finding two novel mutated sites. The genotypes and phenotypes of these six mutations are described and compared. To date, 13 MMP20 mutations causing AI have been reported, making these genotypes and associated hypomature enamel phenotypes the most frequent in AI.

  8. The homozygous VHL(D126N) missense mutation is associated with dramatically elevated erythropoietin levels, consequent polycythemia, and early onset severe pulmonary hypertension.

    PubMed

    Sarangi, Susmita; Lanikova, Lucie; Kapralova, Katarina; Acharya, Suchitra; Swierczek, Sabina; Lipton, Jeffrey M; Wolfe, Lawrence; Prchal, Josef T

    2014-11-01

    von Hippel-Lindau (VHL) protein is the principal negative regulator of hypoxia sensing mediated by transcription factors. Mutations in exon 3 of the VHL gene lead to Chuvash (VHL(R200W)) and Croatian (VHL(H191D)) polycythemias. Here, we describe an infant of Bangladesh ethnicity with a novel homozygous VHL(D126N) mutation with congenital polycythemia and dramatically elevated erythropoietin (EPO) levels, who developed severe fatal pulmonary hypertension. In contrast to Chuvash polycythemia, erythroid progenitors (BFU-Es) did not reveal a marked EPO hypersensitivity. Further, NF-E2 and RUNX1 transcripts that correlate with BFU-Es EPO hypersensitivity in polycythemic mutations were not elevated. © 2014 Wiley Periodicals, Inc.

  9. A homozygous mutation in SLC1A4 in siblings with severe intellectual disability and microcephaly.

    PubMed

    Srour, M; Hamdan, F F; Gan-Or, Z; Labuda, D; Nassif, C; Oskoui, M; Gana-Weisz, M; Orr-Urtreger, A; Rouleau, G A; Michaud, J L

    2015-07-01

    We performed exome analysis in two affected siblings with severe intellectual disability (ID), microcephaly and spasticity from an Ashkenazi Jewish consanguineous family. We identified only one rare variant, a missense in SLC1A4 (c. 766G>A [p. E256K]), that is homozygous in both siblings but not in any of their 11 unaffected siblings or their parents (Logarithm of odds, LOD score: 2.6). This variant is predicted damaging. We genotyped 450 controls of Ashkenazi Jewish ancestry and identified only 5 individuals who are heterozygous for this variant (minor allele frequency: 0.0056). SLC1A4 (ASCT1) encodes a transporter for neutral aminoacids such as alanine, serine, cysteine and threonine. L-Serine is essential for neuronal survival and differentiation. Indeed, L-serine biosynthesis disorders affect brain development and cause severe ID. In the brain, L-serine is synthesized in astrocytes but not in neurons. It has been proposed that ASCT1 mediates the uptake of L-serine into neurons and the release of glia-borne L-serine to neighboring cells. SLC1A4 disruption may thus impair brain development and function by decreasing the levels of L-serine in neurons. The identification of additional families with mutations in SLC1A4 would be necessary to confirm its involvement in ID. © 2015 John Wiley | Clinical Exome Genome Reports.

  10. Copy number neutral loss of heterozygosity at 17p and homozygous mutations of TP53 are associated with complex chromosomal aberrations in patients newly diagnosed with myelodysplastic syndromes.

    PubMed

    Svobodova, Karla; Zemanova, Zuzana; Lhotska, Halka; Novakova, Milena; Podskalska, Lucie; Belickova, Monika; Brezinova, Jana; Sarova, Iveta; Izakova, Silvia; Lizcova, Libuse; Berkova, Adela; Siskova, Magda; Jonasova, Anna; Cermak, Jaroslav; Michalova, Kyra

    2016-03-01

    Complex karyotypes are seen in approximately 20% of patients with myelodysplastic syndromes (MDS) and are associated with a high risk of transformation to acute myeloid leukemia and poor outcomes in patients. Copy number neutral loss of heterozygosity (CN-LOH, i.e., both copies of a chromosomal pair or their parts originate from one parent) might contribute to increased genomic instability in the bone-marrow cells of patients with MDS. The pathological potential of CN-LOH, which arises as a clonal aberration in a proportion of somatic cells, consists of tumor suppressor gene and oncogene homozygous mutations. The aim of our study was to evaluate the frequency of CN-LOH at 17p in bone-marrow cells of newly diagnosed MDS patients with complex chromosomal aberrations and to assess its correlation with mutations in the TP53 gene (17p13.1). CN-LOH was detected in 40 chromosomal regions in 21 (29%) of 72 patients analyzed. The changes in 27 of the 40 regions identified were sporadic. The most common finding was CN-LOH of the short arm of chromosome 17, which was detected in 13 (18%) of 72 patients. A mutational analysis confirmed the homozygous mutation of TP53 in all CN-LOH 17p patients, among which two frameshift mutations are not registered in the International Agency for Research on Cancer TP53 Database. CN-LOH 17p correlated with aggressive disease (median overall survival 4 months) and was strongly associated with a complex karyotype in the cohort studied, which might cause rapid disease progression in high-risk MDS. No other CN-LOH region previously recorded in MDS or AML patients (1p, 4q, 7q, 11q, 13q, 19q, 21q) was detected in our cohort of patients with complex karyotype examined at the diagnosis of MDS. The LOH region appeared to be balanced (i.e., with no DNA copy number change) when examined with conventional and molecular cytogenetic methods. Therefore, a microarray that detects single-nucleotide polymorphisms is an ideal method with which to identify and

  11. Exome sequencing identifies CTSK mutations in patients originally diagnosed as intermediate osteopetrosis.

    PubMed

    Pangrazio, Alessandra; Puddu, Alessandro; Oppo, Manuela; Valentini, Maria; Zammataro, Luca; Vellodi, Ashok; Gener, Blanca; Llano-Rivas, Isabel; Raza, Jamal; Atta, Irum; Vezzoni, Paolo; Superti-Furga, Andrea; Villa, Anna; Sobacchi, Cristina

    2014-02-01

    Autosomal Recessive Osteopetrosis is a genetic disorder characterized by increased bone density due to lack of resorption by the osteoclasts. Genetic studies have widely unraveled the molecular basis of the most severe forms, while cases of intermediate severity are more difficult to characterize, probably because of a large heterogeneity. Here, we describe the use of exome sequencing in the molecular diagnosis of 2 siblings initially thought to be affected by "intermediate osteopetrosis", which identified a homozygous mutation in the CTSK gene. Prompted by this finding, we tested by Sanger sequencing 25 additional patients addressed to us for recessive osteopetrosis and found CTSK mutations in 4 of them. In retrospect, their clinical and radiographic features were found to be compatible with, but not typical for, Pycnodysostosis. We sought to identify modifier genes that might have played a role in the clinical manifestation of the disease in these patients, but our results were not informative. In conclusion, we underline the difficulties of differential diagnosis in some patients whose clinical appearance does not fit the classical malignant or benign picture and recommend that CTSK gene be included in the molecular diagnosis of high bone density conditions. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

  12. An Indian child with Kindler syndrome resulting from a new homozygous nonsense mutation (C468X) in the KIND1 gene.

    PubMed

    Sethuraman, G; Fassihi, H; Ashton, G H S; Bansal, A; Kabra, M; Sharma, V K; McGrath, J A

    2005-05-01

    Kindler syndrome is an inherited skin condition that presents with blistering followed by photosensitivity and a progressive poikiloderma. The disorder results from mutations in the KIND1 gene, encoding the protein kindlin-1, a recently characterized 677-amino acid protein involved in anchorage of the actin cytoskeleton to the extracellular matrix. We report the clinical features of an 11-year-old boy with Kindler syndrome from a consanguineous Indian family and the identification of a homozygous nonsense mutation (C468X) in exon 12 of the KIND1 gene in his genomic DNA. This mutation has not been described previously but is similar to the 17 previously published KIND1 mutations that are all predicted to lead to loss of kindlin-1 protein expression and function. The clinical features in this boy highlight the relevance of kindlin-1 in skin biology, specifically to epidermal adhesion and response to acute and chronic sun exposure. Delineation of this new pathogenic mutation in KIND1 is also useful for genetic counselling in this family and in assessing carrier status in unaffected family members.

  13. Impact of the A2V Mutation on the Heterozygous and Homozygous Aβ1-40 Dimer Structures from Atomistic Simulations.

    PubMed

    Nguyen, Phuong H; Sterpone, Fabio; Campanera, Josep M; Nasica-Labouze, Jessica; Derreumaux, Philippe

    2016-06-15

    The A2V mutation was reported to protect from Alzheimer's disease in its heterozygous form and cause an early Alzheimer's disease type dementia in its homozygous form. Experiments showed that the aggregation rate follows the order A2V > WT (wild-type) > A2V-WT. To understand the impact of this mutation, we carried out replica exchange molecular dynamics simulations of Aβ1-40 WT-A2V and A2V-A2V dimers and compared to the WT dimer. Our atomistic simulations reveal that the mean secondary structure remains constant, but there are substantial differences in the intramolecular and intermolecular conformations upon single and double A2V mutation. Upon single mutation, the intrinsic disorder is reduced, the intermolecular potential energies are reduced, the population of intramolecular three-stranded β-sheets is increased, and the number of all α dimer topologies is decreased. Taken together, these results offer an explanation for the reduced aggregation rate of the Aβ1-40 A2V-WT peptides and the protective effect of A2V in heterozygotes.

  14. Pathogenic mutations in TULP1 responsible for retinitis pigmentosa identified in consanguineous familial cases

    PubMed Central

    Ullah, Inayat; Kabir, Firoz; Iqbal, Muhammad; Gottsch, Clare Brooks S.; Naeem, Muhammad Asif; Assir, Muhammad Zaman; Khan, Shaheen N.; Akram, Javed; Riazuddin, Sheikh; Ayyagari, Radha; Hejtmancik, J. Fielding

    2016-01-01

    Purpose To identify pathogenic mutations responsible for autosomal recessive retinitis pigmentosa (arRP) in consanguineous familial cases. Methods Seven large familial cases with multiple individuals diagnosed with retinitis pigmentosa were included in the study. Affected individuals in these families underwent ophthalmic examinations to document the symptoms and confirm the initial diagnosis. Blood samples were collected from all participating members, and genomic DNA was extracted. An exclusion analysis with microsatellite markers spanning the TULP1 locus on chromosome 6p was performed, and two-point logarithm of odds (LOD) scores were calculated. All coding exons along with the exon–intron boundaries of TULP1 were sequenced bidirectionally. We constructed a single nucleotide polymorphism (SNP) haplotype for the four familial cases harboring the K489R allele and estimated the likelihood of a founder effect. Results The ophthalmic examinations of the affected individuals in these familial cases were suggestive of RP. Exclusion analyses confirmed linkage to chromosome 6p harboring TULP1 with positive two-point LOD scores. Subsequent Sanger sequencing identified the single base pair substitution in exon14, c.1466A>G (p.K489R), in four families. Additionally, we identified a two-base deletion in exon 4, c.286_287delGA (p.E96Gfs77*); a homozygous splice site variant in intron 14, c.1495+4A>C; and a novel missense variation in exon 15, c.1561C>T (p.P521S). All mutations segregated with the disease phenotype in the respective families and were absent in ethnically matched control chromosomes. Haplotype analysis suggested (p<10−6) that affected individuals inherited the causal mutation from a common ancestor. Conclusions Pathogenic mutations in TULP1 are responsible for the RP phenotype in seven familial cases with a common ancestral mutation responsible for the disease phenotype in four of the seven families. PMID:27440997

  15. A SIGMAR1 splice-site mutation causes distal hereditary motor neuropathy.

    PubMed

    Li, Xiaobo; Hu, Zhengmao; Liu, Lei; Xie, Yongzhi; Zhan, Yajing; Zi, Xiaohong; Wang, Junling; Wu, Lixiang; Xia, Kun; Tang, Beisha; Zhang, Ruxu

    2015-06-16

    To identify the underlying genetic cause in a consanguineous Chinese family segregating distal hereditary motor neuropathy (dHMN) in an autosomal recessive pattern. We used whole-exome sequencing and homozygosity mapping to detect the genetic variant in 2 affected individuals of the consanguineous Chinese family with dHMN. RNA analysis of peripheral blood leukocytes and immunofluorescence and immunoblotting of stable cell lines were performed to support the pathogenicity of the identified mutation. We identified 3 shared novel homozygous variants in 3 shared homozygous regions of the affected individuals. Sequencing of these 3 variants in family members revealed the c.151+1G>T mutation in SIGMAR1 gene, which located in homozygous region spanning approximately 5.3 Mb at chromosome 9p13.1-p13.3, segregated with the dHMN phenotype. The mutation causes an alternative splicing event and generates a transcript variant with an in-frame deletion of 60 base pairs in exon 1 (c.92_151del), and results in an internally shortened protein σ1R(31_50del). The proteasomal inhibitor treatment increased the intracellular amount of σ1R(31_50del) and led to the formation of nuclear aggregates. Stable expressing σ1R(31_50del) induced endoplasmic reticulum stress and enhanced apoptosis. The homozygous c.151+1G>T mutation in SIGMAR1 caused a novel form of autosomal recessive dHMN in a Chinese consanguineous family. Endoplasmic reticulum stress may have a role in the pathogenesis of dHMN. © 2015 American Academy of Neurology.

  16. Biallelic germline and somatic mutations in malignant mesothelioma: multiple mutations in transcription regulators including mSWI/SNF genes.

    PubMed

    Yoshikawa, Yoshie; Sato, Ayuko; Tsujimura, Tohru; Otsuki, Taiichiro; Fukuoka, Kazuya; Hasegawa, Seiki; Nakano, Takashi; Hashimoto-Tamaoki, Tomoko

    2015-02-01

    We detected low levels of acetylation for histone H3 tail lysines in malignant mesothelioma (MM) cell lines resistant to histone deacetylase inhibitors. To identify the possible genetic causes related to the low histone acetylation levels, whole-exome sequencing was conducted with MM cell lines established from eight patients. A mono-allelic variant of BRD1 was common to two MM cell lines with very low acetylation levels. We identified 318 homozygous protein-damaging variants/mutations (18-78 variants/mutations per patient); annotation analysis showed enrichment of the molecules associated with mammalian SWI/SNF (mSWI/SNF) chromatin remodeling complexes and co-activators that facilitate initiation of transcription. In seven of the patients, we detected a combination of variants in histone modifiers or transcription factors/co-factors, in addition to variants in mSWI/SNF. Direct sequencing showed that homozygous mutations in SMARCA4, PBRM1 and ARID2 were somatic. In one patient, homozygous germline variants were observed for SMARCC1 and SETD2 in chr3p22.1-3p14.2. These exhibited extended germline homozygosity and were in regions containing somatic mutations, leading to a loss of BAP1 and PBRM1 expression in MM cell line. Most protein-damaging variants were heterozygous in normal tissues. Heterozygous germline variants were often converted into hemizygous variants by mono-allelic deletion, and were rarely homozygous because of acquired uniparental disomy. Our findings imply that MM might develop through the somatic inactivation of mSWI/SNF complex subunits and/or histone modifiers, including BAP1, in subjects that have rare germline variants of these transcription regulators and/or transcription factors/co-factors, and in regions prone to mono-allelic deletion during oncogenesis. © 2014 UICC.

  17. Homozygous EEF1A2 mutation causes dilated cardiomyopathy, failure to thrive, global developmental delay, epilepsy and early death.

    PubMed

    Cao, Siqi; Smith, Laura L; Padilla-Lopez, Sergio R; Guida, Brandon S; Blume, Elizabeth; Shi, Jiahai; Morton, Sarah U; Brownstein, Catherine A; Beggs, Alan H; Kruer, Michael C; Agrawal, Pankaj B

    2017-09-15

    Eukaryotic elongation factor 1A (EEF1A), is encoded by two distinct isoforms, EEF1A1 and EEF1A2; whereas EEF1A1 is expressed almost ubiquitously, EEF1A2 expression is limited such that it is only detectable in skeletal muscle, heart, brain and spinal cord. Currently, the role of EEF1A2 in normal cardiac development and function is unclear. There have been several reports linking de novo dominant EEF1A2 mutations to neurological issues in humans. We report a pair of siblings carrying a homozygous missense mutation p.P333L in EEF1A2 who exhibited global developmental delay, failure to thrive, dilated cardiomyopathy and epilepsy, ultimately leading to death in early childhood. A third sibling also died of a similar presentation, but DNA was unavailable to confirm the mutation. Functional genomic analysis was performed in S. cerevisiae and zebrafish. In S. cerevisiae, there was no evidence for a dominant-negative effect. Previously identified putative de novo mutations failed to complement yeast strains lacking the EEF1A ortholog showing a major growth defect. In contrast, the introduction of the mutation seen in our family led to a milder growth defect. To evaluate its function in zebrafish, we knocked down eef1a2 expression using translation blocking and splice-site interfering morpholinos. EEF1A2-deficient zebrafish had skeletal muscle weakness, cardiac failure and small heads. Human EEF1A2 wild-type mRNA successfully rescued the morphant phenotype, but mutant RNA did not. Overall, EEF1A2 appears to be critical for normal heart function in humans, and its deficiency results in clinical abnormalities in neurologic function as well as in skeletal and cardiac muscle defects. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. Retinal phenotypic characterization of patients with ABCA4 retinopathydue to the homozygous p.Ala1773Val mutation

    PubMed Central

    López-Rubio, Salvador; Chacon-Camacho, Oscar F.; Matsui, Rodrigo; Guadarrama-Vallejo, Dalia; Astiazarán, Mirena C.

    2018-01-01

    Purpose To describe the retinal clinical features of a group of Mexican patients with Stargardt disease carrying the uncommon p.Ala1773Val founder mutation in ABCA4. Methods Ten patients carrying the p.Ala1773Val mutation, nine of them homozygously, were included. Visual function studies included best-corrected visual acuity, electroretinography, Goldmann kinetic visual fields, and full-field electroretinography (ERG). In addition, imaging studies, such as optical coherence tomography (OCT), short-wave autofluorescence imaging, and quantitative analyses of hypofluorescence, were performed in each patient. Results Best-corrected visual acuities ranged from 20/200 to 4/200. The median age of the patients at diagnosis was 23.3 years. The majority of the patients had photophobia and nyctalopia, and were classified as Fishman stage 4 (widespread choriocapillaris atrophy, resorption of flecks, and greatly reduced ERG amplitudes). An atypical retinal pigmentation pattern was observed in the patients, and the majority showed cone-rod dystrophy on full-field ERG. In vivo retinal microstructure assessment with OCT demonstrated central retinal thinning, variable loss of photoreceptors, and three different patterns of structural retinal degeneration. Two dissimilar patterns of abnormal autofluorescence were observed. No apparent age-related differences in the pattern of retinal degeneration were observed. Conclusions The results indicate that this particular mutation in ABCA4 is associated with a severe retinal phenotype and thus, could be classified as null. Careful phenotyping of patients carrying specific mutations in ABCA4 is essential to enhance our understanding of disease expression linked to particular mutations and the resulting genotype–phenotype correlations. PMID:29422768

  19. [A novel homozygous mutation p.E25X in the HSD3B2 gene causing salt wasting 3β-hydroxysteroid dehydrogenases deficiency in a Chinese pubertal girl: a delayed diagnosis until recurrent ovary cysts].

    PubMed

    Huang, Yonglan; Zheng, Jipeng; Xie, Ting; Xiao, Qing; Lu, Shaomei; Li, Xiuzhen; Cheng, Jing; Chen, Lihe; Liu, Li

    2014-12-01

    3β- hydroxysteroid dehydrogenase deficiency (3βHSD), a rare form of congenital adrenal hyperplasia (CAH) resulted from mutations in the HSD3B2 gene that impair steroidogenesis in both adrenals and gonads. We report clinical features and the results of HSD3B2 gene analysis of a Chinese pubertal girl with salt wasting 3βHSD deficiency. We retrospectively reviewed clinical presentations and steroid profiles of the patient diagnosed in Guangzhou Women and Children's Medical Center in 2013. PCR and direct sequencing were used to identify any mutation in the HSD3B2 gene. A 13-year-old girl was diagnosed as CAH after birth because of salt-wasting with mild clitorimegaly and then was treated with glucocorticoid replacement. Breast and pubic hair development were normal, and menarche occurred at 12 yr, followed by menstrual bleeding about every 45 days. In the last one year laparoscopic operation and ovariocentesis were performed one after another for recurrent ovary cysts. Under corticoid acetate therapy, ACTH 17.10 pmol/L (normal 0-10.12), testosterone 1.31 nmol/L (normal <0.7), dehydroepiandrosterone sulfate 13.30 µmol/L (normal 0.95 - 11.67), cortisol 720 nmol/L (normal 130-772.8), androstenedione, 17-hydroxyprogesterone and progesterone were normal. Estradiol 461 pmol/L, follicle-stimulating hormone 3.04 IU/L, luteinizing hormone 8.52 IU/L in follicular phase. A pelvic ultrasound showed lateral ovaries cysts (58 mm × 50 mm × 35 mm) and a midcycle-type endometrium. A novel nonsense mutation c.73G >T (p.E25X) was identified in HSD3B2 gene. The girl was homozygous and her mother was heterozygous, while her father was not identified with this mutation. A classic 3βHSD deficiency is characterized by salt wasting and mild virilization in female. Ovary cysts may be the one of features of gonad phenotype indicating ovary 3βHSD deficiency. A novel homozygous mutation c.73G >T(p.E25X) was related to the classical phenotype.

  20. Lumacaftor/ivacaftor, a novel agent for the treatment of cystic fibrosis patients who are homozygous for the F580del CFTR mutation.

    PubMed

    Bulloch, Marilyn N; Hanna, Cameron; Giovane, Richard

    2017-10-01

    Cystic Fibrosis (CF) is an autosomal recessive disease affecting up to 90,000 people worldwide. Approximately 73% of patients are homozygous for the F508del cystic fibrosis transmembrane conductance regulator [CFTR] mutation. Traditionally treatment has only included supportive care. Therefore, there is a need for safe and effective novel therapies targeting the underlying molecular defects seen with CF. Areas covered: In 2016, the Food and Drug Administration and the European Commission approved LUM/IVA (Orkambi), a CFTR modulator that includes both a CFTR corrector and potentiator, for CF patients homozygous for the F508del CFTR mutation. This article reviews the pharmacologic features, clinical efficacy, and safety of LUM/IVA and summarize the available pre-clinical and clinical data of LUM/IVA use. Expert commentary: LUM/IVA showed modest, but significant improvements from baseline in percent predicted FEV 1 (ppFEV 1 ) as well as a reduction in pulmonary exacerbations by 35% It was shown to be safe for short- and long-term use. Currently, LUM/IVA is the only oral agent in its class available and represents a milestone the development of therapies for the management of CF. Nonetheless, pharmacoeconomic data are necessary to justify its high cost before is use becomes standard of care.

  1. Case report of a novel homozygous splice site mutation in PLA2G6 gene causing infantile neuroaxonal dystrophy in a Sudanese family.

    PubMed

    Elsayed, Liena E O; Mohammed, Inaam N; Hamed, Ahlam A A; Elseed, Maha A; Salih, Mustafa A M; Yahia, Ashraf; Siddig, Rayan A; Amin, Mutaz; Koko, Mahmoud; Elbashir, Mustafa I; Ibrahim, Muntaser E; Brice, Alexis; Ahmed, Ammar E; Stevanin, Giovanni

    2018-05-08

    Infantile neuroaxonal dystrophy (INAD) is a rare hereditary neurological disorder caused by mutations in PLA2G6. The disease commonly affects children below 3 years of age and presents with delay in motor skills, optic atrophy and progressive spastic tetraparesis. Studies of INAD in Africa are extremely rare, and genetic studies from Sub Saharan Africa are almost non-existent. Two Sudanese siblings presented, at ages 18 and 24 months, with regression in both motor milestones and speech development and hyper-reflexia. Brain MRI showed bilateral and symmetrical T2/FLAIR hyperintense signal changes in periventricular areas and basal ganglia and mild cerebellar atrophy. Whole exome sequencing with confirmatory Sanger sequencing were performed for the two patients and healthy family members. A novel variant (NM_003560.2 c.1427 + 2 T > C) acting on a splice donor site and predicted to lead to skipping of exon 10 was found in PLA2G6. It was found in a homozygous state in the two patients and homozygous reference or heterozygous in five healthy family members. This variant has one very strong (loss of function mutation) and three supporting evidences for its pathogenicity (segregation with the disease, multiple computational evidence and specific patients' phenotype). Therefore this variant can be currently annotated as "pathogenic". This is the first study to report mutations in PLA2G6 gene in patients from Sudan.

  2. Clinical expression of patients with the D1152H CFTR mutation.

    PubMed

    Terlizzi, Vito; Carnovale, Vincenzo; Castaldo, Giuseppe; Castellani, Carlo; Cirilli, Natalia; Colombo, Carla; Corti, Fabiola; Cresta, Federico; D'Adda, Alice; Lucarelli, Marco; Lucidi, Vincenzina; Macchiaroli, Annamaria; Madarena, Elisa; Padoan, Rita; Quattrucci, Serena; Salvatore, Donatello; Zarrilli, Federica; Raia, Valeria

    2015-07-01

    Discordant results were reported on the clinical expression of subjects bearing the D1152H CFTR mutation, and also for the small number of cases reported so far. A retrospective review of clinical, genetic and biochemical data was performed from individuals homozygous or compound heterozygous for the D1152H mutation followed in 12 Italian cystic fibrosis (CF) centers. 89 subjects carrying at least D1152H on one allele were identified. 7 homozygous patients had very mild clinical expression. Over half of the 74 subjects compound heterozygous for D1152H and a I-II-III class mutation had borderline or pathological sweat test and respiratory or gastrointestinal symptoms; one third had pulmonary bacteria colonization and 10/74 cases had complications (i.e. diabetes, allergic bronchopulmonary aspergillosis, and hemoptysis). However, their clinical expression was less severe as compared to a group of CF patients homozygous for the F508del mutation. Finally, 8 subjects compound heterozygous for D1152H and a IV-V class mutation showed very mild disease. The natural history of subjects bearing the D1152H mutation is widely heterogeneous and is influenced by the mutation in trans. Copyright © 2014 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

  3. VWF mutations and new sequence variations identified in healthy controls are more frequent in the African-American population.

    PubMed

    Bellissimo, Daniel B; Christopherson, Pamela A; Flood, Veronica H; Gill, Joan Cox; Friedman, Kenneth D; Haberichter, Sandra L; Shapiro, Amy D; Abshire, Thomas C; Leissinger, Cindy; Hoots, W Keith; Lusher, Jeanne M; Ragni, Margaret V; Montgomery, Robert R

    2012-03-01

    Diagnosis and classification of VWD is aided by molecular analysis of the VWF gene. Because VWF polymorphisms have not been fully characterized, we performed VWF laboratory testing and gene sequencing of 184 healthy controls with a negative bleeding history. The controls included 66 (35.9%) African Americans (AAs). We identified 21 new sequence variations, 13 (62%) of which occurred exclusively in AAs and 2 (G967D, T2666M) that were found in 10%-15% of the AA samples, suggesting they are polymorphisms. We identified 14 sequence variations reported previously as VWF mutations, the majority of which were type 1 mutations. These controls had VWF Ag levels within the normal range, suggesting that these sequence variations might not always reduce plasma VWF levels. Eleven mutations were found in AAs, and the frequency of M740I, H817Q, and R2185Q was 15%-18%. Ten AA controls had the 2N mutation H817Q; 1 was homozygous. The average factor VIII level in this group was 99 IU/dL, suggesting that this variation may confer little or no clinical symptoms. This study emphasizes the importance of sequencing healthy controls to understand ethnic-specific sequence variations so that asymptomatic sequence variations are not misidentified as mutations in other ethnic or racial groups.

  4. CNGA3 mutations in two United Arab Emirates families with achromatopsia.

    PubMed

    Ahuja, Yachna; Kohl, Susanne; Traboulsi, Elias I

    2008-07-10

    ACHROMATOPSIA RESULTS FROM MUTATIONS IN ONE OF THREE GENES: cyclic nucleotide-gated channel, alpha-3 (CNGA3); cyclic nucleotide-gated channel, beta-3 (CNGB3); and guanine nucleotide-binding protein, alpha-transducing activity polypeptide 2 (GNAT2). We report the responsible mutations in two United Arab Emirates families who have this autosomal recessive disease. Clinical examinations were performed in seven patients from three nuclear families. Molecular genetic testing for common CNGA3 and CNGB3 mutations was undertaken using standard protocols. All patients were extremely light sensitive and had reduced visual acuity and no color perception. Fundus examinations did not show any visible abnormalities. After further pedigree analysis, two of the families were found to be linked through the paternal line. Two mutations in CNGA3 were identified: Arg283Trp and Gly397Val. Family A, the larger pedigree, had one branch in which two sisters and one brother were homozygous for the Gly397Val mutation and another branch in which a brother and sister were compound heterozygous for both aforenamed mutations. Family B, however, only had two brothers who were homozygous for the Arg283Trp mutation. Achromatopsia in these two United Arab Emirates families results from two different mutations in CNGA3. Two branches of the same pedigree had individuals with both homozygous and compound heterozygous disease, demonstrating a complex molecular pathology in this large family.

  5. Whole-exome sequencing, without prior linkage, identifies a mutation in LAMB3 as a cause of dominant hypoplastic amelogenesis imperfecta.

    PubMed

    Poulter, James A; El-Sayed, Walid; Shore, Roger C; Kirkham, Jennifer; Inglehearn, Chris F; Mighell, Alan J

    2014-01-01

    The conventional approach to identifying the defective gene in a family with an inherited disease is to find the disease locus through family studies. However, the rapid development and decreasing cost of next generation sequencing facilitates a more direct approach. Here, we report the identification of a frameshift mutation in LAMB3 as a cause of dominant hypoplastic amelogenesis imperfecta (AI). Whole-exome sequencing of three affected family members and subsequent filtering of shared variants, without prior genetic linkage, sufficed to identify the pathogenic variant. Simultaneous analysis of multiple family members confirms segregation, enhancing the power to filter the genetic variation found and leading to rapid identification of the pathogenic variant. LAMB3 encodes a subunit of Laminin-5, one of a family of basement membrane proteins with essential functions in cell growth, movement and adhesion. Homozygous LAMB3 mutations cause junctional epidermolysis bullosa (JEB) and enamel defects are seen in JEB cases. However, to our knowledge, this is the first report of dominant AI due to a LAMB3 mutation in the absence of JEB.

  6. Novel ITGB6 mutation in autosomal recessive amelogenesis imperfecta

    PubMed Central

    Seymen, F; Lee, K-E; Koruyucu, M; Gencay, K; Bayram, M; Tuna, EB; Lee, ZH; Kim, J-W

    2015-01-01

    Objective Hereditary defects in tooth enamel formation, amelogenesis imperfecta (AI), can be non-syndromic or syndromic phenotype. Integrins are signaling proteins that mediate cell–cell and cell–extracellular matrix communication, and their involvement in tooth development is well known. The purposes of this study were to identify genetic cause of an AI family and molecular pathogenesis underlying defective enamel formation. Materials and Methods We recruited a Turkish family with isolated AI and performed mutational analyses to clarify the underlying molecular genetic etiology. Results Autozygosity mapping and exome sequencing identified a novel homozygous ITGB6 transversion mutation in exon 4 (c.517G>C, p.Gly173Arg). The glycine at this position in the middle of the βI-domain is conserved among a wide range of vertebrate orthologs and human paralogs. Clinically, the enamel was generally thin and pitted with pigmentation. Thicker enamel was noted at the cervical area of the molars. Conclusions In this study, we identified a novel homozygous ITGB6 mutation causing isolated AI, and this advances the understanding of normal and pathologic enamel development. PMID:25431241

  7. Newly identified mutations at the CSN1S1 gene in Ethiopian goats affect casein content and coagulation properties of their milk.

    PubMed

    Mestawet, T A; Girma, A; Adnøy, T; Devold, T G; Vegarud, G E

    2013-08-01

    Very high casein content and good coagulation properties previously observed in some Ethiopian goat breeds led to investigating the αs1-casein (CSN1S1) gene in these breeds. Selected regions of the CSN1S1 gene were sequenced in 115 goats from 5 breeds (2 indigenous: Arsi-Bale and Somali, 1 exotic: Boer, and 2 crossbreeds: Boer × Arsi-Bale and Boer × Somali). The DNA analysis resulted in 35 new mutations: 3 in exons, 3 in the 5' untranslated region (UTR), and 29 in the introns. The mutations in exons that resulted in an amino acid shift were then picked to evaluate their influence on individual casein content (αs1-, αs2-, β-, and κ-CN), micellar size, and coagulation properties in the milk from the 5 goat breeds. A mutation at nucleotide 10657 (exon 10) involved a transversion: CAG→CCG, resulting in an amino acid exchange Gln77→Pro77. This mutation was associated with the indigenous breeds only. Two new mutations, at nucleotide 6072 (exon 4) and 12165 (exon 12), revealed synonymous transitions: GTC→GTT in Val15 and AGA→AGG in Arg100 of the mature protein. Transitions G→A and C→T at nucleotides 1374 and 1866, respectively, occurred in the 5' UTR, whereas the third mutation involved a transversion T→G at nucleotide location 1592. The goats were grouped into homozygote new (CC), homozygote reference (AA), and heterozygote (CA) based on the nucleotide that involved the transversion. The content of αs1-CN (15.32g/kg) in milk samples of goats homozygous (CC) for this newly identified mutation, Gln77→Pro77 was significantly higher than in milks of heterozygous (CA; 9.05g/kg) and reference (AA; 7.61g/kg) genotype animals. The αs2-, β-, and κ-CN contents showed a similar pattern. Milk from goats with a homozygous new mutation had significantly lower micellar size. Milk from both homozygote and heterozygote new-mutation goats had significantly shorter coagulation rate and stronger gel than the reference genotype. Except the transversion, the

  8. Charcot-Marie-Tooth disease type 2 caused by homozygous MME gene mutation superimposed by chronic inflammatory demyelinating polyneuropathy.

    PubMed

    Fujisawa, Miwako; Sano, Yasuteru; Omoto, Masatoshi; Ogasawara, Jyun-Ichi; Koga, Michiaki; Takashima, Hiroshi; Kanda, Takashi

    2017-09-30

    We report a 59-year-old Japanese male who developed gradually worsening weakness and numbness of distal four extremities since age 50. His parents were first cousins, and blood and cerebral spinal examinations were unremarkable. Homozygous mutation of MME gene was detected and thus he was diagnosed as autosomal-recessive Charcot-Marie-Tooth disease 2T (AR-CMT2T); however, electrophysiological examinations revealed scattered demyelinative changes including elongated terminal latency in several peripheral nerve trunks. Sural nerve biopsy showed endoneurial edema and a lot of thinly myelinated nerve fibers with uneven distribution of remnant myelinated fibers within and between fascicles. Immunoglobulin treatment was initiated considering the possibility of superimposed inflammation and demyelination, and immediate clinical as well as electrophysiological improvements were noted. Our findings indicate that AR-CMT2T caused by MME mutation predisposes to a superimposed inflammatory demyelinating neuropathy. This is the first report which documented the co-existence of CMT2 and chronic inflammatory demyelinating polyneuropathy (CIDP); however, in the peripheral nervous system, neprilysin, a product of MME gene, is more abundant in myelin sheath than in axonal component. The fragility of myelin sheath due to mutated neprilysin may trigger the detrimental immune response against peripheral myelin in this patient.

  9. Forecasting the Long-Term Clinical and Economic Outcomes of Lumacaftor/Ivacaftor in Cystic Fibrosis Patients with Homozygous phe508del Mutation.

    PubMed

    Dilokthornsakul, Piyameth; Patidar, Mausam; Campbell, Jonathan D

    2017-12-01

    To forecast lifetime outcomes and cost of lumacaftor/ivacaftor combination therapy in patients with cystic fibrosis (CF) with homozygous phe508del mutation from the US payer perspective. A lifetime Markov model was developed from a US payer perspective. The model included five health states: 1) mild lung disease (percent predicted forced expiratory volume in 1 second [FEV 1 ] >70%), 2) moderate lung disease (40% ≤ FEV 1 ≤ 70%), 3) severe lung disease (FEV 1 < 40%), 4) lung transplantation, and 5) death. All inputs were derived from published literature. We estimated lumacaftor/ivacaftor's improvement in outcomes compared with a non-CF referent population as well as CF-specific mortality estimates. Lumacaftor/ivacaftor was associated with additional 2.91 life-years (95% credible interval 2.55-3.56) and additional 2.42 quality-adjusted life-years (QALYs) (95% credible interval 2.10-2.98). Lumacaftor/ivacaftor was associated with improvements in survival and QALYs equivalent to 27.6% and 20.7%, respectively, for the survival and QALY gaps between CF usual care and their non-CF peers. The incremental lifetime cost was $2,632,249. Lumacaftor/ivacaftor increased life-years and QALYs in CF patients with the homozygous phe508del mutation and moved morbidity and mortality closer to that of their non-CF peers but it came with higher cost. Copyright © 2017 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  10. Hyperchlorhidrosis caused by homozygous mutation in CA12, encoding carbonic anhydrase XII.

    PubMed

    Feldshtein, Maya; Elkrinawi, Suliman; Yerushalmi, Baruch; Marcus, Barak; Vullo, Daniela; Romi, Hila; Ofir, Rivka; Landau, Daniel; Sivan, Sara; Supuran, Claudiu T; Birk, Ohad S

    2010-11-12

    Excessive chloride secretion in sweat (hyperchlorhidrosis), leading to a positive sweat test, is most commonly indicative of cystic fibrosis yet is found also in conjunction with various metabolic, endocrine, and dermatological disorders. There is conflicting evidence regarding the existence of autosomal-recessive hyperchlorhidrosis. We now describe a consanguineous Israeli Bedouin kindred with autosomal-recessive hyperchlohidrosis whose sole symptoms are visible salt precipitates after sweating, a preponderance to hyponatremic dehydration, and poor feeding and slow weight gain at infancy. Through genome-wide linkage analysis, we demonstrate that the phenotype is due to a homozygous mutation in CA12, encoding carbonic anhydrase XII. The mutant (c.427G>A [p.Glu143Lys]) protein showed 71% activity of the wild-type enzyme for catalyzing the CO₂ hydration to bicarbonate and H(+), and it bound the clinically used sulfonamide inhibitor acetazolamide with high affinity (K(I) of 10 nM). Unlike the wild-type enzyme, which is not inhibited by chloride, bromide, or iodide (K(I)s of 73-215 mM), the mutant is inhibited in the submicromolar range by these anions (K(I)s of 0.37-0.73 mM). Copyright © 2010 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  11. Homozygous inactivation of CHEK2 is linked to a familial case of multiple primary lung cancer with accompanying cancers in other organs

    PubMed Central

    Kukita, Yoji; Okami, Jiro; Yoneda-Kato, Noriko; Nakamae, Ikuko; Kawabata, Takeshi; Higashiyama, Masahiko; Kato, Junya; Kodama, Ken; Kato, Kikuya

    2016-01-01

    In clinical practice, there are a number of cancer patients with clear family histories, but the patients lack mutations in known familial cancer syndrome genes. Recent advances in genomic technologies have enhanced the possibility of identifying causative genes in such cases. Two siblings, an elder sister and a younger brother, were found to have multiple primary lung cancers at the age of 60. The former subsequently developed breast cancer and had a history of uterine myoma. The latter had initially developed prostate cancer at the age of 59 and had a history of colon cancer. Single-nucleotide polymorphism (SNP) genotyping revealed that ∼10% of the genomes were homozygous in both patients. Exome sequencing revealed nonsynonymous mutations in five genes in the runs of homozygosity: CHEK2, FCGRT, INPP5J, MYO18B, and SFI1. Evolutionary conservation of primary protein structures suggested the functional importance of the CHEK2 mutation, p.R474C. This mutation altered the tertiary structure of CHK2 by disrupting the salt bridge between p.R474 and p.E394. No such structural changes were observed with the other mutated genes. Subsequent cell-based transfection analysis revealed that CHK2 p.R474C was unstable and scarcely activated. We concluded that the homozygous CHEK2 variant was contributory in this case of familial cancer. Although homozygous inactivation of CHEK2 in mice led to cancers in multiple organs, accumulation of additional human cases is needed to establish its pathogenic role in humans. PMID:27900359

  12. Homozygous inactivation of CHEK2 is linked to a familial case of multiple primary lung cancer with accompanying cancers in other organs.

    PubMed

    Kukita, Yoji; Okami, Jiro; Yoneda-Kato, Noriko; Nakamae, Ikuko; Kawabata, Takeshi; Higashiyama, Masahiko; Kato, Junya; Kodama, Ken; Kato, Kikuya

    2016-11-01

    In clinical practice, there are a number of cancer patients with clear family histories, but the patients lack mutations in known familial cancer syndrome genes. Recent advances in genomic technologies have enhanced the possibility of identifying causative genes in such cases. Two siblings, an elder sister and a younger brother, were found to have multiple primary lung cancers at the age of 60. The former subsequently developed breast cancer and had a history of uterine myoma. The latter had initially developed prostate cancer at the age of 59 and had a history of colon cancer. Single-nucleotide polymorphism (SNP) genotyping revealed that ∼10% of the genomes were homozygous in both patients. Exome sequencing revealed nonsynonymous mutations in five genes in the runs of homozygosity: CHEK2 , FCGRT , INPP5J , MYO18B , and SFI1 . Evolutionary conservation of primary protein structures suggested the functional importance of the CHEK2 mutation, p.R474C. This mutation altered the tertiary structure of CHK2 by disrupting the salt bridge between p.R474 and p.E394. No such structural changes were observed with the other mutated genes. Subsequent cell-based transfection analysis revealed that CHK2 p.R474C was unstable and scarcely activated. We concluded that the homozygous CHEK2 variant was contributory in this case of familial cancer. Although homozygous inactivation of CHEK2 in mice led to cancers in multiple organs, accumulation of additional human cases is needed to establish its pathogenic role in humans.

  13. Exome Capture and Massively Parallel Sequencing Identifies a Novel HPSE2 Mutation in a Saudi Arabian Child with Ochoa (Urofacial) Syndrome

    PubMed Central

    Al Badr, Wisam; Al Bader, Suha; Otto, Edgar; Hildebrandt, Friedhelm; Ackley, Todd; Peng, Weiping; Xu, Jishu; Li, Jun; Owens, Kailey M.; Bloom, David; Innis, Jeffrey W.

    2011-01-01

    We describe a child of Middle Eastern descent by first-cousin mating with idiopathic neurogenic bladder and high grade vesicoureteral reflux at 1 year of age, whose characteristic facial grimace led to the diagnosis of Ochoa (Urofacial) syndrome at age 5 years. We used homozygosity mapping, exome capture and paired end sequencing to identify the disease causing mutation in the proband. We reviewed the literature with respect to the urologic manifestations of Ochoa syndrome. A large region of marker homozygosity was observed at 10q24, consistent with known autosomal recessive inheritance, family consanguinity and previous genetic mapping in other families with Ochoa syndrome. A homozygous mutation was identified in the proband in HPSE2: c.1374_1378delTGTGC, a deletion of 5 nucleotides in exon 10 that is predicted to lead to a frameshift followed by replacement of 132 C-terminal amino acids with 153 novel amino acids (p.Ala458Alafsdel132ins153). This mutation is novel relative to very recently published mutations in HPSE2 in other families. Early intervention and recognition of Ochoa syndrome with control of risk factors and close surveillance will decrease complications and renal failure. PMID:21450525

  14. Recessive Mutations in ACPT, Encoding Testicular Acid Phosphatase, Cause Hypoplastic Amelogenesis Imperfecta.

    PubMed

    Seymen, Figen; Kim, Youn Jung; Lee, Ye Ji; Kang, Jenny; Kim, Tak-Heun; Choi, Hwajung; Koruyucu, Mine; Kasimoglu, Yelda; Tuna, Elif Bahar; Gencay, Koray; Shin, Teo Jeon; Hyun, Hong-Keun; Kim, Young-Jae; Lee, Sang-Hoon; Lee, Zang Hee; Zhang, Hong; Hu, Jan C-C; Simmer, James P; Cho, Eui-Sic; Kim, Jung-Wook

    2016-11-03

    Amelogenesis imperfecta (AI) is a heterogeneous group of genetic disorders affecting tooth enamel. The affected enamel can be hypoplastic and/or hypomineralized. In this study, we identified ACPT (testicular acid phosphatase) biallelic mutations causing non-syndromic, generalized hypoplastic autosomal-recessive amelogenesis imperfecta (AI) in individuals from six apparently unrelated Turkish families. Families 1, 4, and 5 were affected by the homozygous ACPT mutation c.713C>T (p.Ser238Leu), family 2 by the homozygous ACPT mutation c.331C>T (p.Arg111Cys), family 3 by the homozygous ACPT mutation c.226C>T (p.Arg76Cys), and family 6 by the compound heterozygous ACPT mutations c.382G>C (p.Ala128Pro) and 397G>A (p.Glu133Lys). Analysis of the ACPT crystal structure suggests that these mutations damaged the activity of ACPT by altering the sizes and charges of key amino acid side chains, limiting accessibility of the catalytic core, and interfering with homodimerization. Immunohistochemical analysis confirmed localization of ACPT in secretory-stage ameloblasts. The study results provide evidence for the crucial function of ACPT during amelogenesis. Copyright © 2016 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  15. Severe early onset retinitis pigmentosa in a Moroccan patient with Heimler syndrome due to novel homozygous mutation of PEX1 gene.

    PubMed

    Ratbi, Ilham; Jaouad, Imane Cherkaoui; Elorch, Hamza; Al-Sheqaih, Nada; Elalloussi, Mustapha; Lyahyai, Jaber; Berraho, Amina; Newman, William G; Sefiani, Abdelaziz

    2016-10-01

    Heimler syndrome (HS) is a rare recessive disorder characterized by sensorineural hearing loss (SNHL), amelogenesis imperfecta, nail abnormalities, and occasional or late-onset retinal pigmentation. It is the mildest form known to date of peroxisome biogenesis disorder caused by hypomorphic mutations of PEX1 and PEX6 genes. We report on a second Moroccan family with Heimler syndrome with early onset, severe visual impairment and important phenotypic overlap with Usher syndrome. The patient carried a novel homozygous missense variant c.3140T > C (p.Leu1047Pro) of PEX1 gene. As standard biochemical screening of blood for evidence of a peroxisomal disorder did not provide a diagnosis in the individuals with HS, patients with SNHL and retinal pigmentation should have mutation analysis of PEX1 and PEX6 genes. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  16. TEM-induced gene mutations at enzyme loci in the mouse.

    PubMed

    Soares, E R

    1979-01-01

    Strain DBA/2J male mice were treated with triethylenemelamine (TEM) and subsequently mated to strain C57BL/6J females. Tissues from F1 progeny produced in these crosses were then examined using starch gel electrophoresis for the presence of presumed induced mutations at a series of 11 specific enzyme loci. In the course of this study, four heritable mutations were identified at the following loci: Es-1, Ldh-1, Pgm-1, and Gpi-1. Of these four, the first two were apparently segregating in parental males and were not TEM-induced. Both of these are viable and fertile in the heterozygous and homozygous condition, and neither confers any readily apparent deleterious effect to the animal. The latter mutations (Pgm-1 and Gpi-1) are presumably induced. Although viable and fertile in the heterozygous state, we have not recovered any offsping homozygous for either of these two mutations.

  17. Novel mutations in GALNT3 causing hyperphosphatemic familial tumoral calcinosis.

    PubMed

    Yancovitch, Alan; Hershkovitz, Dov; Indelman, Margareta; Galloway, Peter; Whiteford, Margo; Sprecher, Eli; Kılıç, Esra

    2011-09-01

    Hyperphosphatemic familial tumoral calcinosis (HFTC) is known to be caused by mutations in at least three genes: FGF23, GALNT3 and KL. Two families with two affected members suffering from HFTC were scrutinized for mutations in these candidate genes. We identified in both families homozygous missense mutations affecting highly conserved amino acids in GALNT3. One of the mutations is a novel mutation, whereas the second mutation was reported before in a compound heterozygous state. Our data expand the spectrum of known mutations in GALNT3 and contribute to a better understanding of the phenotypic manifestations of mutations in this gene.

  18. Recurrent mutation of the ID3 gene in Burkitt lymphoma identified by integrated genome, exome and transcriptome sequencing.

    PubMed

    Richter, Julia; Schlesner, Matthias; Hoffmann, Steve; Kreuz, Markus; Leich, Ellen; Burkhardt, Birgit; Rosolowski, Maciej; Ammerpohl, Ole; Wagener, Rabea; Bernhart, Stephan H; Lenze, Dido; Szczepanowski, Monika; Paulsen, Maren; Lipinski, Simone; Russell, Robert B; Adam-Klages, Sabine; Apic, Gordana; Claviez, Alexander; Hasenclever, Dirk; Hovestadt, Volker; Hornig, Nadine; Korbel, Jan O; Kube, Dieter; Langenberger, David; Lawerenz, Chris; Lisfeld, Jasmin; Meyer, Katharina; Picelli, Simone; Pischimarov, Jordan; Radlwimmer, Bernhard; Rausch, Tobias; Rohde, Marius; Schilhabel, Markus; Scholtysik, René; Spang, Rainer; Trautmann, Heiko; Zenz, Thorsten; Borkhardt, Arndt; Drexler, Hans G; Möller, Peter; MacLeod, Roderick A F; Pott, Christiane; Schreiber, Stefan; Trümper, Lorenz; Loeffler, Markus; Stadler, Peter F; Lichter, Peter; Eils, Roland; Küppers, Ralf; Hummel, Michael; Klapper, Wolfram; Rosenstiel, Philip; Rosenwald, Andreas; Brors, Benedikt; Siebert, Reiner

    2012-12-01

    Burkitt lymphoma is a mature aggressive B-cell lymphoma derived from germinal center B cells. Its cytogenetic hallmark is the Burkitt translocation t(8;14)(q24;q32) and its variants, which juxtapose the MYC oncogene with one of the three immunoglobulin loci. Consequently, MYC is deregulated, resulting in massive perturbation of gene expression. Nevertheless, MYC deregulation alone seems not to be sufficient to drive Burkitt lymphomagenesis. By whole-genome, whole-exome and transcriptome sequencing of four prototypical Burkitt lymphomas with immunoglobulin gene (IG)-MYC translocation, we identified seven recurrently mutated genes. One of these genes, ID3, mapped to a region of focal homozygous loss in Burkitt lymphoma. In an extended cohort, 36 of 53 molecularly defined Burkitt lymphomas (68%) carried potentially damaging mutations of ID3. These were strongly enriched at somatic hypermutation motifs. Only 6 of 47 other B-cell lymphomas with the IG-MYC translocation (13%) carried ID3 mutations. These findings suggest that cooperation between ID3 inactivation and IG-MYC translocation is a hallmark of Burkitt lymphomagenesis.

  19. Identification of homozygous WFS1 mutations (p.Asp211Asn, p.Gln486*) causing severe Wolfram syndrome and first report of male fertility

    PubMed Central

    Haghighi, Amirreza; Haghighi, Alireza; Setoodeh, Aria; Saleh-Gohari, Nasrollah; Astuti, Dewi; Barrett, Timothy G

    2013-01-01

    Wolfram syndrome (WFS) is a neurodegenerative genetic condition characterized by juvenile-onset of diabetes mellitus and optic atrophy. We studied clinical features and the molecular basis of severe WFS (neurodegenerative complications) in two consanguineous families from Iran. A clinical and molecular genetic investigation was performed in the affected and healthy members of two families. The clinical diagnosis of WFS was confirmed by the existence of diabetes mellitus and optic atrophy in the affected patients, who in addition had severe neurodegenerative complications. Sequencing of WFS1 was undertaken in one affected member from each family. Targeted mutations were tested in all members of relevant families. Patients had most of the reported features of WFS. Two affected males in the first family had fathered unaffected children. We identified two homozygous mutations previously reported with apparently milder phenotypes: family 1: c.631G>A (p.Asp211Asn) in exon 5, and family 2: c.1456C>T (p.Gln486*) in exon 8. Heterozygous carriers were unaffected. This is the first report of male Wolfram patients who have successfully fathered children. Surprisingly, they also had almost all the complications associated with WFS. Our report has implications for genetic counseling and family planning advice for other affected families. PMID:22781099

  20. Novel homozygous missense mutation in ALDH7A1 causes neonatal pyridoxine dependent epilepsy.

    PubMed

    Coci, Emanuele G; Codutti, Luca; Fink, Christian; Bartsch, Sophie; Grüning, Gunnar; Lücke, Thomas; Kurth, Ingo; Riedel, Joachim

    2017-04-01

    Pyridoxine dependent epilepsy (PDE) (OMIM#266100) is a neonatal form of epilepsy, caused by dysfunction of the enzyme α-aminoadipic semialdehyde dehydrogenase (ALDH7A1 or Antiquitin). This enzyme converts α-aminoadipic semialdehyde (α-AASA) into α-aminoadipate (AAA), a critical step in the lysine metabolism of the brain. ALDH7A1 dysfunction causes an accumulation of α-AASA and δ 1 -piperideine-6-carboxylic acid (P6C), which are in equilibrium with each other. P6C binds and inactivates pyridoxal 5'-phosphate (PLP), the active form of pyridoxine. Individuals affected by ALDH7A1 deficiency show pre-natal and post-natal seizures, which respond to oral pyridoxine but not to other pediatric anti-epileptic drugs. We discovered a novel missense mutation (c.566G > A, p.Gly189Glu) in homozygous state residing in the NAD+ binding domain coding region of exon 6 and affecting an highly conserved amino acid residue. The seizures stopped under post-natal pyridoxine therapy, nevertheless a longer follow-up is needed to evaluate the intellectual development of the child, who is additionally treated with oral l-arginine since the 13th month of life. Developmental delay with or without structural cortex abnormalities were reported in several patients. A brain MRI scan revealed hyperintense white matter in the right cerebellum compatible with cerebellar gliosis. Taken together, our studies enlarge the group of missense pathogenic mutations of ALDH7A1 gene and reveal a novel cerebellar finding within the PDE patients cohort. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Personalized Stem Cell Therapy to Correct Corneal Defects Due to a Unique Homozygous-Heterozygous Mosaicism of Ectrodactyly-Ectodermal Dysplasia-Clefting Syndrome.

    PubMed

    Barbaro, Vanessa; Nasti, Annamaria Assunta; Raffa, Paolo; Migliorati, Angelo; Nespeca, Patrizia; Ferrari, Stefano; Palumbo, Elisa; Bertolin, Marina; Breda, Claudia; Miceli, Francesco; Russo, Antonella; Caenazzo, Luciana; Ponzin, Diego; Palù, Giorgio; Parolin, Cristina; Di Iorio, Enzo

    2016-08-01

    : Ectrodactyly-ectodermal dysplasia-clefting (EEC) syndrome is a rare autosomal dominant disease caused by mutations in the p63 gene. To date, approximately 40 different p63 mutations have been identified, all heterozygous. No definitive treatments are available to counteract and resolve the progressive corneal degeneration due to a premature aging of limbal epithelial stem cells. Here, we describe a unique case of a young female patient, aged 18 years, with EEC and corneal dysfunction, who was, surprisingly, homozygous for a novel and de novo R311K missense mutation in the p63 gene. A detailed analysis of the degree of somatic mosaicism in leukocytes from peripheral blood and oral mucosal epithelial stem cells (OMESCs) from biopsies of buccal mucosa showed that approximately 80% were homozygous mutant cells and 20% were heterozygous. Cytogenetic and molecular analyses excluded genomic alterations, thus suggesting a de novo mutation followed by an allelic gene conversion of the wild-type allele by de novo mutant allele as a possible mechanism to explain the homozygous condition. R311K-p63 OMESCs were expanded in vitro and heterozygous holoclones selected following clonal analysis. These R311K-p63 OMESCs were able to generate well-organized and stratified epithelia in vitro, resembling the features of healthy tissues. This study supports the rationale for the development of cultured autologous oral mucosal epithelial stem cell sheets obtained by selected heterozygous R311K-p63 stem cells, as an effective and personalized therapy for reconstructing the ocular surface of this unique case of EEC syndrome, thus bypassing gene therapy approaches. This case demonstrates that in a somatic mosaicism context, a novel homozygous mutation in the p63 gene can arise as a consequence of an allelic gene conversion event, subsequent to a de novo mutation. The heterozygous mutant R311K-p63 stem cells can be isolated by means of clonal analysis and given their good regenerative

  2. A homozygous mutation in the endothelin-3 gene associated with a combined Waardenburg type 2 and Hirschsprung phenotype (Shah-Waardenburg syndrome).

    PubMed

    Hofstra, R M; Osinga, J; Tan-Sindhunata, G; Wu, Y; Kamsteeg, E J; Stulp, R P; van Ravenswaaij-Arts, C; Majoor-Krakauer, D; Angrist, M; Chakravarti, A; Meijers, C; Buys, C H

    1996-04-01

    Hirschsprung disease (HSCR) or colonic aganglionosis is a congenital disorder characterized by an absence of intramural ganglia along variable lengths of the colon resulting in intestinal obstruction. The incidence of HSCR is 1 in 5,000 live births. Mutations in the RET gene, which codes for a receptor tyrosine kinase, and in EDNRB which codes for the endothelin-B receptor, have been shown to be associated with HSCR in humans. The lethal-spotted mouse which has pigment abnormalities, but also colonic aganglionosis, carries a mutation in the gene coding for endothelin 3 (Edn3), the ligand for the receptor protein encoded by EDNRB. Here, we describe a mutation of the human gene for endothelin 3 (EDN3), homozygously present in a patient with a combined Waardenburg syndrome type 2 (WS2) and HSCR phenotype (Shah-Waardenburg syndrome). The mutation, Cys159Phe, in exon 3 in the ET-3 like domain of EDN3, presumably affects the proteolytic processing of the preproendothelin to the mature peptide EDN3. The patient's parents were first cousins. A previous child in this family had been diagnosed with a similar combination of HSCR, depigmentation and deafness. Depigmentation and deafness were present in other relatives. Moreover, we present a further indication for the involvement of EDNRB in HSCR by reporting a novel mutation detected in one of 40 unselected HSCR patients.

  3. The phenotype of polycythemia due to Croatian homozygous VHL (571C>G:H191D) mutation is different from that of Chuvash polycythemia (VHL 598C>T:R200W)

    PubMed Central

    Tomasic, Nikica Ljubas; Piterkova, Lucie; Huff, Chad; Bilic, Ernest; Yoon, Donghoon; Miasnikova, Galina Y.; Sergueeva, Adelina I.; Niu, Xiaomei; Nekhai, Sergei; Gordeuk, Victor; Prchal, Josef T.

    2013-01-01

    Mutations of VHL (a negative regulator of hypoxia-inducible factors) have position-dependent distinct cancer phenotypes. Only two known inherited homozygous VHL mutations exist and they cause polycythemia: Chuvash R200W and Croatian H191D. We report a second polycythemic Croatian H191D homozygote distantly related to the first propositus. Three generations of both families were genotyped for analysis of shared ancestry. Biochemical and molecular tests were performed to better define their phenotypes, with an emphasis on a comparison with Chuvash polycythemia. The VHL H191D mutation did not segregate in the family defined by the known common ancestors of the two subjects, suggesting a high prevalence in Croatians, but haplotype analysis indicated an undocumented common ancestor ∼six generations ago as the founder of this mutation. We show that erythropoietin levels in homozygous VHL H191D individuals are higher than in VHL R200W patients of similar ages, and their native erythroid progenitors, unlike Chuvash R200W, are not hypersensitive to erythropoietin. This observation contrasts with a report suggesting that polycythemia in VHL R200W and H191D homozygotes is due to the loss of JAK2 regulation from VHL R200W and H191D binding to SOCS1. In conclusion, our studies further define the hematologic phenotype of VHL H191D and provide additional evidence for phenotypic heterogeneity associated with the positional effects of VHL mutations. PMID:23403324

  4. The phenotype of polycythemia due to Croatian homozygous VHL (571C>G:H191D) mutation is different from that of Chuvash polycythemia (VHL 598C>T:R200W).

    PubMed

    Tomasic, Nikica Ljubas; Piterkova, Lucie; Huff, Chad; Bilic, Ernest; Yoon, Donghoon; Miasnikova, Galina Y; Sergueeva, Adelina I; Niu, Xiaomei; Nekhai, Sergei; Gordeuk, Victor; Prchal, Josef T

    2013-04-01

    Mutations of VHL (a negative regulator of hypoxia-inducible factors) have position-dependent distinct cancer phenotypes. Only two known inherited homozygous VHL mutations exist and they cause polycythemia: Chuvash R200W and Croatian H191D. We report a second polycythemic Croatian H191D homozygote distantly related to the first propositus. Three generations of both families were genotyped for analysis of shared ancestry. Biochemical and molecular tests were performed to better define their phenotypes, with an emphasis on a comparison with Chuvash polycythemia. The VHL H191D mutation did not segregate in the family defined by the known common ancestors of the two subjects, suggesting a high prevalence in Croatians, but haplotype analysis indicated an undocumented common ancestor ∼six generations ago as the founder of this mutation. We show that erythropoietin levels in homozygous VHL H191D individuals are higher than in VHL R200W patients of similar ages, and their native erythroid progenitors, unlike Chuvash R200W, are not hypersensitive to erythropoietin. This observation contrasts with a report suggesting that polycythemia in VHL R200W and H191D homozygotes is due to the loss of JAK2 regulation from VHL R200W and H191D binding to SOCS1. In conclusion, our studies further define the hematologic phenotype of VHL H191D and provide additional evidence for phenotypic heterogeneity associated with the positional effects of VHL mutations.

  5. Novel ITGB6 mutation in autosomal recessive amelogenesis imperfecta.

    PubMed

    Seymen, F; Lee, K-E; Koruyucu, M; Gencay, K; Bayram, M; Tuna, E B; Lee, Z H; Kim, J-W

    2015-05-01

    Hereditary defects in tooth enamel formation, amelogenesis imperfecta (AI), can be non-syndromic or syndromic phenotype. Integrins are signaling proteins that mediate cell-cell and cell-extracellular matrix communication, and their involvement in tooth development is well known. The purposes of this study were to identify genetic cause of an AI family and molecular pathogenesis underlying defective enamel formation. We recruited a Turkish family with isolated AI and performed mutational analyses to clarify the underlying molecular genetic etiology. Autozygosity mapping and exome sequencing identified a novel homozygous ITGB6 transversion mutation in exon 4 (c.517G>C, p.Gly173Arg). The glycine at this position in the middle of the βI-domain is conserved among a wide range of vertebrate orthologs and human paralogs. Clinically, the enamel was generally thin and pitted with pigmentation. Thicker enamel was noted at the cervical area of the molars. In this study, we identified a novel homozygous ITGB6 mutation causing isolated AI, and this advances the understanding of normal and pathologic enamel development. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. A Case of Inflammatory Generalized Type of Peeling Skin Syndrome Possibly Caused by a Homozygous Missense Mutation of CDSN

    PubMed Central

    Kawakami, Hiroshi; Uchiyama, Masaki; Maeda, Tatsuo; Tsunoda, Takahiko; Mitsuhashi, Yoshihiko; Tsuboi, Ryoji

    2014-01-01

    A 54-year-old Japanese woman had repetitive superficial skin peeling and ensuing erythematous changes in the sites since infancy. Her parents had a consanguineous marriage, and she was the only individual affected in her family tree. The erythematous changes seemed to worsen in the summer. Histologically, hyperkeratosis and splitting of the epidermis within the stratum corneum was noted, and electron microscopy revealed shedding of corneal cells in the horny layer and normal-looking corneodesmosomes. Gene analysis revealed a homozygous missense mutation at c.1358G>A in CDSN. Electron microscopic examination of the length and number of corneodesmosomes revealed statistically significant shortness and sparsity in the affected individual (mean ± SD 386.2 ± 149.5 nm) compared with that of an age- and site-matched control (406.6 ± 182.3 nm). We speculate that this size shrinkage of corneodesmosomes might be the result of a missense mutation of CDSN and that this could be one of the factors contributing to the pathological process of skin peeling. PMID:25473393

  7. A Case of Inflammatory Generalized Type of Peeling Skin Syndrome Possibly Caused by a Homozygous Missense Mutation of CDSN.

    PubMed

    Kawakami, Hiroshi; Uchiyama, Masaki; Maeda, Tatsuo; Tsunoda, Takahiko; Mitsuhashi, Yoshihiko; Tsuboi, Ryoji

    2014-09-01

    A 54-year-old Japanese woman had repetitive superficial skin peeling and ensuing erythematous changes in the sites since infancy. Her parents had a consanguineous marriage, and she was the only individual affected in her family tree. The erythematous changes seemed to worsen in the summer. Histologically, hyperkeratosis and splitting of the epidermis within the stratum corneum was noted, and electron microscopy revealed shedding of corneal cells in the horny layer and normal-looking corneodesmosomes. Gene analysis revealed a homozygous missense mutation at c.1358G>A in CDSN. Electron microscopic examination of the length and number of corneodesmosomes revealed statistically significant shortness and sparsity in the affected individual (mean ± SD 386.2 ± 149.5 nm) compared with that of an age- and site-matched control (406.6 ± 182.3 nm). We speculate that this size shrinkage of corneodesmosomes might be the result of a missense mutation of CDSN and that this could be one of the factors contributing to the pathological process of skin peeling.

  8. Germline mutations in RYR1 are associated with foetal akinesia deformation sequence/lethal multiple pterygium syndrome.

    PubMed

    McKie, Arthur B; Alsaedi, Atif; Vogt, Julie; Stuurman, Kyra E; Weiss, Marjan M; Shakeel, Hassan; Tee, Louise; Morgan, Neil V; Nikkels, Peter G J; van Haaften, Gijs; Park, Soo-Mi; van der Smagt, Jasper J; Bugiani, Marianna; Maher, Eamonn R

    2014-12-05

    Foetal akinesia deformation sequence syndrome (FADS) is a genetically heterogeneous disorder characterised by the combination of foetal akinesia and developmental defects which may include pterygia (joint webbing). Traditionally multiple pterygium syndrome (MPS) has been divided into two forms: prenatally lethal (LMPS) and non-lethal Escobar type (EVMPS) types. Interestingly, FADS, LMPS and EVMPS may be allelic e.g. each of these phenotypes may result from mutations in the foetal acetylcholine receptor gamma subunit gene (CHRNG). Many cases of FADS and MPS do not have a mutation in a known FADS/MPS gene and we undertook molecular genetic studies to identify novel causes of these phenotypes. After mapping a novel locus for FADS/LMPS to chromosome 19, we identified a homozygous null mutation in the RYR1 gene in a consanguineous kindred with recurrent LMPS pregnancies. Resequencing of RYR1 in a cohort of 66 unrelated probands with FADS/LMPS/EVMPS (36 with FADS/LMPS and 30 with EVMPS) revealed two additional homozygous mutations (in frame deletions). The overall frequency of RYR1 mutations in probands with FADS/LMPS was 8.3%. Our findings report, for the first time, a homozygous RYR1 null mutation and expand the range of RYR1-related phenotypes to include early lethal FADS/LMPS. We suggest that RYR1 mutation analysis should be performed in cases of severe FADS/LMPS even in the absence of specific histopathological indicators of RYR1-related disease.

  9. Mutations in the von Hippel-Lindau (VHL) tumor suppressor gene and VHL-haplotype analysis in patients with presumable congenital erythrocytosis.

    PubMed

    Cario, Holger; Schwarz, Klaus; Jorch, Norbert; Kyank, Ulrike; Petrides, Petro E; Schneider, Dominik T; Uhle, Renate; Debatin, Klaus-Michael; Kohne, Elisabeth

    2005-01-01

    Congenital erythrocytoses or polycythemias are rare and heterogeneous. A homozygous mutation (C598T->Arg200Trp) in the von Hippel-Lindau (VHL) gene was originally identified as the cause of the endemic Chuvash polycythemia. Subsequently this and other mutations in the VHL gene were also detected in several patients of different ethnic origin. Haplotype analyses of the VHL gene suggested a common origin for the Chuvash-type mutation. Thirty-four patients with presumable congenital erythrocytosis due to an unknown underlying disorder were examined for VHL gene mutations and VHL region haplotypes. Four patients were homozygous and one patient heterozygous for the Chuvash-type mutation. One additional patient presented a previously not described heterozygous mutation G311->T VHL in exon 1. The haplotype analyses were in agreement with recently published data for three of the four patients with homozygous mutations as well as for the patient with a heterozygous Chuvash-type mutation. One patient of Turkish origin with homozygous Chuvash-type mutation had a haplotype not previously found in individuals with Chuvash-type mutation. These results confirm that mutations in the VHL gene are responsible for a substantial proportion of patients with congenital erythrocytoses. Erythrocytoses due to a C598->T mutation of the VHL gene are not geographically restricted. The majority of patients with Chuvash polycythemia share a common VHL gene haplotype. The different haplotype in one of the patients with Chuvash-type mutation indicates that this mutation was not spread only from a single founder but developed independently in other individuals.

  10. A homozygous missense variant in VWA2, encoding an interactor of the Fraser-complex, in a patient with vesicoureteral reflux.

    PubMed

    van der Ven, Amelie T; Kobbe, Birgit; Kohl, Stefan; Shril, Shirlee; Pogoda, Hans-Martin; Imhof, Thomas; Ityel, Hadas; Vivante, Asaf; Chen, Jing; Hwang, Daw-Yang; Connaughton, Dervla M; Mann, Nina; Widmeier, Eugen; Taglienti, Mary; Schmidt, Johanna Magdalena; Nakayama, Makiko; Senguttuvan, Prabha; Kumar, Selvin; Tasic, Velibor; Kehinde, Elijah O; Mane, Shrikant M; Lifton, Richard P; Soliman, Neveen; Lu, Weining; Bauer, Stuart B; Hammerschmidt, Matthias; Wagener, Raimund; Hildebrandt, Friedhelm

    2018-01-01

    Congenital anomalies of the kidney and urinary tract (CAKUT) are the most common cause (40-50%) of chronic kidney disease (CKD) in children. About 40 monogenic causes of CAKUT have so far been discovered. To date less than 20% of CAKUT cases can be explained by mutations in these 40 genes. To identify additional monogenic causes of CAKUT, we performed whole exome sequencing (WES) and homozygosity mapping (HM) in a patient with CAKUT from Indian origin and consanguineous descent. We identified a homozygous missense mutation (c.1336C>T, p.Arg446Cys) in the gene Von Willebrand factor A domain containing 2 (VWA2). With immunohistochemistry studies on kidneys of newborn (P1) mice, we show that Vwa2 and Fraser extracellular matrix complex subunit 1 (Fras1) co-localize in the nephrogenic zone of the renal cortex. We identified a pronounced expression of Vwa2 in the basement membrane of the ureteric bud (UB) and derivatives of the metanephric mesenchyme (MM). By applying in vitro assays, we demonstrate that the Arg446Cys mutation decreases translocation of monomeric VWA2 protein and increases translocation of aggregated VWA2 protein into the extracellular space. This is potentially due to the additional, unpaired cysteine residue in the mutated protein that is used for intermolecular disulfide bond formation. VWA2 is a known, direct interactor of FRAS1 of the Fraser-Complex (FC). FC-encoding genes and interacting proteins have previously been implicated in the pathogenesis of syndromic and/or isolated CAKUT phenotypes in humans. VWA2 therefore constitutes a very strong candidate in the search for novel CAKUT-causing genes. Our results from in vitro experiments indicate a dose-dependent neomorphic effect of the Arg446Cys homozygous mutation in VWA2.

  11. Homozygous PMS2 deletion causes a severe colorectal cancer and multiple adenoma phenotype without extraintestinal cancer.

    PubMed

    Will, Olivia; Carvajal-Carmona, Luis G; Gorman, Patricia; Howarth, Kimberley M; Jones, Angela M; Polanco-Echeverry, Guadalupe M; Chinaleong, Jo-Anne; Günther, Thomas; Silver, Andrew; Clark, Susan K; Tomlinson, Ian

    2007-02-01

    We report a patient of Indian descent with parental consanguinity, who developed 10 carcinomas and 35 adenomatous polyps at age 23 and duodenal adenocarcinoma at age 25. He also had dysmorphic features, mental retardation, and café-au-lait spots but no brain tumor. We aimed to establish his molecular diagnosis. Germ-line screening for APC and MYH/MUTYH mutations was normal as was immunohistochemistry for MLH1 and MSH2 proteins. Investigation by array-comparative genomic hybridization revealed deletion of a small region on chromosome 7. Using polymerase chain reaction, this region was refined to a 400-kilobase deletion, which included exons 9-15 of the PMS2 gene, and all coding regions of oncomodulin, TRIAD3, and FSCN1. The deletion was confirmed as homozygous, and both parents were carriers. Immunohistochemistry showed absent PMS2 expression in all tumors and normal tissue. Most tumors showed microsatellite instability, more marked at dinucleotide than mononucleotide repeats. The tumors harbored no somatic mutations in APC, BRAF, AXIN2, or beta-catenin, but KRAS2 and TGFBR2 mutations were found. Our patient represents a novel phenotype for homozygous PMS2 mutation and perhaps the most severe colorectal cancer phenotype-in terms of numbers of malignancies at an early age-described to date. PMS2 mutations-and perhaps other homozygous mismatch repair mutations-should be considered in any patient presenting with multiple gastrointestinal tumors, since our patient could not be distinguished clinically from cases with attenuated familial adenomatous polyposis or MUTYH-associated polyposis.

  12. A novel homozygous mutation IVS6+5G>T in CYP11B1 gene in a Vietnamese patient with 11β-hydroxylase deficiency.

    PubMed

    Nguyen, Thi Phuong Mai; Nguyen, Thu Hien; Ngo, Diem Ngoc; Vu, Chi Dung; Nguyen, Thi Kim Lien; Nong, Van Hai; Nguyen, Huy Hoang

    2015-07-10

    Congenital adrenal hyperplasia (CAH) is an autosomal recessive disease which is characterized by a deficiency of one of the enzymes involved in the synthesis of cortisol from cholesterol by the adrenal cortex. CAH cases arising from impaired 11β-hydroxylase are the second most common form. Mutations in the CYP11B1 gene are the cause of 11β-hydroxylase deficiency. This study was performed on a patient with congenital adrenal hyperplasia and with premature development such as enlarged penis, muscle development, high blood pressure, and bone age equivalent of 5 years old at 2 years of chronological age. Biochemical tests for steroids confirmed the diagnosis of CAH. We used PCR and sequencing to screen for mutations in CYP11B1 gene. Results showed that the patient has a novel homozygous mutation of guanine (G) to thymine (T) in intron 6 (IVS6+5G>T). The analysis of this mutation by MaxEntScan boundary software indicated that this mutant could affect the gene splicing during transcription. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Confirmation that RIPK4 mutations cause not only Bartsocas-Papas syndrome but also CHAND syndrome.

    PubMed

    Busa, Tiffany; Jeraiby, Mohammed; Clémenson, Alix; Manouvrier, Sylvie; Granados, Viviana; Philip, Nicole; Touraine, Renaud

    2017-11-01

    CHAND syndrome is an autosomal recessive disorder characterized by curly hair, ankyloblepharon, and nail dysplasia. Only few patients were reported to date. A homozygous RIPK4 mutation was recently identified by homozygosity mapping and whole exome sequencing in three patients from an expanded consanguineous kindred with a clinical diagnosis of CHAND syndrome. RIPK4 was previously known to be implicated in Bartsocas-Papas syndrome, the autosomal recessive form of popliteal pterygium syndrome. We report here two cases of RIPK4 homozygous mutations in a fetus with severe Bartsocas-Papas syndrome and a patient with CHAND syndrome. The patient with CHAND syndrome harbored the same mutation as the one identified in the family previously reported. We thus confirm the implication of RIPK4 gene in CHAND syndrome in addition to Bartsocas-Papas syndrome and discuss genotype/phenotype correlations. © 2017 Wiley Periodicals, Inc.

  14. [A boy with Meier-Gorlin syndrome carrying a novel ORC6 mutation and uniparental disomy of chromosome 16].

    PubMed

    Li, Juan; Ding, Yu; Chang, Guoying; Cheng, Qing; Li, Xin; Wang, Jian; Wang, Xiumin; Shen, Yiping

    2017-02-10

    To identify the genetic cause for a 11-year-old Chinese boy with Meier-Gorlin syndrome (MGS). Chromosomal microarray analysis (CMA) was used to detect potential variations, while whole exome sequencing (WES) was used to identify sequence variants. Sanger sequencing was used to confirm the suspected variants. The boy has featured short stature, microtia, small patella, slender body build, craniofacial anomalies, and small testes with normal gonadotropin. A complete uniparental disomy of chromosome 16 was revealed by CMA. WES has identified a novel homozygous mutation c.67A>G (p.Lys23Glu) in ORC6 gene mapped to chromosome 16. As predicted by Alamut functional software, the mutation may affect the function of structural domain of the ORC6 protein. The patient is probably the first diagnosed MGS case in China, who carried a novel homozygous mutation of the ORC6 gene and uniparental disomy of chromosome 16. The effect of this novel mutation on the growth and development needs to be further investigated.

  15. Central nervous system involvement in severe congenital neutropenia: neurological and neuropsychological abnormalities associated with specific HAX1 mutations.

    PubMed

    Carlsson, G; van't Hooft, I; Melin, M; Entesarian, M; Laurencikas, E; Nennesmo, I; Trebińska, A; Grzybowska, E; Palmblad, J; Dahl, N; Nordenskjöld, M; Fadeel, B; Henter, J-I

    2008-10-01

    Homozygous mutations in the HAX1 gene were recently identified in severe congenital neutropenia patients belonging to the original Kostmann family in northern Sweden. Our observations suggested that these patients also develop neurological and neuropsychological symptoms. Detailed clinical studies and mutation analyses were performed in the surviving patients belonging to the Kostmann kindred and in two patients not related to this family, along with studies of HAX1 splice variant expression in normal human tissues. Five of six Kostmann family patients and one other patient from northern Sweden harboured homozygous HAX1 mutations (568C-->T, Q190X) and one carried a heterozygous ELA2 gene mutation. One Swedish patient of Kurdish extraction carried alternative homozygous HAX1 mutations (131G-->A, W44X). All the three patients with Q190X mutations who were alive and available for evaluation developed neurological disease with decreased cognitive function, and three of four patients who reached 10 years developed epilepsy. In contrast, the patients with the ELA2 and W44X HAX1 mutations, respectively, showed no obvious neurological abnormalities. Moreover, two alternative HAX1 splice variants were identified in normal human tissues, including the brain. Both transcripts contained exon 5, harbouring the Q190X mutation, whereas the 5' end of exon 2 containing the W44X mutation was spliced out from the second transcript. We describe neurological and neuropsychological abnormalities for the first time in Kostmann disease patients. These central nervous system symptoms appear to be associated with specific HAX1 mutations.

  16. Association of the widespread A149P hereditary fructose intolerance mutation with newly identified sequence polymorphisms in the aldolase B gene

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Brooks, C.C.; Tolan, D.R.

    1993-04-01

    Hereditary fructose intolerance (HFI) is a potentially fatal autosomal recessive disease resulting from the catalytic deficiency of fructose 1-phosphate aldolase (aldolase B) in fructose-metabolizing tissues. The A149P mutation in exon 5 of the aldolase B gene, located on chromosome 9q2l.3-q22.2, is widespread and the most common HFI mutation, accounting for 57% of HFI chromosomes. The possible origin of this mutation was studied by linkage to polymorphisms within the aldolase B gene. DNA fragments of the aldolase B gene containing the polymorphic marker loci from HFI patients homozygous for the A149P allele were amplified by PCR. Absolute linkage to a commonmore » Pvull RFLP allele was observed in 10 A149P homozygotes. In a more informative study, highly heterozygous polymorphisms were detected by direct sequence determination of a PCR-amplified aldolase B gene fragment. Two two-allele, single-base-pair polymorphisms, themselves in absolute linkage disequilibrium, in intron 8 (C at nucleotide 84 and A at nucleotide 105, or T at 84 and G at 105) of the aldolase B gene were identified. Mendelian segregation of these polymorphisms was confirmed in three families. Allele-specific oligonucleotide (ASO) hybridizations with probes for both sequence polymorphisms showed that 47% of 32 unrelated individuals were heterozygous at these loci; the calculated PIC value was .37. Finally, ASO hybridizations of PCR-amplified DNA from 15 HFI patients homozygous for the A149P allele with probes for these sequence polymorphisms revealed absolute linkage disequilibrium between the A149P mutation and the 84T/105G allele. These results are consistent with a single origin of the A149P allele and subsequent spread by genetic drift. 32 refs., 4 figs., 3 tabs.« less

  17. Phenotypical features of two patients diagnosed with PHARC syndrome and carriers of a new homozygous mutation in the ABHD12 gene.

    PubMed

    Frasquet, Marina; Lupo, Vincenzo; Chumillas, María José; Vázquez-Costa, Juan Francisco; Espinós, Carmen; Sevilla, Teresa

    2018-04-15

    PHARC (Polyneuropathy, Hearing loss, Ataxia, Retinitis pigmentosa and Cataracts) (MIM# 612674) is an autosomal recessive neurodegenerative disease caused by mutations in the ABHD12 gene. We evaluated two Spanish siblings affected with pes cavus, sensorimotor neuropathy, hearing loss, retinitis pigmentosa and juvenile cataracts in whom the genetic test of ABHD12 revealed a novel homozygous frameshift mutation, c.211_223del (p.Arg71Tyrfs*26). The earliest clinical manifestation in these patients was a demyelinating neuropathy manifested with a Charcot-Marie-Tooth phenotype over three decades. Progressive hearing loss, cataracts and retinitis pigmentosa appeared after the age of 30. We herein describe the complete clinical picture of these two patients, and focus particularly on neuropathy characteristics. This study supports the fact that although PHARC is rare, its phenotype is very characteristic and we should include its study in patients affected with demyelinating polyneuropathy, hearing loss and retinopathy. Copyright © 2018 Elsevier B.V. All rights reserved.

  18. Donnai–Barrow Syndrome (DBS/FOAR) in a Child With a Homozygous LRP2 Mutation Due to Complete Chromosome 2 Paternal Isodisomy

    PubMed Central

    Kantarci, Sibel; Ragge, Nicola K.; Thomas, N. Simon; Robinson, David O.; Noonan, Kristin M.; Russell, Meaghan K.; Donnai, Dian; Raymond, F. Lucy; Walsh, Christopher A.; Donahoe, Patricia K.; Pober, Barbara R.

    2010-01-01

    Donnai–Barrow syndrome [Faciooculoacousticorenal (FOAR) syndrome; DBS/FOAR] is a rare autosomal recessive disorder resulting from mutations in the LRP2 gene located on chromosome 2q31.1. We report a unique DBS/FOAR patient homozygous for a 4-bp LRP2 deletion secondary to paternal uniparental isodisomy for chromosome 2. The propositus inherited the mutation from his heterozygous carrier father, whereas the mother carried only wild-type LRP2 alleles. This is the first case of DBS/FOAR resulting from uniparental disomy (UPD) and the fourth published case of any paternal UPD 2 ascertained through unmasking of an autosomal recessive disorder. The absence of clinical symptoms above and beyond the classical phenotype in this and the other disorders suggests that paternal chromosome 2 is unlikely to contain imprinted genes notably affecting either growth or development. This report highlights the importance of parental genotyping in order to give accurate genetic counseling for autosomal recessive disorders. PMID:18553518

  19. New MCM8 mutation associated with premature ovarian insufficiency and chromosomal instability in a highly consanguineous Tunisian family.

    PubMed

    Bouali, Nouha; Francou, Bruno; Bouligand, Jérôme; Imanci, Dilek; Dimassi, Sarra; Tosca, Lucie; Zaouali, Monia; Mougou, Soumaya; Young, Jacques; Saad, Ali; Guiochon-Mantel, Anne

    2017-10-01

    To identify the gene(s) involved in the etiology of premature ovarian insufficiency in a highly consanguineous Tunisian family. Genetic analysis of a large consanguineous family with several affected siblings. University hospital-based cytogenetics and molecular genetics laboratories. A highly consanguineous Tunisian family with several affected siblings born to healthy second-degree cousins. None. Targeted exome sequencing was performed by next-generation sequencing for affected family members. Mutations were validated by Sanger sequencing. Functional experiments were performed to explore the deleterious effects of the identified mutation. DNA damage was induced by increasing mitomycin C (MMC) concentrations on cultured peripheral lymphocytes. Analysis of the next-generation sequencing data revealed a new homozygous missense mutation in the minichromosome maintenance 8 gene (MCM8).This homozygous mutation (c. 482A>C; p.His161Pro) was predicted to be deleterious and segregated with the disease in the family. MCM8 participates in homologous recombination during meiosis and DNA double-stranded break repair by dimerizing with MCM9. Mcm8 knock out results in an early block in follicle development and small gonads. Given this, we tested the chromosomal breakage repair capacity of homozygous and heterozygous MCM8 p.His161Pro mutation on cultured peripheral lymphocytes exposed to increasing MMC concentrations. We found that chromosomal breakage after MMC exposure was significantly higher in cells from homozygously affected individuals than in those from a healthy control. Our findings provide additional support to the view that MCM8 mutations are involved in the primary ovarian insufficiency phenotype. Copyright © 2017 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  20. GNE missense mutation in recessive familial amyotrophic lateral sclerosis.

    PubMed

    Köroğlu, Çiğdem; Yılmaz, Rezzak; Sorgun, Mine Hayriye; Solakoğlu, Seyhun; Şener, Özden

    2017-12-01

    Amyotrophic lateral sclerosis (ALS) is a motor neuron disease eventually leading to death from respiratory failure. Recessive inheritance is very rare. Here, we describe the clinical findings in a consanguineous family with five men afflicted with recessive ALS and the identification of the homozygous mutation responsible for the disorder. The onset of the disease ranged from 12 to 35 years of age, with variable disease progressions. We performed clinical investigations including metabolic and paraneoplastic screening, cranial and cervical imaging, and electrophysiology. We mapped the disease gene to 9p21.1-p12 with a LOD score of 5.2 via linkage mapping using genotype data for single-nucleotide polymorphism markers and performed exome sequence analysis to identify the disease-causing gene variant. We also Sanger sequenced all coding sequences of SIGMAR1, a gene reported as responsible for juvenile ALS in a family. We did not find any mutation in SIGMAR1. Instead, we identified a novel homozygous missense mutation p.(His705Arg) in GNE which was predicted as damaging by online tools. GNE has been associated with inclusion body myopathy and is expressed in many tissues. We propose that the GNE mutation underlies the pathology in the family.

  1. XPC gene mutations in families with xeroderma pigmentosum from Pakistan; prevalent founder effect.

    PubMed

    Ijaz, Ambreen; Basit, Sulman; Gul, Ajab; Batool, Lilas; Hussain, Abrar; Afzal, Sibtain; Ramzan, Khushnooda; Ahmad, Jamil; Wali, Abdul

    2018-03-23

    Xeroderma pigmentosum (XP) is a rare autosomal recessive skin disorder characterized by hyperpigmentation, premature skin aging, ocular and cutaneous photosensitivity, and increased risk of skin carcinoma. We investigated seven consanguineous XP families with nine patients from Pakistan. All the Patients exhibited typical clinical symptoms of XP since first year of life. Whole genome SNP genotyping identified a 14 Mb autozygous region segregating with the disease phenotype on chromosome 3p25.1. DNA sequencing of XPC gene revealed a founder homozygous splice site mutation (c.2251-1G>C) in patients from six families (A-F) and a homozygous nonsense mutation (c.1399C>T; p.Gln467*) in patients of family G. This is the first report of XPC mutations, underlying XP phenotype, in Pakistani population. © 2018 Japanese Teratology Society.

  2. Complex phenotype of dyskeratosis congenita and mood dysregulation with novel homozygous RTEL1 and TPH1 variants.

    PubMed

    Ungar, Rachel A; Giri, Neelam; Pao, Maryland; Khincha, Payal P; Zhou, Weiyin; Alter, Blanche P; Savage, Sharon A

    2018-06-01

    Dyskeratosis congenita (DC) is an inherited bone marrow failure syndrome caused by germline mutations in telomere biology genes. Patients have extremely short telomeres for their age and a complex phenotype including oral leukoplakia, abnormal skin pigmentation, and dysplastic nails in addition to bone marrow failure, pulmonary fibrosis, stenosis of the esophagus, lacrimal ducts and urethra, developmental anomalies, and high risk of cancer. We evaluated a patient with features of DC, mood dysregulation, diabetes, and lack of pubertal development. Family history was not available but genome-wide genotyping was consistent with consanguinity. Whole exome sequencing identified 82 variants of interest in 80 genes based on the following criteria: homozygous, <0.1% minor allele frequency in public and in-house databases, nonsynonymous, and predicted deleterious by multiple in silico prediction programs. Six genes were identified likely contributory to the clinical presentation. The cause of DC is likely due to homozygous splice site variants in regulator of telomere elongation helicase 1, a known DC and telomere biology gene. A homozygous, missense variant in tryptophan hydroxylase 1 may be clinically important as this gene encodes the rate limiting step in serotonin biosynthesis, a biologic pathway connected with mood disorders. Four additional genes (SCN4A, LRP4, GDAP1L1, and SPTBN5) had rare, missense homozygous variants that we speculate may contribute to portions of the clinical phenotype. This case illustrates the value of conducting detailed clinical and genomic evaluations on rare patients in order to identify new areas of research into the functional consequences of rare variants and their contribution to human disease. © 2018 Wiley Periodicals, Inc.

  3. Treatment of homozygous familial hypercholesterolaemia in paediatric patients: A monocentric experience.

    PubMed

    Buonuomo, Paola S; Macchiaiolo, Marina; Leone, Giovanna; Valente, Paola; Mastrogiorgio, Gerarda; Gnazzo, Maria; Rana, Ippolita; Gonfiantini, Michaela V; Gagliardi, Maria G; Romano, Francesca; Bartuli, Andrea

    2018-01-01

    Background Homozygous familial hypercholesterolaemia is a rare life-threatening disease characterized by markedly elevated low-density lipoprotein cholesterol (LDL-C) concentrations and accelerated atherosclerosis. The presence of double gene defects in the LDL-Receptor, either the same defect (homozygous) or two different LDL-raising mutations (compound heterozygotes) or other variants, identify the homozygous phenotype (HopFH). Apheresis is a procedure in which plasma is separated from red blood cells before the physical removal of LDL-C or the LDL-C is directly removed from whole blood. It is currently the treatment of choice for patients with HopFH whose LDL-C levels are not able to be reduced to target levels with conventional lipid-lowering drug therapy. Design The aim of this study is to report a cohort of six paediatric patients and to evaluate the long term efficacy of combined medical therapy and LDL-apheresis on LDL-C reduction. Methods We collected data from six children with confirmed diagnosis of HopFH (two females and four males; age range at diagnosis 3-8 years, mean 6 ± 1 years) from a single clinical hospital in Italy from 2007 to 2017. Results Clinical manifestations and outcomes may greatly vary in children with HopFH. Medical therapy and LDL-apheresis for the severe form should be started promptly in order to prevent cardiovascular disease. Conclusions Lipoprotein apheresis is a very important tool in managing patients with HopFH at high risk of cardiovascular disease. Based on our experience and the literature data, the method is feasible in very young children, efficient regarding biological results and cardiac events, and safe with minor side-effects and technical problems. We advise treating homozygous and compound heterozygous children as soon as possible.

  4. Mutations in Prickle Orthologs Cause Seizures in Flies, Mice, and Humans

    PubMed Central

    Tao, Hirotaka; Manak, J. Robert; Sowers, Levi; Mei, Xue; Kiyonari, Hiroshi; Abe, Takaya; Dahdaleh, Nader S.; Yang, Tian; Wu, Shu; Chen, Shan; Fox, Mark H.; Gurnett, Christina; Montine, Thomas; Bird, Thomas; Shaffer, Lisa G.; Rosenfeld, Jill A.; McConnell, Juliann; Madan-Khetarpal, Suneeta; Berry-Kravis, Elizabeth; Griesbach, Hilary; Saneto, Russell P.; Scott, Matthew P.; Antic, Dragana; Reed, Jordan; Boland, Riley; Ehaideb, Salleh N.; El-Shanti, Hatem; Mahajan, Vinit B.; Ferguson, Polly J.; Axelrod, Jeffrey D.; Lehesjoki, Anna-Elina; Fritzsch, Bernd; Slusarski, Diane C.; Wemmie, John; Ueno, Naoto; Bassuk, Alexander G.

    2011-01-01

    Epilepsy is heritable, yet few causative gene mutations have been identified, and thus far no human epilepsy gene mutations have been found to produce seizures in invertebrates. Here we show that mutations in prickle genes are associated with seizures in humans, mice, and flies. We identified human epilepsy patients with heterozygous mutations in either PRICKLE1 or PRICKLE2. In overexpression assays in zebrafish, prickle mutations resulted in aberrant prickle function. A seizure phenotype was present in the Prickle1-null mutant mouse, two Prickle1 point mutant (missense and nonsense) mice, and a Prickle2-null mutant mouse. Drosophila with prickle mutations displayed seizures that were responsive to anti-epileptic medication, and homozygous mutant embryos showed neuronal defects. These results suggest that prickle mutations have caused seizures throughout evolution. PMID:21276947

  5. Prevalence of glucocerebrosidase mutations in the Israeli Ashkenazi Jewish population.

    PubMed

    Horowitz, M; Pasmanik-Chor, M; Borochowitz, Z; Falik-Zaccai, T; Heldmann, K; Carmi, R; Parvari, R; Beit-Or, H; Goldman, B; Peleg, L; Levy-Lahad, E; Renbaum, P; Legum, S; Shomrat, R; Yeger, H; Benbenisti, D; Navon, R; Dror, V; Shohat, M; Magal, N; Navot, N; Eyal, N

    1998-01-01

    Gaucher disease is the most prevalent inherited disease among Ashkenazi Jews. It is very heterogeneous due to a large number of mutations within the glucocerebrosidase gene, whose impaired activity is the cause for this disease. Aiming at determining Gaucher carrier frequency among the Ashkenazi Jewish population in Israel, 1,208 individuals were molecularly diagnosed for six mutations known to occur among Ashkenazi Jewish Gaucher patients, using the newly developed Pronto Gaucher kit. The following mutations were tested: N370S, 84GG, IVS2+1, D409H, L444P, and V394L. Molecular testing of these mutations also allows identification of the recTL allele. The results indicated that Gaucher carrier frequency is 1:17 within the tested population. The prevalence of N370S carriers is 1:17.5. This implies that approximately 1:1225 Ashkenazi Jews will be homozygous for the N370S mutation. Actually, in our study of 1,208 individuals one was found to be homozygous for the N370S mutation. The actual number of known Ashkenazi Jewish Gaucher patients with this genotype is much lower than that expected according to the frequency of the N370S mutation, suggesting a low penetrance of this mutation. Results of loading experiments in cells homozygous for the N370S mutation, as well as cells homozygous for the L444P and the D409H mutations, exemplified this phenomenon.

  6. Identification of a pathogenic FTO mutation by next-generation sequencing in a newborn with growth retardation and developmental delay.

    PubMed

    Daoud, Hussein; Zhang, Dong; McMurray, Fiona; Yu, Andrea; Luco, Stephanie M; Vanstone, Jason; Jarinova, Olga; Carson, Nancy; Wickens, James; Shishodia, Shifali; Choi, Hwanho; McDonough, Michael A; Schofield, Christopher J; Harper, Mary-Ellen; Dyment, David A; Armour, Christine M

    2016-03-01

    A homozygous loss-of-function mutation p.(Arg316Gln) in the fat mass and obesity-associated (FTO) gene, which encodes for an iron and 2-oxoglutarate-dependent oxygenase, was previously identified in a large family in which nine affected individuals present with a lethal syndrome characterised by growth retardation and multiple malformations. To date, no other pathogenic mutation in FTO has been identified as a cause of multiple congenital malformations. We investigated a 21-month-old girl who presented distinctive facial features, failure to thrive, global developmental delay, left ventricular cardiac hypertrophy, reduced vision and bilateral hearing loss. We performed targeted next-generation sequencing of 4813 clinically relevant genes in the patient and her parents. We identified a novel FTO homozygous missense mutation (c.956C>T; p.(Ser319Phe)) in the affected individual. This mutation affects a highly conserved residue located in the same functional domain as the previously characterised mutation p.(Arg316Gln). Biochemical studies reveal that p.(Ser319Phe) FTO has reduced 2-oxoglutarate turnover and N-methyl-nucleoside demethylase activity. Our findings are consistent with previous reports that homozygous mutations in FTO can lead to rare growth retardation and developmental delay syndrome, and further support the proposal that FTO plays an important role in early development of human central nervous and cardiovascular systems. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  7. Exome Sequencing Identifies a Founder Frameshift Mutation in an Alternative Exon of USH1C as the Cause of Autosomal Recessive Retinitis Pigmentosa with Late-Onset Hearing Loss

    PubMed Central

    Khateb, Samer; Zelinger, Lina; Ben-Yosef, Tamar; Crystal-Shalit, Ornit; Gross, Menachem; Banin, Eyal; Sharon, Dror

    2012-01-01

    We used a combined approach of homozygosity mapping and whole exome sequencing (WES) to search for the genetic cause of autosomal recessive retinitis pigmentosa (arRP) in families of Yemenite Jewish origin. Homozygosity mapping of two arRP Yemenite Jewish families revealed a few homozygous regions. A subsequent WES analysis of the two index cases revealed a shared homozygous novel nucleotide deletion (c.1220delG) leading to a frameshift (p.Gly407Glufs*56) in an alternative exon (#15) of USH1C. Screening of additional Yemenite Jewish patients revealed a total of 16 homozygous RP patients (with a carrier frequency of 0.008 in controls). Funduscopic and electroretinography findings were within the spectrum of typical RP. While other USH1C mutations usually cause Usher type I (including RP, vestibular dysfunction and congenital deafness), audiometric screening of 10 patients who are homozygous for c.1220delG revealed that patients under 40 years of age had normal hearing while older patients showed mild to severe high tone sensorineural hearing loss. This is the first report of a mutation in a known USH1 gene that causes late onset rather than congenital sensorineural hearing loss. The c.1220delG mutation of USH1C accounts for 23% of RP among Yemenite Jewish patients in our cohort. PMID:23251578

  8. Partial lipodystrophy and insulin resistant diabetes in a patient with a homozygous nonsense mutation in CIDEC

    PubMed Central

    Rubio-Cabezas, Oscar; Puri, Vishwajeet; Murano, Incoronata; Saudek, Vladimir; Semple, Robert K; Dash, Satya; Hyden, Caroline S S; Bottomley, William; Vigouroux, Corinne; Magré, Jocelyne; Raymond-Barker, Philippa; Murgatroyd, Peter R; Chawla, Anil; Skepper, Jeremy N; Chatterjee, V Krishna; Suliman, Sara; Patch, Ann-Marie; Agarwal, Anil K; Garg, Abhimanyu; Barroso, Inês; Cinti, Saverio; Czech, Michael P; Argente, Jesús; O'Rahilly, Stephen; Savage, David B

    2009-01-01

    Lipodystrophic syndromes are characterized by adipose tissue deficiency. Although rare, they are of considerable interest as they, like obesity, typically lead to ectopic lipid accumulation, dyslipidaemia and insulin resistant diabetes. In this paper we describe a female patient with partial lipodystrophy (affecting limb, femorogluteal and subcutaneous abdominal fat), white adipocytes with multiloculated lipid droplets and insulin-resistant diabetes, who was found to be homozygous for a premature truncation mutation in the lipid droplet protein cell death-inducing Dffa-like effector C (CIDEC) (E186X). The truncation disrupts the highly conserved CIDE-C domain and the mutant protein is mistargeted and fails to increase the lipid droplet size in transfected cells. In mice, Cidec deficiency also reduces fat mass and induces the formation of white adipocytes with multilocular lipid droplets, but in contrast to our patient, Cidec null mice are protected against diet-induced obesity and insulin resistance. In addition to describing a novel autosomal recessive form of familial partial lipodystrophy, these observations also suggest that CIDEC is required for unilocular lipid droplet formation and optimal energy storage in human fat. PMID:20049731

  9. Partial lipodystrophy and insulin resistant diabetes in a patient with a homozygous nonsense mutation in CIDEC.

    PubMed

    Rubio-Cabezas, Oscar; Puri, Vishwajeet; Murano, Incoronata; Saudek, Vladimir; Semple, Robert K; Dash, Satya; Hyden, Caroline S S; Bottomley, William; Vigouroux, Corinne; Magré, Jocelyne; Raymond-Barker, Philippa; Murgatroyd, Peter R; Chawla, Anil; Skepper, Jeremy N; Chatterjee, V Krishna; Suliman, Sara; Patch, Ann-Marie; Agarwal, Anil K; Garg, Abhimanyu; Barroso, Inês; Cinti, Saverio; Czech, Michael P; Argente, Jesús; O'Rahilly, Stephen; Savage, David B

    2009-08-01

    Lipodystrophic syndromes are characterized by adipose tissue deficiency. Although rare, they are of considerable interest as they, like obesity, typically lead to ectopic lipid accumulation, dyslipidaemia and insulin resistant diabetes. In this paper we describe a female patient with partial lipodystrophy (affecting limb, femorogluteal and subcutaneous abdominal fat), white adipocytes with multiloculated lipid droplets and insulin-resistant diabetes, who was found to be homozygous for a premature truncation mutation in the lipid droplet protein cell death-inducing Dffa-like effector C (CIDEC) (E186X). The truncation disrupts the highly conserved CIDE-C domain and the mutant protein is mistargeted and fails to increase the lipid droplet size in transfected cells. In mice, Cidec deficiency also reduces fat mass and induces the formation of white adipocytes with multilocular lipid droplets, but in contrast to our patient, Cidec null mice are protected against diet-induced obesity and insulin resistance. In addition to describing a novel autosomal recessive form of familial partial lipodystrophy, these observations also suggest that CIDEC is required for unilocular lipid droplet formation and optimal energy storage in human fat.

  10. A homozygous transthyretin variant associated with senile systemic amyloidosis: evidence for a late-onset disease of genetic etiology.

    PubMed Central

    Jacobson, D R; Gorevic, P D; Buxbaum, J N

    1990-01-01

    Senile systemic amyloidosis (SSA) is a late-onset disease characterized by deposition of amyloid fibrils containing transthyretin (TTR). Amino acid sequencing of protein isolated from the amyloid fibrils of a patient with SSA identified TTR containing a position - 122 isoleucine-for-valine substitution. This change led to the prediction of a genomic G-to-A transition, destroying an MaeIII restriction site. We confirmed the presence of the variant DNA fragment both by Southern blotting and by visualization of MaeIII digests of DNA amplified around codon 122, by using the polymerase chain reaction. The patient's DNA was entirely resistant to MaeIII cleavage; therefore, only the mutant sequence was present. DNA from none of either 24 controls or six other SSA patients contained the variant. Quantitative Southern blotting demonstrated that the patient's DNA contained two copies of the TTR gene per genome; the mutation was therefore homozygous rather than hemizygous. In the present case, the homozygous mutation TTR (122 Val----Ile) is associated with SSA, a finding which is consistent with autosomal recessive inheritance of this condition. Images Figure 2 Figure 4 Figure 5 Figure 6 Figure 7 PMID:2349941

  11. Carbonic anhydrase II deficiency: Single-base deletion in exon 7 is the predominant mutation in Caribbean Hispanic patients

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hu, P.Y.; Ernst, A.R.; Sly, W.S.

    1994-04-01

    To date, three different structural gene mutations have been identified in patients with carbonic anhydrase II deficiency (osteopetrosis with renal tubular acidosis and cerebral calcification). These include a missense mutation (H107Y) in two families, a splice junction mutation in intron 5 in one of these families, and a splice junction mutation in intron 2 for which many Arabic patients are homozygous. The authors report here a novel mutation for which carbonic anhydrase II-deficient patients from seven unrelated Hispanic families were found to be homozygous. The proband was a 2 1/2-year-old Hispanic girl of Puerto Rican ancestry who was unique clinically,more » in that she had no evidence of renal tubular acidosis, even though she did have osteopetrosis, developmental delay, and cerebral calcification. She proved to be homozygous for a single-base deletion in the coding region of exon 7 that produces a frameshift that changes the next 12 amino acids before leading to chain termination and that also introduces a new MaeIII restriction site. The 27-kD truncated enzyme produced when the mutant cDNA was expressed in COS cells was enzymatically inactive, present mainly in insoluble aggregates, and detectable immunologically at only 5% the level of the 29-kD normal carbonic anhydrase II expressed from the wild-type cDNA. Metabolic labeling revealed that this 27-kD mutant protein has an accelerated rate of degradation. Six subsequent Hispanic patients of Caribbean ancestry, all of whom had osteopetrosis and renal tubular acidosis but who varied widely in clinical severity, were found to be homozygous for the same mutation. These findings identify a novel mutation common to Hispanic patients from the Caribbean islands and provide a ready means for PCR-based diagnosis of the [open quotes]Hispanic mutation.[close quotes] The basis for their phenotypic variability is not yet clear. 15 refs., 5 figs., 1 tab.« less

  12. Mutations in a novel gene with transmembrane domains underlie Usher syndrome type 3.

    PubMed

    Joensuu, T; Hämäläinen, R; Yuan, B; Johnson, C; Tegelberg, S; Gasparini, P; Zelante, L; Pirvola, U; Pakarinen, L; Lehesjoki, A E; de la Chapelle, A; Sankila, E M

    2001-10-01

    Usher syndrome type 3 (USH3) is an autosomal recessive disorder characterized by progressive hearing loss, severe retinal degeneration, and variably present vestibular dysfunction, assigned to 3q21-q25. Here, we report on the positional cloning of the USH3 gene. By haplotype and linkage-disequilibrium analyses in Finnish carriers of a putative founder mutation, the critical region was narrowed to 250 kb, of which we sequenced, assembled, and annotated 207 kb. Two novel genes-NOPAR and UCRP-and one previously identified gene-H963-were excluded as USH3, on the basis of mutational analysis. USH3, the candidate gene that we identified, encodes a 120-amino-acid protein. Fifty-two Finnish patients were homozygous for a termination mutation, Y100X; patients in two Finnish families were compound heterozygous for Y100X and for a missense mutation, M44K, whereas patients in an Italian family were homozygous for a 3-bp deletion leading to an amino acid deletion and substitution. USH3 has two predicted transmembrane domains, and it shows no homology to known genes. As revealed by northern blotting and reverse-transcriptase PCR, it is expressed in many tissues, including the retina.

  13. Next generation sequencing identifies mutations in Atonal homolog 7 (ATOH7) in families with global eye developmental defects

    PubMed Central

    Khan, Kamron; Logan, Clare V.; McKibbin, Martin; Sheridan, Eamonn; Elçioglu, Nursel H.; Yenice, Ozlem; Parry, David A.; Fernandez-Fuentes, Narcis; Abdelhamed, Zakia I.A.; Al-Maskari, Ahmed; Poulter, James A.; Mohamed, Moin D.; Carr, Ian M.; Morgan, Joanne E.; Jafri, Hussain; Raashid, Yasmin; Taylor, Graham R.; Johnson, Colin A.; Inglehearn, Chris F.; Toomes, Carmel; Ali, Manir

    2012-01-01

    The atonal homolog 7 (ATOH7) gene encodes a transcription factor involved in determining the fate of retinal progenitor cells and is particularly required for optic nerve and ganglion cell development. Using a combination of autozygosity mapping and next generation sequencing, we have identified homozygous mutations in this gene, p.E49V and p.P18RfsX69, in two consanguineous families diagnosed with multiple ocular developmental defects, including severe vitreoretinal dysplasia, optic nerve hypoplasia, persistent fetal vasculature, microphthalmia, congenital cataracts, microcornea, corneal opacity and nystagmus. Most of these clinical features overlap with defects in the Norrin/β-catenin signalling pathway that is characterized by dysgenesis of the retinal and hyaloid vasculature. Our findings document Mendelian mutations within ATOH7 and imply a role for this molecule in the development of structures at the front as well as the back of the eye. This work also provides further insights into the function of ATOH7, especially its importance in retinal vascular development and hyaloid regression. PMID:22068589

  14. Seven novel mutations in the factor XIII A-subunit gene causing hereditary factor XIII deficiency in 10 unrelated families.

    PubMed

    Vysokovsky, A; Saxena, R; Landau, M; Zivelin, A; Eskaraev, R; Rosenberg, N; Seligsohn, U; Inbal, A

    2004-10-01

    Hereditary factor (F)XIII deficiency is a rare bleeding disorder mostly due to mutations in FXIII A subunit. We studied the molecular basis of FXIII deficiency in patients from 10 unrelated families originating from Israel, India and Tunisia. Exons 2-15 of genomic DNA consisting of coding regions and intron/exon boundaries were amplified and sequenced. Structural analysis of the mutations was undertaken by computer modeling. Seven novel mutations were identified in the FXIIIA gene. The propositus from the Ethiopian-Jewish family was found to be a compound heterozygote for two novel mutations: a 10-bp deletion in exon 12 at nucleotides 1652-1661 (followed by 22 altered amino acids and termination codon) and Ala318Val mutation. The propositus of the Tunisian family was homozygous for C insertion after nucleotide 863 within a stretch of six cytosines of exon 7. This insertion results in generation of eight altered amino acids followed by a termination codon downstream. The propositus from Indian-Jewish origin was found to be homozygous for G to T substitution at IVS 11 [+1] resulting in skipping of exons 10 and 11. In addition to the Ala318Val mutation, three of the novel mutations identified are missense mutations: Arg260Leu, Thr398Asn and Gly210Arg each occurring in a homozygous state in an Israeli-Arab and two Indian families, respectively. Structure-function correlation analysis by computer modeling of the new missense mutations predicted that Gly210Arg will cause protein misfolding, Ala318Val and Thr398Asn will interfere with the catalytic process or protein stability, and Arg260Leu will impair dimerization.

  15. Identification of novel mutations of the WFS1 gene in Brazilian patients with Wolfram syndrome.

    PubMed

    Gasparin, Maria Regina R; Crispim, Felipe; Paula, Sílvia L; Freire, Maria Beatriz S; Dalbosco, Ivaldir S; Manna, Thais Della; Salles, João Eduardo N; Gasparin, Fábio; Guedes, Aléxis; Marcantonio, João M; Gambini, Márcio; Salim, Camila P; Moisés, Regina S

    2009-02-01

    Wolfram syndrome (WS) is a rare, progressive, neurodegenerative disorder with an autosomal recessive pattern of inheritance. The gene for WS, WFS1, was identified on chromosome 4p16 and most WS patients carry mutations in this gene. However, some studies have provided evidence for genetic heterogeneity and the genotype-phenotype relationships are not clear. Our aim was to ascertain the spectrum of WFS1 mutations in Brazilian patients with WS and to examine the phenotype-genotype relationships in these patients. Clinical characterization and analyses of the WFS1 gene were performed in 27 Brazilian patients with WS from 19 families. We identified 15 different mutations in the WFS1 gene in 26 patients, among which nine are novel. All mutations occurred in exon 8, except for one missense mutation which was located in exon 5. Although we did not find any clear phenotype-genotype relationship in patients with mutations in exon 8, the homozygous missense mutation in exon 5 was associated with a mild phenotype: onset of diabetes mellitus and optic atrophy during adulthood with good metabolic control being achieved with low doses of sulfonylurea. Our data show that WFS1 is the major gene involved in WS in Brazilian patients and most mutations are concentrated in exon 8. Also, our study increases the spectrum of WFS1 mutations. Although no clear phenotype-genotype relationship was found for mutations in exon 8, a mild phenotype was associated with a homozygous missense mutation in exon 5.

  16. Clinical Course of Homozygous Hemoglobin Constant Spring in Pediatric Patients.

    PubMed

    Komvilaisak, Patcharee; Jetsrisuparb, Arunee; Fucharoen, Goonnapa; Komwilaisak, Ratana; Jirapradittha, Junya; Kiatchoosakun, Pakaphan

    2018-04-17

    Hemoglobin (Hb) Constant Spring is an alpha-globin gene variant due to a mutation of the stop codon resulting in the elongation of the encoded polypeptide from 141 to 172 amino acid residues. Patients with homozygous Hb Constant Spring are usually mildly anemic. We retrospectively describe clinical manifestations, diagnosis, laboratory investigations, treatment, and associated findings in pediatric patients with homozygous Hb Constant Spring followed-up at Srinagarind Hospital. Sixteen pediatric cases (5 males and 11 females) were diagnosed in utero (N=6) or postnatal (n=10). Eleven cases were diagnosed with homozygous Hb Constant Spring, 4 with homozygous Hb Constant Spring with heterozygous Hb E, and 1 with homozygous Hb Constant Spring with homozygous Hb E. Three cases were delivered preterm. Six patients had low birth weights. Clinical manifestations included fetal anemia in 6 cases, hepatomegaly in 1 case, hepatosplenomegaly in 2 cases, splenomegaly in 1 case. Twelve cases exhibited early neonatal jaundice, 9 of which required phototherapy. Six cases received red cell transfusions; 1 (3), >1 (3). After the first few months of life, almost all patients had mild microcytic hypochromic anemia and an increased reticulocyte count with a wide red cell distribution (RDW), but no longer required red cell transfusion. At 1 to 2 years of age, some patients still had mild microcytic hypochromic anemia and some had normocytic hypochromic anemia with Hb around 10 g/dL, increased reticulocyte count and wide RDW. Associated findings included hypothyroidism (2), congenital heart diseases (4), genitourinary abnormalities (3), gastrointestinal abnormalities (2), and developmental delay (1). Pediatric patients with homozygous Hb Constant Spring developed severe anemia in utero and up to the age of 2 to 3 months postnatal, requiring blood transfusions. Subsequently, their anemia was mild with no evidence of hepatosplenomegaly. Their Hb level was above 9 g/dL with hypochromic

  17. EIF2AK4 Mutations in Patients Diagnosed With Pulmonary Arterial Hypertension.

    PubMed

    Best, D Hunter; Sumner, Kelli L; Smith, Benjamin P; Damjanovich-Colmenares, Kristy; Nakayama, Ikue; Brown, Lynette M; Ha, Youna; Paul, Eleri; Morris, Ashley; Jama, Mohamed A; Dodson, Mark W; Bayrak-Toydemir, Pinar; Elliott, C Gregory

    2017-04-01

    Differentiating pulmonary venoocclusive disease (PVOD) and pulmonary capillary hemangiomatosis (PCH) from idiopathic pulmonary arterial hypertension (IPAH) or heritable pulmonary arterial hypertension (HPAH) is important clinically. Mutations in eukaryotic translation initiation factor 2 alpha kinase 4 (EIF2AK4) cause heritable PVOD and PCH, whereas mutations in other genes cause HPAH. The aim of this study was to describe the frequency of pathogenic EIF2AK4 mutations in patients diagnosed clinically with IPAH or HPAH. Sanger sequencing and deletion/duplication analysis were performed to detect mutations in the bone morphogenetic protein receptor type II (BMPR2) gene in 81 patients diagnosed at 30 North American medical centers with IPAH (n = 72) or HPAH (n = 9). BMPR2 mutation-negative patients (n = 67) were sequenced for mutations in four other genes (ACVRL1, ENG, CAV1, and KCNK3) known to cause HPAH. Patients negative for mutations in all known PAH genes (n = 66) were then sequenced for mutations in EIF2AK4. We assessed the pathogenicity of EIF2AK4 mutations and reviewed clinical characteristics of patients with pathogenic EIF2AK4 mutations. Pathogenic BMPR2 mutations were identified in 8 of 72 (11.1%) patients with IPAH and 6 of 9 (66.7%) patients with HPAH. A novel homozygous EIF2AK4 mutation (c.257+4A>C) was identified in 1 of 9 (11.1%) patients diagnosed with HPAH. The novel EIF2AK4 mutation (c.257+4A>C) was homozygous in two sisters with severe pulmonary hypertension. None of the 72 patients with IPAH had biallelic EIF2AK4 mutations. Pathogenic biallelic EIF2AK4 mutations are rarely identified in patients diagnosed with HPAH. Identification of pathogenic biallelic EIF2AK4 mutations can aid clinicians in differentiating HPAH from heritable PVOD or PCH. Copyright © 2016 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

  18. Juvenile Paget’s Disease In An Iranian Kindred With Vitamin D Deficiency And Novel Homozygous TNFRSF11B Mutation

    PubMed Central

    Saki, Forough; Karamizadeh, Zohreh; Nasirabadi, Shiva; Mumm, Steven; McAlister, William H.; Whyte, Michael P.

    2013-01-01

    Juvenile Paget’s disease (JPD) is a rare heritable osteopathy characterized biochemically by markedly increased serum alkaline phosphatase (ALP) activity emanating from generalized acceleration of skeletal turnover. Affected infants and children typically suffer bone pain and fractures and deformities, become deaf, and have macrocranium. Some who survive to young adult life develop blindness from retinopathy engendered by vascular microcalcification. Most cases of JPD are caused by osteoprotegerin (OPG) deficiency due to homozygous loss-of-function mutations within the TNFRSF11B gene that encodes OPG. We report a 3-year-old Iranian girl with JPD and craniosynostosis who had vitamin D deficiency in infancy. She presented with fractures during the first year-of-life followed by bone deformities, delayed development, failure-to-thrive, and pneumonias. At 1 year-of-age, biochemical studies of serum revealed marked hyperphosphatasemia together with low-normal calcium and low inorganic phosphate and 25-hydroxyvitamin D levels. Several family members in previous generations of this consanguineous kindred may also have had JPD and vitamin D deficiency. Mutation analysis showed homozygosity for a unique missense change (c.130T>C, p.Cys44Arg) in TNFRSF11B that would compromise the cysteine-rich domain of OPG that binds receptor activator of NF-κB ligand (RANKL). Both parents were heterozygous for this mutation. The patient’s serum OPG level was extremely low and RANKL level markedly elevated. She responded well to rapid oral vitamin D repletion followed by pamidronate treatment given intravenously. Our patient is the first Iranian reported with JPD. Her novel mutation in TNFRSF11B plus vitamin D deficiency in infancy was associated with severe JPD uniquely complicated by craniosynostosis. Pamidronate treatment with vitamin D sufficiency can be effective treatment for the skeletal disease caused by the OPG deficiency form of JPD. PMID:23322328

  19. Emerging Treatments for Heterozygous and Homozygous Familial Hypercholesterolemia.

    PubMed

    Baum, Seth J; Soffer, Daniel; Barton Duell, P

    Familial hypercholesterolemia (FH) is an autosomal co-dominant disorder marked by extremely high low-density lipoprotein (LDL) cholesterol levels and concomitant premature vascular disease. FH is caused by mutations that most commonly affect three genes integrally involved in the LDL receptor's ability to clear LDL particles from the circulation. Primary intervention efforts to lower LDL cholesterol have centered on therapies that upregulate the LDL receptor. Unfortunately, most patients are insufficiently responsive to traditional LDL-lowering medications. This article focuses primarily on the clinical management of homozygous FH.

  20. Pathogenic mutations of TGFBI and CHST6 genes in Chinese patients with Avellino, lattice, and macular corneal dystrophies.

    PubMed

    Huo, Ya-nan; Yao, Yu-feng; Yu, Ping

    2011-09-01

    To investigate gene mutations associated with three different types of corneal dystrophies (CDs), and to establish a phenotype-genotype correlation. Two patients with Avellino corneal dystrophy (ACD), four patients with lattice corneal dystrophy type I (LCD I) from one family, and three patients with macular corneal dystrophy type I (MCD I) were subjected to both clinical and genetic examinations. Slit lamp examination was performed for all the subjects to assess their corneal phenotypes. Genomic DNA was extracted from peripheral blood leukocytes. The coding regions of the human transforming growth factor β-induced (TGFBI) gene and carbohydrate sulfotransferase 6 (CHST6) gene were amplified by polymerase chain reaction (PCR) and subjected to direct sequencing. DNA samples from 50 healthy volunteers were used as controls. Clinical examination showed three different phenotypes of CDs. Genetic examination identified that two ACD subjects were associated with homozygous R124H mutation of TGFBI, and four LCD I subjects were all associated with R124C heterozygous mutation. One MCD I subject was associated with a novel S51X homozygous mutation in CHST6, while the other two MCD I subjects harbored a previously reported W232X homozygous mutation. Our study highlights the prevalence of codon 124 mutations in the TGFBI gene among the Chinese ACD and LCD I patients. Moreover, we found a novel mutation among MCD I patients.

  1. Identification of MPL R102P Mutation in Hereditary Thrombocytosis.

    PubMed

    Bellanné-Chantelot, Christine; Mosca, Matthieu; Marty, Caroline; Favier, Rémi; Vainchenker, William; Plo, Isabelle

    2017-01-01

    The molecular basis of hereditary thrombocytosis is germline mutations affecting the thrombopoietin (TPO)/TPO receptor (MPL)/JAK2 signaling axis. Here, we report one family presenting two cases with a mild thrombocytosis. By sequencing JAK2 and MPL coding exons, we identified a germline MPL R102P heterozygous mutation in the proband and his daughter. Concomitantly, we detected high TPO levels in the serum of these two patients. The mutation was not found in three other unaffected cases from the family except in another proband's daughter who did not present thrombocytosis but had a high TPO level. The MPL R102P mutation was first described in congenital amegakaryocytic thrombocytopenia in a homozygous state with a loss-of-function activity. It was previously shown that MPL R102P was blocked in the endoplasmic reticulum without being able to translocate to the plasma membrane. Thus, this case report identifies for the first time that MPL R102P mutation can differently impact megakaryopoiesis: thrombocytosis or thrombocytopenia depending on the presence of the heterozygous or homozygous state, respectively. The paradoxical effect associated with heterozygous MPL R102P may be due to subnormal cell-surface expression of wild-type MPL in platelets inducing a defective TPO clearance. As a consequence, increased TPO levels may activate megakaryocyte progenitors that express a lower, but still sufficient level of MPL for the induction of proliferation.

  2. Clinical and genetic characterization of a founder PKHD1 mutation in Afrikaners with ARPKD.

    PubMed

    Lambie, Lindsay; Amin, Rasheda; Essop, Fahmida; Cnaan, Avital; Krause, Amanda; Guay-Woodford, Lisa M

    2015-02-01

    Autosomal recessive polycystic kidney disease (ARPKD; MIM 263200) occurs in 1:20,000 live births. Disease expression is widely variable, with approximately 30 % of affected neonates dying perinatally, while others survive to adulthood. Mutations at the PKHD1 locus are responsible for all typical presentations. The objectives of this study were to define the clinical and genetic characteristics in a cohort of South African patients of Afrikaner origin, a population with a high prevalence of ARPKD. DNA from the cohort was analyzed for background haplotypes and the p.M627K mutation previously identified in two unrelated Afrikaner patients. The clinical phenotype of the homozygous group was characterized. Analysis of 36 Afrikaner families revealed that 27 patients, from 24 (67 %) families, were homozygous for the p.M627K substitution, occurring on a common haplotype. The clinical phenotype of the homozygous individuals was variable. Our data provide strong evidence that the p.M627K substitution is a founder mutation in the Afrikaner population and can be used for streamlined diagnostic testing for at-risk pregnancies. The observed clinical variability suggests that disease expression is modulated by other genetic loci or by gene-environment interactions.

  3. WNT10A missense mutation associated with a complete Odonto-Onycho-Dermal Dysplasia syndrome

    PubMed Central

    Nawaz, Sadia; Klar, Joakim; Wajid, Muhammad; Aslam, Muhammad; Tariq, Muhammad; Schuster, Jens; Baig, Shahid Mahmood; Dahl, Niklas

    2009-01-01

    Wnt signalling is one of a few pathways that are crucial for controlling genetic programs during embryonic development as well as in adult tissues. WNT10A is expressed in the skin and epidermis and it has shown to be critical for the development of ectodermal appendages. A nonsense mutation in WNT10A was recently identified in odonto-onycho-dermal dysplasia (OODD; MIM 257980), a rare syndrome characterised by severe hypodontia, nail dystrophy, smooth tongue, dry skin, keratoderma and hyperhydrosis of palms and soles. We identified a large consanguineous Pakistani pedigree comprising six individuals affected by a complete OODD syndrome. Autozygosity mapping using SNP array analysis showed that the affected individuals are homozygous for the WNT10A gene region. Subsequent mutation screening showed a homozygous c.392C>T transition in exon 3 of WNT10A, which predicts a p.A131V substitution in a conserved α-helix domain. We report here on the first inherited missense mutation in WNT10A with associated ectodermal features. PMID:19471313

  4. WNT10A missense mutation associated with a complete odonto-onycho-dermal dysplasia syndrome.

    PubMed

    Nawaz, Sadia; Klar, Joakim; Wajid, Muhammad; Aslam, Muhammad; Tariq, Muhammad; Schuster, Jens; Baig, Shahid Mahmood; Dahl, Niklas

    2009-12-01

    Wnt signalling is one of a few pathways that are crucial for controlling genetic programs during embryonic development as well as in adult tissues. WNT10A is expressed in the skin and epidermis and it has shown to be critical for the development of ectodermal appendages. A nonsense mutation in WNT10A was recently identified in odonto-onycho-dermal dysplasia (OODD; MIM 257980), a rare syndrome characterised by severe hypodontia, nail dystrophy, smooth tongue, dry skin, keratoderma and hyperhydrosis of palms and soles. We identified a large consanguineous Pakistani pedigree comprising six individuals affected by a complete OODD syndrome. Autozygosity mapping using SNP array analysis showed that the affected individuals are homozygous for the WNT10A gene region. Subsequent mutation screening showed a homozygous c.392C>T transition in exon 3 of WNT10A, which predicts a p.A131V substitution in a conserved alpha-helix domain. We report here on the first inherited missense mutation in WNT10A with associated ectodermal features.

  5. Novel USH2A compound heterozygous mutations cause RP/USH2 in a Chinese family.

    PubMed

    Liu, Xiaowen; Tang, Zhaohui; Li, Chang; Yang, Kangjuan; Gan, Guanqi; Zhang, Zibo; Liu, Jingyu; Jiang, Fagang; Wang, Qing; Liu, Mugen

    2010-03-17

    To identify the disease-causing gene in a four-generation Chinese family affected with retinitis pigmentosa (RP). Linkage analysis was performed with a panel of microsatellite markers flanking the candidate genetic loci of RP. These loci included 38 known RP genes. The complete coding region and exon-intron boundaries of Usher syndrome 2A (USH2A) were sequenced with the proband DNA to screen the disease-causing gene mutation. Restriction fragment length polymorphism (RFLP) analysis and direct DNA sequence analysis were done to demonstrate co-segregation of the USH2A mutations with the family disease. One hundred normal controls were used without the mutations. The disease-causing gene in this Chinese family was linked to the USH2A locus on chromosome 1q41. Direct DNA sequence analysis of USH2A identified two novel mutations in the patients: one missense mutation p.G1734R in exon 26 and a splice site mutation, IVS32+1G>A, which was found in the donor site of intron 32 of USH2A. Neither the p.G1734R nor the IVS32+1G>A mutation was found in the unaffected family members or the 100 normal controls. One patient with a homozygous mutation displayed only RP symptoms until now, while three patients with compound heterozygous mutations in the family of study showed both RP and hearing impairment. This study identified two novel mutations: p.G1734R and IVS32+1G>A of USH2A in a four-generation Chinese RP family. In this study, the heterozygous mutation and the homozygous mutation in USH2A may cause Usher syndrome Type II or RP, respectively. These two mutations expand the mutant spectrum of USH2A.

  6. TREM2 mutations are rare in a French cohort of patients with frontotemporal dementia.

    PubMed

    Lattante, Serena; Le Ber, Isabelle; Camuzat, Agnès; Dayan, Sarah; Godard, Chloé; Van Bortel, Inge; De Septenville, Anne; Ciura, Sorana; Brice, Alexis; Kabashi, Edor

    2013-10-01

    Homozygous mutations in TREM2 have been recently identified by exome sequencing in families presenting with frontotemporal dementia (FTD)-like phenotype. No study has evaluated the exact frequency of TREM2 mutations in cohorts of FTD patients so far. We sequenced TREM2 in 175 patients with pure FTD, mostly French, to test whether mutations could be implicated in the pathogenesis of the disease. No disease-causing mutation was identified in 175 individuals from the French cohort of FTD patients. We did not identify the polymorphism p.R47H (rs75932628), strongly associated with an increased risk of developing Alzheimer's disease. We conclude that TREM2 mutations are extremely rare in patients with pure FTD, although further investigation in larger populations is needed. Copyright © 2013 Elsevier Inc. All rights reserved.

  7. Identifying pathways affected by cancer mutations.

    PubMed

    Iengar, Prathima

    2017-12-16

    Mutations in 15 cancers, sourced from the COSMIC Whole Genomes database, and 297 human pathways, arranged into pathway groups based on the processes they orchestrate, and sourced from the KEGG pathway database, have together been used to identify pathways affected by cancer mutations. Genes studied in ≥15, and mutated in ≥10 samples of a cancer have been considered recurrently mutated, and pathways with recurrently mutated genes have been considered affected in the cancer. Novel doughnut plots have been presented which enable visualization of the extent to which pathways and genes, in each pathway group, are targeted, in each cancer. The 'organismal systems' pathway group (including organism-level pathways; e.g., nervous system) is the most targeted, more than even the well-recognized signal transduction, cell-cycle and apoptosis, and DNA repair pathway groups. The important, yet poorly-recognized, role played by the group merits attention. Pathways affected in ≥7 cancers yielded insights into processes affected. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Homozygous Mutation G539R in the Gene for P450 Oxidoreductase in a Family Previously Diagnosed as Having 17,20-Lyase Deficiency

    PubMed Central

    Hershkovitz, Eli; Parvari, Ruthi; Wudy, Stefan A.; Hartmann, Michaela F.; Gomes, Larissa G.; Loewental, Neta; Miller, Walter L.

    2008-01-01

    Context: Very few patients have been described with isolated 17,20-lyase deficiency who have had their mutations in P450c17 (17α-hydroxylase/17,20-lyase) proven by DNA sequencing and in vitro characterization of the mutations. Most patients with 17,20-lyase deficiency have mutations in the domain of P450c17 that interact with the electron-donating redox partner, P450 oxidoreductase (POR). Objective: Our objective was to clarify the genetic and functional basis of isolated 17,20-lyase deficiency in familial cases who were previously reported as having 17,20-lyase deficiency. Patients: Four undervirilized males of an extended Bedouin family were investigated. One of these has previously been reported to carry mutations in the CYP17A1 gene encoding P450c17 causing isolated 17,20-lyase deficiency. Methods: Serum hormones were evaluated before and after stimulation with ACTH. Urinary steroid metabolites were profiled by gas chromatography-mass spectrometry. Exons 1 and 8 of CYP17A1 previously reported to harbor mutations in one of these patients and all 15 coding exons of POR were sequenced. Results: Gas chromatography-mass spectrometry (GC-MS) urinary steroid profiling and serum steroid measurements showed combined deficiencies of 17,20-lyase and 21-hydroxylase. Sequencing of exons 1 and 8 of CYP17A1 in two different laboratories showed no mutations. Sequencing of POR showed that all four patients were homozygous for G539R, a previously studied mutation that retains 46% of normal capacity to support the 17α-hydroxylase activity but only 8% of the 17,20-lyase activity of P450c17. Conclusion: POR deficiency can masquerade clinically as isolated 17,20-lyase deficiency. PMID:18559916

  9. Homozygous mutation G539R in the gene for P450 oxidoreductase in a family previously diagnosed as having 17,20-lyase deficiency.

    PubMed

    Hershkovitz, Eli; Parvari, Ruthi; Wudy, Stefan A; Hartmann, Michaela F; Gomes, Larissa G; Loewental, Neta; Miller, Walter L

    2008-09-01

    Very few patients have been described with isolated 17,20-lyase deficiency who have had their mutations in P450c17 (17alpha-hydroxylase/17,20-lyase) proven by DNA sequencing and in vitro characterization of the mutations. Most patients with 17,20-lyase deficiency have mutations in the domain of P450c17 that interact with the electron-donating redox partner, P450 oxidoreductase (POR). Our objective was to clarify the genetic and functional basis of isolated 17,20-lyase deficiency in familial cases who were previously reported as having 17,20-lyase deficiency. Four undervirilized males of an extended Bedouin family were investigated. One of these has previously been reported to carry mutations in the CYP17A1 gene encoding P450c17 causing isolated 17,20-lyase deficiency. Serum hormones were evaluated before and after stimulation with ACTH. Urinary steroid metabolites were profiled by gas chromatography-mass spectrometry. Exons 1 and 8 of CYP17A1 previously reported to harbor mutations in one of these patients and all 15 coding exons of POR were sequenced. Gas chromatography-mass spectrometry (GC-MS) urinary steroid profiling and serum steroid measurements showed combined deficiencies of 17,20-lyase and 21-hydroxylase. Sequencing of exons 1 and 8 of CYP17A1 in two different laboratories showed no mutations. Sequencing of POR showed that all four patients were homozygous for G539R, a previously studied mutation that retains 46% of normal capacity to support the 17alpha-hydroxylase activity but only 8% of the 17,20-lyase activity of P450c17. POR deficiency can masquerade clinically as isolated 17,20-lyase deficiency.

  10. Recurrent Muscle Weakness with Rhabdomyolysis, Metabolic Crises, and Cardiac Arrhythmia Due to Bi-allelic TANGO2 Mutations

    PubMed Central

    Lalani, Seema R.; Liu, Pengfei; Rosenfeld, Jill A.; Watkin, Levi B.; Chiang, Theodore; Leduc, Magalie S.; Zhu, Wenmiao; Ding, Yan; Pan, Shujuan; Vetrini, Francesco; Miyake, Christina Y.; Shinawi, Marwan; Gambin, Tomasz; Eldomery, Mohammad K.; Akdemir, Zeynep Hande Coban; Emrick, Lisa; Wilnai, Yael; Schelley, Susan; Koenig, Mary Kay; Memon, Nada; Farach, Laura S.; Coe, Bradley P.; Azamian, Mahshid; Hernandez, Patricia; Zapata, Gladys; Jhangiani, Shalini N.; Muzny, Donna M.; Lotze, Timothy; Clark, Gary; Wilfong, Angus; Northrup, Hope; Adesina, Adekunle; Bacino, Carlos A.; Scaglia, Fernando; Bonnen, Penelope E.; Crosson, Jane; Duis, Jessica; Maegawa, Gustavo H.B.; Coman, David; Inwood, Anita; McGill, Jim; Boerwinkle, Eric; Graham, Brett; Beaudet, Art; Eng, Christine M.; Hanchard, Neil A.; Xia, Fan; Orange, Jordan S.; Gibbs, Richard A.; Lupski, James R.; Yang, Yaping

    2016-01-01

    The underlying genetic etiology of rhabdomyolysis remains elusive in a significant fraction of individuals presenting with recurrent metabolic crises and muscle weakness. Using exome sequencing, we identified bi-allelic mutations in TANGO2 encoding transport and Golgi organization 2 homolog (Drosophila) in 12 subjects with episodic rhabdomyolysis, hypoglycemia, hyperammonemia, and susceptibility to life-threatening cardiac tachyarrhythmias. A recurrent homozygous c.460G>A (p.Gly154Arg) mutation was found in four unrelated individuals of Hispanic/Latino origin, and a homozygous ∼34 kb deletion affecting exons 3–9 was observed in two families of European ancestry. One individual of mixed Hispanic/European descent was found to be compound heterozygous for c.460G>A (p.Gly154Arg) and the deletion of exons 3–9. Additionally, a homozygous exons 4–6 deletion was identified in a consanguineous Middle Eastern Arab family. No homozygotes have been reported for these changes in control databases. Fibroblasts derived from a subject with the recurrent c.460G>A (p.Gly154Arg) mutation showed evidence of increased endoplasmic reticulum stress and a reduction in Golgi volume density in comparison to control. Our results show that the c.460G>A (p.Gly154Arg) mutation and the exons 3–9 heterozygous deletion in TANGO2 are recurrent pathogenic alleles present in the Latino/Hispanic and European populations, respectively, causing considerable morbidity in the homozygotes in these populations. PMID:26805781

  11. Homozygous single base deletion in TUSC3 causes intellectual disability with developmental delay in an Omani family.

    PubMed

    Al-Amri, Ahmed; Saegh, Abeer Al; Al-Mamari, Watfa; El-Asrag, Mohammed E; Ivorra, Jose L; Cardno, Alastair G; Inglehearn, Chris F; Clapcote, Steven J; Ali, Manir

    2016-07-01

    Intellectual disability (ID) is the term used to describe a diverse group of neurological conditions with congenital or juvenile onset, characterized by an IQ score of less than 70 and difficulties associated with limitations in cognitive function and adaptive behavior. The condition can be inherited or caused by environmental factors. The genetic forms are heterogeneous, with mutations in over 500 known genes shown to cause the disorder. We report a consanguineous Omani family in which multiple individuals have ID and developmental delay together with some variably present features including short stature, microcephaly, moderate facial dysmorphism, and congenital malformations of the toes or hands. Homozygosity mapping combined with whole exome next generation sequencing identified a novel homozygous single base pair deletion in TUSC3, c.222delA, p.R74 fs. The mutation segregates with the disease phenotype in a recessive manner and is absent in 60,706 unrelated individuals from various disease-specific and population genetic studies. TUSC3 mutations have been previously identified as causing either syndromic or non-syndromic ID in patients from France, Italy, Iran and Pakistan. This paper supports the previous clinical descriptions of the condition caused by TUSC3 mutations and describes the seventh family with mutations in this gene, thus contributing to the genetic spectrum of mutations. This is the first report of a family from the Arabian peninsula with this form of ID. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  12. Microbial Disease Spectrum Linked to a Novel IL-12Rβ1 N-Terminal Signal Peptide Stop-Gain Homozygous Mutation with Paradoxical Receptor Cell-Surface Expression

    PubMed Central

    Louvain de Souza, Thais; de Souza Campos Fernandes, Regina C.; Azevedo da Silva, Juliana; Gomes Alves Júnior, Vladimir; Gomes Coelho, Adelia; Souza Faria, Afonso C.; Moreira Salomão Simão, Nabia M.; Souto Filho, João T.; Deswarte, Caroline; Boisson-Dupuis, Stéphanie; Torgerson, Dara; Casanova, Jean-Laurent; Bustamante, Jacinta; Medina-Acosta, Enrique

    2017-01-01

    Patients with Mendelian Susceptibility to Mycobacterial Diseases (MSMD) exhibit variable vulnerability to infections by mycobacteria and other intramacrophagic bacteria (e.g., Salmonella and Klebsiella) and fungi (e.g., Histoplasma, Candida, Paracoccidioides, Coccidioides, and Cryptococcus). The hallmark of MSMD is the inherited impaired production of interferon gamma (IFN-γ) or the lack of response to it. Mutations in the interleukin (IL)-12 receptor subunit beta 1 (IL12RB1) gene accounts for 38% of cases of MSMD. Most IL12RB1 pathogenic allele mutations, including ten known stop-gain variants, cause IL-12Rβ1 complete deficiency (immunodeficiency-30, IMD30) by knocking out receptor cell-surface expression. IL12RB1 loss-of-function genotypes impair both IL-12 and IL-23 responses. Here, we assess the health effects of a rare, novel IL12RB1 stop-gain homozygous genotype with paradoxical IL-12Rβ1 cell-surface expression. We appraise four MSMD children from three unrelated Brazilian kindreds by clinical consultation, medical records, and genetic and immunologic studies. The clinical spectrum narrowed down to Bacillus Calmette-Guerin (BCG) vaccine-related suppurative adenitis in all patients with one death, and recrudescence in two, histoplasmosis, and recurrence in one patient, extraintestinal salmonellosis in one child, and cutaneous vasculitis in another. In three patients, we established the homozygous Trp7Ter predicted loss-of-function inherited genotype and inferred it from the heterozygote parents of the fourth case. The Trp7Ter mutation maps to the predicted IL-12Rβ1 N-terminal signal peptide sequence. BCG- or phytohemagglutinin-blasts from the three patients have reduced cell-surface expression of IL-12Rβ1 with impaired production of IFN-γ and IL-17A. Screening of 227 unrelated healthy subjects from the same geographic region revealed one heterozygous genotype (allele frequency 0.0022) vs. one in over 841,883 public genome/exomes. We also show that the

  13. Hereditary sensory and autonomic neuropathy type IID caused by an SCN9A mutation.

    PubMed

    Yuan, Junhui; Matsuura, Eiji; Higuchi, Yujiro; Hashiguchi, Akihiro; Nakamura, Tomonori; Nozuma, Satoshi; Sakiyama, Yusuke; Yoshimura, Akiko; Izumo, Shuji; Takashima, Hiroshi

    2013-04-30

    To identify the clinical features of Japanese patients with suspected hereditary sensory and autonomic neuropathy (HSAN) on the basis of genetic diagnoses. On the basis of clinical, in vivo electrophysiologic, and pathologic findings, 9 Japanese patients with sensory and autonomic nervous dysfunctions were selected. Eleven known HSAN disease-causing genes and 5 related genes were screened using a next-generation sequencer. A homozygous mutation, c.3993delGinsTT, was identified in exon 22 of SCN9A from 2 patients/families. The clinical phenotype was characterized by adolescent or congenital onset with loss of pain and temperature sensation, autonomic nervous dysfunctions, hearing loss, and hyposmia. Subsequently, this mutation was discovered in one of patient 1's sisters, who also exhibited sensory and autonomic nervous system dysfunctions, with recurrent fractures being the most predominant feature. Nerve conduction studies revealed definite asymmetric sensory nerve involvement in patient 1. In addition, sural nerve pathologic findings showed loss of large myelinated fibers in patient 1, whereas the younger patient showed normal sural nerve pathology. We identified a novel homozygous mutation in SCN9A from 2 Japanese families with autosomal recessive HSAN. This loss-of-function SCN9A mutation results in disturbances in the sensory, olfactory, and autonomic nervous systems. We propose that SCN9A mutation results in the new entity of HSAN type IID, with additional symptoms including hyposmia, hearing loss, bone dysplasia, and hypogeusia.

  14. Pathogenic mutations of TGFBI and CHST6 genes in Chinese patients with Avellino, lattice, and macular corneal dystrophies

    PubMed Central

    Huo, Ya-nan; Yao, Yu-feng; Yu, Ping

    2011-01-01

    Objective: To investigate gene mutations associated with three different types of corneal dystrophies (CDs), and to establish a phenotype-genotype correlation. Methods: Two patients with Avellino corneal dystrophy (ACD), four patients with lattice corneal dystrophy type I (LCD I) from one family, and three patients with macular corneal dystrophy type I (MCD I) were subjected to both clinical and genetic examinations. Slit lamp examination was performed for all the subjects to assess their corneal phenotypes. Genomic DNA was extracted from peripheral blood leukocytes. The coding regions of the human transforming growth factor β-induced (TGFBI) gene and carbohydrate sulfotransferase 6 (CHST6) gene were amplified by polymerase chain reaction (PCR) and subjected to direct sequencing. DNA samples from 50 healthy volunteers were used as controls. Results: Clinical examination showed three different phenotypes of CDs. Genetic examination identified that two ACD subjects were associated with homozygous R124H mutation of TGFBI, and four LCD I subjects were all associated with R124C heterozygous mutation. One MCD I subject was associated with a novel S51X homozygous mutation in CHST6, while the other two MCD I subjects harbored a previously reported W232X homozygous mutation. Conclusions: Our study highlights the prevalence of codon 124 mutations in the TGFBI gene among the Chinese ACD and LCD I patients. Moreover, we found a novel mutation among MCD I patients. PMID:21887843

  15. A Homozygous Mutation in a Novel Zinc-Finger Protein, ERIS, Is Responsible for Wolfram Syndrome 2

    PubMed Central

    Amr, Sami ; Heisey, Cindy ; Zhang, Min ; Xia, Xia-Juan ; Shows, Kathryn H. ; Ajlouni, Kamel ; Pandya, Arti ; Satin, Leslie S. ; El-Shanti, Hatem ; Shiang, Rita 

    2007-01-01

    A single missense mutation was identified in a novel, highly conserved zinc-finger gene, ZCD2, in three consanguineous families of Jordanian descent with Wolfram syndrome (WFS). It had been shown that these families did not have mutations in the WFS1 gene (WFS1) but were mapped to the WFS2 locus at 4q22-25. A G→C transversion at nucleotide 109 predicts an amino acid change from glutamic acid to glutamine (E37Q). Although the amino acid is conserved and the mutation is nonsynonymous, the pathogenesis for the disorder is because the mutation also causes aberrant splicing. The mutation was found to disrupt messenger RNA splicing by eliminating exon 2, and it results in the introduction of a premature stop codon. Mutations in WFS1 have also been found to cause low-frequency nonsyndromic hearing loss, progressive hearing loss, and isolated optic atrophy associated with hearing loss. Screening of 377 probands with hearing loss did not identify mutations in the WFS2 gene. The WFS1-encoded protein, Wolframin, is known to localize to the endoplasmic reticulum and plays a role in calcium homeostasis. The ZCD2-encoded protein, ERIS (endoplasmic reticulum intermembrane small protein), is also shown to localize to the endoplasmic reticulum but does not interact directly with Wolframin. Lymphoblastoid cells from affected individuals show a significantly greater rise in intracellular calcium when stimulated with thapsigargin, compared with controls, although no difference was observed in resting concentrations of intracellular calcium. PMID:17846994

  16. Primary hyperoxaluria type 1: diagnostic relevance of mutations and polymorphisms in the alanine:glyoxylate aminotransferase gene (AGXT).

    PubMed

    Tarn, A C; von Schnakenburg, C; Rumsby, G

    1997-09-01

    Primary hyperoxaluria type 1 (PH1) is an autosomal recessive disorder of glyoxylate metabolism caused by deficiency of the hepatic peroxisomal enzyme alanine:glyoxylate aminotransferase (AGT). The disease shows considerable phenotypic, enzymatic and genetic heterogeneity. To date, 7 polymorphisms and 11 point mutations have been described in the gene encoding AGT. We report on the prevalence of these polymorphisms and mutations in 79 patients with PH1 with the aim of assessing their diagnostic relevance. A strong association of the C154T, intron 1 insertion and C386T polymorphisms is confirmed and this linkage extends to include the type 1 variant of a polymorphic tandem repeat in intron 4. Only 64 of 158 (40%) PH1 alleles have one of the defined mutations, with the G630A mutation accounting for 39 of these and T853C for 14. Overall only 20 (25%) of the patients studied had the genetic basis of their disease fully explained: 7 were homozygous for the G630A mutation, 5 were homozygous for the T853C mutation, 1 was homozygous for the C819T mutation, and 7 had two different mutations identified and were presumed to be compound heterozygotes. Only the two more frequent G630A and T853C mutations are of general diagnostic relevance for mutation screening. It seems likely that there are a significant number of other mutations, perhaps family-specific, still to be described. There was no apparent difference in the types of mutations in patients presenting in the first year of life (36%), suggesting that other factors, such as periods of dehydration or urinary tract infections, might contribute more to the clinical manifestation than genotype.

  17. Portuguese family with the co-occurrence of frontotemporal lobar degeneration and neuronal ceroid lipofuscinosis phenotypes due to progranulin gene mutation.

    PubMed

    Almeida, Maria R; Macário, Maria C; Ramos, Lina; Baldeiras, Inês; Ribeiro, Maria H; Santana, Isabel

    2016-05-01

    We and others have reported heterozygous progranulin mutations as an important cause of frontotemporal lobar degeneration (FTLD). It has been identified a complete progranulin deficiency because of a homozygous mutation in a sibling pair with neuronal ceroid lipofuscinosis (NCL). Here, we describe the first case of NCL caused by a homozygous progranulin mutation segregating in a family with neuropathological confirmed FTLD. In this FTLD-NCL family, we detail the clinical phenotype, neuropsychological evaluation and imaging data of our proband harboring a homozygous mutation, c.900_901dupGT, with serum progranulin level (<6 ng/mL). Symptoms included rapidly progressive visual deficit, slightly dysarthria, and cerebellar ataxia. The electroretinogram confirmed a severe attenuation of rod and cone responses compatible with retinal dystrophy diagnosis and magnetic resonance imaging showed severe global cerebellar atrophy. In contrast, heterozygous relatives presented behavioral variant of frontotemporal dementia (FTD) and some also developed extrapyramidal features compatible with corticobasal syndrome. Our findings suggest the importance of assessing serum progranulin levels in suspected recessive adult-onset NCL cases. Overall, a more holistic neurologic intervention is needed to guarantee a proper genetic counseling in cases like the present family where two distinct phenotypes are generated according to the individuals' mutation state. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. A Catalog of Genes Homozygously Deleted in Human Lung Cancer and the Candidacy of PTPRD as a Tumor Suppressor Gene

    PubMed Central

    Kohno, Takashi; Otsuka, Ayaka; Girard, Luc; Sato, Masanori; Iwakawa, Reika; Ogiwara, Hideaki; Sanchez-Cespedes, Montse; Minna, John D.; Yokota, Jun

    2010-01-01

    A total of 176 genes homozygously deleted in human lung cancer were identified by DNA array-based whole genome scanning of 52 lung cancer cell lines and subsequent genomic PCR in 74 cell lines, including the 52 cell lines scanned. One or more exons of these genes were homozygously deleted in one (1%) to 20 (27%) cell lines. These genes included known tumor suppressor genes, e.g., CDKN2A/p16, RB1, and SMAD4, and candidate tumor suppressor genes whose hemizygous or homozygous deletions were reported in several types of human cancers, such as FHIT, KEAP1, and LRP1B/LRP-DIP. CDKN2A/p16 and p14ARF located in 9p21 were most frequently deleted (20/74, 27%). The PTPRD gene was most frequently deleted (8/74, 11%) among genes mapping to regions other than 9p21. Somatic mutations, including a nonsense mutation, of the PTPRD gene were detected in 8/74 (11%) of cell lines and 4/95 (4%) of surgical specimens of lung cancer. Reduced PTPRD expression was observed in the majority (>80%) of cell lines and surgical specimens of lung cancer. Therefore, PTPRD is a candidate tumor suppressor gene in lung cancer. Microarray-based expression profiling of 19 lung cancer cell lines also indicated that some of the 176 genes, such as KANK and ADAMTS1, are preferentially inactivated by epigenetic alterations. Genetic/epigenetic as well as functional studies of these 176 genes will increase our understanding of molecular mechanisms behind lung carcinogenesis. PMID:20073072

  19. Exome Sequencing Identifies Potentially Druggable Mutations in Nasopharyngeal Carcinoma.

    PubMed

    Chow, Yock Ping; Tan, Lu Ping; Chai, San Jiun; Abdul Aziz, Norazlin; Choo, Siew Woh; Lim, Paul Vey Hong; Pathmanathan, Rajadurai; Mohd Kornain, Noor Kaslina; Lum, Chee Lun; Pua, Kin Choo; Yap, Yoke Yeow; Tan, Tee Yong; Teo, Soo Hwang; Khoo, Alan Soo-Beng; Patel, Vyomesh

    2017-03-03

    In this study, we first performed whole exome sequencing of DNA from 10 untreated and clinically annotated fresh frozen nasopharyngeal carcinoma (NPC) biopsies and matched bloods to identify somatically mutated genes that may be amenable to targeted therapeutic strategies. We identified a total of 323 mutations which were either non-synonymous (n = 238) or synonymous (n = 85). Furthermore, our analysis revealed genes in key cancer pathways (DNA repair, cell cycle regulation, apoptosis, immune response, lipid signaling) were mutated, of which those in the lipid-signaling pathway were the most enriched. We next extended our analysis on a prioritized sub-set of 37 mutated genes plus top 5 mutated cancer genes listed in COSMIC using a custom designed HaloPlex target enrichment panel with an additional 88 NPC samples. Our analysis identified 160 additional non-synonymous mutations in 37/42 genes in 66/88 samples. Of these, 99/160 mutations within potentially druggable pathways were further selected for validation. Sanger sequencing revealed that 77/99 variants were true positives, giving an accuracy of 78%. Taken together, our study indicated that ~72% (n = 71/98) of NPC samples harbored mutations in one of the four cancer pathways (EGFR-PI3K-Akt-mTOR, NOTCH, NF-κB, DNA repair) which may be potentially useful as predictive biomarkers of response to matched targeted therapies.

  20. Exome Sequencing Identifies Potentially Druggable Mutations in Nasopharyngeal Carcinoma

    PubMed Central

    Chow, Yock Ping; Tan, Lu Ping; Chai, San Jiun; Abdul Aziz, Norazlin; Choo, Siew Woh; Lim, Paul Vey Hong; Pathmanathan, Rajadurai; Mohd Kornain, Noor Kaslina; Lum, Chee Lun; Pua, Kin Choo; Yap, Yoke Yeow; Tan, Tee Yong; Teo, Soo Hwang; Khoo, Alan Soo-Beng; Patel, Vyomesh

    2017-01-01

    In this study, we first performed whole exome sequencing of DNA from 10 untreated and clinically annotated fresh frozen nasopharyngeal carcinoma (NPC) biopsies and matched bloods to identify somatically mutated genes that may be amenable to targeted therapeutic strategies. We identified a total of 323 mutations which were either non-synonymous (n = 238) or synonymous (n = 85). Furthermore, our analysis revealed genes in key cancer pathways (DNA repair, cell cycle regulation, apoptosis, immune response, lipid signaling) were mutated, of which those in the lipid-signaling pathway were the most enriched. We next extended our analysis on a prioritized sub-set of 37 mutated genes plus top 5 mutated cancer genes listed in COSMIC using a custom designed HaloPlex target enrichment panel with an additional 88 NPC samples. Our analysis identified 160 additional non-synonymous mutations in 37/42 genes in 66/88 samples. Of these, 99/160 mutations within potentially druggable pathways were further selected for validation. Sanger sequencing revealed that 77/99 variants were true positives, giving an accuracy of 78%. Taken together, our study indicated that ~72% (n = 71/98) of NPC samples harbored mutations in one of the four cancer pathways (EGFR-PI3K-Akt-mTOR, NOTCH, NF-κB, DNA repair) which may be potentially useful as predictive biomarkers of response to matched targeted therapies. PMID:28256603

  1. HOGA1 Gene Mutations of Primary Hyperoxaluria Type 3 in Tunisian Patients.

    PubMed

    M'dimegh, Saoussen; Aquaviva-Bourdain, Cécile; Omezzine, Asma; Souche, Geneviéve; M'barek, Ibtihel; Abidi, Kamel; Gargah, Tahar; Abroug, Saoussen; Bouslama, Ali

    2017-05-01

    Primary hyperoxaluria type 3 (PH3) is due to mutations in the recently identified 4-hydroxy-2-oxoglutarate aldolase (HOGA1) gene. PH3 might be the least severe form with a milder phenotype with good preservation of kidney function in most patients. The aim of this study was to report three PH3 cases carrying mutations in HOGA1. Genetic analysis of HOGA1 was performed in patients with a high clinical suspicion of PH after sequencing of AGXT and GRHPR genes, which was negative. Also, a complete AGXT/GRHPR MLPA was performed in these patients in order to detect large deletions/insertions. Two different HOGA1 gene mutations were identified: the p.Pro190Leu in a homozygous state and the p.Gly287Val in two patients in homozygous and heterozygous carriers. The median age at onset of clinical symptoms was 3.93 years. Most of the patients had a positive family history for recurrent urolithiasis. The p.Pro190Leu mutation was reported with impaired renal function at follow-up; however, the p.Gly287Val was presented with normal renal function. All patients were presented with urolithiasis, but only one had a nephrocalcinosis. This study expanded the number of PH3 patients from 63 to 66 cases. The p.Pro190Leu and the p.Gly287Val mutations found in this study can provide a first-line investigation in Tunisian PH1 patients. © 2016 Wiley Periodicals, Inc.

  2. A Novel FOXE1 Mutation (R73S) in Bamforth–Lazarus Syndrome Causing Increased Thyroidal Gene Expression

    PubMed Central

    Carré, Aurore; Hamza, Rasha T.; Kariyawasam, Dulanjalee; Guillot, Loïc; Teissier, Raphaël; Tron, Elodie; Castanet, Mireille; Dupuy, Corinne; El Kholy, Mohamed; Polak, Michel

    2014-01-01

    Background: Homozygous loss-of-function mutations in the FOXE1 gene have been reported in several patients with partial or complete Bamforth–Lazarus syndrome: congenital hypothyroidism (CH) with thyroid dysgenesis (usually athyreosis), cleft palate, spiky hair, with or without choanal atresia, and bifid epiglottis. Here, our objective was to evaluate potential functional consequences of a FOXE1 mutation in a patient with a similar clinical phenotype. Methods: FOXE1 was sequenced in eight patients with thyroid dysgenesis and cleft palate. Transient transfection was performed in HEK293 cells using the thyroglobulin (TG) and thyroid peroxidase (TPO) promoters in luciferase reporter plasmids to assess the functional impact of the FOXE1 mutations. Primary human thyrocytes transfected with wild type and mutant FOXE1 served to assess the impact of the mutation on endogenous TG and TPO expression. Results: We identified and characterized the function of a new homozygous FOXE1 missense mutation (p.R73S) in a boy with a typical phenotype (athyreosis, cleft palate, and partial choanal atresia). This new mutation located within the forkhead domain was inherited from the heterozygous healthy consanguineous parents. In vitro functional studies in HEK293 cells showed that this mutant gene enhanced the activity of the TG and TPO gene promoters (1.5-fold and 1.7-fold respectively vs. wild type FOXE1; p<0.05), unlike the five mutations previously reported in Bamforth–Lazarus syndrome. The gain-of-function effect of the FOXE1-p.R73S mutant gene was confirmed by an increase in endogenous TG production in primary human thyrocytes. Conclusion: We identified a new homozygous FOXE1 mutation responsible for enhanced expression of the TG and TPO genes in a boy whose phenotype is similar to that reported previously in patients with loss-of-function FOXE1 mutations. This finding further delineates the role for FOXE1 in both thyroid and palate development, and shows that enhanced gene

  3. Novel mutations in RASGRP2, which encodes CalDAG-GEFI, abrogate Rap1 activation, causing platelet dysfunction

    PubMed Central

    Lozano, María Luisa; Cook, Aaron; Bastida, José María; Paul, David S.; Iruin, Gemma; Cid, Ana Rosa; Adan-Pedroso, Rosa; Ramón González-Porras, José; Hernández-Rivas, Jesús María; Fletcher, Sarah J.; Johnson, Ben; Morgan, Neil; Ferrer-Marin, Francisca; Vicente, Vicente; Sondek, John; Watson, Steve P.; Bergmeier, Wolfgang

    2016-01-01

    In addition to mutations in ITG2B or ITGB3 genes that cause defective αIIbβ3 expression and/or function in Glanzmann’s thrombasthenia patients, platelet dysfunction can be a result of genetic variability in proteins that mediate inside-out activation of αIIbβ3. The RASGRP2 gene is strongly expressed in platelets and neutrophils, where its encoded protein CalDAG-GEFI facilitates the activation of Rap1 and subsequent activation of integrins. We used next-generation sequencing (NGS) and whole-exome sequencing (WES) to identify 2 novel function-disrupting mutations in RASGRP2 that account for bleeding diathesis and platelet dysfunction in 2 unrelated families. By using a panel of 71 genes, we identified a homozygous change (c.1142C>T) in exon 10 of RASGRP2 in a 9-year-old child of Chinese origin (family 1). This variant led to a p.Ser381Phe substitution in the CDC25 catalytic domain of CalDAG-GEFI. In 2 Spanish siblings from family 2, WES identified a nonsense homozygous variation (c.337C>T) (p.Arg113X) in exon 5 of RASGRP2. CalDAG-GEFI expression was markedly reduced in platelets from all patients, and by using a novel in vitro assay, we found that the nucleotide exchange activity was dramatically reduced in CalDAG-GEFI p.Ser381Phe. Platelets from homozygous patients exhibited agonist-specific defects in αIIbβ3 integrin activation and aggregation. In contrast, α- and δ-granule secretion, platelet spreading, and clot retraction were not markedly affected. Integrin activation in the patients’ neutrophils was also impaired. These patients are the first cases of a CalDAG-GEFI deficiency due to homozygous RASGRP2 mutations that are linked to defects in both leukocyte and platelet integrin activation. PMID:27235135

  4. Validation of dye-binding/high-resolution thermal denaturation for the identification of mutations in the SLC22A5 gene.

    PubMed

    Dobrowolski, Steven F; McKinney, Jason T; Amat di San Filippo, Cristina; Giak Sim, Keow; Wilcken, Bridget; Longo, Nicola

    2005-03-01

    Primary carnitine deficiency is an autosomal recessive disorder of fatty acid oxidation resulting from defective carnitine transport. This disease is caused by mutations in the OCTN2 carnitine transporter encoded by the SLC22A5 gene. Here we validate dye-binding/high-resolution thermal denaturation as a screening procedure to identify novel mutations in this gene. This procedure is based on the amplification of DNA by PCR in capillaries with the dsDNA binding dye LCGreen I. The PCR reaction is then analyzed in the same capillary by high-resolution thermal denaturation. Samples with abnormal melting profiles are sequenced. This technique correctly identified all known patients who were compound heterozygotes for different mutations in the carnitine transporter gene and about 30% of homozygous patients. The remaining 70% of homozygous patients were identified by a second amplification, in which the patient's DNA was mixed with the DNA of a normal control. This screening system correctly identified eight novel mutations and both abnormal alleles in six new families with primary carnitine deficiency. The causative role of the missense mutations identified (c.3G>T/p.M1I, c.695C>T/p.T232M, and c.1403 C>G/p.T468R) was confirmed by expression in Chinese hamster ovary (CHO) cells. These results expand the mutational spectrum in primary carnitine deficiency and indicate dye-binding/high-resolution thermal denaturation as an ideal system to screen for mutations in diseases with no prevalent molecular alteration. (c) 2005 Wiley-Liss, Inc.

  5. Multiscale mutation clustering algorithm identifies pan-cancer mutational clusters associated with pathway-level changes in gene expression

    PubMed Central

    Poole, William; Leinonen, Kalle; Shmulevich, Ilya

    2017-01-01

    Cancer researchers have long recognized that somatic mutations are not uniformly distributed within genes. However, most approaches for identifying cancer mutations focus on either the entire-gene or single amino-acid level. We have bridged these two methodologies with a multiscale mutation clustering algorithm that identifies variable length mutation clusters in cancer genes. We ran our algorithm on 539 genes using the combined mutation data in 23 cancer types from The Cancer Genome Atlas (TCGA) and identified 1295 mutation clusters. The resulting mutation clusters cover a wide range of scales and often overlap with many kinds of protein features including structured domains, phosphorylation sites, and known single nucleotide variants. We statistically associated these multiscale clusters with gene expression and drug response data to illuminate the functional and clinical consequences of mutations in our clusters. Interestingly, we find multiple clusters within individual genes that have differential functional associations: these include PTEN, FUBP1, and CDH1. This methodology has potential implications in identifying protein regions for drug targets, understanding the biological underpinnings of cancer, and personalizing cancer treatments. Toward this end, we have made the mutation clusters and the clustering algorithm available to the public. Clusters and pathway associations can be interactively browsed at m2c.systemsbiology.net. The multiscale mutation clustering algorithm is available at https://github.com/IlyaLab/M2C. PMID:28170390

  6. Multiscale mutation clustering algorithm identifies pan-cancer mutational clusters associated with pathway-level changes in gene expression.

    PubMed

    Poole, William; Leinonen, Kalle; Shmulevich, Ilya; Knijnenburg, Theo A; Bernard, Brady

    2017-02-01

    Cancer researchers have long recognized that somatic mutations are not uniformly distributed within genes. However, most approaches for identifying cancer mutations focus on either the entire-gene or single amino-acid level. We have bridged these two methodologies with a multiscale mutation clustering algorithm that identifies variable length mutation clusters in cancer genes. We ran our algorithm on 539 genes using the combined mutation data in 23 cancer types from The Cancer Genome Atlas (TCGA) and identified 1295 mutation clusters. The resulting mutation clusters cover a wide range of scales and often overlap with many kinds of protein features including structured domains, phosphorylation sites, and known single nucleotide variants. We statistically associated these multiscale clusters with gene expression and drug response data to illuminate the functional and clinical consequences of mutations in our clusters. Interestingly, we find multiple clusters within individual genes that have differential functional associations: these include PTEN, FUBP1, and CDH1. This methodology has potential implications in identifying protein regions for drug targets, understanding the biological underpinnings of cancer, and personalizing cancer treatments. Toward this end, we have made the mutation clusters and the clustering algorithm available to the public. Clusters and pathway associations can be interactively browsed at m2c.systemsbiology.net. The multiscale mutation clustering algorithm is available at https://github.com/IlyaLab/M2C.

  7. Thioredoxin Reductase 2 (TXNRD2) mutation associated with familial glucocorticoid deficiency (FGD).

    PubMed

    Prasad, Rathi; Chan, Li F; Hughes, Claire R; Kaski, Juan P; Kowalczyk, Julia C; Savage, Martin O; Peters, Catherine J; Nathwani, Nisha; Clark, Adrian J L; Storr, Helen L; Metherell, Louise A

    2014-08-01

    Classic ACTH resistance, due to disruption of ACTH signaling, accounts for the majority of cases of familial glucocorticoid deficiency (FGD). Recently FGD cases caused by mutations in the mitochondrial antioxidant, nicotinamide nucleotide transhydrogenase, have highlighted the importance of redox regulation in steroidogenesis. We hypothesized that other components of mitochondrial antioxidant systems would be good candidates in the etiology of FGD. Whole-exome sequencing was performed on three related patients, and segregation of putative causal variants confirmed by Sanger sequencing of all family members. A TXNRD2-knockdown H295R cell line was created to investigate redox homeostasis. The study was conducted on patients from three pediatric centers in the United Kingdom. Seven individuals from a consanguineous Kashmiri kindred, six of whom presented with FGD between 0.1 and 10.8 years, participated in the study. There were no interventions. Identification and functional interrogation of a novel homozygous mutation segregating with the disease trait were measured. A stop gain mutation, p.Y447X in TXNRD2, encoding the mitochondrial selenoprotein thioredoxin reductase 2 (TXNRD2) was identified and segregated with disease in this extended kindred. RT-PCR and Western blotting revealed complete absence of TXNRD2 in patients homozygous for the mutation. TXNRD2 deficiency leads to impaired redox homeostasis in a human adrenocortical cell line. In contrast to the Txnrd2-knockout mouse model, in which embryonic lethality as a consequence of hematopoietic and cardiac defects is described, absence of TXNRD2 in humans leads to glucocorticoid deficiency. This is the first report of a homozygous mutation in any component of the thioredoxin antioxidant system leading to inherited disease in humans.

  8. Mutation analysis of the carbohydrate sulfotransferase gene in Vietnamese with macular corneal dystrophy.

    PubMed

    Ha, Nguyen Thanh; Chau, Hoang Minh; Cung, Le Xuan; Thanh, Ton Kim; Fujiki, Keiko; Murakami, Akira; Hiratsuka, Yoshimune; Kanai, Atsushi

    2003-08-01

    Mutations in a new carbohydrate sulfotransferase gene (CHST6) encoding corneal N-acetylglucosamine-6-sulfotransferase (C-GlcNac-6-ST) have been identified as the cause of macular corneal dystrophy (MCD) in various ethnicities. This study was conducted to examine the CHST6 gene in Vietnamese with MCD. Nineteen unrelated families, including 35 patients and 38 unaffected relatives were examined clinically. Blood samples were collected. Fifty normal Vietnamese individuals served as control subjects. Genomic DNA was extracted from leukocytes. Analysis of the CHST6 gene was performed with polymerase chain reaction and direct sequencing. Corneal buttons were studied histopathologically. A slit lamp examination revealed clinical features of MCD with gray-white opacities and stromal haze between. On histopathology, corneal sections showed positive staining with colloidal iron. Sequencing of the CHST6 gene revealed six homozygous and three compound heterozygous mutations. The homozygous mutations, including L59P, V66L, R211Q, W232X, Y268C, and 1067-1068ins(GGCCGTG) were detected, respectively, in two, one, eight, one, one, and two families. Compound heterozygous mutations R211Q/Q82X, S51L/Y268C, and Y268C/1067-1068ins(GGCCGTG) were identified, each in one family. A single heterozygous change at codon 76 (GTG-->ATG) was detected in family L, resulting in a valine-to-methionine substitution (V76M). None of these mutations was detected in the control group. Mutations identified in the CHST6 gene cosegregated with the disease phenotype in all but one family studied and thus caused MCD. Among these, the R211Q detected in 9 of 19 families may be the most common mutation in Vietnamese. These data also indicate that significant allelic heterogeneity exists for MCD.

  9. Homozygosity Mapping in Patients with Cone–Rod Dystrophy: Novel Mutations and Clinical Characterizations

    PubMed Central

    Littink, Karin W.; Koenekoop, Robert K.; van den Born, L. Ingeborgh; Collin, Rob W. J.; Moruz, Luminita; Veltman, Joris A.; Roosing, Susanne; Zonneveld, Marijke N.; Omar, Amer; Darvish, Mahshad; Lopez, Irma; Kroes, Hester Y.; van Genderen, Maria M.; Hoyng, Carel B.; Rohrschneider, Klaus; van Schooneveld, Mary J.; Cremers, Frans P. M.

    2010-01-01

    Purpose. To determine the genetic defect and to describe the clinical characteristics in a cohort of mainly nonconsanguineous cone–rod dystrophy (CRD) patients. Methods. One hundred thirty-nine patients with diagnosed CRD were recruited. Ninety of them were screened for known mutations in ABCA4, and those carrying one or two mutations were excluded from further research. Genome-wide homozygosity mapping was performed in the remaining 108. Known genes associated with autosomal recessive retinal dystrophies located within a homozygous region were screened for mutations. Patients in whom a mutation was detected underwent further ophthalmic examination. Results. Homozygous sequence variants were identified in eight CRD families, six of which were nonconsanguineous. The variants were detected in the following six genes: ABCA4, CABP4, CERKL, EYS, KCNV2, and PROM1. Patients carrying mutations in ABCA4, CERKL, and PROM1 had typical CRD symptoms, but a variety of retinal appearances on funduscopy, optical coherence tomography, and autofluorescence imaging. Conclusions. Homozygosity mapping led to the identification of new mutations in consanguineous and nonconsanguineous patients with retinal dystrophy. Detailed clinical characterization revealed a variety of retinal appearances, ranging from nearly normal to extensive retinal remodeling, retinal thinning, and debris accumulation. Although CRD was initially diagnosed in all patients, the molecular findings led to a reappraisal of the diagnosis in patients carrying mutations in EYS, CABP4, and KCNV2. PMID:20554613

  10. Novel mutations in the CHST6 gene associated with macular corneal dystrophy in southern India.

    PubMed

    Warren, John F; Aldave, Anthony J; Srinivasan, M; Thonar, Eugene J; Kumar, Abha B; Cevallos, Vicky; Whitcher, John P; Margolis, Todd P

    2003-11-01

    To further characterize the role of the carbohydrate sulfotransferase (CHST6) gene in macular corneal dystrophy (MCD) through identification of causative mutations in a cohort of affected patients from southern India. Genomic DNA was extracted from buccal epithelium of 75 patients (51 families) with MCD, 33 unaffected relatives, and 48 healthy volunteers. The coding region of the CHST6 gene was evaluated by means of polymerase chain reaction amplification and direct sequencing. Subtyping of MCD into types I and II was performed by measuring serum levels of antigenic keratan sulfate. Seventy patients were classified as having type I MCD, and 5 patients as having type II MCD. Analysis of the CHST6 coding region in patients with type I MCD identified 11 homozygous missense mutations (Leu22Arg, His42Tyr, Arg50Cys, Arg50Leu, Ser53Leu, Arg97Pro, Cys102Tyr, Arg127Cys, Arg205Gln, His249Pro, and Glu274Lys), 2 compound heterozygous missense mutations (Arg93His and Ala206Thr), 5 homozygous deletion mutations (delCG707-708, delC890, delA1237, del1748-1770, and delORF), and 2 homozygous replacement mutations (ACCTAC 1273 GGT, and GCG 1304 AT). One patient with type II MCD was heterozygous for the C890 deletion mutation, whereas 4 possessed no CHST6 coding region mutations. A variety of previously unreported mutations in the coding region of the CHST6 gene are associated with type I MCD in a cohort of patients in southern India. An improved understanding of the genetic basis of MCD allows for earlier, more accurate diagnosis of affected individuals, and may provide the foundation for the development of novel disease treatments.

  11. dUTPase (DUT) Is Mutated in a Novel Monogenic Syndrome With Diabetes and Bone Marrow Failure.

    PubMed

    Dos Santos, Reinaldo Sousa; Daures, Mathilde; Philippi, Anne; Romero, Sophie; Marselli, Lorella; Marchetti, Piero; Senée, Valérie; Bacq, Delphine; Besse, Céline; Baz, Baz; Marroquí, Laura; Ivanoff, Sarah; Masliah-Planchon, Julien; Nicolino, Marc; Soulier, Jean; Socié, Gérard; Eizirik, Decio L; Gautier, Jean-François; Julier, Cécile

    2017-04-01

    We describe a new syndrome characterized by early-onset diabetes associated with bone marrow failure, affecting mostly the erythrocytic lineage. Using whole-exome sequencing in a remotely consanguineous patient from a family with two affected siblings, we identified a single homozygous missense mutation (chr15.hg19:g.48,626,619A>G) located in the dUTPase ( DUT ) gene (National Center for Biotechnology Information Gene ID 1854), affecting both the mitochondrial (DUT-M p.Y142C) and the nuclear (DUT-N p.Y54C) isoforms. We found the same homozygous mutation in an unrelated consanguineous patient with diabetes and bone marrow aplasia from a family with two affected siblings, whereas none of the >60,000 subjects from the Exome Aggregation Consortium (ExAC) was homozygous for this mutation. This replicated observation probability was highly significant, thus confirming the role of this DUT mutation in this syndrome. DUT is a key enzyme for maintaining DNA integrity by preventing misincorporation of uracil into DNA, which results in DNA toxicity and cell death. We showed that DUT silencing in human and rat pancreatic β-cells results in apoptosis via the intrinsic cell death pathway. Our findings support the importance of tight control of DNA metabolism for β-cell integrity and warrant close metabolic monitoring of patients treated by drugs affecting dUTP balance. © 2017 by the American Diabetes Association.

  12. Analysis of the Spanish CCR5-∆32 inventory of cord blood units: lower cell counts in homozygous donors.

    PubMed

    Enrich, Emma; Vidal, Francisco; Sánchez-Gordo, Francisco; Gómez-Zumaquero, Juan M; Balas, Antonio; Rudilla, Francesc; Barea, Luisa; Castro, Ana; Larrea, Luis; Perez-Vaquero, Miguel A; Prat, Isidro; Querol, Sergio; Garrido, Gregorio; Matesanz, Rafael; Carreras, Enric; Duarte, Rafael F

    2018-02-06

    The possibility to use CCR5-∆32 umbilical cord blood to cure HIV infection in patients in need of a hematopoietic transplant has been suggested. The less stringent HLA compatibility needed in this type of transplant facilitates the search of a suitable donor having the CCR5-∆32 mutation. To achieve an inventory of CCR5-∆32 cord blood units, the 20,236 best cell quality units of the Spanish Registry were genotyped. Furthermore, their CD34 + and total nucleated cells counts, blood type, gender, HLA and donor's geographical and ancestral origin were analyzed. The results showed 130 (0.64%) units homozygous for the deletion, 2,646 (13.08%) heterozygous and 17,460 (86.28%) did not present the mutation. Interestingly, a significant lower amount of CD34 + cells was found in the CCR5-∆32 homozygous units. In addition, a significant association was found among donor's ancestral origin and the mutation, with a higher percentage of CCR5-∆32 units with a European ancestry. In summary, identification of a relatively high number of CCR5-∆32 units is feasible and will facilitate the development of clinical trials for HIV cure in patients requiring hematopoietic transplantation. Further studies are required to understand the significance of lower cell counts within the CCR5-∆32 homozygous group and its clinical impact.

  13. Statistical Methods for Identifying Sequence Motifs Affecting Point Mutations

    PubMed Central

    Zhu, Yicheng; Neeman, Teresa; Yap, Von Bing; Huttley, Gavin A.

    2017-01-01

    Mutation processes differ between types of point mutation, genomic locations, cells, and biological species. For some point mutations, specific neighboring bases are known to be mechanistically influential. Beyond these cases, numerous questions remain unresolved, including: what are the sequence motifs that affect point mutations? How large are the motifs? Are they strand symmetric? And, do they vary between samples? We present new log-linear models that allow explicit examination of these questions, along with sequence logo style visualization to enable identifying specific motifs. We demonstrate the performance of these methods by analyzing mutation processes in human germline and malignant melanoma. We recapitulate the known CpG effect, and identify novel motifs, including a highly significant motif associated with A→G mutations. We show that major effects of neighbors on germline mutation lie within ±2 of the mutating base. Models are also presented for contrasting the entire mutation spectra (the distribution of the different point mutations). We show the spectra vary significantly between autosomes and X-chromosome, with a difference in T→C transition dominating. Analyses of malignant melanoma confirmed reported characteristic features of this cancer, including statistically significant strand asymmetry, and markedly different neighboring influences. The methods we present are made freely available as a Python library https://bitbucket.org/pycogent3/mutationmotif. PMID:27974498

  14. Mutation screening of Chinese Treacher Collins syndrome patients identified novel TCOF1 mutations.

    PubMed

    Chen, Ying; Guo, Luo; Li, Chen-Long; Shan, Jing; Xu, Hai-Song; Li, Jie-Ying; Sun, Shan; Hao, Shao-Juan; Jin, Lei; Chai, Gang; Zhang, Tian-Yu

    2018-04-01

    Treacher Collins syndrome (TCS) (OMIM 154500) is a rare congenital craniofacial disorder with an autosomal dominant manner of inheritance in most cases. To date, three pathogenic genes (TCOF1, POLR1D and POLR1C) have been identified. In this study, we conducted mutational analysis on Chinese TCS patients to reveal a mutational spectrum of known causative genes and show phenotype-genotype data to provide more information for gene counselling and future studies on the pathogenesis of TCS. Twenty-two TCS patients were recruited from two tertiary referral centres, and Sanger sequencing for the coding exons and exon-intron boundaries of TCOF1, POLR1D and POLR1C was performed. For patients without small variants, further copy number variations (CNVs) analysis was conducted using high-density SNP array platforms. The Sanger sequencing overall mutation detection rate was as high as 86.3% (19/22) for our cohort. Fifteen TCOF1 pathogenic variants, including ten novel mutations, were identified in nineteen patients. No causative mutations in POLR1D and POLR1C genes and no CNVs mutations were detected. A suspected autosomal dominant inheritance case that implies germinal mosaicism was described. Our study confirmed that TCOF1 was the main disease-causing gene for the Chinese TCS population and revealed its mutation spectrum. We also addressed the need for more studies of mosaicism in TCS cases, which could explain the mechanism of autosomal dominant inheritance in TCS cases and benefit the prevention of TCS.

  15. Recessive myosin myopathy with external ophthalmoplegia associated with MYH2 mutations.

    PubMed

    Tajsharghi, Homa; Hammans, Simon; Lindberg, Christopher; Lossos, Alexander; Clarke, Nigel F; Mazanti, Ingrid; Waddell, Leigh B; Fellig, Yakov; Foulds, Nicola; Katifi, Haider; Webster, Richard; Raheem, Olayinka; Udd, Bjarne; Argov, Zohar; Oldfors, Anders

    2014-06-01

    Myosin myopathies comprise a group of inherited diseases caused by mutations in myosin heavy chain (MyHC) genes. Homozygous or compound heterozygous truncating MYH2 mutations have been demonstrated to cause recessive myopathy with ophthalmoplegia, mild-to-moderate muscle weakness and complete lack of type 2A muscle fibers. In this study, we describe for the first time the clinical and morphological characteristics of recessive myosin IIa myopathy associated with MYH2 missense mutations. Seven patients of five different families with a myopathy characterized by ophthalmoplegia and mild-to-moderate muscle weakness were investigated. Muscle biopsy was performed to study morphological changes and MyHC isoform expression. Five of the patients were homozygous for MYH2 missense mutations, one patient was compound heterozygous for a missense and a nonsense mutation and one patient was homozygous for a frame-shift MYH2 mutation. Muscle biopsy demonstrated small or absent type 2A muscle fibers and reduced or absent expression of the corresponding MyHC IIa transcript and protein. We conclude that mild muscle weakness and ophthalmoplegia in combination with muscle biopsy demonstrating small or absent type 2A muscle fibers are the hallmark of recessive myopathy associated with MYH2 mutations.

  16. Mutation Analysis of SLC26A4 for Pendred Syndrome and Nonsyndromic Hearing Loss by High-Resolution Melting

    PubMed Central

    Chen, Neng; Tranebjærg, Lisbeth; Rendtorff, Nanna Dahl; Schrijver, Iris

    2011-01-01

    Pendred syndrome and DFNB4 (autosomal recessive nonsyndromic congenital deafness, locus 4) are associated with autosomal recessive congenital sensorineural hearing loss and mutations in the SLC26A4 gene. Extensive allelic heterogeneity, however, necessitates analysis of all exons and splice sites to identify mutations for individual patients. Although Sanger sequencing is the gold standard for mutation detection, screening methods supplemented with targeted sequencing can provide a cost-effective alternative. One such method, denaturing high-performance liquid chromatography, was developed for clinical mutation detection in SLC26A4. However, this method inherently cannot distinguish homozygous changes from wild-type sequences. High-resolution melting (HRM), on the other hand, can detect heterozygous and homozygous changes cost-effectively, without any post-PCR modifications. We developed a closed-tube HRM mutation detection method specific for SLC26A4 that can be used in the clinical diagnostic setting. Twenty-eight primer pairs were designed to cover all 21 SLC26A4 exons and splice junction sequences. Using the resulting amplicons, initial HRM analysis detected all 45 variants previously identified by sequencing. Subsequently, a 384-well plate format was designed for up to three patient samples per run. Blinded HRM testing on these plates of patient samples collected over 1 year in a clinical diagnostic laboratory accurately detected all variants identified by sequencing. In conclusion, HRM with targeted sequencing is a reliable, simple, and cost-effective method for SLC26A4 mutation screening and detection. PMID:21704276

  17. Prevalence of GJB2 Mutations in Affected Individuals from United Arab Emirates with Autosomal Recessive Nonsyndromic Hearing Loss.

    PubMed

    Tlili, Abdelaziz; Al Mutery, Abdullah; Kamal Eddine Ahmad Mohamed, Walaa; Mahfood, Mona; Hadj Kacem, Hassen

    2017-11-01

    Mutations in the gap junction protein beta 2 (GJB2) gene are responsible for more cases of nonsyndromic recessive hearing loss than any other gene. The purpose of our study was to evaluate the prevalence of GJB2 mutations among affected individuals from United Arab Emirates (UAE). There were 50 individuals diagnosed with hereditary hearing loss and 120 healthy individuals enrolled in the study. The Sanger sequencing method was used to screen the GJB2 coding region in all affected individuals. The c.-1G>A variant was determined by the polymerase chain reaction-restriction fragment length polymorphism method in normal individuals. Nine cases with bi-allelic mutations and three cases with mono-allelic mutations were detected in 12 out of 50 patients (24%). The homozygous mutation c.35delG was identified as the cause of hearing loss in six participants (12%). The mutation c.506G>A was identified in three affected individuals (6%). The allelic frequency (14%) and low percentage of individuals that were homozygous (2%) for the c.35delG mutation suggest that there are other genes responsible for nonsyndromic deafness in the UAE population. The results reported here are a preliminary step in collecting epidemiological data regarding autosomal recessive nonsyndromic hearing loss related to GJB2 gene mutations among the UAE population. The c.35delG mutation of the GJB2 gene is the most frequently seen causative mutation in the UAE and is followed by the p.Cys169Tyr mutation.

  18. Whole-exome sequencing and digital PCR identified a novel compound heterozygous mutation in the NPHP1 gene in a case of Joubert syndrome and related disorders.

    PubMed

    Koyama, Shingo; Sato, Hidenori; Wada, Manabu; Kawanami, Toru; Emi, Mitsuru; Kato, Takeo

    2017-03-27

    Joubert syndrome and related disorders (JSRD) is a clinically and genetically heterogeneous condition with autosomal recessive or X-linked inheritance, which share a distinctive neuroradiological hallmark, the so-called molar tooth sign. JSRD is classified into six clinical subtypes based on associated variable multiorgan involvement. To date, 21 causative genes have been identified in JSRD, which makes genetic diagnosis difficult. We report here a case of a 28-year-old Japanese woman diagnosed with JS with oculorenal defects with a novel compound heterozygous mutation (p.Ser219*/deletion) in the NPHP1 gene. Whole-exome sequencing (WES) of the patient identified the novel nonsense mutation in an apparently homozygous state. However, it was absent in her mother and heterozygous in her father. A read depth-based copy number variation (CNV) detection algorithm using WES data of the family predicted a large heterozygous deletion mutation in the patient and her mother, which was validated by digital polymerase chain reaction, indicating that the patient was compound heterozygous for the paternal nonsense mutation and the maternal deletion mutation spanning the site of the single nucleotide change. It should be noted that analytical pipelines that focus purely on sequence information cannot distinguish homozygosity from hemizygosity because of its inability to detect large deletions. The ability to detect CNVs in addition to single nucleotide variants and small insertion/deletions makes WES an attractive diagnostic tool for genetically heterogeneous disorders.

  19. Common pathogenic effects of missense mutations in the P-type ATPase ATP13A2 (PARK9) associated with early-onset parkinsonism.

    PubMed

    Podhajska, Agata; Musso, Alessandra; Trancikova, Alzbeta; Stafa, Klodjan; Moser, Roger; Sonnay, Sarah; Glauser, Liliane; Moore, Darren J

    2012-01-01

    Mutations in the ATP13A2 gene (PARK9) cause autosomal recessive, juvenile-onset Kufor-Rakeb syndrome (KRS), a neurodegenerative disease characterized by parkinsonism. KRS mutations produce truncated forms of ATP13A2 with impaired protein stability resulting in a loss-of-function. Recently, homozygous and heterozygous missense mutations in ATP13A2 have been identified in subjects with early-onset parkinsonism. The mechanism(s) by which missense mutations potentially cause parkinsonism are not understood at present. Here, we demonstrate that homozygous F182L, G504R and G877R missense mutations commonly impair the protein stability of ATP13A2 leading to its enhanced degradation by the proteasome. ATP13A2 normally localizes to endosomal and lysosomal membranes in neurons and the F182L and G504R mutations disrupt this vesicular localization and promote the mislocalization of ATP13A2 to the endoplasmic reticulum. Heterozygous T12M, G533R and A746T mutations do not obviously alter protein stability or subcellular localization but instead impair the ATPase activity of microsomal ATP13A2 whereas homozygous missense mutations disrupt the microsomal localization of ATP13A2. The overexpression of ATP13A2 missense mutants in SH-SY5Y neural cells does not compromise cellular viability suggesting that these mutant proteins lack intrinsic toxicity. However, the overexpression of wild-type ATP13A2 may impair neuronal integrity as it causes a trend of reduced neurite outgrowth of primary cortical neurons, whereas the majority of disease-associated missense mutations lack this ability. Finally, ATP13A2 overexpression sensitizes cortical neurons to neurite shortening induced by exposure to cadmium or nickel ions, supporting a functional interaction between ATP13A2 and heavy metals in post-mitotic neurons, whereas missense mutations influence this sensitizing effect. Collectively, our study provides support for common loss-of-function effects of homozygous and heterozygous missense

  20. Common Pathogenic Effects of Missense Mutations in the P-Type ATPase ATP13A2 (PARK9) Associated with Early-Onset Parkinsonism

    PubMed Central

    Podhajska, Agata; Musso, Alessandra; Trancikova, Alzbeta; Stafa, Klodjan; Moser, Roger; Sonnay, Sarah; Glauser, Liliane; Moore, Darren J.

    2012-01-01

    Mutations in the ATP13A2 gene (PARK9) cause autosomal recessive, juvenile-onset Kufor-Rakeb syndrome (KRS), a neurodegenerative disease characterized by parkinsonism. KRS mutations produce truncated forms of ATP13A2 with impaired protein stability resulting in a loss-of-function. Recently, homozygous and heterozygous missense mutations in ATP13A2 have been identified in subjects with early-onset parkinsonism. The mechanism(s) by which missense mutations potentially cause parkinsonism are not understood at present. Here, we demonstrate that homozygous F182L, G504R and G877R missense mutations commonly impair the protein stability of ATP13A2 leading to its enhanced degradation by the proteasome. ATP13A2 normally localizes to endosomal and lysosomal membranes in neurons and the F182L and G504R mutations disrupt this vesicular localization and promote the mislocalization of ATP13A2 to the endoplasmic reticulum. Heterozygous T12M, G533R and A746T mutations do not obviously alter protein stability or subcellular localization but instead impair the ATPase activity of microsomal ATP13A2 whereas homozygous missense mutations disrupt the microsomal localization of ATP13A2. The overexpression of ATP13A2 missense mutants in SH-SY5Y neural cells does not compromise cellular viability suggesting that these mutant proteins lack intrinsic toxicity. However, the overexpression of wild-type ATP13A2 may impair neuronal integrity as it causes a trend of reduced neurite outgrowth of primary cortical neurons, whereas the majority of disease-associated missense mutations lack this ability. Finally, ATP13A2 overexpression sensitizes cortical neurons to neurite shortening induced by exposure to cadmium or nickel ions, supporting a functional interaction between ATP13A2 and heavy metals in post-mitotic neurons, whereas missense mutations influence this sensitizing effect. Collectively, our study provides support for common loss-of-function effects of homozygous and heterozygous missense

  1. Congenital hypogonadotropic hypogonadism with split hand/foot malformation: a clinical entity with a high frequency of FGFR1 mutations

    PubMed Central

    Villanueva, Carine; Jacobson-Dickman, Elka; Xu, Cheng; Manouvrier, Sylvie; Dwyer, Andrew A.; Sykiotis, Gerasimos P.; Beenken, Andrew; Liu, Yang; Tommiska, Johanna; Hu, Youli; Tiosano, Dov; Gerard, Marion; Leger, Juliane; Drouin-Garraud, Valérie; Lefebvre, Hervé; Polak, Michel; Carel, Jean-Claude; Phan-Hug, Franziska; Hauschild, Michael; Plummer, Lacey; Rey, Jean-Pierre; Raivio, Taneli; Bouloux, Pierre; Sidis, Yisrael; Mohammadi, Moosa; de Roux, Nicolas; Pitteloud, Nelly

    2014-01-01

    Purpose Congenital hypogonadotropic hypogonadism (CHH) and split hand/foot malformation (SHFM) are two rare genetic conditions. Here we report a clinical entity comprising CHH and SHFM. Methods We identified patients with CHH and SHFM through international collaboration. Probands and available family members underwent phenotyping and screening for FGFR1 mutations. The impact of identified mutations was assessed by sequence- and structure-based predictions, and/or functional assays. Results We identified 8 probands with CHH with (n=3, Kallmann Syndrome) or without anosmia (n=5) and SHFM, 7 of whom (88%) harbor FGFR1 mutations: one individual is homozygous for p.V429E; six individuals are heterozygous for p.G348R, p.G485R, p.Q594*, p.E670A, p.V688L, and p.L712P. All mutations were predicted to be loss-of-function by in silico analysis. Probands with FGFR1 mutations have severe GnRH deficiency (absent puberty and/or cryptorchidism and/or micropenis). SHFM in both hands and feet was only observed in the patient with the homozygous p.V429E mutation; V429 maps to the FRS2α binding domain of FGFR1, and functional studies of the p.V429E mutation demonstrated that it decreased recruitment and phosphorylation of FRS2α to FG FR 1 , thereby resulting in reduced MAPK signaling. Conclusion FGFR1 should be prioritized for genetic testing in patients with CHH and SHFM, because the likelihood of a mutation increases from 10% in the general CHH population to 88%. PMID:25394172

  2. Similarities and discrepancies in homozygous factor VII defects due to mutations in the region of residues Met298 to Cys310 (exon 8) in the catalytic domain of factor VII.

    PubMed

    Girolami, A; Berti de Marinis, G; Bonamigo, E; Vettore, S

    2011-06-01

    Patients with the Arg304Gln mutation in factor VII Padua (FVII Padua) show discrepant activity levels that depend on the thromboplastin used in the assay system. This report investigates the possibility that residues close to Arg304 (exon 8) show the same discrepant behavior. All available homozygous patients with a mutation in a 13-residue region (preceding and following Arg304) have been evaluated. Only the Arg304Trp mutation showed a discrepancy similar to that shown by the Arg304Gln mutation. Other homozygotes failed to show differences, despite their all being positive for cross-reacting material. Another FVII amino acid residue involved in tissue factor binding and activation is Arg79 (exon 4). No comparison could be carried out because no homozygotes for deficiency in this region have ever been described. The relationship between these 2 residues involved in tissue factor binding and activation has not yet been completely clarified; however, Arg residues 79 and 304 are the only 2 residues definitely shown thus far to be involved in this important function.

  3. Cortical atrophy and hypofibrinogenemia due to FGG and TBCD mutations in a single family: a case report.

    PubMed

    Stephen, Joshi; Nampoothiri, Sheela; Vinayan, K P; Yesodharan, Dhanya; Remesh, Preetha; Gahl, William A; Malicdan, May Christine V

    2018-05-16

    Blended phenotypes or co-occurrence of independent phenotypically distinct conditions are extremely rare and are due to coincidence of multiple pathogenic mutations, especially due to consanguinity. Hereditary fibrinogen deficiencies result from mutations in the genes FGA, FGB, and FGG, encoding the three different polypeptide chains that comprise fibrinogen. Neurodevelopmental abnormalities have not been associated with fibrinogen deficiencies. In this study, we report an unusual patient with a combination of two independently inherited genetic conditions; fibrinogen deficiency and early onset cortical atrophy. The study describes a male child from consanguineous family presented with hypofibrinogenemia, diffuse cortical atrophy, microcephaly, hypertonia and axonal motor neuropathy. Through a combination of homozygosity mapping and exome sequencing, we identified bi-allelic pathogenic mutations in two genes: a homozygous novel truncating mutation in FGG (c.554del; p.Lys185Argfs*14) and a homozygous missense mutation in TBCD (c.1423G > A;p.Ala475Thr). Loss of function mutations in FGG have been associated with fibrinogen deficiency, while the c.1423G > A mutation in TBCD causes a novel syndrome of neurodegeneration and early onset encephalopathy. Our study highlights the importance of homozygosity mapping and exome sequencing in molecular prenatal diagnosis, especially when multiple gene mutations are responsible for the phenotype.

  4. Clinical expression of C282Y homozygous HFE haemochromatosis at 14 years of age.

    PubMed

    Rossi, Enrico; Wallace, Daniel F; Subramaniam, V Nathan; St Pierre, Timothy G; Mews, Catherine; Jeffrey, Gary P

    2006-05-01

    A 14-year-old boy who presented with debilitating lethargy was shown to have an elevated serum ferritin of 572 microg/L and a C282Y homozygous HFE genotype. Liver iron concentration was measured non-invasively by magnetic resonance imaging, which revealed a liver iron concentration of 59 micromol/g dry weight (children's reference range < 14). The early phenotypic expression was further investigated by screening genomic DNA for the presence of co-inherited mutations in genes responsible for non-HFE haemochromatosis. Coding regions and splice sites in genes encoding hepcidin and haemojuvelin were sequenced and previously described mutations in ferroportin 1 and transferrin receptor 2 genes were screened. Although no mutations were found, the most likely cause for the early expression is the presence of novel mutations or gene(s).

  5. A KCNJ10 mutation previously identified in the Russell group of terriers also occurs in Smooth-Haired Fox Terriers with hereditary ataxia and in related breeds.

    PubMed

    Rohdin, Cecilia; Gilliam, Douglas; O'Leary, Caroline A; O'Brien, Dennis P; Coates, Joan R; Johnson, Gary S; Jäderlund, Karin Hultin

    2015-05-23

    Hereditary ataxias with similar phenotypes were reported in the Smooth-Haired Fox Terrier, the Jack Russell Terrier and the Parson Russell Terrier. However, segregation analyses showed differing inheritance modes in these breeds. Recently, molecular genetic studies on the Russell group of terriers found independent mutations in KCNJ10 and CAPN1, each associated with a specific clinical subtype of inherited ataxia. The aim of this study was to clarify whether or not Smooth-Haired Fox Terriers with hereditary ataxia and dogs of other related breeds harbor either of the same mutations. A sub goal was to update the results of KCNJ10 genotyping in Russell group terriers. Three Smooth-Haired Fox Terriers with hereditary ataxia and two Toy Fox Terriers with a similar phenotype were all homozygous for the KCNJ10 mutation. The same mutation was also found in a heterozygous state in clinically unaffected Tenterfield Terriers (n = 5) and, in agreement with previous studies, in Jack Russell Terriers, Parson Russell Terriers, and Russell Terriers. A KCNJ10 mutation, previously associated with an autosomal recessive spinocerebellar ataxia in Jack Russell Terriers, Parson Russell Terriers, and Russell Terriers segregates in at least three more breeds descended from British hunting terriers. Ataxic members of two of these breeds, the Smooth-Haired Fox Terrier and the Toy Fox Terrier, were homozygous for the mutation, strengthening the likelihood that this genetic defect is indeed the causative mutation for the disease known as "hereditary ataxia" in Fox Terriers and "spinocerebellar ataxia with myokymia, seizures or both" in the Russell group of terriers.

  6. Identification of a Novel Dentin Matrix Protein-1 (DMP-1) Mutation and Dental Anomalies in a Kindred with Autosomal Recessive Hypophosphatemia

    PubMed Central

    Turan, Serap; Aydin, Cumhur; Bereket, Abdullah; Akcay, Teoman; Güran, Tülay; Yaralioglu, Betul Akmen; Bastepe, Murat; Jüppner, Harald

    2009-01-01

    An autosomal recessive form of hypophosphatemia (ARHP) was recently shown to be caused by homozygous mutations in DMP1, the gene encoding dentin matrix protein-1 (DMP-1), a non-collagenous bone matrix protein with an important role in the development and mineralization of bone and teeth. Here, we report a previously not reported consanguineous ARHP kindred in which the three affected individuals carry a novel homozygous DMP-1 mutation. The index case presented at the age of 3 years with bowing of his legs, and showed hypophosphatemia due to insufficient renal phosphate retention. Serum alkaline phosphatase activity was elevated, with initially normal PTH. FGF23 was inappropriately normal at an older age while being treated with oral phosphate and 1,25(OH)2D. Similar clinical and biochemical findings, except for elevated FGF23 levels, were present in his 16 month-old brother and his 12.5 year-old female cousin; the parents of the three affected children are first-degree cousins. Nucleotide sequence analysis was performed on PCR-amplified exons encoding DMP-1 and flanking intronic regions. A novel homozygous frame-shift mutation (c.485Tdel; p.Glu163ArgfsX53) in exon 6 resulting in a premature stop codon was identified in all effected individuals. The parents and available unaffected siblings were heterozygous for c.485Tdel. Tooth growth and shape were normal for the index case, his affected brother and cousin, but their permanent and deciduous teeth displayed enlarged pulp chambers. The identified genetic mutation underscores the importance of DMP-1 mutations in the pathogenesis of ARHP. Furthermore, DMP-1 mutations appear to contribute, through yet unknown mechanisms, to tooth development. PMID:19796717

  7. LDLR promoter variant and exon 14 mutation on the same chromosome are associated with an unusually severe FH phenotype and treatment resistance

    PubMed Central

    Snozek, Christine LH; Lagerstedt, Susan A; Khoo, Teck K; Rubenfire, Melvyn; Isley, William L; Train, Laura J; Baudhuin, Linnea M

    2009-01-01

    Familial hypercholesterolemia (FH) is the most common form of autosomal-dominant hypercholesterolemia, and is caused by mutations in the low-density lipoprotein receptor (LDLR) gene. Heterozygous FH is characterized by elevated low-density lipoprotein (LDL) cholesterol and early-onset cardiovascular disease, whereas homozygous FH results in more severe LDL cholesterol elevation with death by 20 years of age. We present here the case of an African-American female FH patient presenting with a myocardial infarction at the age of 48, recurrent angina pectoris and numerous coronary artery stents. Her pretreated LDL cholesterol levels were more typical of a homozygous FH pattern and she was resistant to conventional lipid-lowering treatment, yet her other clinical parameters were not necessarily consistent with homozygous FH. Genetic testing revealed two LDLR variants on the same chromosome: one a novel missense mutation in exon 14 (Cys681Gly) and the other a promoter variant (IVS1-217C>T) previously shown to result in increased LDLR transcription. Disease-associated PCSK9 or APOB mutations were not identified in this individual. Overall, her genetic and clinical profile suggests that enhanced expression of the mutant LDLR allele resulted in a severe phenotype with characteristics of both heterozygous and homozygous FH. PMID:18648394

  8. Mutations in Alström protein impair terminal differentiation of cardiomyocytes.

    PubMed

    Shenje, Lincoln T; Andersen, Peter; Halushka, Marc K; Lui, Cecillia; Fernandez, Laviel; Collin, Gayle B; Amat-Alarcon, Nuria; Meschino, Wendy; Cutz, Ernest; Chang, Kenneth; Yonescu, Raluca; Batista, Denise A S; Chen, Yan; Chelko, Stephen; Crosson, Jane E; Scheel, Janet; Vricella, Luca; Craig, Brian D; Marosy, Beth A; Mohr, David W; Hetrick, Kurt N; Romm, Jane M; Scott, Alan F; Valle, David; Naggert, Jürgen K; Kwon, Chulan; Doheny, Kimberly F; Judge, Daniel P

    2014-03-04

    Cardiomyocyte cell division and replication in mammals proceed through embryonic development and abruptly decline soon after birth. The process governing cardiomyocyte cell cycle arrest is poorly understood. Here we carry out whole-exome sequencing in an infant with evidence of persistent postnatal cardiomyocyte replication to determine the genetic risk factors. We identify compound heterozygous ALMS1 mutations in the proband, and confirm their presence in her affected sibling, one copy inherited from each heterozygous parent. Next, we recognize homozygous or compound heterozygous truncating mutations in ALMS1 in four other children with high levels of postnatal cardiomyocyte proliferation. Alms1 mRNA knockdown increases multiple markers of proliferation in cardiomyocytes, the percentage of cardiomyocytes in G2/M phases, and the number of cardiomyocytes by 10% in cultured cells. Homozygous Alms1-mutant mice have increased cardiomyocyte proliferation at 2 weeks postnatal compared with wild-type littermates. We conclude that deficiency of Alström protein impairs postnatal cardiomyocyte cell cycle arrest.

  9. Mutations in Alström Protein Impair Terminal Differentiation of Cardiomyocytes

    PubMed Central

    Shenje, Lincoln T.; Andersen, Peter; Halushka, Marc K.; Lui, Cecillia; Fernandez, Laviel; Collin, Gayle B.; Amat-Alarcon, Nuria; Meschino, Wendy; Cutz, Ernest; Chang, Kenneth; Yonescu, Raluca; Batista, Denise A. S.; Chen, Yan; Chelko, Stephen; Crosson, Jane E.; Scheel, Janet; Vricella, Luca; Craig, Brian D.; Marosy, Beth A.; Mohr, David W.; Hetrick, Kurt N.; Romm, Jane M.; Scott, Alan F.; Valle, David; Naggert, Jürgen K.; Kwon, Chulan; Doheny, Kimberly F.; Judge, Daniel P.

    2014-01-01

    Cardiomyocyte cell division and replication in mammals proceed through embryonic development and abruptly decline soon after birth. The process governing cardiomyocyte cell cycle arrest is poorly understood. Here we carry out whole exome sequencing in an infant with evidence of persistent postnatal cardiomyocyte replication to determine the genetic risk factors. We identify compound heterozygous ALMS1 mutations in the proband, and confirm their presence in her affected sibling, one copy inherited from each heterozygous parent. Next, we recognise homozygous or compound heterozygous truncating mutations in ALMS1 in four other children with high levels of postnatal cardiomyocyte proliferation. Alms1 mRNA knockdown increases multiple markers of proliferation in cardiomyocytes, the percentage of cardiomyocytes in G2/M phases, and the number of cardiomyocytes by 10% in cultured cells. Homozygous Alms1-mutant mice have increased cardiomyocyte proliferation at two weeks postnatal compared to wild-type littermates. We conclude that deficiency of Alström protein impairs postnatal cardiomyocyte cell cycle arrest. PMID:24595103

  10. [Association between homozygous c.318A>GT mutation in exon 2 of the EIF2B5 gene and the infantile form of vanishing white matter leukoencephalopathy].

    PubMed

    Esmer, Carmen; Blanco Hernández, Gabriela; Saavedra Alanís, Víctor; Reyes Vaca, Jorge Guillermo; Bravo Oro, Antonio

    Vanishing white matter disease is one of the most frequent leukodystrophies in childhood with an autosomal recessive inheritance. A mutation in one of the genes encoding the five subunits of the eukaryotic initiation factor 2 (EIF2B5) is present in 90% of the cases. The diagnosis can be accomplished by the clinical and neuroradiological findings and molecular tests. We describe a thirteen-month-old male with previous normal neurodevelopment, who was hospitalized for vomiting, hyperthermia and irritability. On examination, cephalic perimeter and cranial pairs were normal. Hypotonia, increased muscle stretching reflexes, generalized white matter hypodensity on cranial tomography were found. Fifteen days after discharge, he suffered minor head trauma presenting drowsiness and focal seizures. Magnetic resonance showed generalized hypointensity of white matter. Vanishing white matter disease was suspected, and confirmed by sequencing of the EIF2B5 gene, revealing a homozygous c.318A> T mutation in exon 2. Subsequently, visual acuity was lost and cognitive and motor deterioration was evident. The patient died at six years of age due to severe pneumonia. This case contributes to the knowledge of the mutational spectrum present in Mexican patients and allows to extend the phenotype associated to this mutation. Copyright © 2017. Publicado por Masson Doyma México S.A.

  11. Recessive HYDIN Mutations Cause Primary Ciliary Dyskinesia without Randomization of Left-Right Body Asymmetry

    PubMed Central

    Olbrich, Heike; Schmidts, Miriam; Werner, Claudius; Onoufriadis, Alexandros; Loges, Niki T.; Raidt, Johanna; Banki, Nora Fanni; Shoemark, Amelia; Burgoyne, Tom; Al Turki, Saeed; Hurles, Matthew E.; Köhler, Gabriele; Schroeder, Josef; Nürnberg, Gudrun; Nürnberg, Peter; Chung, Eddie M.K.; Reinhardt, Richard; Marthin, June K.; Nielsen, Kim G.; Mitchison, Hannah M.; Omran, Heymut

    2012-01-01

    Primary ciliary dyskinesia (PCD) is a genetically heterogeneous recessive disorder characterized by defective cilia and flagella motility. Chronic destructive-airway disease is caused by abnormal respiratory-tract mucociliary clearance. Abnormal propulsion of sperm flagella contributes to male infertility. Genetic defects in most individuals affected by PCD cause randomization of left-right body asymmetry; approximately half show situs inversus or situs ambiguous. Almost 70 years after the hy3 mouse possessing Hydin mutations was described as a recessive hydrocephalus model, we report HYDIN mutations in PCD-affected persons without hydrocephalus. By homozygosity mapping, we identified a PCD-associated locus, chromosomal region 16q21-q23, which contains HYDIN. However, a nearly identical 360 kb paralogous segment (HYDIN2) in chromosomal region 1q21.1 complicated mutational analysis. In three affected German siblings linked to HYDIN, we identified homozygous c.3985G>T mutations that affect an evolutionary conserved splice acceptor site and that subsequently cause aberrantly spliced transcripts predicting premature protein termination in respiratory cells. Parallel whole-exome sequencing identified a homozygous nonsense HYDIN mutation, c.922A>T (p.Lys307∗), in six individuals from three Faroe Island PCD-affected families that all carried an 8.8 Mb shared haplotype across HYDIN, indicating an ancestral founder mutation in this isolated population. We demonstrate by electron microscopy tomography that, consistent with the effects of loss-of-function mutations, HYDIN mutant respiratory cilia lack the C2b projection of the central pair (CP) apparatus; similar findings were reported in Hydin-deficient Chlamydomonas and mice. High-speed videomicroscopy demonstrated markedly reduced beating amplitudes of respiratory cilia and stiff sperm flagella. Like the hy3 mouse model, all nine PCD-affected persons had normal body composition because nodal cilia function is apparently

  12. In silico analysis of novel mutations in maple syrup urine disease patients from Iran.

    PubMed

    Abiri, Maryam; Karamzadeh, Razieh; Mojbafan, Marziyeh; Alaei, Mohammad Reza; Jodaki, Atefeh; Safi, Masomeh; Kianfar, Soodeh; Bandehi Sarhaddi, Ameneh; Noori-Daloii, Mohammad Reza; Karimipoor, Morteza; Zeinali, Sirous

    2017-02-01

    Maple Syrup Urine Disease (MSUD) is a rare autosomal recessive disorder of branched-chain amino acid (BCAA) metabolism. The disease is mainly caused by mutations either in the BCKDHA, BCKDHB, DBT or DLD genes encoding components of the E1α, E1β, E2 and E3 subunits of branched-chain α-keto acid dehydrogenase complex (BCKDC), respectively. BCKDC is a mitochondrial enzyme which is responsible for the normal breakdown of BCAA. The rate of consanguineous marriage in Iran is 38.6 %, so the prevalence of autosomal recessive disorders is higher in comparison to other countries. Consanguinity increases the chance of the presence of pathogenic mutations in a homoallelic state. This phenomenon has made homozygosity mapping a powerful tool for finding the probable causative gene in heterogeneous disorders like IEM (Inborn Errors of Metabolism). In this study, two sets of multiplex polymorphic STR (Short Tandem Repeat) markers linked to the above-mentioned genes were selected to identify the probable pathogenic gene in the studied families. The families who showed a homozygous haplotype for the STR markers of the BCKDHB gene were subsequently sequenced. Four novel mutations including c.633 + 1G > A, c.988G > A, c.833_834insCAC, and a homozygous deletion of whole exon 3 c. (274 + 1_275-1) _(343 + 1_344-1), as well as one recently reported (c. 508G > T) mutation have been identified. Interestingly, three families shared a common haplotype structure along with the c. 508G > T mutation. Also, four other families revealed another similar haplotype with c.988G > A mutation. Founder effect can be a suggestive mechanism for the disease. Additionally, structural models of MSUD mutations have been performed to predict the pathogenesis of the newly identified variants.

  13. [From gene to disease; primary hyperoxaluria type I caused by mutations in the AGXT gene].

    PubMed

    van Woerden, C S; Groothof, J W; Wanders, R J A; Waterham, H R; Wijburg, F R

    2006-07-29

    Primary hyperoxaluria type I (PH1) is a congenital defect in glyoxylate metabolism caused by a deficiency in the liver-specific peroxisomal enzyme known as alanine glyoxylate aminotransferase (AGT). The deficiency is due to mutations in the AGXT gene, located on chromosome 2q37.3, and results in the conversion of glyoxylate to oxalate. The crystallisation of oxalate with calcium results in symptoms varying from a solitary kidney stone to end-stage renal disease with systemic oxalosis. The diagnosis is based on increased oxalate and glycolate excretion in the urine, reduced AGT activity in liver tissue, and confirmed mutations in the AGXT gene. Over 50 disease-causing mutations have been identified in PH1, which are associated with a wide range of effects on the AGT enzyme. Homozygous Gly170Arg or Phei52Ile mutations are associated with a reduction in urinary oxalate excretion upon pyridoxine administration and long-term preservation of renal function when treatment is initiated in a timely manner. Homozygous 33insC and Gly82Arg mutations result in a much poorer prognosis. Mutational analysis of the AGXT gene in PH1 patients can be a useful tool for establishing the diagnosis and choosing an appropriate therapeutic strategy.

  14. Homozygous missense mutation in the LMAN2L gene segregates with intellectual disability in a large consanguineous Pakistani family.

    PubMed

    Rafiullah, Rafiullah; Aslamkhan, Muhammad; Paramasivam, Nagarajan; Thiel, Christian; Mustafa, Ghulam; Wiemann, Stefan; Schlesner, Matthias; Wade, Rebecca C; Rappold, Gudrun A; Berkel, Simone

    2016-02-01

    Intellectual disability (ID) is a neurodevelopmental disorder affecting 1%-3% of the population worldwide. It is characterised by high phenotypic and genetic heterogeneity and in most cases the underlying cause of the disorder is unknown. In our study we investigated a large consanguineous family from Baluchistan, Pakistan, comprising seven affected individuals with a severe form of autosomal recessive ID (ARID) and epilepsy, to elucidate a putative genetic cause. Whole exome sequencing (WES) of a trio, including a child with ID and epilepsy and its healthy parents that were part of this large family, revealed a homozygous missense variant p.R53Q in the lectin mannose-binding 2-like (LMAN2L) gene. This homozygous variant was co-segregating in the family with the phenotype of severe ID and infantile epilepsy; unaffected family members were heterozygous variant carriers. The variant was predicted to be pathogenic by five different in silico programmes and further three-dimensional structure modelling of the protein suggests that variant p.R53Q may impair protein-protein interaction. LMAN2L (OMIM: 609552) encodes for the lectin, mannose-binding 2-like protein which is a cargo receptor in the endoplasmic reticulum important for glycoprotein transport. Genome-wide association studies have identified an association of LMAN2L to different neuropsychiatric disorders. This is the first report linking LMAN2L to a phenotype of severe ARID and seizures, indicating that the deleterious homozygous p.R53Q variant very likely causes the disorder. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  15. A homozygous mutation in RNU4ATAC as a cause of microcephalic osteodysplastic primordial dwarfism type I (MOPD I) with associated pigmentary disorder.

    PubMed

    Abdel-Salam, Ghada M H; Miyake, Noriko; Eid, Maha M; Abdel-Hamid, Mohamed S; Hassan, Nihal A; Eid, Ola M; Effat, Laila K; El-Badry, Tarek H; El-Kamah, Ghada Y; El-Darouti, Mohamed; Matsumoto, Naomichi

    2011-11-01

    The designation microcephalic osteodysplastic primordial dwarfism (MOPD) refers to a group of autosomal recessive disorders, comprising microcephaly, growth retardation, and a skeletal dysplasia. The different types of MOPD have been delineated on the basis of clinical, radiological, and genetic criteria. We describe two brothers, born to healthy, consanguineous parents, with intrauterine and postnatal growth retardation, microcephaly with abnormal gyral pattern and partial agenesis of corpus callosum, and skeletal anomalies reminiscent of those described in MOPD type I. This was confirmed by the identification of the homozygous g.55G > A mutation of RNU4ATAC encoding U4atac snRNA. The sibs had yellowish-gray hair, fair skin, and deficient retinal pigmentation. Skin biopsy showed abnormal melanin function but OCA genes were normal. The older sib had an intracranial hemorrhage at 1 week after birth, the younger developed chilblains-like lesions at the age 2½ years old but analysis of the SAMHD1 and TREX1 genes did not show any mutations. To the best of our knowledge, vasculopathy and pigmentary disorders have not been reported in MOPD I. Copyright © 2011 Wiley Periodicals, Inc.

  16. Identification of a region of homozygous deletion in cervical carcinoma

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Aburatani, H.; Housman, D.E.; Wang, Y.

    1994-09-01

    To identify the possible location of a tumor suppressor gene (TSG) for cervical carcinoma, we have scanned the tumor DNAs for homozygous deletion by Representational Difference Analysis (RDA). Matched pairs of tumor and normal DNA were restriction digested and PCR-amplified. The tumor DNA amplicon was used as a driver for subtraction to identify DNA fragments homozygously deleted in tumor DNA. We analysed 6 cervical cancer specimens (5 cell lines, 1 fresh tumor). Four out of 6 analyses produced difference products present only in normal DNA, which were either hemizygously or homozygously deleted in tumor DNA. The two samples which failedmore » to produce any difference products were cell lines established from dysplasia patients, on which genetic changes might be minimal. One cervical carcinoma cell line CC6 produced 11 difference products deleted homozygously, all of which are clustered in 3p12-13 region. The proximal short arm of chromosome 3 is known to have a high incidence of L.O.H. in cervical carcinoma and thus may be a locus for TSG. A 4 Mb YAC contig has been established over the deletion and its characterization is under way to facilitate the identification of possible TSGs in this region.« less

  17. Exome-wide Association Study Identifies GREB1L Mutations in Congenital Kidney Malformations.

    PubMed

    Sanna-Cherchi, Simone; Khan, Kamal; Westland, Rik; Krithivasan, Priya; Fievet, Lorraine; Rasouly, Hila Milo; Ionita-Laza, Iuliana; Capone, Valentina P; Fasel, David A; Kiryluk, Krzysztof; Kamalakaran, Sitharthan; Bodria, Monica; Otto, Edgar A; Sampson, Matthew G; Gillies, Christopher E; Vega-Warner, Virginia; Vukojevic, Katarina; Pediaditakis, Igor; Makar, Gabriel S; Mitrotti, Adele; Verbitsky, Miguel; Martino, Jeremiah; Liu, Qingxue; Na, Young-Ji; Goj, Vinicio; Ardissino, Gianluigi; Gigante, Maddalena; Gesualdo, Loreto; Janezcko, Magdalena; Zaniew, Marcin; Mendelsohn, Cathy Lee; Shril, Shirlee; Hildebrandt, Friedhelm; van Wijk, Joanna A E; Arapovic, Adela; Saraga, Marijan; Allegri, Landino; Izzi, Claudia; Scolari, Francesco; Tasic, Velibor; Ghiggeri, Gian Marco; Latos-Bielenska, Anna; Materna-Kiryluk, Anna; Mane, Shrikant; Goldstein, David B; Lifton, Richard P; Katsanis, Nicholas; Davis, Erica E; Gharavi, Ali G

    2017-11-02

    Renal agenesis and hypodysplasia (RHD) are major causes of pediatric chronic kidney disease and are highly genetically heterogeneous. We conducted whole-exome sequencing in 202 case subjects with RHD and identified diagnostic mutations in genes known to be associated with RHD in 7/202 case subjects. In an additional affected individual with RHD and a congenital heart defect, we found a homozygous loss-of-function (LOF) variant in SLIT3, recapitulating phenotypes reported with Slit3 inactivation in the mouse. To identify genes associated with RHD, we performed an exome-wide association study with 195 unresolved case subjects and 6,905 control subjects. The top signal resided in GREB1L, a gene implicated previously in Hoxb1 and Shha signaling in zebrafish. The significance of the association, which was p = 2.0 × 10 -5 for novel LOF, increased to p = 4.1 × 10 -6 for LOF and deleterious missense variants combined, and augmented further after accounting for segregation and de novo inheritance of rare variants (joint p = 2.3 × 10 -7 ). Finally, CRISPR/Cas9 disruption or knockdown of greb1l in zebrafish caused specific pronephric defects, which were rescued by wild-type human GREB1L mRNA, but not mRNA containing alleles identified in case subjects. Together, our study provides insight into the genetic landscape of kidney malformations in humans, presents multiple candidates, and identifies SLIT3 and GREB1L as genes implicated in the pathogenesis of RHD. Copyright © 2017 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  18. Mutation of CDH23, encoding a new member of the cadherin gene family, causes Usher syndrome type 1D.

    PubMed

    Bolz, H; von Brederlow, B; Ramírez, A; Bryda, E C; Kutsche, K; Nothwang, H G; Seeliger, M; del C-Salcedó Cabrera, M; Vila, M C; Molina, O P; Gal, A; Kubisch, C

    2001-01-01

    Usher syndrome type I (USH1) is an autosomal recessive disorder characterized by congenital sensorineural hearing loss, vestibular dysfunction and visual impairment due to early onset retinitis pigmentosa (RP). So far, six loci (USH1A-USH1F) have been mapped, but only two USH1 genes have been identified: MYO7A for USH1B and the gene encoding harmonin for USH1C. We identified a Cuban pedigree linked to the locus for Usher syndrome type 1D (MIM 601067) within the q2 region of chromosome 10). Affected individuals present with congenital deafness and a highly variable degree of retinal degeneration. Using a positional candidate approach, we identified a new member of the cadherin gene superfamily, CDH23. It encodes a protein of 3,354 amino acids with a single transmembrane domain and 27 cadherin repeats. In the Cuban family, we detected two different mutations: a severe course of the retinal disease was observed in individuals homozygous for what is probably a truncating splice-site mutation (c.4488G-->C), whereas mild RP is present in individuals carrying the homozygous missense mutation R1746Q. A variable expression of the retinal phenotype was seen in patients with a combination of both mutations. In addition, we identified two mutations, Delta M1281 and IVS51+5G-->A, in a German USH1 patient. Our data show that different mutations in CDH23 result in USH1D with a variable retinal phenotype. In an accompanying paper, it is shown that mutations in the mouse ortholog cause disorganization of inner ear stereocilia and deafness in the waltzer mouse.

  19. A novel homozygous Arg222Trp missense mutation in WNT7A in two sisters with severe Al-Awadi/Raas-Rothschild/Schinzel phocomelia syndrome.

    PubMed

    Kantaputra, Piranit N; Mundlos, Stefan; Sripathomsawat, Warissara

    2010-11-01

    Al-Awadi/Raas-Rothschild/Schinzel phocomelia (AARRS) syndrome, a rare autosomal recessive disorder, comprises malformations of upper and lower limbs with severely hypoplastic pelvis and abnormal genitalia. Mutations in WNT7A have been reported as cause of the syndrome. We report on two sisters in a Thai family with short and malformed long bones, absent fibulae, flexion contracture of digits, and a/hypoplastic nails. Fusion between severely malformed femora and slender tibiae has never been reported in patients with WNT7A mutations. Lower limbs were more severely malformed than the upper ones and the pelvis was also severely affected. Multiple fusions of long bones and of the femoral heads to the acetabula were evident. A novel homozygous missense mutation in coding exon 4 of the WNT7A was detected in both affected daughters (c.664C > T) leading to an amino acid exchange from arginine to tryptophan (p.Arg222Trp; R222W). The phenotype is likely to result from an abnormality of all three signaling centers in the developing limb resulting in ventralization with a loss of dorsal structures (aplasia/hypoplasia of nails) a loss of anterior-posterior identity (single distal bones in lower limb without polarity) and an outgrowth defect resulting in distal truncations. © 2010 Wiley-Liss, Inc.

  20. Novel mutations in PATL2 cause female infertility with oocyte germinal vesicle arrest.

    PubMed

    Huang, Lingli; Tong, Xianhong; Wang, Fengsong; Luo, Lihua; Jin, Rentao; Fu, Yingyun; Zhou, Guixiang; Li, Daojing; Song, Gaojie; Liu, Yusheng; Zhu, Fuxi

    2018-06-01

    Do PATL2 mutations account for female infertility with oocyte germinal vesicle (GV) arrest? Four of nine independent families with oocyte GV arrest were identified with biallelic PATL2 mutations, suggesting that these mutations may be responsible for oocyte maturation arrest in primary infertile women. Recently, two independent studies have demonstrated that infertility in some women with oocyte maturation arrest at the GV stage was caused by biallelic mutations in PATL2. PATL2 encodes protein PAT1 homolog 2, an RNA-binding protein that may act as a translational repressor. In this study, nine unrelated primary infertile females presenting with oocyte GV arrest were recruited during the treatment of early rescue ICSI or ICSI from January 2013 to December 2016. Genomic DNA was isolated from blood samples obtained from all nine affected individuals and all of their available family members. All the coding regions of PATL2 were sequenced by Sanger sequencing. The pathogenicity of the identified variants and their possible effects on the protein were evaluated in silico. Five novel point mutations and one recurrent splicing mutation in PATL2 were identified in four of nine (44.4%) unrelated patients. We found a consanguineous family with a homozygous missense mutation in two affected sisters, and their fertile brother. There were no clear phenotypic differences in oocytes between the patient with the homozygous missense mutation, patients with nonsense mutations and undiagnosed patients. n/a. The function of PATL2 remains largely unknown. Both the exact pathogenic mechanism(s) of mutated PATL2 causing human oocyte maturation arrest and the strategies to overcome this condition should be further investigated in the future. According to our data, mutations in PATL2 account for 44.4% of the individuals with oocyte GV arrest. Our study further confirms that PATL2 is required for human oocyte maturation and female fertility, which indicates a potential prognostic value of

  1. Constitutional Mismatch Repair Deficiency in Israel: High Proportion of Founder Mutations in MMR Genes and Consanguinity.

    PubMed

    Baris, Hagit N; Barnes-Kedar, Inbal; Toledano, Helen; Halpern, Marisa; Hershkovitz, Dov; Lossos, Alexander; Lerer, Israela; Peretz, Tamar; Kariv, Revital; Cohen, Shlomi; Half, Elizabeth E; Magal, Nurit; Drasinover, Valerie; Wimmer, Katharina; Goldberg, Yael; Bercovich, Dani; Levi, Zohar

    2016-03-01

    Heterozygous germline mutations in any of the mismatch repair (MMR) genes, MLH1, MSH2, MSH6, and PMS2, cause Lynch syndrome (LS), an autosomal dominant cancer predisposition syndrome conferring a high risk of colorectal, endometrial, and other cancers in adulthood. Offspring of couples where both spouses have LS have a 1:4 risk of inheriting biallelic MMR gene mutations. These cause constitutional MMR deficiency (CMMRD) syndrome, a severe recessively inherited cancer syndrome with a broad tumor spectrum including mainly hematological malignancies, brain tumors, and colon cancer in childhood and adolescence. Many CMMRD children also present with café au lait spots and axillary freckling mimicking neurofibromatosis type 1. We describe our experience in seven CMMRD families demonstrating the role and importance of founder mutations and consanguinity on its prevalence. Clinical presentations included brain tumors, colon cancer, lymphoma, and small bowel cancer. In children from two nonconsanguineous Ashkenazi Jewish (AJ) families, the common Ashkenazi founder mutations were detected; these were homozygous in one family and compound heterozygous in the other. In four consanguineous families of various ancestries, different homozygous mutations were identified. In a nonconsanguineous Caucasus/AJ family, lack of PMS2 was demonstrated in tumor and normal tissues; however, mutations were not identified. CMMRD is rare, but, especially in areas where founder mutations for LS and consanguinity are common, pediatricians should be aware of it since they are the first to encounter these children. Early diagnosis will enable tailored cancer surveillance in the entire family and a discussion regarding prenatal genetic diagnosis. © 2015 Wiley Periodicals, Inc.

  2. Mutation and deletion analysis of GFRα-1, encoding the co-receptor for the GDNF/RET complex, in human brain tumours

    PubMed Central

    Gimm, O; Gössling, A; Marsh, D J; Dahia, P L M; Mulligan, L M; Deimling, A von; Eng, C

    1999-01-01

    Glial cell line-derived neurotrophic factor (GDNF) plays a key role in the control of vertebrate neuron survival and differentiation in both the central and peripheral nervous systems. GDNF preferentially binds to GFRα-1 which then interacts with the receptor tyrosine kinase RET. We investigated a panel of 36 independent cases of mainly advanced sporadic brain tumours for the presence of mutations in GDNF and GFRα-1. No mutations were found in the coding region of GDNF. We identified six previously described GFRα-1 polymorphisms, two of which lead to an amino acid change. In 15 of 36 brain tumours, all polymorphic variants appeared to be homozygous. Of these 15 tumours, one also had a rare, apparently homozygous, sequence variant at codon 361. Because of the rarity of the combination of homozygous sequence variants, analysis for hemizygous deletion was pursued in the 15 samples and loss of heterozygosity was found in 11 tumours. Our data suggest that intragenic point mutations of GDNF or GFRα-1 are not a common aetiologic event in brain tumours. However, either deletion of GFRα-1 and/or nearby genes may contribute to the pathogenesis of these tumours. © 1999 Cancer Research Campaign PMID:10408842

  3. Founder Fukutin mutation causes Walker-Warburg syndrome in four Ashkenazi Jewish families†

    PubMed Central

    Chang, Wendy; Winder, Thomas L.; LeDuc, Charles A.; Simpson, Lynn L.; Millar, William S.; Dungan, Jeffrey; Ginsberg, Norman; Plaga, Stacey; Moore, Steven A.; Chung, Wendy K.

    2009-01-01

    Objective Walker-Warburg syndrome (WWS) is a genetically heterogeneous congenital muscular dystrophy caused by abnormal glycosylation of α-dystroglycan (α-DG) that is associated with brain malformations and eye anomalies. The Fukutin (FKTN) gene, which causes autosomal recessively inherited WWS is most often associated with Fukuyama congenital muscular dystrophy in Japan. We describe the clinical features of four nonconsanguinous Ashkenazi Jewish families with WWS and identify the underlying genetic basis for WWS. Method We screened for mutations in POMGnT1, POMT1, POMT2, and FKTN, genes causing WWS, by dideoxy sequence analysis. Results We identified an identical homozygous c.1167insA mutation in the FKTN gene on a common haplotype in all four families and identified 2/299 (0.7%) carriers for the c.1167insA mutation among normal American Ashkenazi Jewish adults. Conclusion These data suggest that the c.1167insA FKTN mutation described by us is a founder mutation that can be used to target diagnostic testing and carrier screening in the Ashkenazi Jewish population. PMID:19266496

  4. Founder Fukutin mutation causes Walker-Warburg syndrome in four Ashkenazi Jewish families.

    PubMed

    Chang, Wendy; Winder, Thomas L; LeDuc, Charles A; Simpson, Lynn L; Millar, William S; Dungan, Jeffrey; Ginsberg, Norman; Plaga, Stacey; Moore, Steven A; Chung, Wendy K

    2009-06-01

    Walker-Warburg syndrome (WWS) is a genetically heterogeneous congenital muscular dystrophy caused by abnormal glycosylation of alpha-dystroglycan (alpha-DG) that is associated with brain malformations and eye anomalies. The Fukutin (FKTN) gene, which causes autosomal recessively inherited WWS is most often associated with Fukuyama congenital muscular dystrophy in Japan. We describe the clinical features of four nonconsanguinous Ashkenazi Jewish families with WWS and identify the underlying genetic basis for WWS. We screened for mutations in POMGnT1, POMT1, POMT2, and FKTN, genes causing WWS, by dideoxy sequence analysis. We identified an identical homozygous c.1167insA mutation in the FKTN gene on a common haplotype in all four families and identified 2/299 (0.7%) carriers for the c.1167insA mutation among normal American Ashkenazi Jewish adults. These data suggest that the c.1167insA FKTN mutation described by us is a founder mutation that can be used to target diagnostic testing and carrier screening in the Ashkenazi Jewish population. Copyright (c) 2009 John Wiley & Sons, Ltd.

  5. Bone marrow failure unresponsive to bone marrow transplant is caused by mutations in thrombopoietin.

    PubMed

    Seo, Aaron; Ben-Harosh, Miri; Sirin, Mehtap; Stein, Jerry; Dgany, Orly; Kaplelushnik, Joseph; Hoenig, Manfred; Pannicke, Ulrich; Lorenz, Myriam; Schwarz, Klaus; Stockklausner, Clemens; Walsh, Tom; Gulsuner, Suleyman; Lee, Ming K; Sendamarai, Anoop; Sanchez-Bonilla, Marilyn; King, Mary-Claire; Cario, Holger; Kulozik, Andreas E; Debatin, Klaus-Michael; Schulz, Ansgar; Tamary, Hannah; Shimamura, Akiko

    2017-08-17

    We report 5 individuals in 3 unrelated families with severe thrombocytopenia progressing to trilineage bone marrow failure (BMF). Four of the children received hematopoietic stem cell transplants and all showed poor graft function with persistent severe cytopenias even after repeated transplants with different donors. Exome and targeted sequencing identified mutations in the gene encoding thrombopoietin ( THPO ): THPO R99W, homozygous in affected children in 2 families, and THPO R157X, homozygous in the affected child in the third family. Both mutations result in a lack of THPO in the patients' serum. For the 2 surviving patients, improvement in trilineage hematopoiesis was achieved following treatment with a THPO receptor agonist. These studies demonstrate that biallelic loss-of-function mutations in THPO cause BMF, which is unresponsive to transplant due to a hematopoietic cell-extrinsic mechanism. These studies provide further support for the critical role of the MPL-THPO pathway in hematopoiesis and highlight the importance of accurate genetic diagnosis to inform treatment decisions for BMF. © 2017 by The American Society of Hematology.

  6. Mutations in the interleukin receptor IL11RA cause autosomal recessive Crouzon-like craniosynostosis

    PubMed Central

    Keupp, Katharina; Li, Yun; Vargel, Ibrahim; Hoischen, Alexander; Richardson, Rebecca; Neveling, Kornelia; Alanay, Yasemin; Uz, Elif; Elcioğlu, Nursel; Rachwalski, Martin; Kamaci, Soner; Tunçbilek, Gökhan; Akin, Burcu; Grötzinger, Joachim; Konas, Ersoy; Mavili, Emin; Müller-Newen, Gerhard; Collmann, Hartmut; Roscioli, Tony; Buckley, Michael F; Yigit, Gökhan; Gilissen, Christian; Kress, Wolfram; Veltman, Joris; Hammerschmidt, Matthias; Akarsu, Nurten A; Wollnik, Bernd

    2013-01-01

    We have characterized a novel autosomal recessive Crouzon-like craniosynostosis syndrome in a 12-affected member family from Antakya, Turkey, the presenting features of which include: multiple suture synostosis, midface hypoplasia, variable degree of exophthalmos, relative prognathism, a beaked nose, and conductive hearing loss. Homozygosity mapping followed by targeted next-generation sequencing identified a c.479+6T>G mutation in the interleukin 11 receptor alpha gene (IL11RA) on chromosome 9p21. This donor splice-site mutation leads to a high percentage of aberrant IL11RA mRNA transcripts in an affected individual and altered mRNA splicing determined by in vitro exon trapping. An extended IL11RA mutation screen was performed in a cohort of 79 patients with an initial clinical diagnosis of Crouzon syndrome, pansynostosis, or unclassified syndromic craniosynostosis. We identified mutations segregating with the disease in five families: a German patient of Turkish origin and a Turkish family with three affected sibs all of whom were homozygous for the previously identified IL11RA c.479+6T>G mutation; a family with pansynostosis with compound heterozygous missense mutations, p.Pro200Thr and p.Arg237Pro; and two further Turkish families with Crouzon-like syndrome carrying the homozygous nonsense mutations p.Tyr232* and p.Arg292*. Using transient coexpression in HEK293T and COS7 cells, we demonstrated dramatically reduced IL11-mediated STAT3 phosphorylation for all mutations. Immunofluorescence analysis of mouse Il11ra demonstrated specific protein expression in cranial mesenchyme which was localized around the coronal suture tips and in the lambdoidal suture. In situ hybridization analysis of adult zebrafish also detected zfil11ra expression in the coronal suture between the overlapping frontal and parietal plates. This study demonstrates that mutations in the IL11RA gene cause an autosomal recessive Crouzon-like craniosynostosis. PMID:24498618

  7. Bi-allelic Mutations in PKD1L1 Are Associated with Laterality Defects in Humans.

    PubMed

    Vetrini, Francesco; D'Alessandro, Lisa C A; Akdemir, Zeynep C; Braxton, Alicia; Azamian, Mahshid S; Eldomery, Mohammad K; Miller, Kathryn; Kois, Chelsea; Sack, Virginia; Shur, Natasha; Rijhsinghani, Asha; Chandarana, Jignesh; Ding, Yan; Holtzman, Judy; Jhangiani, Shalini N; Muzny, Donna M; Gibbs, Richard A; Eng, Christine M; Hanchard, Neil A; Harel, Tamar; Rosenfeld, Jill A; Belmont, John W; Lupski, James R; Yang, Yaping

    2016-10-06

    Disruption of the establishment of left-right (L-R) asymmetry leads to situs anomalies ranging from situs inversus totalis (SIT) to situs ambiguus (heterotaxy). The genetic causes of laterality defects in humans are highly heterogeneous. Via whole-exome sequencing (WES), we identified homozygous mutations in PKD1L1 from three affected individuals in two unrelated families. PKD1L1 encodes a polycystin-1-like protein and its loss of function is known to cause laterality defects in mouse and medaka fish models. Family 1 had one fetus and one deceased child with heterotaxy and complex congenital heart malformations. WES identified a homozygous splicing mutation, c.6473+2_6473+3delTG, which disrupts the invariant splice donor site in intron 42, in both affected individuals. In the second family, a homozygous c.5072G>C (p.Cys1691Ser) missense mutation was detected in an individual with SIT and congenital heart disease. The p.Cys1691Ser substitution affects a highly conserved cysteine residue and is predicted by molecular modeling to disrupt a disulfide bridge essential for the proper folding of the G protein-coupled receptor proteolytic site (GPS) motif. Damaging effects associated with substitutions of this conserved cysteine residue in the GPS motif have also been reported in other genes, namely GPR56, BAI3, and PKD1 in human and lat-1 in C. elegans, further supporting the likely pathogenicity of p.Cys1691Ser in PKD1L1. The identification of bi-allelic PKD1L1 mutations recapitulates previous findings regarding phenotypic consequences of loss of function of the orthologous genes in mice and medaka fish and further expands our understanding of genetic contributions to laterality defects in humans. Copyright © 2016 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  8. A double EPSPS gene mutation endowing glyphosate resistance shows a remarkably high resistance cost.

    PubMed

    Han, Heping; Vila-Aiub, Martin M; Jalaludin, Adam; Yu, Qin; Powles, Stephen B

    2017-12-01

    A novel glyphosate resistance double point mutation (T102I/P106S, TIPS) in the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene has been recently identified for the first time only in the weed species Eleusine indica. Quantification of plant resistance cost associated with the TIPS and the often reported glyphosate resistance single P106S mutation was performed. A significant resistance cost (50% in seed number currency) associated with the homozygous TIPS but not the homozygous P106S EPSPS variant was identified in E. indica plants. The resistance cost associated with the TIPS mutation escalated to 85% in plants under resource competition with rice crops. The resistance cost was not detected in nonhomozygous TIPS plants denoting the recessive nature of the cost associated with the TIPS allele. An excess of 11-fold more shikimate and sixfold more quinate in the shikimate pathway was detected in TIPS plants in the absence of glyphosate treatment compared to wild type, whereas no changes in these compounds were observed in P106S plants when compared to wild type. TIPS plants show altered metabolite levels in several other metabolic pathways that may account for the expression of the observed resistance cost. © 2017 John Wiley & Sons Ltd.

  9. Congenital hypogonadotropic hypogonadism with split hand/foot malformation: a clinical entity with a high frequency of FGFR1 mutations.

    PubMed

    Villanueva, Carine; Jacobson-Dickman, Elka; Xu, Cheng; Manouvrier, Sylvie; Dwyer, Andrew A; Sykiotis, Gerasimos P; Beenken, Andrew; Liu, Yang; Tommiska, Johanna; Hu, Youli; Tiosano, Dov; Gerard, Marion; Leger, Juliane; Drouin-Garraud, Valérie; Lefebvre, Hervé; Polak, Michel; Carel, Jean-Claude; Phan-Hug, Franziska; Hauschild, Michael; Plummer, Lacey; Rey, Jean-Pierre; Raivio, Taneli; Bouloux, Pierre; Sidis, Yisrael; Mohammadi, Moosa; de Roux, Nicolas; Pitteloud, Nelly

    2015-08-01

    Congenital hypogonadotropic hypogonadism (CHH) and split hand/foot malformation (SHFM) are two rare genetic conditions. Here we report a clinical entity comprising the two. We identified patients with CHH and SHFM through international collaboration. Probands and available family members underwent phenotyping and screening for FGFR1 mutations. The impact of identified mutations was assessed by sequence- and structure-based predictions and/or functional assays. We identified eight probands with CHH with (n = 3; Kallmann syndrome) or without anosmia (n = 5) and SHFM, seven of whom (88%) harbor FGFR1 mutations. Of these seven, one individual is homozygous for p.V429E and six individuals are heterozygous for p.G348R, p.G485R, p.Q594*, p.E670A, p.V688L, or p.L712P. All mutations were predicted by in silico analysis to cause loss of function. Probands with FGFR1 mutations have severe gonadotropin-releasing hormone deficiency (absent puberty and/or cryptorchidism and/or micropenis). SHFM in both hands and feet was observed only in the patient with the homozygous p.V429E mutation; V429 maps to the fibroblast growth factor receptor substrate 2α binding domain of FGFR1, and functional studies of the p.V429E mutation demonstrated that it decreased recruitment and phosphorylation of fibroblast growth factor receptor substrate 2α to FGFR1, thereby resulting in reduced mitogen-activated protein kinase signaling. FGFR1 should be prioritized for genetic testing in patients with CHH and SHFM because the likelihood of a mutation increases from 10% in the general CHH population to 88% in these patients.

  10. Identification of eight novel coagulation factor XIII subunit A mutations: implied consequences for structure and function

    PubMed Central

    Ivaskevicius, Vytautas; Biswas, Arijit; Bevans, Carville; Schroeder, Verena; Kohler, Hans Peter; Rott, Hannelore; Halimeh, Susan; Petrides, Petro E.; Lenk, Harald; Krause, Manuele; Miterski, Bruno; Harbrecht, Ursula; Oldenburg, Johannes

    2010-01-01

    Background Severe hereditary coagulation factor XIII deficiency is a rare homozygous bleeding disorder affecting one person in every two million individuals. In contrast, heterozygous factor XIII deficiency is more common, but usually not associated with severe hemorrhage such as intracranial bleeding or hemarthrosis. In most cases, the disease is caused by F13A gene mutations. Causative mutations associated with the F13B gene are rarer. Design and Methods We analyzed ten index patients and three relatives for factor XIII activity using a photometric assay and sequenced their F13A and F13B genes. Additionally, structural analysis of the wild-type protein structure from a previously reported X-ray crystallographic model identified potential structural and functional effects of the missense mutations. Results All individuals except one were heterozygous for factor XIIIA mutations (average factor XIII activity 51%), while the remaining homozygous individual was found to have severe factor XIII deficiency (<5% of normal factor XIII activity). Eight of the 12 heterozygous patients exhibited a bleeding tendency upon provocation. Conclusions The identified missense (Pro289Arg, Arg611His, Asp668Gly) and nonsense (Gly390X, Trp664X) mutations are causative for factor XIII deficiency. A Gly592Ser variant identified in three unrelated index patients, as well as in 200 healthy controls (minor allele frequency 0.005), and two further Tyr167Cys and Arg540Gln variants, represent possible candidates for rare F13A gene polymorphisms since they apparently do not have a significant influence on the structure of the factor XIIIA protein. Future in vitro expression studies of the factor XIII mutations are required to confirm their pathological mechanisms. PMID:20179087

  11. Identification of eight novel coagulation factor XIII subunit A mutations: implied consequences for structure and function.

    PubMed

    Ivaskevicius, Vytautas; Biswas, Arijit; Bevans, Carville; Schroeder, Verena; Kohler, Hans Peter; Rott, Hannelore; Halimeh, Susan; Petrides, Petro E; Lenk, Harald; Krause, Manuele; Miterski, Bruno; Harbrecht, Ursula; Oldenburg, Johannes

    2010-06-01

    Severe hereditary coagulation factor XIII deficiency is a rare homozygous bleeding disorder affecting one person in every two million individuals. In contrast, heterozygous factor XIII deficiency is more common, but usually not associated with severe hemorrhage such as intracranial bleeding or hemarthrosis. In most cases, the disease is caused by F13A gene mutations. Causative mutations associated with the F13B gene are rarer. We analyzed ten index patients and three relatives for factor XIII activity using a photometric assay and sequenced their F13A and F13B genes. Additionally, structural analysis of the wild-type protein structure from a previously reported X-ray crystallographic model identified potential structural and functional effects of the missense mutations. All individuals except one were heterozygous for factor XIIIA mutations (average factor XIII activity 51%), while the remaining homozygous individual was found to have severe factor XIII deficiency (<5% of normal factor XIII activity). Eight of the 12 heterozygous patients exhibited a bleeding tendency upon provocation. The identified missense (Pro289Arg, Arg611His, Asp668Gly) and nonsense (Gly390X, Trp664X) mutations are causative for factor XIII deficiency. A Gly592Ser variant identified in three unrelated index patients, as well as in 200 healthy controls (minor allele frequency 0.005), and two further Tyr167Cys and Arg540Gln variants, represent possible candidates for rare F13A gene polymorphisms since they apparently do not have a significant influence on the structure of the factor XIIIA protein. Future in vitro expression studies of the factor XIII mutations are required to confirm their pathological mechanisms.

  12. Identification of a novel dentin matrix protein-1 (DMP-1) mutation and dental anomalies in a kindred with autosomal recessive hypophosphatemia.

    PubMed

    Turan, Serap; Aydin, Cumhur; Bereket, Abdullah; Akcay, Teoman; Güran, Tülay; Yaralioglu, Betul Akmen; Bastepe, Murat; Jüppner, Harald

    2010-02-01

    An autosomal recessive form of hypophosphatemia (ARHP) was recently shown to be caused by homozygous mutations in DMP1, the gene encoding dentin matrix protein-1 (DMP-1), a non-collagenous bone matrix protein with an important role in the development and mineralization of bone and teeth. Here, we describe a previously not reported consanguineous ARHP kindred in which the three affected individuals carry a novel homozygous DMP-1 mutation. The index case presented at the age of 3 years with bowing of his legs and showed hypophosphatemia due to insufficient renal phosphate retention. Serum alkaline phosphatase activity was elevated, with initially normal PTH. FGF23 was inappropriately normal at an older age while being treated with oral phosphate and 1,25(OH)(2)D. Similar clinical and biochemical findings, except for elevated FGF23 levels, were present in his 16-month-old brother and his 12.5-year-old female cousin; the parents of the three affected children are first-degree cousins. Nucleotide sequence analysis was performed on PCR-amplified exons encoding DMP-1 and flanking intronic regions. A novel homozygous frame-shift mutation (c.485Tdel; p.Glu163ArgfsX53) in exon 6 resulting in a premature stop codon was identified in all effected individuals. The parents and available unaffected siblings were heterozygous for c.485Tdel. Tooth growth and shape were normal for the index case, his affected brother and cousin, but their permanent and deciduous teeth displayed enlarged pulp chambers. The identified genetic mutation underscores the importance of DMP-1 mutations in the pathogenesis of ARHP. Furthermore, DMP-1 mutations appear to contribute, through yet unknown mechanisms, to tooth development. (c) 2009 Elsevier Inc. All rights reserved.

  13. Novel C8orf37 mutations cause retinitis pigmentosa in consanguineous families of Pakistani origin

    PubMed Central

    Ravesh, Zeinab; El Asrag, Mohammed E.; Weisschuh, Nicole; McKibbin, Martin; Reuter, Peggy; Watson, Christopher M.; Baumann, Britta; Poulter, James A.; Sajid, Sundus; Panagiotou, Evangelia S.; O’Sullivan, James; Abdelhamed, Zakia; Bonin, Michael; Soltanifar, Mehdi; Black, Graeme C.M.; Din, Muhammad Amin-ud; Toomes, Carmel; Ansar, Muhammad; Inglehearn, Chris F.; Wissinger, Bernd

    2015-01-01

    Purpose To investigate the molecular basis of retinitis pigmentosa in two consanguineous families of Pakistani origin with multiple affected members. Methods Homozygosity mapping and Sanger sequencing of candidate genes were performed in one family while the other was analyzed with whole exome next-generation sequencing. A minigene splicing assay was used to confirm the splicing defects. Results In family MA48, a novel homozygous nucleotide substitution in C8orf37, c.244–2A>C, that disrupted the consensus splice acceptor site of exon 3 was found. The minigene splicing assay revealed that this mutation activated a cryptic splice site within exon 3, causing a 22 bp deletion in the transcript that is predicted to lead to a frameshift followed by premature protein truncation. In family MA13, a novel homozygous null mutation in C8orf37, c.555G>A, p.W185*, was identified. Both mutations segregated with the disease phenotype as expected in a recessive manner and were absent in 8,244 unrelated individuals of South Asian origin. Conclusions In this report, we describe C8orf37 mutations that cause retinal dystrophy in two families of Pakistani origin, contributing further data on the phenotype and the spectrum of mutations in this form of retinitis pigmentosa. PMID:25802487

  14. Mutations of E3 Ubiquitin Ligase Cbl Family Members Constitute a Novel Common Pathogenic Lesion in Myeloid Malignancies

    PubMed Central

    Makishima, Hideki; Cazzolli, Heather; Szpurka, Hadrian; Dunbar, Andrew; Tiu, Ramon; Huh, Jungwon; Muramatsu, Hideki; O'Keefe, Christine; Hsi, Eric; Paquette, Ronald L.; Kojima, Seiji; List, Alan F.; Sekeres, Mikkael A.; McDevitt, Michael A.; Maciejewski, Jaroslaw P.

    2009-01-01

    Purpose Acquired somatic uniparental disomy (UPD) is commonly observed in myelodysplastic syndromes (MDS), myelodysplastic/myeloproliferative neoplasms (MDS/MPN), or secondary acute myelogenous leukemia (sAML) and may point toward genes harboring mutations. Recurrent UPD11q led to identification of homozygous mutations in c-Cbl, an E3 ubiquitin ligase involved in attenuation of proliferative signals transduced by activated receptor tyrosine kinases. We examined the role and frequency of Cbl gene family mutations in MPN and related conditions. Methods We applied high-density SNP-A karyotyping to identify loss of heterozygosity of 11q in 442 patients with MDS, MDS/MPN, MPN, sAML evolved from these conditions, and primary AML. We sequenced c-Cbl, Cbl-b, and Cbl-c in patients with or without corresponding UPD or deletions and correlated mutational status with clinical features and outcomes. Results We identified c-Cbl mutations in 5% and 9% of patients with chronic myelomonocytic leukemia (CMML) and sAML, and also in CML blast crisis and juvenile myelomonocytic leukemia (JMML). Most mutations were homozygous and affected c-Cbl; mutations in Cbl-b were also found in patients with similar clinical features. Patients with Cbl family mutations showed poor prognosis, with a median survival of 5 months. Pathomorphologic features included monocytosis, monocytoid blasts, aberrant expression of phosphoSTAT5, and c-kit overexpression. Serial studies showed acquisition of c-Cbl mutations during malignant evolution. Conclusion Mutations in the Cbl family RING finger domain or linker sequence constitute important pathogenic lesions associated with not only preleukemic CMML, JMML, and other MPN, but also progression to AML, suggesting that impairment of degradation of activated tyrosine kinases constitutes an important cancer mechanism. PMID:19901108

  15. Mapping Challenging Mutations by Whole-Genome Sequencing

    PubMed Central

    Smith, Harold E.; Fabritius, Amy S.; Jaramillo-Lambert, Aimee; Golden, Andy

    2016-01-01

    Whole-genome sequencing provides a rapid and powerful method for identifying mutations on a global scale, and has spurred a renewed enthusiasm for classical genetic screens in model organisms. The most commonly characterized category of mutation consists of monogenic, recessive traits, due to their genetic tractability. Therefore, most of the mapping methods for mutation identification by whole-genome sequencing are directed toward alleles that fulfill those criteria (i.e., single-gene, homozygous variants). However, such approaches are not entirely suitable for the characterization of a variety of more challenging mutations, such as dominant and semidominant alleles or multigenic traits. Therefore, we have developed strategies for the identification of those classes of mutations, using polymorphism mapping in Caenorhabditis elegans as our model for validation. We also report an alternative approach for mutation identification from traditional recombinant crosses, and a solution to the technical challenge of sequencing sterile or terminally arrested strains where population size is limiting. The methods described herein extend the applicability of whole-genome sequencing to a broader spectrum of mutations, including classes that are difficult to map by traditional means. PMID:26945029

  16. Hereditary Angioedema Nationwide Study in Slovenia Reveals Four Novel Mutations in SERPING1 Gene

    PubMed Central

    Rijavec, Matija; Korošec, Peter; Šilar, Mira; Zidarn, Mihaela; Miljković, Jovan; Košnik, Mitja

    2013-01-01

    Hereditary angioedema (HAE) is a rare autosomal dominant disease characterized by swelling of the face, lips, tongue, larynx, genitalia, or extremities, with abdominal pain caused by intra-abdominal edema. HAE is caused by mutations affecting the C1 inhibitor gene, SERPING1, resulting in low levels of C1 inhibitor (Type I HAE) or normal levels of ineffective C1 inhibitor (Type II HAE). A nationwide survey identified nine unrelated families with HAE in Slovenia, among whom 17 individuals from eight families were recruited for genetic analyses. A diagnosis of HAE was established in the presence of clinical and laboratory criteria (low C1 inhibitor antigenic levels and/or function), followed up by a positive family history. Genetic studies were carried out using PCR and sequencing to detect SERPING1 mutations in promoter, noncoding exon 1, the 7 coding exons, and exon-intron boundaries. Multiplex ligation-dependent probe amplification was performed in order to search for large deletions/duplications in SERPING1 gene. A mutation responsible for HAE was identified in patients from seven families with the disease. In HAE type I families, one previously reported substitution (Gln67Stop, c.265C>T) and four novel mutations were identified. The new mutations included two missense substitutions, Ser128Phe (c.449C>T), and Glu429Lys (c.1351G>A), together with two frameshift mutations, indel (c.49delGinsTT) and deletion (c.593_594delCT). Both families with HAE type II harbored the two well-known substitutions affecting the arginyl residue at the reactive center in exon 8, Arg444Cys (c.1396C>T) and Arg444His (c.1397G>A), respectively. In one patient only the homozygous variant g.566T>C (c.-21T>C) was identified. Our study identified four novel mutations in the Slovenian HAE population, highlighting the heterogeneity of mutations in the SERPING1 gene causing C1 inhibitor deficiency and HAE. In a single patient with HAE a homozygous variant g.566T>C (c.-21T>C) might be responsible

  17. Hereditary angioedema nationwide study in Slovenia reveals four novel mutations in SERPING1 gene.

    PubMed

    Rijavec, Matija; Korošec, Peter; Šilar, Mira; Zidarn, Mihaela; Miljković, Jovan; Košnik, Mitja

    2013-01-01

    Hereditary angioedema (HAE) is a rare autosomal dominant disease characterized by swelling of the face, lips, tongue, larynx, genitalia, or extremities, with abdominal pain caused by intra-abdominal edema. HAE is caused by mutations affecting the C1 inhibitor gene, SERPING1, resulting in low levels of C1 inhibitor (Type I HAE) or normal levels of ineffective C1 inhibitor (Type II HAE). A nationwide survey identified nine unrelated families with HAE in Slovenia, among whom 17 individuals from eight families were recruited for genetic analyses. A diagnosis of HAE was established in the presence of clinical and laboratory criteria (low C1 inhibitor antigenic levels and/or function), followed up by a positive family history. Genetic studies were carried out using PCR and sequencing to detect SERPING1 mutations in promoter, noncoding exon 1, the 7 coding exons, and exon-intron boundaries. Multiplex ligation-dependent probe amplification was performed in order to search for large deletions/duplications in SERPING1 gene. A mutation responsible for HAE was identified in patients from seven families with the disease. In HAE type I families, one previously reported substitution (Gln67Stop, c.265C>T) and four novel mutations were identified. The new mutations included two missense substitutions, Ser128Phe (c.449C>T), and Glu429Lys (c.1351G>A), together with two frameshift mutations, indel (c.49delGinsTT) and deletion (c.593_594delCT). Both families with HAE type II harbored the two well-known substitutions affecting the arginyl residue at the reactive center in exon 8, Arg444Cys (c.1396C>T) and Arg444His (c.1397G>A), respectively. In one patient only the homozygous variant g.566T>C (c.-21T>C) was identified. Our study identified four novel mutations in the Slovenian HAE population, highlighting the heterogeneity of mutations in the SERPING1 gene causing C1 inhibitor deficiency and HAE. In a single patient with HAE a homozygous variant g.566T>C (c.-21T>C) might be responsible

  18. A Novel Missense Mutation in SLC5A5 Gene in a Sudanese Family with Congenital Hypothyroidism.

    PubMed

    Watanabe, Yui; Ebrhim, Reham S; Abdullah, Mohamed A; Weiss, Roy E

    2018-06-05

    Thyroid hormone synthesis requires the presence of iodide. The sodium-iodide symporter (NIS) is a glycoprotein that mediates the active uptake of iodide from the blood stream into the thyroid grand. NIS defects due to SLC5A5 gene mutations are known to cause congenital hypothyroidism (CH). The proposita is a 28-year-old female whose origin is North Sudan where neonatal screening for CH is not available. She presented with severe constipation and a goiter at the age of 40 days. Laboratory testing confirmed CH, and she was started on levothyroxine. Presumably due to the delayed treatment, the patient developed mental retardation. Her younger sister presented with a goiter, tongue protrusion, and umbilical hernia, and the youngest brother was also diagnosed with CH based on a thyrotropin level >100 μIU/mL at the age of 22 days and 8 days, respectively. The two siblings were treated with levothyroxine and had normal development. Their consanguineous parents had no history of thyroid disorders. Whole-exome sequencing was performed on the proposita. This identified a novel homozygous missense mutation in the SLC5A5 gene-c.1042T>G, p.Y348D-which was subsequently confirmed by Sanger sequencing. All affected children were homozygous for the same mutation, and their unaffected mother was heterozygous. The NIS protein is composed of 13 transmembrane segments (TMS), an extracellular amino-terminus, and an intracellular carboxy-terminus. The mutation is located in the TMS IX, which has the most β-OH group-containing amino acids (serine and threonine), which is implicated in Na + binding and translocation. In conclusion, a novel homozygous missense mutation in the SLC5A5 gene was identified in this Sudanese family with CH. The mutation is located in the TMS IX of the NIS protein, which is essential for NIS function. Low iodine intake in Sudan is considered to affect the severity of hypothyroidism in patients.

  19. A Novel Loss-of-Sclerostin Function Mutation in a First Egyptian Family with Sclerosteosis

    PubMed Central

    Fayez, Alaaeldin; Aglan, Mona; Esmaiel, Nora; El Zanaty, Taher; Abdel Kader, Mohamed; El Ruby, Mona

    2015-01-01

    Sclerosteosis is a rare autosomal recessive condition characterized by increased bone density. Mutations in SOST gene coding for sclerostin are linked to sclerosteosis. Two Egyptian brothers with sclerosteosis and their apparently normal consanguineous parents were included in this study. Clinical evaluation and genomic sequencing of the SOST gene were performed followed by in silico analysis of the resulting variation. A novel homozygous frameshift mutation in the SOST gene, characterized as one nucleotide cytosine insertion that led to premature stop codon and loss of functional sclerostin, was identified in the two affected brothers. Their parents were heterozygous for the same mutation. To our knowledge this is the first Egyptian study of sclerosteosis and SOST gene causing mutation. PMID:25984533

  20. Novel mutations in CRB1 and ABCA4 genes cause Leber congenital amaurosis and Stargardt disease in a Swedish family

    PubMed Central

    Jonsson, Frida; Burstedt, Marie S; Sandgren, Ola; Norberg, Anna; Golovleva, Irina

    2013-01-01

    This study aimed to identify genetic mechanisms underlying severe retinal degeneration in one large family from northern Sweden, members of which presented with early-onset autosomal recessive retinitis pigmentosa and juvenile macular dystrophy. The clinical records of affected family members were analysed retrospectively and ophthalmological and electrophysiological examinations were performed in selected cases. Mutation screening was initially performed with microarrays, interrogating known mutations in the genes associated with recessive retinitis pigmentosa, Leber congenital amaurosis and Stargardt disease. Searching for homozygous regions with putative causative disease genes was done by high-density SNP-array genotyping, followed by segregation analysis of the family members. Two distinct phenotypes of retinal dystrophy, Leber congenital amaurosis and Stargardt disease were present in the family. In the family, four patients with Leber congenital amaurosis were homozygous for a novel c.2557C>T (p.Q853X) mutation in the CRB1 gene, while of two cases with Stargardt disease, one was homozygous for c.5461-10T>C in the ABCA4 gene and another was carrier of the same mutation and a novel ABCA4 mutation c.4773+3A>G. Sequence analysis of the entire ABCA4 gene in patients with Stargardt disease revealed complex alleles with additional sequence variants, which were evaluated by bioinformatics tools. In conclusion, presence of different genetic mechanisms resulting in variable phenotype within the family is not rare and can challenge molecular geneticists, ophthalmologists and genetic counsellors. PMID:23443024

  1. CBS mutations and MTFHR SNPs causative of hyperhomocysteinemia in Pakistani children.

    PubMed

    Ibrahim, Shahnaz; Maqbool, Saadia; Azam, Maleeha; Iqbal, Mohammad Perwaiz; Qamar, Raheel

    2018-03-29

    Three index patients with hyperhomocysteinemia and ocular anomalies were screened for cystathionine beta synthase (CBS) and methylenetetrahydrofolate reductase (MTHFR) polymorphisms. Genotyping of hyperhomocysteinemia associated MTHFR polymorphisms C677T (rs1801133) and A1298C (rs1801131) was done by PCR-restriction fragment length polymorphism. Sanger sequencing was performed for CBS exonic sequences along with consensus splice sites. In the case of MTHFR polymorphisms, all the patients were heterozygous CT for the single nucleotide polymorphism (SNP) C677T and were therefore carriers of the risk allele (T), while the patients were homozygous CC for the risk genotype of the SNP A1298C. CBS sequencing resulted in the identification of two novel mutations, a missense change (c.467T>C; p.Leu156Pro) in exon 7 and an in-frame deletion (c.808_810del; p.Glu270del) in exon 10. In addition, a recurrent missense mutation (c.770C>T; p.Thr257Met) in exon 10 of the gene was also identified. The mutations were present homozygously in the patients and were inherited from the carrier parents. This is the first report from Pakistan where novel as well as recurrent CBS mutations causing hyperhomocysteinemia and lens dislocation in three patients from different families are being reported with the predicted effect of the risk allele of the MTHFR SNP in causing hyperhomocysteinemia.

  2. Homozygous nonsense mutation in SGCA is a common cause of limb-girdle muscular dystrophy in Assiut, Egypt.

    PubMed

    Reddy, Hemakumar M; Hamed, Sherifa A; Lek, Monkol; Mitsuhashi, Satomi; Estrella, Elicia; Jones, Michael D; Mahoney, Lane J; Duncan, Anna R; Cho, Kyung-Ah; Macarthur, Daniel G; Kunkel, Louis M; Kang, Peter B

    2016-10-01

    The genetic causes of limb-girdle muscular dystrophy (LGMD) have been studied in numerous countries, but such investigations have been limited in Egypt. A cohort of 30 families with suspected LGMD from Assiut, Egypt, was studied using immunohistochemistry, homozygosity mapping, Sanger sequencing, and whole exome sequencing. Six families were confirmed to have pathogenic mutations, 4 in SGCA and 2 in DMD. Of these, 3 families harbored a single nonsense mutation in SGCA, suggesting that this may be a common mutation in Assiut, Egypt, originating from a founder effect. The Assiut region in Egypt appears to share at least several of the common LGMD genes found in other parts of the world. It is notable that 4 of the 6 mutations were ascertained by means of whole exome sequencing, even though it was the last approach adopted. This illustrates the power of this technique for identifying causative mutations for muscular dystrophies. Muscle Nerve 54: 690-695, 2016. © 2016 Wiley Periodicals, Inc.

  3. DNA Fragmentation Factor 45 (DFF45) Gene at 1p36.2 Is Homozygously Deleted and Encodes Variant Transcripts in Neuroblastoma Cell Line1

    PubMed Central

    Yang, Hong Wei; Chen, Ying Zhang; Piao, Hui Ying; Takita, Junko; Soeda, Eiichi; Hayashi, Yasuhide

    2001-01-01

    Abstract Recently, loss of heterozygosity (LOH) studies suggest that more than two tumor suppressor genes lie on the short arm of chromosome 1 (1p) in neuroblastoma (NB). To identify candidate tumor suppressor genes in NB, we searched for homozygous deletions in 20 NB cell lines using a high-density STS map spanning chromosome 1p36, a common LOH region in NB. We found that the 45-kDa subunit of the DNA fragmentation factor (DFF45) gene was homozygously deleted in an NB cell line, NB-1. DFF45 is the chaperon of DFF40, and both molecules are necessary for caspase 3 to induce apoptosis. DFF35, a splicing variant of DFF45, is an inhibitor of DFF40. We examined 20 NB cell lines for expression and mutation of DFF45 gene by reverse transcription (RT)-polymerase chain reaction (PCR) and RT-PCR-single-strand conformation polymorphism. Some novel variant transcripts of the DFF45 gene were found in NB cell lines, but not in normal adrenal gland and peripheral blood. These variants may not serve as chaperons of DFF40, but as inhibitors like DFF35, thus disrupting the balance between DFF45 and DFF40. No mutations of the DFF45 gene were found in any NB cell line, suggesting that the DFF45 is not a tumor suppressor gene for NB. However, homozygous deletion of the DFF45 gene in the NB-1 cell line may imply the presence of unknown tumor suppressor genes in this region. PMID:11420752

  4. Mutation detection using automated fluorescence-based sequencing.

    PubMed

    Montgomery, Kate T; Iartchouck, Oleg; Li, Li; Perera, Anoja; Yassin, Yosuf; Tamburino, Alex; Loomis, Stephanie; Kucherlapati, Raju

    2008-04-01

    The development of high-throughput DNA sequencing techniques has made direct DNA sequencing of PCR-amplified genomic DNA a rapid and economical approach to the identification of polymorphisms that may play a role in disease. Point mutations as well as small insertions or deletions are readily identified by DNA sequencing. The mutations may be heterozygous (occurring in one allele while the other allele retains the normal sequence) or homozygous (occurring in both alleles). Sequencing alone cannot discriminate between true homozygosity and apparent homozygosity due to the loss of one allele due to a large deletion. In this unit, strategies are presented for using PCR amplification and automated fluorescence-based sequencing to identify sequence variation. The size of the project and laboratory preference and experience will dictate how the data is managed and which software tools are used for analysis. A high-throughput protocol is given that has been used to search for mutations in over 200 different genes at the Harvard Medical School - Partners Center for Genetics and Genomics (HPCGG, http://www.hpcgg.org/). Copyright 2008 by John Wiley & Sons, Inc.

  5. Characterization of Homozygous Hb Setif (HBA2: c.283G>T) in the Iranian Population.

    PubMed

    Farashi, Samaneh; Garous, Negin F; Vakili, Shadi; Ashki, Mehri; Imanian, Hashem; Azarkeivan, Azita; Najmabadi, Hossein

    2016-01-01

    Hemoglobin (Hb) variants are abnormalities resulting from point mutations in either of the two α-globin genes (HBA2 or HBA1) or the β-globin gene (HBB). Various reports of Hb variants have been described in Iran and other countries around the world. Hb Setif (or HBA2: c.283G>T) is one of these variants with a mutation at codon 94 of of the α2-globin gene that is characterized in clinically normal heterozygous individuals. We here report clinical and hematological findings in two homozygous cases of Iranian origin for this unstable Hb variant.

  6. Linkage Study Revealed Complex Haplotypes in a Multifamily due to Different Mutations in CAPN3 Gene in an Iranian Ethnic Group.

    PubMed

    Mojbafan, Marzieh; Tonekaboni, Seyed Hassan; Abiri, Maryam; Kianfar, Soudeh; Sarhadi, Ameneh; Nilipour, Yalda; Tavakkoly-Bazzaz, Javad; Zeinali, Sirous

    2016-07-01

    Calpainopathy is an autosomal recessive form of limb girdle muscular dystrophies which is caused by mutation in CAPN3 gene. In the present study, co-segregation of this disorder was analyzed with four short tandem repeat markers linked to the CAPN3 gene. Three apparently unrelated Iranian families with same ethnicity were investigated. Haplotype analysis and sequencing of the CAPN3 gene were performed. DNA sample from one of the patients was simultaneously sent for next-generation sequencing. DNA sequencing identified two mutations. It was seen as a homozygous c.2105C>T in exon 19 in one family, a homozygous novel mutation c.380G>A in exon 3 in another family, and a compound heterozygote form of these two mutations in the third family. Next-generation sequencing also confirmed our results. It was expected that, due to the rare nature of limb girdle muscular dystrophies, affected individuals from the same ethnic group share similar mutations. Haplotype analysis showed two different homozygote patterns in two families, yet a compound heterozygote pattern in the third family as seen in the mutation analysis. This study shows that haplotype analysis would help in determining presence of different founders.

  7. Loss-of-Function Mutations in SERPINB8 Linked to Exfoliative Ichthyosis with Impaired Mechanical Stability of Intercellular Adhesions.

    PubMed

    Pigors, Manuela; Sarig, Ofer; Heinz, Lisa; Plagnol, Vincent; Fischer, Judith; Mohamad, Janan; Malchin, Natalia; Rajpopat, Shefali; Kharfi, Monia; Lestringant, Giles G; Sprecher, Eli; Kelsell, David P; Blaydon, Diana C

    2016-08-04

    SERPINS comprise a large and functionally diverse family of serine protease inhibitors. Here, we report three unrelated families with loss-of-function mutations in SERPINB8 in association with an autosomal-recessive form of exfoliative ichthyosis. Whole-exome sequencing of affected individuals from a consanguineous Tunisian family and a large Israeli family revealed a homozygous frameshift mutation, c.947delA (p.Lys316Serfs(∗)90), and a nonsense mutation, c.850C>T (p.Arg284(∗)), respectively. These two mutations are located in the last exon of SERPINB8 and, hence, would not be expected to lead to nonsense-mediated decay of the mRNA; nonetheless, both mutations are predicted to lead to loss of the reactive site loop of SERPINB8, which is crucial for forming the SERPINB8-protease complex. Using Sanger sequencing, a homozygous missense mutation, c.2T>C (p.Met1?), predicted to result in an N-terminal truncated protein, was identified in an additional family from UAE. Histological analysis of a skin biopsy from an individual homozygous for the variant p.Arg284(∗) showed disadhesion of keratinocytes in the lower epidermal layers plus decreased SERPINB8 levels compared to control. In vitro studies utilizing siRNA-mediated knockdown of SERPINB8 in keratinocytes demonstrated that in the absence of the protein, there is a cell-cell adhesion defect, particularly when cells are subjected to mechanical stress. In addition, immunoblotting and immunostaining revealed an upregulation of desmosomal proteins. In conclusion, we report mutations in SERPINB8 that are associated with exfoliative ichthyosis and provide evidence that SERPINB8 contributes to the mechanical stability of intercellular adhesions in the epidermis. Copyright © 2016 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  8. Molecular genetic analysis in mild hyperhomocysteinemia: A common mutation in the methylenetetrahydrofolate reductase gene is a genetic risk factor for cardiovascular disease

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kluijtmans, L.A.J.; Heuvel, L.P.W.J. van den; Stevens, E.M.B.

    1996-01-01

    Mild hyperhomocysteinemia is an established risk factor for cardiovascular disease. Genetic aberrations in the cystathionine P-synthase (CBS) and methylenetetrahydrofolate reductase (MTHFR) genes may account for reduced enzyme activities and elevated plasma homocysteine levels. In 15 unrelated Dutch patients with homozygous CBS deficiency, we observed the 833T{yields}C (1278T) mutation in 50% of the alleles. Very recently, we identified a common mutation (677C{yields}T; A{yields}V) in the MTHFR gene, which, in homozygous state, is responsible for the thermolabile phenotype and which is associated with decreased specific MTHFR activity and elevated homocysteine levels. We screened 60 cardiovascular patients and 111 controls for these twomore » mutations, to determine whether these mutations are risk factors for premature cardiovascular disease. Heterozygosity for the 833T{yields}C mutation in the CBS gene was observed in one individual of the control group but was absent in patients with premature cardiovascular disease. Homozygosity for the 677C-{yields}T mutation in the MTHFR gene was found in 9 (15%) of 60 cardiovascular patients and in only 6 ({approximately}5%) of 111 control individuals (odds ratio 3.1 [95% confidence interval 1.0-9.21]). Because of both the high prevalence of the 833T-{yields}C mutation among homozygotes for CBS deficiency and its absence in 60 cardiovascular patients, we may conclude that heterozygosity for CBS deficiency does not appear to be involved in premature cardiovascular disease. However, a frequent homozygous mutation in the MTHFR gene is associated with a threefold increase in risk for premature cardiovascular disease. 35 refs., 3 figs., 1 tab.« less

  9. Key clinical features to identify girls with CDKL5 mutations.

    PubMed

    Bahi-Buisson, Nadia; Nectoux, Juliette; Rosas-Vargas, Haydeé; Milh, Mathieu; Boddaert, Nathalie; Girard, Benoit; Cances, Claude; Ville, Dorothée; Afenjar, Alexandra; Rio, Marlène; Héron, Delphine; N'guyen Morel, Marie Ange; Arzimanoglou, Alexis; Philippe, Christophe; Jonveaux, Philippe; Chelly, Jamel; Bienvenu, Thierry

    2008-10-01

    Mutations in the human X-linked cyclin-dependent kinase-like 5 (CDKL5) gene have been shown to cause infantile spasms as well as Rett syndrome (RTT)-like phenotype. To date, less than 25 different mutations have been reported. So far, there are still little data on the key clinical diagnosis criteria and on the natural history of CDKL5-associated encephalopathy. We screened the entire coding region of CDKL5 for mutations in 183 females with encephalopathy with early seizures by denaturing high liquid performance chromatography and direct sequencing, and we identified in 20 unrelated girls, 18 different mutations including 7 novel mutations. These mutations were identified in eight patients with encephalopathy with RTT-like features, five with infantile spasms and seven with encephalopathy with refractory epilepsy. Early epilepsy with normal interictal EEG and severe hypotonia are the key clinical features in identifying patients likely to have CDKL5 mutations. Our study also indicates that these patients clearly exhibit some RTT features such as deceleration of head growth, stereotypies and hand apraxia and that these RTT features become more evident in older and ambulatory patients. However, some RTT signs are clearly absent such as the so called RTT disease profile (period of nearly normal development followed by regression with loss of acquired fine finger skill in early childhood and characteristic intensive eye communication) and the characteristic evolution of the RTT electroencephalogram. Interestingly, in addition to the overall stereotypical symptomatology (age of onset and evolution of the disease) resulting from CDKL5 mutations, atypical forms of CDKL5-related conditions have also been observed. Our data suggest that phenotypic heterogeneity does not correlate with the nature or the position of the mutations or with the pattern of X-chromosome inactivation, but most probably with the functional transcriptional and/or translational consequences of CDKL5

  10. A Novel Nonsense Mutation in the DMP1 Gene Identified by a Genome-Wide Association Study Is Responsible for Inherited Rickets in Corriedale Sheep

    PubMed Central

    Blair, Hugh T.; Thompson, Keith G.; Rothschild, Max F.; Garrick, Dorian J.

    2011-01-01

    Inherited rickets of Corriedale sheep is characterized by decreased growth rate, thoracic lordosis and angular limb deformities. Previous outcross and backcross studies implicate inheritance as a simple autosomal recessive disorder. A genome wide association study was conducted using the Illumina OvineSNP50 BeadChip on 20 related sheep comprising 17 affected and 3 carriers. A homozygous region of 125 consecutive single-nucleotide polymorphism (SNP) loci was identified in all affected sheep, covering a region of 6 Mb on ovine chromosome 6. Among 35 candidate genes in this region, the dentin matrix protein 1 gene (DMP1) was sequenced to reveal a nonsense mutation 250C/T on exon 6. This mutation introduced a stop codon (R145X) and could truncate C-terminal amino acids. Genotyping by PCR-RFLP for this mutation showed all 17 affected sheep were “T T” genotypes; the 3 carriers were “C T”; 24 phenotypically normal related sheep were either “C T” or “C C”; and 46 unrelated normal control sheep from other breeds were all “C C”. The other SNPs in DMP1 were not concordant with the disease and can all be ruled out as candidates. Previous research has shown that mutations in the DMP1 gene are responsible for autosomal recessive hypophosphatemic rickets in humans. Dmp1_knockout mice exhibit rickets phenotypes. We believe the R145X mutation to be responsible for the inherited rickets found in Corriedale sheep. A simple diagnostic test can be designed to identify carriers with the defective “T” allele. Affected sheep could be used as animal models for this form of human rickets, and for further investigation of the role of DMP1 in phosphate homeostasis. PMID:21747952

  11. A new mutation identified in SPATA16 in two globozoospermic patients.

    PubMed

    ElInati, Elias; Fossard, Camille; Okutman, Ozlem; Ghédir, Houda; Ibala-Romdhane, Samira; Ray, Pierre F; Saad, Ali; Hennebicq, Sylvianne; Viville, Stéphane

    2016-06-01

    The aim of this study is to identify potential genes involved in human globozoopsermia. Nineteen globozoospermic patients (previously screened for DPY19L2 mutations with no causative mutation) were recruited in this study and screened for mutations in genes implicated in human globozoospermia SPATA16 and PICK1. Using the candidate gene approach and the determination of Spata16 partners by Glutathione S-transferase (GST) pull-down four genes were also selected and screened for mutations. We identified a novel mutation of SPATA16: deletion of 22.6 Kb encompassing the first coding exon in two unrelated Tunisian patients who presented the same deletion breakpoints. The two patients shared the same haplotype, suggesting a possible ancestral founder effect for this new deletion. Four genes were selected using the candidate gene approach and the GST pull-down (GOPC, PICK1, AGFG1 and IRGC) and were screened for mutation, but no variation was identified. The present study confirms the pathogenicity of the SPATA16 mutations. The fact that no variation was detected in the coding sequence of AFGF1, GOPC, PICK1 and IRGC does not mean that they are not involved in human globozoospermia. A larger globozoospermic cohort must be studied in order to accelerate the process of identifying new genes involved in such phenotypes. Until sufficient numbers of patients have been screened, AFGF1, GOPC, PICK1 and IRGC should still be considered as candidate genes.

  12. Analysis of transcription factors key for mouse pancreatic development establishes NKX2-2 and MNX1 mutations as causes of neonatal diabetes in man.

    PubMed

    Flanagan, Sarah E; De Franco, Elisa; Lango Allen, Hana; Zerah, Michele; Abdul-Rasoul, Majedah M; Edge, Julie A; Stewart, Helen; Alamiri, Elham; Hussain, Khalid; Wallis, Sam; de Vries, Liat; Rubio-Cabezas, Oscar; Houghton, Jayne A L; Edghill, Emma L; Patch, Ann-Marie; Ellard, Sian; Hattersley, Andrew T

    2014-01-07

    Understanding transcriptional regulation of pancreatic development is required to advance current efforts in developing beta cell replacement therapies for patients with diabetes. Current knowledge of key transcriptional regulators has predominantly come from mouse studies, with rare, naturally occurring mutations establishing their relevance in man. This study used a combination of homozygosity analysis and Sanger sequencing in 37 consanguineous patients with permanent neonatal diabetes to search for homozygous mutations in 29 transcription factor genes important for murine pancreatic development. We identified homozygous mutations in 7 different genes in 11 unrelated patients and show that NKX2-2 and MNX1 are etiological genes for neonatal diabetes, thus confirming their key role in development of the human pancreas. The similar phenotype of the patients with recessive mutations and mice with inactivation of a transcription factor gene support there being common steps critical for pancreatic development and validate the use of rodent models for beta cell development. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  13. Analysis of Transcription Factors Key for Mouse Pancreatic Development Establishes NKX2-2 and MNX1 Mutations as Causes of Neonatal Diabetes in Man

    PubMed Central

    Flanagan, Sarah E.; De Franco, Elisa; Lango Allen, Hana; Zerah, Michele; Abdul-Rasoul, Majedah M.; Edge, Julie A.; Stewart, Helen; Alamiri, Elham; Hussain, Khalid; Wallis, Sam; de Vries, Liat; Rubio-Cabezas, Oscar; Houghton, Jayne A.L.; Edghill, Emma L.; Patch, Ann-Marie; Ellard, Sian; Hattersley, Andrew T.

    2014-01-01

    Summary Understanding transcriptional regulation of pancreatic development is required to advance current efforts in developing beta cell replacement therapies for patients with diabetes. Current knowledge of key transcriptional regulators has predominantly come from mouse studies, with rare, naturally occurring mutations establishing their relevance in man. This study used a combination of homozygosity analysis and Sanger sequencing in 37 consanguineous patients with permanent neonatal diabetes to search for homozygous mutations in 29 transcription factor genes important for murine pancreatic development. We identified homozygous mutations in 7 different genes in 11 unrelated patients and show that NKX2-2 and MNX1 are etiological genes for neonatal diabetes, thus confirming their key role in development of the human pancreas. The similar phenotype of the patients with recessive mutations and mice with inactivation of a transcription factor gene support there being common steps critical for pancreatic development and validate the use of rodent models for beta cell development. PMID:24411943

  14. Whole-genome sequencing identifies recurrent mutations in chronic lymphocytic leukaemia

    PubMed Central

    Puente, Xose S.; Pinyol, Magda; Quesada, Víctor; Conde, Laura; Ordóñez, Gonzalo R.; Villamor, Neus; Escaramis, Georgia; Jares, Pedro; Beà, Sílvia; González-Díaz, Marcos; Bassaganyas, Laia; Baumann, Tycho; Juan, Manel; López-Guerra, Mónica; Colomer, Dolors; Tubío, José M. C.; López, Cristina; Navarro, Alba; Tornador, Cristian; Aymerich, Marta; Rozman, María; Hernández, Jesús M.; Puente, Diana A.; Freije, José M. P.; Velasco, Gloria; Gutiérrez-Fernández, Ana; Costa, Dolors; Carrió, Anna; Guijarro, Sara; Enjuanes, Anna; Hernández, Lluís; Yagüe, Jordi; Nicolás, Pilar; Romeo-Casabona, Carlos M.; Himmelbauer, Heinz; Castillo, Ester; Dohm, Juliane C.; de Sanjosé, Silvia; Piris, Miguel A.; de Alava, Enrique; Miguel, Jesús San; Royo, Romina; Gelpí, Josep L.; Torrents, David; Orozco, Modesto; Pisano, David G.; Valencia, Alfonso; Guigó, Roderic; Bayés, Mónica; Heath, Simon; Gut, Marta; Klatt, Peter; Marshall, John; Raine, Keiran; Stebbings, Lucy A.; Futreal, P. Andrew; Stratton, Michael R.; Campbell, Peter J.; Gut, Ivo; López-Guillermo, Armando; Estivill, Xavier; Montserrat, Emili; López-Otín, Carlos; Campo, Elías

    2012-01-01

    Chronic lymphocytic leukaemia (CLL), the most frequent leukaemia in adults in Western countries, is a heterogeneous disease with variable clinical presentation and evolution1,2. Two major molecular subtypes can be distinguished, characterized respectively by a high or low number of somatic hypermutations in the variable region of immunoglobulin genes3,4. The molecular changes leading to the pathogenesis of the disease are still poorly understood. Here we performed whole-genome sequencing of four cases of CLL and identified 46 somatic mutations that potentially affect gene function. Further analysis of these mutations in 363 patients with CLL identified four genes that are recurrently mutated: notch 1 (NOTCH1), exportin 1 (XPO1), myeloid differentiation primary response gene 88 (MYD88) and kelch-like 6 (KLHL6). Mutations in MYD88 and KLHL6 are predominant in cases of CLL with mutated immunoglobulin genes, whereas NOTCH1 and XPO1 mutations are mainly detected in patients with unmutated immunoglobulins. The patterns of somatic mutation, supported by functional and clinical analyses, strongly indicate that the recurrent NOTCH1, MYD88 and XPO1 mutations are oncogenic changes that contribute to the clinical evolution of the disease. To our knowledge, this is the first comprehensive analysis of CLL combining whole-genome sequencing with clinical characteristics and clinical outcomes. It highlights the usefulness of this approach for the identification of clinically relevant mutations in cancer. PMID:21642962

  15. Mutations in STRA6 Cause a Broad Spectrum of Malformations Including Anophthalmia, Congenital Heart Defects, Diaphragmatic Hernia, Alveolar Capillary Dysplasia, Lung Hypoplasia, and Mental Retardation

    PubMed Central

    Pasutto, Francesca; Sticht, Heinrich; Hammersen, Gerhard; Gillessen-Kaesbach, Gabriele; FitzPatrick, David R.; Nürnberg, Gudrun; Brasch, Frank; Schirmer-Zimmermann, Heidemarie; Tolmie, John L.; Chitayat, David; Houge, Gunnar; Fernández-Martínez, Lorena; Keating, Sarah; Mortier, Geert; Hennekam, Raoul C. M.; von der Wense, Axel; Slavotinek, Anne; Meinecke, Peter; Bitoun, Pierre; Becker, Christian; Nürnberg, Peter; Reis, André; Rauch, Anita

    2007-01-01

    We observed two unrelated consanguineous families with malformation syndromes sharing anophthalmia and distinct eyebrows as common signs, but differing for alveolar capillary dysplasia or complex congenital heart defect in one and diaphragmatic hernia in the other family. Homozygosity mapping revealed linkage to a common locus on chromosome 15, and pathogenic homozygous mutations were identified in STRA6, a member of a large group of “stimulated by retinoic acid” genes encoding novel transmembrane proteins, transcription factors, and secreted signaling molecules or proteins of largely unknown function. Subsequently, homozygous STRA6 mutations were also demonstrated in 3 of 13 patients chosen on the basis of significant phenotypic overlap to the original cases. While a homozygous deletion generating a premature stop codon (p.G50AfsX22) led to absence of the immunoreactive protein in patient’s fibroblast culture, structural analysis of three missense mutations (P90L, P293L, and T321P) suggested significant effects on the geometry of the loops connecting the transmembrane helices of STRA6. Two further variations in the C-terminus (T644M and R655C) alter specific functional sites, an SH2-binding motif and a phosphorylation site, respectively. STRA6 mutations thus define a pleiotropic malformation syndrome representing the first human phenotype associated with mutations in a gene from the “STRA” group. PMID:17273977

  16. Integrin Alpha 8 Recessive Mutations Are Responsible for Bilateral Renal Agenesis in Humans

    PubMed Central

    Humbert, Camille; Silbermann, Flora; Morar, Bharti; Parisot, Mélanie; Zarhrate, Mohammed; Masson, Cécile; Tores, Frédéric; Blanchet, Patricia; Perez, Marie-José; Petrov, Yuliya; Khau Van Kien, Philippe; Roume, Joelle; Leroy, Brigitte; Gribouval, Olivier; Kalaydjieva, Luba; Heidet, Laurence; Salomon, Rémi; Antignac, Corinne; Benmerah, Alexandre; Saunier, Sophie; Jeanpierre, Cécile

    2014-01-01

    Renal hypodysplasia (RHD) is a heterogeneous condition encompassing a spectrum of kidney development defects including renal agenesis, hypoplasia, and (cystic) dysplasia. Heterozygous mutations of several genes have been identified as genetic causes of RHD with various severity. However, these genes and mutations are not associated with bilateral renal agenesis, except for RET mutations, which could be involved in a few cases. The pathophysiological mechanisms leading to total absence of kidney development thus remain largely elusive. By using a whole-exome sequencing approach in families with several fetuses with bilateral renal agenesis, we identified recessive mutations in the integrin α8-encoding gene ITGA8 in two families. Itga8 homozygous knockout in mice is known to result in absence of kidney development. We provide evidence of a damaging effect of the human ITGA8 mutations. These results demonstrate that mutations of ITGA8 are a genetic cause of bilateral renal agenesis and that, at least in some cases, bilateral renal agenesis is an autosomal-recessive disease. PMID:24439109

  17. Alpha-tubulin missense mutations correlate with antimicrotubule drug resistance in Eleusine indica.

    PubMed Central

    Yamamoto, E; Zeng, L; Baird, W V

    1998-01-01

    Dinitroaniline herbicides are antimicrotubule drugs that bind to tubulins and inhibit polymerization. As a result of repeated application of dinitroaniline herbicides, highly resistant and intermediately resistant biotypes of goosegrass (Eleusine indica) developed in previously wild-type populations. Three alpha-tubulin cDNA classes (designated TUA1, TUA2, and TUA3) were isolated from each biotype. Nucleotide differences between the susceptible and the resistant (R) alpha-tubulins were identified in TUA1 and TUA2. The most significant differences were missense mutations that occurred in TUA1 of the R and intermediately resistant (I) biotypes. Such mutations convert Thr-239 to Ile in the R biotype and Met-268 to Thr in the I biotype. These amino acid substitutions alter hydrophobicity; therefore, they may alter the dinitroaniline binding property of the protein. These mutations were correlated with the dinitroaniline response phenotypes (Drp). Plants homozygous for susceptibility possessed the wild-type TUA1 allele; plants homozygous for resistance possessed the mutant tua1 allele; and plants heterozygous for susceptibility possessed both wild-type and mutant alleles. Thus, we conclude that TUA1 is at the Drp locus. Using polymerase chain reaction primer-introduced restriction analysis, we demonstrated that goosegrass genomic DNA can be diagnosed for Drp alleles. Although not direct proof, these results suggest that a mutation in an alpha-tubulin gene confers resistance to dinitroanilines in goosegrass. PMID:9490751

  18. Alpha-tubulin missense mutations correlate with antimicrotubule drug resistance in Eleusine indica.

    PubMed

    Yamamoto, E; Zeng, L; Baird, W V

    1998-02-01

    Dinitroaniline herbicides are antimicrotubule drugs that bind to tubulins and inhibit polymerization. As a result of repeated application of dinitroaniline herbicides, highly resistant and intermediately resistant biotypes of goosegrass (Eleusine indica) developed in previously wild-type populations. Three alpha-tubulin cDNA classes (designated TUA1, TUA2, and TUA3) were isolated from each biotype. Nucleotide differences between the susceptible and the resistant (R) alpha-tubulins were identified in TUA1 and TUA2. The most significant differences were missense mutations that occurred in TUA1 of the R and intermediately resistant (I) biotypes. Such mutations convert Thr-239 to Ile in the R biotype and Met-268 to Thr in the I biotype. These amino acid substitutions alter hydrophobicity; therefore, they may alter the dinitroaniline binding property of the protein. These mutations were correlated with the dinitroaniline response phenotypes (Drp). Plants homozygous for susceptibility possessed the wild-type TUA1 allele; plants homozygous for resistance possessed the mutant tua1 allele; and plants heterozygous for susceptibility possessed both wild-type and mutant alleles. Thus, we conclude that TUA1 is at the Drp locus. Using polymerase chain reaction primer-introduced restriction analysis, we demonstrated that goosegrass genomic DNA can be diagnosed for Drp alleles. Although not direct proof, these results suggest that a mutation in an alpha-tubulin gene confers resistance to dinitroanilines in goosegrass.

  19. Somatic mutations in histiocytic sarcoma identified by next generation sequencing.

    PubMed

    Liu, Qingqing; Tomaszewicz, Keith; Hutchinson, Lloyd; Hornick, Jason L; Woda, Bruce; Yu, Hongbo

    2016-08-01

    Histiocytic sarcoma is a rare malignant neoplasm of presumed hematopoietic origin showing morphologic and immunophenotypic evidence of histiocytic differentiation. Somatic mutation importance in the pathogenesis or disease progression of histiocytic sarcoma was largely unknown. To identify somatic mutations in histiocytic sarcoma, we studied 5 histiocytic sarcomas [3 female and 2 male patients; mean age 54.8 (20-72), anatomic sites include lymph node, uterus, and pleura] and matched normal tissues from each patient as germ line controls. Somatic mutations in 50 "Hotspot" oncogenes and tumor suppressor genes were examined using next generation sequencing. Three (out of five) histiocytic sarcoma cases carried somatic mutations in BRAF. Among them, G464V [variant frequency (VF) of 43.6 %] and G466R (VF of 29.6 %) located at the P loop potentially interfere with the hydrophobic interaction between P and activating loops and ultimately activation of BRAF. Also detected was BRAF somatic mutation N581S (VF of 7.4 %), which was located at the catalytic loop of BRAF kinase domain: its role in modifying kinase activity was unclear. A similar mutational analysis was also performed on nine acute monocytic/monoblastic leukemia cases, which did not identify any BRAF somatic mutations. Our study detected several BRAF mutations in histiocytic sarcomas, which may be important in understanding the tumorigenesis of this rare neoplasm and providing mechanisms for potential therapeutical opportunities.

  20. SIGMAR1 mutation associated with autosomal recessive Silver-like syndrome

    PubMed Central

    Horga, Alejandro; Tomaselli, Pedro J.; Gonzalez, Michael A.; Laurà, Matilde; Muntoni, Francesco; Manzur, Adnan Y.; Hanna, Michael G.; Blake, Julian C.; Houlden, Henry; Züchner, Stephan

    2016-01-01

    Objective: To describe the genetic and clinical features of a simplex patient with distal hereditary motor neuropathy (dHMN) and lower limb spasticity (Silver-like syndrome) due to a mutation in the sigma nonopioid intracellular receptor–1 gene (SIGMAR1) and review the phenotypic spectrum of mutations in this gene. Methods: We used whole-exome sequencing to investigate the proband. The variants of interest were investigated for segregation in the family using Sanger sequencing. Subsequently, a larger cohort of 16 unrelated dHMN patients was specifically screened for SIGMAR1 mutations. Results: In the proband, we identified a homozygous missense variant (c.194T>A, p.Leu65Gln) in exon 2 of SIGMAR1 as the probable causative mutation. Pathogenicity is supported by evolutionary conservation, in silico analyses, and the strong phenotypic similarities with previously reported cases carrying coding sequence mutations in SIGMAR1. No other mutations were identified in 16 additional patients with dHMN. Conclusions: We suggest that coding sequence mutations in SIGMAR1 present clinically with a combination of dHMN and pyramidal tract signs, with or without spasticity, in the lower limbs. Preferential involvement of extensor muscles of the upper limbs may be a distinctive feature of the disease. These observations should be confirmed in future studies. PMID:27629094

  1. SIGMAR1 mutation associated with autosomal recessive Silver-like syndrome.

    PubMed

    Horga, Alejandro; Tomaselli, Pedro J; Gonzalez, Michael A; Laurà, Matilde; Muntoni, Francesco; Manzur, Adnan Y; Hanna, Michael G; Blake, Julian C; Houlden, Henry; Züchner, Stephan; Reilly, Mary M

    2016-10-11

    To describe the genetic and clinical features of a simplex patient with distal hereditary motor neuropathy (dHMN) and lower limb spasticity (Silver-like syndrome) due to a mutation in the sigma nonopioid intracellular receptor-1 gene (SIGMAR1) and review the phenotypic spectrum of mutations in this gene. We used whole-exome sequencing to investigate the proband. The variants of interest were investigated for segregation in the family using Sanger sequencing. Subsequently, a larger cohort of 16 unrelated dHMN patients was specifically screened for SIGMAR1 mutations. In the proband, we identified a homozygous missense variant (c.194T>A, p.Leu65Gln) in exon 2 of SIGMAR1 as the probable causative mutation. Pathogenicity is supported by evolutionary conservation, in silico analyses, and the strong phenotypic similarities with previously reported cases carrying coding sequence mutations in SIGMAR1. No other mutations were identified in 16 additional patients with dHMN. We suggest that coding sequence mutations in SIGMAR1 present clinically with a combination of dHMN and pyramidal tract signs, with or without spasticity, in the lower limbs. Preferential involvement of extensor muscles of the upper limbs may be a distinctive feature of the disease. These observations should be confirmed in future studies. © 2016 American Academy of Neurology.

  2. Biallelic Mutations in MRPS34 Lead to Instability of the Small Mitoribosomal Subunit and Leigh Syndrome.

    PubMed

    Lake, Nicole J; Webb, Bryn D; Stroud, David A; Richman, Tara R; Ruzzenente, Benedetta; Compton, Alison G; Mountford, Hayley S; Pulman, Juliette; Zangarelli, Coralie; Rio, Marlene; Boddaert, Nathalie; Assouline, Zahra; Sherpa, Mingma D; Schadt, Eric E; Houten, Sander M; Byrnes, James; McCormick, Elizabeth M; Zolkipli-Cunningham, Zarazuela; Haude, Katrina; Zhang, Zhancheng; Retterer, Kyle; Bai, Renkui; Calvo, Sarah E; Mootha, Vamsi K; Christodoulou, John; Rötig, Agnes; Filipovska, Aleksandra; Cristian, Ingrid; Falk, Marni J; Metodiev, Metodi D; Thorburn, David R

    2017-08-03

    The synthesis of all 13 mitochondrial DNA (mtDNA)-encoded protein subunits of the human oxidative phosphorylation (OXPHOS) system is carried out by mitochondrial ribosomes (mitoribosomes). Defects in the stability of mitoribosomal proteins or mitoribosome assembly impair mitochondrial protein translation, causing combined OXPHOS enzyme deficiency and clinical disease. Here we report four autosomal-recessive pathogenic mutations in the gene encoding the small mitoribosomal subunit protein, MRPS34, in six subjects from four unrelated families with Leigh syndrome and combined OXPHOS defects. Whole-exome sequencing was used to independently identify all variants. Two splice-site mutations were identified, including homozygous c.321+1G>T in a subject of Italian ancestry and homozygous c.322-10G>A in affected sibling pairs from two unrelated families of Puerto Rican descent. In addition, compound heterozygous MRPS34 mutations were identified in a proband of French ancestry; a missense (c.37G>A [p.Glu13Lys]) and a nonsense (c.94C>T [p.Gln32 ∗ ]) variant. We demonstrated that these mutations reduce MRPS34 protein levels and the synthesis of OXPHOS subunits encoded by mtDNA. Examination of the mitoribosome profile and quantitative proteomics showed that the mitochondrial translation defect was caused by destabilization of the small mitoribosomal subunit and impaired monosome assembly. Lentiviral-mediated expression of wild-type MRPS34 rescued the defect in mitochondrial translation observed in skin fibroblasts from affected subjects, confirming the pathogenicity of MRPS34 mutations. Our data establish that MRPS34 is required for normal function of the mitoribosome in humans and furthermore demonstrate the power of quantitative proteomic analysis to identify signatures of defects in specific cellular pathways in fibroblasts from subjects with inherited disease. Copyright © 2017 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  3. Simple and rapid determination of homozygous transgenic mice via in vivo fluorescence imaging.

    PubMed

    Lin, Xiaolin; Jia, Junshuang; Qin, Yujuan; Lin, Xia; Li, Wei; Xiao, Gaofang; Li, Yanqing; Xie, Raoying; Huang, Hailu; Zhong, Lin; Wu, Qinghong; Wang, Wanshan; Huang, Wenhua; Yao, Kaitai; Xiao, Dong; Sun, Yan

    2015-11-17

    Setting up breeding programs for transgenic mouse strains require to distinguish homozygous from the heterozygous transgenic animals. The combinational use of the fluorescence reporter transgene and small animal in-vivo imaging system might allow us to rapidly and visually determine the transgenic mice homozygous for transgene(s) by the in vivo fluorescence imaging. RLG, RCLG or Rm17LG transgenic mice ubiquitously express red fluorescent protein (RFP). To identify homozygous RLG transgenic mice, whole-body fluorescence imaging for all of newborn F2-generation littermates produced by mating of RFP-positive heterozygous transgenic mice (F1-generation) derived from the same transgenic founder was performed. Subsequently, the immediate data analysis of the in vivo fluorescence imaging was carried out, which greatly facilitated us to rapidly and readily distinguish RLG transgenic individual(s) with strong fluorescence from the rest of F2-generation littermates, followed by further determining this/these RLG individual(s) showing strong fluorescence to be homozygous, as strongly confirmed by mouse mating. Additionally, homozygous RCLG or Rm17LG transgenic mice were also rapidly and precisely distinguished by the above-mentioned optical approach. This approach allowed us within the shortest time period to obtain 10, 8 and 2 transgenic mice homozygous for RLG, RCLG and Rm17LG transgene, respectively, as verified by mouse mating, indicating the practicality and reliability of this optical method. Taken together, our findings fully demonstrate that the in vivo fluorescence imaging offers a visual, rapid and reliable alternative method to the traditional approaches (i.e., mouse mating and real-time quantitative PCR) in identifying homozygous transgenic mice harboring fluorescence reporter transgene under the control of a ubiquitous promoter in the situation mentioned in this study.

  4. Simple and rapid determination of homozygous transgenic mice via in vivo fluorescence imaging

    PubMed Central

    Li, Wei; Xiao, Gaofang; Li, Yanqing; Xie, Raoying; Huang, Hailu; Zhong, Lin; Wu, Qinghong; Wang, Wanshan; Huang, Wenhua; Yao, Kaitai; Xiao, Dong; Sun, Yan

    2015-01-01

    Setting up breeding programs for transgenic mouse strains require to distinguish homozygous from the heterozygous transgenic animals. The combinational use of the fluorescence reporter transgene and small animal in-vivo imaging system might allow us to rapidly and visually determine the transgenic mice homozygous for transgene(s) by the in vivo fluorescence imaging. RLG, RCLG or Rm17LG transgenic mice ubiquitously express red fluorescent protein (RFP). To identify homozygous RLG transgenic mice, whole-body fluorescence imaging for all of newborn F2-generation littermates produced by mating of RFP-positive heterozygous transgenic mice (F1-generation) derived from the same transgenic founder was performed. Subsequently, the immediate data analysis of the in vivo fluorescence imaging was carried out, which greatly facilitated us to rapidly and readily distinguish RLG transgenic individual(s) with strong fluorescence from the rest of F2-generation littermates, followed by further determining this/these RLG individual(s) showing strong fluorescence to be homozygous, as strongly confirmed by mouse mating. Additionally, homozygous RCLG or Rm17LG transgenic mice were also rapidly and precisely distinguished by the above-mentioned optical approach. This approach allowed us within the shortest time period to obtain 10, 8 and 2 transgenic mice homozygous for RLG, RCLG and Rm17LG transgene, respectively, as verified by mouse mating, indicating the practicality and reliability of this optical method. Taken together, our findings fully demonstrate that the in vivo fluorescence imaging offers a visual, rapid and reliable alternative method to the traditional approaches (i.e., mouse mating and real-time quantitative PCR) in identifying homozygous transgenic mice harboring fluorescence reporter transgene under the control of a ubiquitous promoter in the situation mentioned in this study. PMID:26472024

  5. Mutations in SNX14 Cause a Distinctive Autosomal-Recessive Cerebellar Ataxia and Intellectual Disability Syndrome

    PubMed Central

    Thomas, Anna C.; Williams, Hywel; Setó-Salvia, Núria; Bacchelli, Chiara; Jenkins, Dagan; O’Sullivan, Mary; Mengrelis, Konstantinos; Ishida, Miho; Ocaka, Louise; Chanudet, Estelle; James, Chela; Lescai, Francesco; Anderson, Glenn; Morrogh, Deborah; Ryten, Mina; Duncan, Andrew J.; Pai, Yun Jin; Saraiva, Jorge M.; Ramos, Fabiana; Farren, Bernadette; Saunders, Dawn; Vernay, Bertrand; Gissen, Paul; Straatmaan-Iwanowska, Anna; Baas, Frank; Wood, Nicholas W.; Hersheson, Joshua; Houlden, Henry; Hurst, Jane; Scott, Richard; Bitner-Glindzicz, Maria; Moore, Gudrun E.; Sousa, Sérgio B.; Stanier, Philip

    2014-01-01

    Intellectual disability and cerebellar atrophy occur together in a large number of genetic conditions and are frequently associated with microcephaly and/or epilepsy. Here we report the identification of causal mutations in Sorting Nexin 14 (SNX14) found in seven affected individuals from three unrelated consanguineous families who presented with recessively inherited moderate-severe intellectual disability, cerebellar ataxia, early-onset cerebellar atrophy, sensorineural hearing loss, and the distinctive association of progressively coarsening facial features, relative macrocephaly, and the absence of seizures. We used homozygosity mapping and whole-exome sequencing to identify a homozygous nonsense mutation and an in-frame multiexon deletion in two families. A homozygous splice site mutation was identified by Sanger sequencing of SNX14 in a third family, selected purely by phenotypic similarity. This discovery confirms that these characteristic features represent a distinct and recognizable syndrome. SNX14 encodes a cellular protein containing Phox (PX) and regulator of G protein signaling (RGS) domains. Weighted gene coexpression network analysis predicts that SNX14 is highly coexpressed with genes involved in cellular protein metabolism and vesicle-mediated transport. All three mutations either directly affected the PX domain or diminished SNX14 levels, implicating a loss of normal cellular function. This manifested as increased cytoplasmic vacuolation as observed in cultured fibroblasts. Our findings indicate an essential role for SNX14 in neural development and function, particularly in development and maturation of the cerebellum. PMID:25439728

  6. Mutations in SNX14 cause a distinctive autosomal-recessive cerebellar ataxia and intellectual disability syndrome.

    PubMed

    Thomas, Anna C; Williams, Hywel; Setó-Salvia, Núria; Bacchelli, Chiara; Jenkins, Dagan; O'Sullivan, Mary; Mengrelis, Konstantinos; Ishida, Miho; Ocaka, Louise; Chanudet, Estelle; James, Chela; Lescai, Francesco; Anderson, Glenn; Morrogh, Deborah; Ryten, Mina; Duncan, Andrew J; Pai, Yun Jin; Saraiva, Jorge M; Ramos, Fabiana; Farren, Bernadette; Saunders, Dawn; Vernay, Bertrand; Gissen, Paul; Straatmaan-Iwanowska, Anna; Baas, Frank; Wood, Nicholas W; Hersheson, Joshua; Houlden, Henry; Hurst, Jane; Scott, Richard; Bitner-Glindzicz, Maria; Moore, Gudrun E; Sousa, Sérgio B; Stanier, Philip

    2014-11-06

    Intellectual disability and cerebellar atrophy occur together in a large number of genetic conditions and are frequently associated with microcephaly and/or epilepsy. Here we report the identification of causal mutations in Sorting Nexin 14 (SNX14) found in seven affected individuals from three unrelated consanguineous families who presented with recessively inherited moderate-severe intellectual disability, cerebellar ataxia, early-onset cerebellar atrophy, sensorineural hearing loss, and the distinctive association of progressively coarsening facial features, relative macrocephaly, and the absence of seizures. We used homozygosity mapping and whole-exome sequencing to identify a homozygous nonsense mutation and an in-frame multiexon deletion in two families. A homozygous splice site mutation was identified by Sanger sequencing of SNX14 in a third family, selected purely by phenotypic similarity. This discovery confirms that these characteristic features represent a distinct and recognizable syndrome. SNX14 encodes a cellular protein containing Phox (PX) and regulator of G protein signaling (RGS) domains. Weighted gene coexpression network analysis predicts that SNX14 is highly coexpressed with genes involved in cellular protein metabolism and vesicle-mediated transport. All three mutations either directly affected the PX domain or diminished SNX14 levels, implicating a loss of normal cellular function. This manifested as increased cytoplasmic vacuolation as observed in cultured fibroblasts. Our findings indicate an essential role for SNX14 in neural development and function, particularly in development and maturation of the cerebellum. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  7. Deleterious Mutations in LRBA Are Associated with a Syndrome of Immune Deficiency and Autoimmunity

    PubMed Central

    Lopez-Herrera, Gabriela; Tampella, Giacomo; Pan-Hammarström, Qiang; Herholz, Peer; Trujillo-Vargas, Claudia M.; Phadwal, Kanchan; Simon, Anna Katharina; Moutschen, Michel; Etzioni, Amos; Mory, Adi; Srugo, Izhak; Melamed, Doron; Hultenby, Kjell; Liu, Chonghai; Baronio, Manuela; Vitali, Massimiliano; Philippet, Pierre; Dideberg, Vinciane; Aghamohammadi, Asghar; Rezaei, Nima; Enright, Victoria; Du, Likun; Salzer, Ulrich; Eibel, Hermann; Pfeifer, Dietmar; Veelken, Hendrik; Stauss, Hans; Lougaris, Vassilios; Plebani, Alessandro; Gertz, E. Michael; Schäffer, Alejandro A.; Hammarström, Lennart; Grimbacher, Bodo

    2012-01-01

    Most autosomal genetic causes of childhood-onset hypogammaglobulinemia are currently not well understood. Most affected individuals are simplex cases, but both autosomal-dominant and autosomal-recessive inheritance have been described. We performed genetic linkage analysis in consanguineous families affected by hypogammaglobulinemia. Four consanguineous families with childhood-onset humoral immune deficiency and features of autoimmunity shared genotype evidence for a linkage interval on chromosome 4q. Sequencing of positional candidate genes revealed that in each family, affected individuals had a distinct homozygous mutation in LRBA (lipopolysaccharide responsive beige-like anchor protein). All LRBA mutations segregated with the disease because homozygous individuals showed hypogammaglobulinemia and autoimmunity, whereas heterozygous individuals were healthy. These mutations were absent in healthy controls. Individuals with homozygous LRBA mutations had no LRBA, had disturbed B cell development, defective in vitro B cell activation, plasmablast formation, and immunoglobulin secretion, and had low proliferative responses. We conclude that mutations in LRBA cause an immune deficiency characterized by defects in B cell activation and autophagy and by susceptibility to apoptosis, all of which are associated with a clinical phenotype of hypogammaglobulinemia and autoimmunity. PMID:22608502

  8. NDST1 missense mutations in autosomal recessive intellectual disability.

    PubMed

    Reuter, Miriam S; Musante, Luciana; Hu, Hao; Diederich, Stefan; Sticht, Heinrich; Ekici, Arif B; Uebe, Steffen; Wienker, Thomas F; Bartsch, Oliver; Zechner, Ulrich; Oppitz, Cornelia; Keleman, Krystyna; Jamra, Rami Abou; Najmabadi, Hossein; Schweiger, Susann; Reis, André; Kahrizi, Kimia

    2014-11-01

    NDST1 was recently proposed as a candidate gene for autosomal recessive intellectual disability in two families. It encodes a bifunctional GlcNAc N-deacetylase/N-sulfotransferase with important functions in heparan sulfate biosynthesis. In mice, Ndst1 is crucial for embryonic development and homozygous null mutations are perinatally lethal. We now report on two additional unrelated families with homozygous missense NDST1 mutations. All mutations described to date predict the substitution of conserved amino acids in the sulfotransferase domain, and mutation modeling predicts drastic alterations in the local protein conformation. Comparing the four families, we noticed significant overlap in the clinical features, including both demonstrated and apparent intellectual disability, muscular hypotonia, epilepsy, and postnatal growth deficiency. Furthermore, in Drosophila, knockdown of sulfateless, the NDST ortholog, impairs long-term memory, highlighting its function in cognition. Our data confirm NDST1 mutations as a cause of autosomal recessive intellectual disability with a distinctive phenotype, and support an important function of NDST1 in human development. © 2014 Wiley Periodicals, Inc.

  9. NT5E Mutations and Arterial Calcifications

    PubMed Central

    St. Hilaire, Cynthia; Ziegler, Shira G.; Markello, Thomas C.; Brusco, Alfredo; Groden, Catherine; Gill, Fred; Carlson-Donohoe, Hannah; Lederman, Robert J.; Chen, Marcus Y.; Yang, Dan; Siegenthaler, Michael P.; Arduino, Carlo; Mancini, Cecilia; Freudenthal, Bernard; Stanescu, Horia C.; Zdebik, Anselm A.; Chaganti, R. Krishna; Nussbaum, Robert L.; Kleta, Robert; Gahl, William A.; Boehm, Manfred

    2011-01-01

    BACKGROUND Arterial calcifications are associated with increased cardiovascular risk, but the genetic basis of this association is unclear. METHODS We performed clinical, radiographic, and genetic studies in three families with symptomatic arterial calcifications. Single-nucleotide-polymorphism analysis, targeted gene sequencing, quantitative polymerase-chain-reaction assays, Western blotting, enzyme measurements, transduction rescue experiments, and in vitro calcification assays were performed. RESULTS We identified nine persons with calcifications of the lower-extremity arteries and hand and foot joint capsules: all five siblings in one family, three siblings in another, and one patient in a third family. Serum calcium, phosphate, and vitamin D levels were normal. Affected members of Family 1 shared a single 22.4-Mb region of homozygosity on chromosome 6 and had a homozygous nonsense mutation (c.662C→A, p.S221X) in NT5E, encoding CD73, which converts AMP to adenosine. Affected members of Family 2 had a homozygous missense mutation (c.1073G→A, p.C358Y) in NT5E. The proband of Family 3 was a compound heterozygote for c.662C→A and c.1609dupA (p.V537fsX7). All mutations found in the three families result in nonfunctional CD73. Cultured fibroblasts from affected members of Family 1 showed markedly reduced expression of NT5E messenger RNA, CD73 protein, and enzyme activity, as well as increased alkaline phosphatase levels and accumulated calcium phosphate crystals. Genetic rescue experiments normalized the CD73 and alkaline phosphatase activity in patients’ cells, and adenosine treatment reduced the levels of alkaline phosphatase and calcification. CONCLUSIONS We identified mutations in NT5E in members of three families with symptomatic arterial and joint calcifications. This gene encodes CD73, which converts AMP to adenosine, supporting a role for this metabolic pathway in inhibiting ectopic tissue calcification. (Funded by the National Human Genome Research

  10. Highly Prevalent LIPH Founder Mutations Causing Autosomal Recessive Woolly Hair/Hypotrichosis in Japan and the Genotype/Phenotype Correlations

    PubMed Central

    Kono, Michihiro; Takama, Hiromichi; Hamajima, Nobuyuki; Akiyama, Masashi

    2014-01-01

    Mutations in LIPH cause of autosomal recessive woolly hair/hypotrichosis (ARWH), and the 2 missense mutations c.736T>A (p.Cys246Ser) and c.742C>A (p.His248Asn) are considered prevalent founder mutations for ARWH in the Japanese population. To reveal genotype/phenotype correlations in ARWH cases in Japan and the haplotypes in 14 Japanese patients from 14 unrelated Japanese families. 13 patients had woolly hair, and 1 patient had complete baldness since birth. An LIPH mutation search revealed homozygous c.736T>A mutations in 10 of the patients. Compound heterozygous c.736T>A and c.742C>A mutations were found in 3 of the patients, and homozygous c.742C>A mutation in 1 patient. The phenotype of mild hypotrichosis with woolly hair was restricted to the patients with the homozygous c.736T>A mutation. The severe phenotype of complete baldness was seen in only 1 patient with homozygous c.742C>A. Haplotype analysis revealed that the alleles containing the LIPH c.736T>A mutation had a haplotype identical to that reported previously, although 4 alleles out of 5 chromosomes containing the LIPH c.742C>A mutation had a different haplotype from the previously reported founder allele. These alleles with c.742C>A are thought to be the third founder LIPH mutation causing ARWH. To accurately determine the prevalence of the founder mutations, we investigated allele frequencies of those mutations in 819 Japanese controls. Heterozygous c.736T>A mutations were found in 13 controls (allele frequency: 0.0079; carrier rate: 0.016), and heterozygous c.742C>A mutations were found in 2 controls (allele frequency: 0.0012; carrier rate: 0.0024). In conclusion, this study confirms the more accurate allele frequencies of the pathogenic founder mutations of LIPH and shows that there is a third founder mutation in Japan. In addition, the present findings suggest that the mutation patterns of LIPH might be associated with hypotrichosis severity in ARWH. PMID:24586639

  11. Sizes of abdominal organs in adults with severe short stature due to severe, untreated, congenital GH deficiency caused by a homozygous mutation in the GHRH receptor gene

    PubMed Central

    Oliveira, Carla R. P.; Salvatori, Roberto; Nóbrega, Luciana M. A.; Carvalho, Erick O. M.; Menezes, Menilson; Farias, Catarine T.; Britto, Allan V. O.; Pereira, Rossana M. C.; Aguiar-Oliveira, Manuel H.

    2008-01-01

    Summary Objective To assess the sizes of intra-abdominal organs of adult subjects with untreated severe congenital isolated GH deficiency (IGHD) due to lack of functional GHRH receptor (GHRH-R), and to verify whether there is proportionality between size of organ and adult stature and body surface area (BSA). Subjects and methods By using ultrasound, we studied the sizes (absolute and corrected by height, weight and BSA) of the intra-abdominal organs of 18 adult subjects with IGHD (eight females, IGHD group) who have never received GH replacement therapy. They were all homozygous for the same null mutation (IVS1 + 1G → A) in the GHRH receptor gene (GHRH-R). They were compared with normal controls from the same region. Results After correction for BSA, subjects lacking a functional GHRH-R have normal prostate and ovaries size, small spleen and uterus, and large liver, pancreas and kidney. Conclusions Size of individual abdominal organs is influenced in different ways by severe and congenital lack of GH due to a GHRH-R mutation. PMID:18034778

  12. Parent-progeny sequencing indicates higher mutation rates in heterozygotes.

    PubMed

    Yang, Sihai; Wang, Long; Huang, Ju; Zhang, Xiaohui; Yuan, Yang; Chen, Jian-Qun; Hurst, Laurence D; Tian, Dacheng

    2015-07-23

    Mutation rates vary within genomes, but the causes of this remain unclear. As many prior inferences rely on methods that assume an absence of selection, potentially leading to artefactual results, we call mutation events directly using a parent-offspring sequencing strategy focusing on Arabidopsis and using rice and honey bee for replication. Here we show that mutation rates are higher in heterozygotes and in proximity to crossover events. A correlation between recombination rate and intraspecific diversity is in part owing to a higher mutation rate in domains of high recombination/diversity. Implicating diversity per se as a cause, we find an ∼3.5-fold higher mutation rate in heterozygotes than in homozygotes, with mutations occurring in closer proximity to heterozygous sites than expected by chance. In a genome that is a patchwork of heterozygous and homozygous domains, mutations occur disproportionately more often in the heterozygous domains. If segregating mutations predispose to a higher local mutation rate, clusters of genes dominantly under purifying selection (more commonly homozygous) and under balancing selection (more commonly heterozygous), might have low and high mutation rates, respectively. Our results are consistent with this, there being a ten times higher mutation rate in pathogen resistance genes, expected to be under positive or balancing selection. Consequently, we do not necessarily need to evoke extremely weak selection on the mutation rate to explain why mutational hot and cold spots might correspond to regions under positive/balancing and purifying selection, respectively.

  13. A novel NDUFS4 frameshift mutation causes Leigh disease in the Hutterite population.

    PubMed

    Lamont, Ryan E; Beaulieu, Chandree L; Bernier, Francois P; Sparkes, Rebecca; Innes, A Micheil; Jackel-Cram, Candice; Ober, Carole; Parboosingh, Jillian S; Lemire, Edmond G

    2017-03-01

    Leigh disease is a progressive, infantile-onset, neurodegenerative disorder characterized by feeding difficulties, failure to thrive, hypotonia, seizures, and central respiratory compromise. Metabolic and neuroimaging investigations typically identify abnormalities consistent with a disorder of mitochondrial energy metabolism. Mutations in more than 35 genes affecting the mitochondrial respiratory chain encoded from both the nuclear and mitochondrial genomes have been associated with Leigh disease. The clinical presentations of five individuals of Hutterite descent with Leigh disease are described herein. An identity-by-descent mapping and candidate gene approach was used to identify a novel homozygous c.393dupA frameshift mutation in the NADH dehydrogenase (ubiquinone) Fe-S protein 4 (NDUFS4) gene. The carrier frequency of this mutation was estimated in >1,300 Hutterite individuals to be 1 in 27. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  14. a/alpha-specific effect on the mms3 mutation on ultraviolet mutagenesis in Saccharomyces cerevisiae.

    PubMed

    Martin, P; Prakash, L; Prakash, S

    1981-05-01

    A new gene involved in error-prone repair of ultraviolet (UV) damage has been identified in Saccharomyces cerevisiae by the mms3-1 mutation. UV-induced reversion is reduced in diploids that are homozygous for mms3-1, only if they are also heterozygous (MATa/MAT alpha) at the mating type locus. The mms3-1 mutation has no effect on UV-induced reversion either in haploids or MATa/MATa or MAT alpha/MAT alpha diploids. The mutation confers sensitivity to UV and methyl methane sulfonate in both haploids and diploids. Even though mutation induction by UV is restored to wild-type levels in MATa/MATa mms3-1/mms3-1 or MAT alpha/MAT alpha mms3-1/mms3-1 diploids, such strains still retain sensitivity to the lethal effects of UV. Survival after UV irradiation in mms3-1 rad double mutant combinations indicates that mms3-1 is epistatic to rad6-1 whereas non-epistatic interactions are observed with rad3 and rad52 mutants. When present in the homozygous state in MATa/MAT alpha his1-1/his1-315 heteroallelic diploids, mms3-1 was found to lower UV-induced mitotic recombination.

  15. Novel Mutations Causing C5 Deficiency in Three North-African Families.

    PubMed

    Colobran, Roger; Franco-Jarava, Clara; Martín-Nalda, Andrea; Baena, Neus; Gabau, Elisabeth; Padilla, Natàlia; de la Cruz, Xavier; Pujol-Borrell, Ricardo; Comas, David; Soler-Palacín, Pere; Hernández-González, Manuel

    2016-05-01

    The complement system plays a central role in defense to encapsulated bacteria through opsonization and membrane attack complex (MAC) dependent lysis. The three activation pathways (classical, lectin, and alternative) converge in the cleavage of C5, which initiates MAC formation and target lysis. C5 deficiency is associated to recurrent infections by Neisseria spp. In the present study, complement deficiency was suspected in three families of North-African origin after one episode of invasive meningitis due to a non-groupable and two uncommon Meningococcal serotypes (E29, Y). Activity of alternative and classical pathways of complement were markedly reduced and the measurement of terminal complement components revealed total C5 absence. C5 gene analysis revealed two novel mutations as causative of the deficiency: Family A propositus carried a homozygous deletion of two adenines in the exon 21 of C5 gene, resulting in a frameshift and a truncated protein (c.2607_2608del/p.Ser870ProfsX3 mutation). Families B and C probands carried the same homozygous deletion of three consecutive nucleotides (CAA) in exon 9 of the C5 gene, leading to the deletion of asparagine 320 (c.960_962del/p.Asn320del mutation). Family studies confirmed an autosomal recessive inheritance pattern. Although sharing the same geographical origin, families B and C were unrelated. This prompted us to investigate this mutation prevalence in a cohort of 768 North-African healthy individuals. We identified one heterozygous carrier of the p.Asn320del mutation (allelic frequency = 0.065 %), indicating that this mutation is present at low frequency in North-African population.

  16. Congenital myopathy is caused by mutation of HACD1.

    PubMed

    Muhammad, Emad; Reish, Orit; Ohno, Yusuke; Scheetz, Todd; Deluca, Adam; Searby, Charles; Regev, Miriam; Benyamini, Lilach; Fellig, Yakov; Kihara, Akio; Sheffield, Val C; Parvari, Ruti

    2013-12-20

    Congenital myopathies are heterogeneous inherited diseases of muscle characterized by a range of distinctive histologic abnormalities. We have studied a consanguineous family with congenital myopathy. Genome-wide linkage analysis and whole-exome sequencing identified a homozygous non-sense mutation in 3-hydroxyacyl-CoA dehydratase 1 (HACD1) in affected individuals. The mutation results in non-sense mediated decay of the HACD1 mRNA to 31% of control levels in patient muscle and completely abrogates the enzymatic activity of dehydration of 3-hydroxyacyl-CoA, the third step in the elongation of very long-chain fatty acids (VLCFAs). We describe clinical findings correlated with a deleterious mutation in a gene not previously known to be associated with congenital myopathy in humans. We suggest that the mutation in the HACD1 gene causes a reduction in the synthesis of VLCFAs, which are components of membrane lipids and participants in physiological processes, leading to congenital myopathy. These data indicate that HACD1 is necessary for muscle function.

  17. A screen to identify Drosophila genes required for integrin-mediated adhesion.

    PubMed Central

    Walsh, E P; Brown, N H

    1998-01-01

    Drosophila integrins have essential adhesive roles during development, including adhesion between the two wing surfaces. Most position-specific integrin mutations cause lethality, and clones of homozygous mutant cells in the wing do not adhere to the apposing surface, causing blisters. We have used FLP-FRT induced mitotic recombination to generate clones of randomly induced mutations in the F1 generation and screened for mutations that cause wing blisters. This phenotype is highly selective, since only 14 lethal complementation groups were identified in screens of the five major chromosome arms. Of the loci identified, 3 are PS integrin genes, 2 are blistered and bloated, and the remaining 9 appear to be newly characterized loci. All 11 nonintegrin loci are required on both sides of the wing, in contrast to integrin alpha subunit genes. Mutations in 8 loci only disrupt adhesion in the wing, similar to integrin mutations, while mutations in the 3 other loci cause additional wing defects. Mutations in 4 loci, like the strongest integrin mutations, cause a "tail-up" embryonic lethal phenotype, and mutant alleles of 1 of these loci strongly enhance an integrin mutation. Thus several of these loci are good candidates for genes encoding cytoplasmic proteins required for integrin function. PMID:9755209

  18. Next-generation sequencing identifies three novel missense variants in ILDR1 and MYO6 genes in an Iranian family with hearing loss with review of the literature.

    PubMed

    Talebi, Farah; Mardasi, Farideh Ghanbari; Asl, Javad Mohammadi; Sayahi, Masoomeh

    2017-12-01

    Hearing impairment is the most common sensorineural disorder and is genetically heterogeneous. Identification of the pathogenic mutations underlying hearing impairment is difficult, since causative mutations in 127 different genes have so far been reported. In this study, we performed Next-generation sequencing (NGS) in 2 individuals from a consanguineous family with hearing loss. Three novel mutations in known deafness genes were identified in the family; MYO6-p.R928C and -p.D1223N in heterozygous state and ILDR1-p.Y143C in homozygous state. Sanger sequencing confirmed co-segregation of the three mutations with deafness in the family. The identified mutation in ILDR1 gene is located in the immunoglobulin-type domain of the ILDR1 protein and the detected mutations in MY06 are located in the tail domain of the MYO6 protein. The mutations are predicted to be pathogenic by SIFT, PolyPhen and Mutation Taster. Our results suggest that either the homozygous ILDR1-p.Y143C mutation might be the pathogenic variant for ARNSHL or heterozygous MYO6- p.R928C, -p.D1223N might be involved in these patient's disorder due to compound heterozygousity. To our knowledge, this is the first ILDR1 and MYO6 mutations recognized in the southwest Iran. Our data expands the spectrum of mutations in ILDR1 and MYO6 genes. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Spectrum of Mutations in Hypertrophic Cardiomyopathy Genes Among Tunisian Patients.

    PubMed

    Jaafar, Nawel; Gómez, Juan; Kammoun, Ikram; Zairi, Ihsen; Amara, Wael Ben; Kachboura, Salem; Kraiem, Sondes; Hammami, Mohamed; Iglesias, Sara; Alonso, Belén; Coto, Eliecer

    2016-11-01

    Hypertrophic cardiomyopathy (HCM) is a common cardiac genetic disorder associated with heart failure and sudden death. Mutations in the cardiac sarcomere genes are found in approximately half of HCM patients and are more common among cases with a family history of the disease. Data about the mutational spectrum of the sarcomeric genes in HCM patients from Northern Africa are limited. The population of Tunisia is particularly interesting due to its Berber genetic background. As founder mutations have been reported in other disorders. We performed semiconductor chip (Ion Torrent PGM) next generation sequencing of the nine main sarcomeric genes (MYH7, MYBPC3, TNNT2, TNNI3, ACTC1, TNNC1, MYL2, MYL3, TPM1) as well as the recently identified as an HCM gene, FLNC, in 45 Tunisian HCM patients. We found sarcomere gene polymorphisms in 12 patients (27%), with MYBPC3 and MYH7 representing 83% (10/12) of the mutations. One patient was homozygous for a new MYL3 mutation and two were double MYBPC3 + MYH7 mutation carriers. Screening of the FLNC gene identified three new mutations, which points to FLNC mutations as an important cause of HCM among Tunisians. The mutational background of HCM in Tunisia is heterogeneous. Unlike other Mendelian disorders, there were no highly prevalent mutations that could explain most of the cases. Our study also suggested that FLNC mutations may play a role on the risk for HCM among Tunisians.

  20. Isogenic transgenic homozygous fish induced by artificial parthenogenesis.

    PubMed

    Nam, Y K; Cho, Y S; Kim, D S

    2000-12-01

    As a model system for vertebrate transgenesis, fish have many attractive advantages, especially with respect to the characteristics of eggs, allowing us to produce isogenic, transgenic, homozygous vertebrates by combining with chromosome-set manipulation. Here, we describe the large-scale production of isogenic transgenic homozygous animals using our experimental organism, the mud loach Misgurnus mizolepis, by the simple process of artificial parthenogenesis in a single generation. These isogenic fish have retained transgenic homozygous status in a stable manner during the subsequent 5 years, and exhibited increased levels of transgene expression. Furthermore, their isogenic nature was confirmed by cloned transgenic homozygous offspring produced via another step of parthenogenic reproduction of the isogenic homozygous transgenic fish. These results demonstrate that a combination of transgenesis and artificial parthenogenesis will make the rapid utilization of genetically pure homozygous transgenic system in vertebrate transgenesis possible.

  1. Relative high frequency of the c.255delA parkin gene mutation in Spanish patients with autosomal recessive parkinsonism

    PubMed Central

    Munoz, E; Tolosa, E; Pastor, P; Marti, M; Valldeoriola, F; Campdelacreu, J; Oliva, R

    2002-01-01

    Objectives: To search for the presence of parkin gene mutations in Spanish patients with Parkinson's disease (PD) and characterise the phenotype associated with these mutations. Methods: Thirty seven PD patients with either early onset or autosomal recessive pattern of inheritance were selected for genetic study. Results: Mutations were identified in seven index patients (19%). Homozygous mutations were detected in six patients and a heterozygous mutation in one. The age at onset was lower in patients with mutations than in patients without mutations. Dystonia at onset was present in two patients with parkin gene mutations. The disease began in two patients with postural tremor in the upper limbs mimicking essential tremor. Four patients exhibited a long term response to dopamine agonists. The c.255delA mutation was identified in four unrelated families. This is a frameshift mutation leading to protein truncation. Conclusions: Parkin gene mutations are present in Spanish patients with early onset and/or an autosomal recessive parkinsonism. The c.255delA is the most frequent mutation found, suggesting a relative high prevalence in the Spanish population. PMID:12397156

  2. Exome sequencing identifies recurrent somatic RAC1 mutations in melanoma

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Krauthammer, Michael; Kong, Yong; Ha, Byung Hak

    We characterized the mutational landscape of melanoma, the form of skin cancer with the highest mortality rate, by sequencing the exomes of 147 melanomas. Sun-exposed melanomas had markedly more ultraviolet (UV)-like C>T somatic mutations compared to sun-shielded acral, mucosal and uveal melanomas. Among the newly identified cancer genes was PPP6C, encoding a serine/threonine phosphatase, which harbored mutations that clustered in the active site in 12% of sun-exposed melanomas, exclusively in tumors with mutations in BRAF or NRAS. Notably, we identified a recurrent UV-signature, an activating mutation in RAC1 in 9.2% of sun-exposed melanomas. This activating mutation, the third most frequentmore » in our cohort of sun-exposed melanoma after those of BRAF and NRAS, changes Pro29 to serine (RAC1{sup P29S}) in the highly conserved switch I domain. Crystal structures, and biochemical and functional studies of RAC1{sup P29S} showed that the alteration releases the conformational restraint conferred by the conserved proline, causes an increased binding of the protein to downstream effectors, and promotes melanocyte proliferation and migration. These findings raise the possibility that pharmacological inhibition of downstream effectors of RAC1 signaling could be of therapeutic benefit.« less

  3. Mutation analysis of the STRA6 gene in isolated and non-isolated anophthalmia/microphthalmia.

    PubMed

    Chassaing, N; Ragge, N; Kariminejad, A; Buffet, A; Ghaderi-Sohi, S; Martinovic, J; Calvas, P

    2013-03-01

    PDAC syndrome [Pulmonary hypoplasia/agenesis, Diaphragmatic hernia/eventration, Anophthalmia/microphthalmia (A/M) and Cardiac Defect] is a condition associated with recessive mutations in the STRA6 gene in some of these patients. Recently, cases with isolated anophthalmia have been associated with STRA6 mutations. To determine the minimal findings associated with STRA6 mutations, we performed mutation analysis of the STRA6 gene in 28 cases with anophthalmia. In 7 of the cases the anophthalmia was isolated, in 14 cases it was associated with one of the major features included in PDAC and 7 had other abnormalities. Mutations were identified in two individuals: one with bilateral anophthalmia and some features included in PDAC, who was a compound heterozygote for a missense mutation and a large intragenic deletion, and the second case with all the major features of PDAC and who had a homozygous splicing mutation. This study suggests that STRA6 mutations are more likely to be identified in individuals with A/M and other abnormalities included in the PDAC spectrum, rather than in isolated A/M cases. © 2012 John Wiley & Sons A/S.

  4. Novel and recurrent XYLT1 mutations in two Turkish families with Desbuquois dysplasia, type 2.

    PubMed

    Guo, Long; Elcioglu, Nursel H; Iida, Aritoshi; Demirkol, Yasemin K; Aras, Seda; Matsumoto, Naomichi; Nishimura, Gen; Miyake, Noriko; Ikegawa, Shiro

    2017-03-01

    Desbuquois dysplasia (DBQD) is an autosomal recessive skeletal disorder characterized by growth retardation, joint laxity, short extremities, and progressive scoliosis. DBQD is classified into two types based on the presence (DBQD1) or absence (DBQD2) of characteristic hand abnormalities. CANT1 mutations have been reported in both DBQD1 and DBQD2. Recently, mutations in the gene encoding xylosyltransferase 1 (XYLT1) were identified in several families with DBQD2. In this study, we performed whole-exome sequencing in two Turkish families with DBQD2. We found a novel and a recurrent XYLT1 mutation in each family. The patients were homozygous for the mutations. Our results further support that XYLT1 is responsible for a major subset of DBQD2.

  5. A novel homozygous missense variant in NECTIN4 (PVRL4) causing ectodermal dysplasia cutaneous syndactyly syndrome.

    PubMed

    Ahmad, Farooq; Nasir, Abdul; Thiele, Holger; Umair, Muhammad; Borck, Guntram; Ahmad, Wasim

    2018-02-12

    Ectodermal dysplasia syndactyly syndrome 1 (EDSS1) is a rare form of ectodermal dysplasia including anomalies of hair, nails, and teeth along with bilateral cutaneous syndactyly of hands and feet. In the present report, we performed a clinical and genetic characterization of a consanguineous Pakistani family with four individuals affected by EDSS1. We performed exome sequencing using DNA of one affected individual. Exome data analysis identified a novel homozygous missense variant (c.242T>C; p.(Leu81Pro)) in NECTIN4 (PVRL4). Sanger sequencing validated this variant and confirmed its cosegregation with the disease phenotype in the family members. Thus, our report adds a novel variant to the NECTIN4 mutation spectrum and contributes to the NECTIN4-related clinical characterization. © 2018 John Wiley & Sons Ltd/University College London.

  6. Exome capture sequencing identifies a novel mutation in BBS4

    PubMed Central

    Wang, Hui; Chen, Xianfeng; Dudinsky, Lynn; Patenia, Claire; Chen, Yiyun; Li, Yumei; Wei, Yue; Abboud, Emad B.; Al-Rajhi, Ali A.; Lewis, Richard Alan; Lupski, James R.; Mardon, Graeme; Gibbs, Richard A.; Perkins, Brian D.

    2011-01-01

    Purpose Leber congenital amaurosis (LCA) is one of the most severe eye dystrophies characterized by severe vision loss at an early stage and accounts for approximately 5% of all retinal dystrophies. The purpose of this study was to identify a novel LCA disease allele or gene and to develop an approach combining genetic mapping with whole exome sequencing. Methods Three patients from King Khaled Eye Specialist Hospital (KKESH205) underwent whole genome single nucleotide polymorphism genotyping, and a single candidate region was identified. Taking advantage of next-generation high-throughput DNA sequencing technologies, whole exome capture sequencing was performed on patient KKESH205#7. Sanger direct sequencing was used during the validation step. The zebrafish model was used to examine the function of the mutant allele. Results A novel missense mutation in Bardet-Biedl syndrome 4 protein (BBS4) was identified in a consanguineous family from Saudi Arabia. This missense mutation in the fifth exon (c.253G>C;p.E85Q) of BBS4 is likely a disease-causing mutation as it segregates with the disease. The mutation is not found in the single nucleotide polymorphism (SNP) database, the 1000 Genomes Project, or matching normal controls. Functional analysis of this mutation in zebrafish indicates that the G253C allele is pathogenic. Coinjection of the G253C allele cannot rescue the mislocalization of rhodopsin in the retina when BBS4 is knocked down by morpholino injection. Immunofluorescence analysis in cell culture shows that this missense mutation in BBS4 does not cause obvious defects in protein expression or pericentriolar localization. Conclusions This mutation likely mainly reduces or abolishes BBS4 function in the retina. Further studies of this allele will provide important insights concerning the pleiotropic nature of BBS4 function. PMID:22219648

  7. Biallelic Mutations in GNB3 Cause a Unique Form of Autosomal-Recessive Congenital Stationary Night Blindness

    PubMed Central

    Vincent, Ajoy; Audo, Isabelle; Tavares, Erika; Maynes, Jason T.; Tumber, Anupreet; Wright, Thomas; Li, Shuning; Michiels, Christelle; Banin, Eyal; Bocquet, Beatrice; De Baere, Elfride; Casteels, Ingele; Defoort-Dhellemmes, Sabine; Drumare, Isabelle; Friedburg, Christoph; Gottlob, Irene; Jacobson, Samuel G.; Kellner, Ulrich; Koenekoop, Robert; Kohl, Susanne; Leroy, Bart P.; Lorenz, Birgit; McLean, Rebecca; Meire, Francoise; Meunier, Isabelle; Munier, Francis; de Ravel, Thomy; Reiff, Charlotte M.; Mohand-Saïd, Saddek; Sharon, Dror; Schorderet, Daniel; Schwartz, Sharon; Zanlonghi, Xavier; Condroyer, Christel; MacDonald, Heather; Verdet, Robert; Sahel, José-Alain; Hamel, Christian P.; Zeitz, Christina; Héon, Elise

    2016-01-01

    Congenital stationary night blindness (CSNB) is a heterogeneous group of non-progressive inherited retinal disorders with characteristic electroretinogram (ERG) abnormalities. Riggs and Schubert-Bornschein are subtypes of CSNB and demonstrate distinct ERG features. Riggs CSNB demonstrates selective rod photoreceptor dysfunction and occurs due to mutations in genes encoding proteins involved in rod phototransduction cascade; night blindness is the only symptom and eye examination is otherwise normal. Schubert-Bornschein CSNB is a consequence of impaired signal transmission between the photoreceptors and bipolar cells. Schubert-Bornschein CSNB is subdivided into complete CSNB with an ON bipolar signaling defect and incomplete CSNB with both ON and OFF pathway involvement. Both subtypes are associated with variable degrees of night blindness or photophobia, reduced visual acuity, high myopia, and nystagmus. Whole-exome sequencing of a family screened negative for mutations in genes associated with CSNB identified biallelic mutations in the guanine nucleotide-binding protein subunit beta-3 gene (GNB3). Two siblings were compound heterozygous for a deletion (c.170_172delAGA [p.Lys57del]) and a nonsense mutation (c.1017G>A [p.Trp339∗]). The maternal aunt was homozygous for the nonsense mutation (c.1017G>A [p.Trp339∗]). Mutational analysis of GNB3 in a cohort of 58 subjects with CSNB identified a sporadic case individual with a homozygous GNB3 mutation (c.200C>T [p.Ser67Phe]). GNB3 encodes the β subunit of G protein heterotrimer (Gαβγ) and is known to modulate ON bipolar cell signaling and cone transducin function in mice. Affected human subjects showed an unusual CSNB phenotype with variable degrees of ON bipolar dysfunction and reduced cone sensitivity. This unique retinal disorder with dual anomaly in visual processing expands our knowledge about retinal signaling. PMID:27063057

  8. Novel mutation of Endothelin-B receptor gene in Waardenburg-Hirschsprung disease.

    PubMed

    Sangkhathat, Surasak; Chiengkriwate, Piyawan; Kusafuka, Takeshi; Patrapinyokul, Sakda; Fukuzawa, Masahiro

    2005-12-01

    Homozygous mutations of EDNRB in human have been reported to result in Waardenburg-Hirschsprung disease (WS4), while mutated heterozygotes manifested isolated Hirschsprung disease in lower penetrance. We investigated a case of WS4 together with all members of her nuclear family for the alteration of the EDNRB gene by using PCR-SSCP and direct sequencing technique. The index patient, who was born to a family with no history of Hirschsprung disease, presented total colonic aganglionosis with small bowel extension, sensorineural hearing loss and generalized cutaneous pigmentary defects. Interestingly, both irides were normally black. The study detected a homozygous missense mutation at codon 196 in exon 2 (Ser196Asn), which has not been reported. Both parents and four in six siblings harbored heterozygous mutation without any clinical manifestation. Our findings were consistent with previous observations that full spectrum of WS4 occurred to the mutate homozygotes. Moreover, the non-penetrance of heterozygotes in our pedigree, which differs from other reports, demonstrates the high pleiotropic effect of EDNRB mutations in human.

  9. Frequency of mutations in PROP-1 gene in Turkish children with combined pituitary hormone deficiency.

    PubMed

    Kandemir, Nurgün; Vurallı, Doğuş; Taşkıran, Ekim; Gönç, Nazlı; Özön, Alev; Alikaşifoğlu, Ayfer; Yılmaz, Engin

    2012-01-01

    Mutations in the prophet of Pit-1 (PROP-1) gene are responsible for most of the cases of combined pituitary hormone deficiencies (CPHD). We performed this study to determine the prevalence of PROP-1 mutations in a group of Turkish children with CPHD. Fifty-three children with the diagnosis of CPHD were included in this study. Clinical data were obtained from medical files, and hormonal evaluation and genetic screening for PROP-1 mutations were performed. A homozygous S109X mutation was found in the second exon in two brothers, and they had growth hormone (GH) and thyroid-stimulating hormone (TSH) deficiencies and normal prolactin levels. In the third exon of the PROP-1 gene, a heterozygous A142T polymorphism was found in 14 patients and a homozygous A142T polymorphism was found in 3 patients. In the first exon, a homozygous A9A polymorphism was found in 7 patients and a heterozygous A9A polymorphism was found in 31 patients. We assumed that mutations in the PROP-1 gene in cases with CPHD were expected to be more prevalent in our population due to consanguinity, but it was found that these mutations were far less than expected and that it was rare in non-familial cases.

  10. Compound heterozygous HAX1 mutations in a Swedish patient with severe congenital neutropenia and no neurodevelopmental abnormalities.

    PubMed

    Carlsson, Göran; Elinder, Göran; Malmgren, Helena; Trebinska, Alicja; Grzybowska, Ewa; Dahl, Niklas; Nordenskjöld, Magnus; Fadeel, Bengt

    2009-12-01

    Kostmann disease or severe congenital neutropenia (SCN) is an autosomal recessive disorder of neutrophil production. Homozygous HAX1 mutations were recently identified in SCN patients belonging to the original family in northern Sweden described by Kostmann. Moreover, recent studies have suggested an association between neurological dysfunction and HAX1 deficiency. Here we describe a patient with a compound heterozygous HAX1 mutation consisting of a nonsense mutation (c.568C > T, p.Glu190X) and a frame-shift mutation (c.91delG, p.Glu31LysfsX54) resulting in a premature stop codon. The patient has a history of neutropenia and a propensity for infections, but has shown no signs of neurodevelopmental abnormalities.

  11. Identifying allelic loss and homozygous deletions in pancreatic cancer without matched normals using high-density single-nucleotide polymorphism arrays.

    PubMed

    Calhoun, Eric S; Hucl, Tomas; Gallmeier, Eike; West, Kristen M; Arking, Dan E; Maitra, Anirban; Iacobuzio-Donahue, Christine A; Chakravarti, Aravinda; Hruban, Ralph H; Kern, Scott E

    2006-08-15

    Recent advances in oligonucleotide arrays and whole-genome complexity reduction data analysis now permit the evaluation of tens of thousands of single-nucleotide polymorphisms simultaneously for a genome-wide analysis of allelic status. Using these arrays, we created high-resolution allelotype maps of 26 pancreatic cancer cell lines. The areas of heterozygosity implicitly served to reveal regions of allelic loss. The array-derived maps were verified by a panel of 317 microsatellite markers used in a subset of seven samples, showing a 97.1% concordance between heterozygous calls. Three matched tumor/normal pairs were used to estimate the false-negative and potential false-positive rates for identifying loss of heterozygosity: 3.6 regions (average minimal region of loss, 720,228 bp) and 2.3 regions (average heterozygous gap distance, 4,434,994 bp) per genome, respectively. Genomic fractional allelic loss calculations showed that cumulative levels of allelic loss ranged widely from 17.1% to 79.9% of the haploid genome length. Regional increases in "NoCall" frequencies combined with copy number loss estimates were used to identify 41 homozygous deletions (19 first reports), implicating an additional 13 regions disrupted in pancreatic cancer. Unexpectedly, 23 of these occurred in just two lines (BxPc3 and MiaPaCa2), suggesting the existence of at least two subclasses of chromosomal instability (CIN) patterns, distinguished here by allelic loss and copy number changes (original CIN) and those also highly enriched in the genomic "holes" of homozygous deletions (holey CIN). This study provides previously unavailable high-resolution allelotype and deletion breakpoint maps in widely shared pancreatic cancer cell lines and effectively eliminates the need for matched normal tissue to define informative loci.

  12. Validation of Deleterious Mutations in Vorderwald Cattle

    PubMed Central

    Reinartz, Sina; Distl, Ottmar

    2016-01-01

    In Montbéliarde cattle two candidate mutations on bovine chromosomes 19 and 29 responsible for embryonic lethality have been detected. Montbéliarde bulls have been introduced into Vorderwald cattle to improve milk and fattening performance. Due to the small population size of Vorderwald cattle and the wide use of a few Montbéliarde bulls through artificial insemination, inbreeding on Montbéliarde bulls in later generations was increasing. Therefore, we genotyped an aborted fetus which was inbred on Montbéliarde as well as Vorderwald x Montbéliarde crossbred bulls for both deleterious mutations. The abortion was observed in an experimental herd of Vorderwald cattle. The objectives of the present study were to prove if one or both lethal mutations may be assumed to have caused this abortion and to show whether these deleterious mutations have been introduced into the Vorderwald cattle population through Montbéliarde bulls. The aborted fetus was homozygous for the SLC37A2:g.28879810C>T mutation (ss2019324563) on BTA29 and both parents as well as the paternal and maternal grandsire were heterozygous for this mutation. In addition, the parents and the paternal grandsire were carriers of the MH2-haplotype linked with the T-allele of the SLC37A2:g.28879810C>T mutation. For the SHBG:g.27956790C>T mutation (rs38377500) on BTA19 (MH1), the aborted fetus and its sire were heterozygous. Among all further 341 Vorderwald cattle genotyped we found 27 SLC37A2:g.28879810C>T heterozygous animals resulting in an allele frequency of 0.0396. Among the 120 male Vorderwald cattle, there were 12 heterozygous with an allele frequency of 0.05. The SLC37A2:g.28879810C>T mutation could not be found in further nine cattle breeds nor in Vorderwald cattle with contributions from Ayrshire bulls. In 69 Vorderwald cattle without genes from Montbéliarde bulls the mutated allele of SLC37A2:g.28879810C>T could not be detected. The SHBG:g.27956790C>T mutation appeared unlikely to be responsible

  13. DCLRE1C (ARTEMIS) mutations causing phenotypes ranging from atypical severe combined immunodeficiency to mere antibody deficiency

    PubMed Central

    Volk, Timo; Pannicke, Ulrich; Reisli, Ismail; Bulashevska, Alla; Ritter, Julia; Björkman, Andrea; Schäffer, Alejandro A.; Fliegauf, Manfred; Sayar, Esra H.; Salzer, Ulrich; Fisch, Paul; Pfeifer, Dietmar; Di Virgilio, Michela; Cao, Hongzhi; Yang, Fang; Zimmermann, Karin; Keles, Sevgi; Caliskaner, Zafer; Güner, S¸ükrü; Schindler, Detlev; Hammarström, Lennart; Rizzi, Marta; Hummel, Michael; Pan-Hammarström, Qiang; Schwarz, Klaus; Grimbacher, Bodo

    2015-01-01

    Null mutations in genes involved in V(D)J recombination cause a block in B- and T-cell development, clinically presenting as severe combined immunodeficiency (SCID). Hypomorphic mutations in the non-homologous end-joining gene DCLRE1C (encoding ARTEMIS) have been described to cause atypical SCID, Omenn syndrome, Hyper IgM syndrome and inflammatory bowel disease—all with severely impaired T-cell immunity. By whole-exome sequencing, we investigated the molecular defect in a consanguineous family with three children clinically diagnosed with antibody deficiency. We identified perfectly segregating homozygous variants in DCLRE1C in three index patients with recurrent respiratory tract infections, very low B-cell numbers and serum IgA levels. In patients, decreased colony survival after irradiation, impaired proliferative response and reduced counts of naïve T cells were observed in addition to a restricted T-cell receptor repertoire, increased palindromic nucleotides in the complementarity determining regions 3 and long stretches of microhomology at switch junctions. Defective V(D)J recombination was complemented by wild-type ARTEMIS protein in vitro. Subsequently, homozygous or compound heterozygous DCLRE1C mutations were identified in nine patients from the same geographic region. We demonstrate that DCLRE1C mutations can cause a phenotype presenting as only antibody deficiency. This novel association broadens the clinical spectrum associated with ARTEMIS mutations. Clinicians should consider the possibility that an immunodeficiency with a clinically mild initial presentation could be a combined immunodeficiency, so as to provide appropriate care for affected patients. PMID:26476407

  14. Phenotypic Heterogeneity in a DFNA20/26 family segregating a novel ACTG1 mutation.

    PubMed

    Yuan, Yongyi; Gao, Xue; Huang, Bangqing; Lu, Jingqiao; Wang, Guojian; Lin, Xi; Qu, Yan; Dai, Pu

    2016-02-01

    Genetic factors play an important role in hearing loss, contributing to approximately 60% of cases of congenital hearing loss. Autosomal dominant deafness accounts for approximately 20% of cases of hereditary hearing loss. Diseases with autosomal dominant inheritance often show pleiotropy, different degrees of penetrance, and variable expressivity. A three-generation Chinese family with autosomal dominant nonsyndromic hearing impairment (ADNSHI) was enrolled in this study. Audiometric data and blood samples were collected from the family. In total, 129 known human deafness genes were sequenced using next-generation sequencing (NGS) to identify the responsible gene mutation in the family. Whole Exome Sequencing (WES) was performed to exclude any other variant that cosegregated with the phenotype. The age of onset of the affected family members was the second decade of life. The condition began with high-frequency hearing impairment in all family members excluding III:2. The novel ACTG1 c.638A > G (p.K213R) mutation was found in all affected family members and was not found in the unaffected family members. A heterozygous c.638A > G mutation in ACTG1 and homozygous c.109G > A (p.V37I) mutation in GJB2 were found in III:2, who was born with hearing loss. The WES result concurred with that of targeted sequencing of known deafness genes. The novel mutation p.K213R in ACTG1 was found to be co-segregated with hearing loss and the genetic cause of ADNSHI in this family. A homozygous mutation associated with recessive inheritance only rarely co-acts with a dominant mutation to result in hearing loss in a dominant family. In such cases, the mutations in the two genes, as in ACTG1 and GJB2 in the present study, may result in a more severe phenotype. Targeted sequencing of known deafness genes is one of the best choices to identify the genetic cause in hereditary hearing loss families.

  15. Primary Ovarian Insufficiency Induced by Fanconi Anemia E Mutation in a Mouse Model.

    PubMed

    Fu, Chun; Begum, Khurshida; Overbeek, Paul A

    2016-01-01

    In most cases of primary ovarian insufficiency (POI), the cause of the depletion of ovarian follicles is unknown. Fanconi anemia (FA) proteins are known to play important roles in follicular development. Using random insertional mutagenesis with a lentiviral transgene, we identified a family with reduced fertility in the homozygous transgenic mice. We identified the integration site and found that the lentivirus had integrated into intron 8 of the Fanconi E gene (Fance). By RT-PCR and in situ hybridization, we found that Fance transcript levels were significantly reduced. The Fance homozygous mutant mice were assayed for changes in ovarian development, follicle numbers and estrous cycle. Ovarian dysplasias and a severe lack of follicles were seen in the mutant mice. In addition, the estrous cycle was disrupted in adult females. Our results suggest that POI has been induced by the Fance mutation in this new mouse model.

  16. Exome-wide Sequencing Shows Low Mutation Rates and Identifies Novel Mutated Genes in Seminomas.

    PubMed

    Cutcutache, Ioana; Suzuki, Yuka; Tan, Iain Beehuat; Ramgopal, Subhashini; Zhang, Shenli; Ramnarayanan, Kalpana; Gan, Anna; Lee, Heng Hong; Tay, Su Ting; Ooi, Aikseng; Ong, Choon Kiat; Bolthouse, Jonathan T; Lane, Brian R; Anema, John G; Kahnoski, Richard J; Tan, Patrick; Teh, Bin Tean; Rozen, Steven G

    2015-07-01

    Testicular germ cell tumors are the most common cancer diagnosed in young men, and seminomas are the most common type of these cancers. There have been no exome-wide examinations of genes mutated in seminomas or of overall rates of nonsilent somatic mutations in these tumors. The objective was to analyze somatic mutations in seminomas to determine which genes are affected and to determine rates of nonsilent mutations. Eight seminomas and matched normal samples were surgically obtained from eight patients. DNA was extracted from tissue samples and exome sequenced on massively parallel Illumina DNA sequencers. Single-nucleotide polymorphism chip-based copy number analysis was also performed to assess copy number alterations. The DNA sequencing read data were analyzed to detect somatic mutations including single-nucleotide substitutions and short insertions and deletions. The detected mutations were validated by independent sequencing and further checked for subclonality. The rate of nonsynonymous somatic mutations averaged 0.31 mutations/Mb. We detected nonsilent somatic mutations in 96 genes that were not previously known to be mutated in seminomas, of which some may be driver mutations. Many of the mutations appear to have been present in subclonal populations. In addition, two genes, KIT and KRAS, were affected in two tumors each with mutations that were previously observed in other cancers and are presumably oncogenic. Our study, the first report on exome sequencing of seminomas, detected somatic mutations in 96 new genes, several of which may be targetable drivers. Furthermore, our results show that seminoma mutation rates are five times higher than previously thought, but are nevertheless low compared to other common cancers. Similar low rates are seen in other cancers that also have excellent rates of remission achieved with chemotherapy. We examined the DNA sequences of seminomas, the most common type of testicular germ cell cancer. Our study identified 96

  17. Mutations participating in interallelic complementation in propionic acidemia

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gravel, R.A.; Akerman, B.R.; Lamhonwah, A.M.

    1994-07-01

    Deficiency of propionyl-CoA carboxylase (PCC; [alpha][sub 4][beta][sub 4]) results in the rare, autosomal recessive disease propionic acidemia. Cell fusion experiments have revealed two complementation groups, pccA and pccB, corresponding to defects of the PCCA ([alpha]-subunit) and PCCB ([beta]-subunit) genes, respectively. The pccBCC group includes subgroups, pccB and pccC, which are thought to reflect interallelic complementation between certain mutations of the PCCB gene. In this study, the authors have identified the mutations in two pccB, one pccC, and two pccBC cell lines and have deduced those alleles participating in interallelic complementation. One pccB line was a compound hetrozygote of Pro228Leu andmore » Asn536Asp. The latter mutation was also detected in a noncomplementing pccBC line. This leaves Pro228Leu responsible for complementation in the pccB cells. The second pccB line contained an insertional duplication, dupKICK140-143, and a splice mutation IVS+1 G[yields]T, located after Lys466. The authors suggest that the dupKICK mutation is the complementing allele, since the second allele is incompatible with normal splicing. The pccC line studied was homozygous for Arg410Trp, which is necessarily the complementing allele in that line. For a second pccC line, they previously had proposed that [Delta]Ile408 was the complementing allele. They now show that its second allele, [open quotes]Ins[center dot]Del[close quotes], a 14-bp deletion replaced by a 12-bp insertion beginning at codon 407, fails to complement in homozygous form. The authors conclude that the interallelic complementation results from mutations in domains that can interact between [beta]-subunits in the PCC heteromer to restore enzymatic function. On the basis of sequence homology with the Propionibacterium shermanii transcarboxylase 12S subunit, they suggest that the pccC domain, defined by Ile408 and Arg410, may involve the propionyl-CoA binding site. 37 refs., 5 figs., 2 tabs.« less

  18. Exome sequencing identifies MAX mutations as a cause of hereditary pheochromocytoma.

    PubMed

    Comino-Méndez, Iñaki; Gracia-Aznárez, Francisco J; Schiavi, Francesca; Landa, Iñigo; Leandro-García, Luis J; Letón, Rocío; Honrado, Emiliano; Ramos-Medina, Rocío; Caronia, Daniela; Pita, Guillermo; Gómez-Graña, Alvaro; de Cubas, Aguirre A; Inglada-Pérez, Lucía; Maliszewska, Agnieszka; Taschin, Elisa; Bobisse, Sara; Pica, Giuseppe; Loli, Paola; Hernández-Lavado, Rafael; Díaz, José A; Gómez-Morales, Mercedes; González-Neira, Anna; Roncador, Giovanna; Rodríguez-Antona, Cristina; Benítez, Javier; Mannelli, Massimo; Opocher, Giuseppe; Robledo, Mercedes; Cascón, Alberto

    2011-06-19

    Hereditary pheochromocytoma (PCC) is often caused by germline mutations in one of nine susceptibility genes described to date, but there are familial cases without mutations in these known genes. We sequenced the exomes of three unrelated individuals with hereditary PCC (cases) and identified mutations in MAX, the MYC associated factor X gene. Absence of MAX protein in the tumors and loss of heterozygosity caused by uniparental disomy supported the involvement of MAX alterations in the disease. A follow-up study of a selected series of 59 cases with PCC identified five additional MAX mutations and suggested an association with malignant outcome and preferential paternal transmission of MAX mutations. The involvement of the MYC-MAX-MXD1 network in the development and progression of neural crest cell tumors is further supported by the lack of functional MAX in rat PCC (PC12) cells and by the amplification of MYCN in neuroblastoma and suggests that loss of MAX function is correlated with metastatic potential.

  19. Homozygous factor V Leiden mutation in type IV Ehlers-Danlos patient

    PubMed Central

    Refaat, Marwan; Hotait, Mostafa; Winston, Brion

    2014-01-01

    Ehlers-Danlos syndrome (EDS) is a group of inherited connective tissue disorders caused by collagen synthesis defects. Several hemostatic abnormalities have been described in EDS patients that increase the bleeding tendencies of these patients. This case report illustrates a patient with an unusual presentation of a patient with type IV EDS, platelet δ-storage pool disease and factor V Leiden mutation. Young woman having previous bilateral deep vein thrombosis and pulmonary emboli coexisting with ruptured splenic aneurysm and multiple other aneurysms now presented with myocardial infarction. Presence of factor V Leiden mutation raises the possibility that the infarct was due to acute coronary thrombosis, although coronary artery aneurysm and dissection with myocardial infarction is known to occur in vascular type EDS. This is the first report in the medical literature of factor V Leiden mutation in an EDS patient which made the management of our patient challenging with propensity to both bleeding and clotting. PMID:24653990

  20. Myocardial 123I-metaiodobenzylguanidine scintigraphy in patients with homozygous and heterozygous parkin mutations.

    PubMed

    De Rosa, Anna; Pellegrino, Teresa; Pappatà, Sabina; Pellecchia, Maria Teresa; Peluso, Silvio; Saccà, Francesco; Barone, Paolo; Cuocolo, Alberto; De Michele, Giuseppe

    2017-02-01

    PARK2 is an autosomal recessive parkinsonism caused by parkin gene mutations. Several Parkinson's Disease (PD) cases harbor single parkin mutations, raising a debate about the pathogenic meaning of heterozygous mutations. Here, we evaluate cardiac autonomic innervation in patients with either two or one parkin mutations compared to patients with idiopathic PD (IPD). Myocardial 123 I-metaiodobenzylguanidine (MIBG) scintigraphy was performed in six PD patients with single parkin mutations (HET), four with two mutations (PARK2), and eight with IPD. In comparison to control group, IPD patients showed lower early and late heart-to-mediastinum (H/M) ratios and higher washout rates, whereas HET patients had only lower early H/M ratio, and PARK2 patients were not different for any parameter. At individual level, MIBG findings were abnormal in 7/8 IPD, in 4/6 HET and in 1/4 PARK2 patients. Preserved cardiac 123 I-MIBG uptake confirms that PARK2 pathogenic mechanism, at least partially, differs from that responsible for IPD. HET subjects show intermediate findings, suggesting possible heterogeneity.

  1. Mitochondrial DNA Polymerase W748S Mutation: A Common Cause of Autosomal Recessive Ataxia with Ancient European Origin

    PubMed Central

    Hakonen, Anna H.; Heiskanen, Silja; Juvonen, Vesa; Lappalainen, Ilse; Luoma, Petri T.; Rantamäki, Maria; Goethem, Gert Van; Löfgren, Ann; Hackman, Peter; Paetau, Anders; Kaakkola, Seppo; Majamaa, Kari; Varilo, Teppo; Udd, Bjarne; Kääriäinen, Helena; Bindoff, Laurence A.; Suomalainen, Anu

    2005-01-01

    Mutations in the catalytic subunit of the mitochondrial DNA polymerase γ (POLG) have been found to be an important cause of neurological disease. Recently, we and collaborators reported a new neurodegenerative disorder with autosomal recessive ataxia in four patients homozygous for two amino acid changes in POLG: W748S in cis with E1143G. Here, we studied the frequency of this allele and found it to be among the most common genetic causes of inherited ataxia in Finland. We identified 27 patients with mitochondrial recessive ataxia syndrome (MIRAS) from 15 Finnish families, with a carrier frequency in the general population of 1:125. Since the mutation pair W748S+E1143G has also been described in European patients, we examined the haplotypes of 13 non-Finnish, European patients with the W748S mutation. Haplotype analysis revealed that all the chromosomes carrying these two changes, in patients from Finland, Norway, the United Kingdom, and Belgium, originate from a common ancient founder. In Finland and Norway, long, common, northern haplotypes, outside the core haplotype, could be identified. Despite having identical homozygous mutations, the Finnish patients with this adult- or juvenile-onset disease had surprisingly heterogeneous phenotypes, albeit with a characteristic set of features, including ataxia, peripheral neuropathy, dysarthria, mild cognitive impairment, involuntary movements, psychiatric symptoms, and epileptic seizures. The high carrier frequency in Finland, the high number of patients in Norway, and the ancient European founder chromosome indicate that this newly identified ataxia should be considered in the first-line differential diagnosis of progressive ataxia syndromes. PMID:16080118

  2. Mutations in the mitochondrial seryl-tRNA synthetase cause hyperuricemia, pulmonary hypertension, renal failure in infancy and alkalosis, HUPRA syndrome.

    PubMed

    Belostotsky, Ruth; Ben-Shalom, Efrat; Rinat, Choni; Becker-Cohen, Rachel; Feinstein, Sofia; Zeligson, Sharon; Segel, Reeval; Elpeleg, Orly; Nassar, Suheir; Frishberg, Yaacov

    2011-02-11

    An uncharacterized multisystemic mitochondrial cytopathy was diagnosed in two infants from consanguineous Palestinian kindred living in a single village. The most significant clinical findings were tubulopathy (hyperuricemia, metabolic alkalosis), pulmonary hypertension, and progressive renal failure in infancy (HUPRA syndrome). Analysis of the consanguineous pedigree suggested that the causative mutation is in the nuclear DNA. By using genome-wide SNP homozygosity analysis, we identified a homozygous identity-by-descent region on chromosome 19 and detected the pathogenic mutation c.1169A>G (p.Asp390Gly) in SARS2, encoding the mitochondrial seryl-tRNA synthetase. The same homozygous mutation was later identified in a third infant with HUPRA syndrome. The carrier rate of this mutation among inhabitants of this Palestinian isolate was found to be 1:15. The mature enzyme catalyzes the ligation of serine to two mitochondrial tRNA isoacceptors: tRNA(Ser)(AGY) and tRNA(Ser)(UCN). Analysis of amino acylation of the two target tRNAs, extracted from immortalized peripheral lymphocytes derived from two patients, revealed that the p.Asp390Gly mutation significantly impacts on the acylation of tRNA(Ser)(AGY) but probably not that of tRNA(Ser)(UCN). Marked decrease in the expression of the nonacylated transcript and the complete absence of the acylated tRNA(Ser)(AGY) suggest that this mutation leads to significant loss of function and that the uncharged transcripts undergo degradation. Copyright © 2011 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  3. Exome sequencing reveals a thrombopoietin ligand mutation in a Micronesian family with autosomal recessive aplastic anemia.

    PubMed

    Dasouki, Majed J; Rafi, Syed K; Olm-Shipman, Adam J; Wilson, Nathan R; Abhyankar, Sunil; Ganter, Brigitte; Furness, L Mike; Fang, Jianwen; Calado, Rodrigo T; Saadi, Irfan

    2013-11-14

    We recently identified 2 siblings afflicted with idiopathic, autosomal recessive aplastic anemia. Whole-exome sequencing identified a novel homozygous missense mutation in thrombopoietin (THPO, c.112C>T) in both affected siblings. This mutation encodes an arginine to cysteine substitution at residue 38 or residue 17 excluding the 21-amino acid signal peptide of THPO receptor binding domain (RBD). THPO has 4 conserved cysteines in its RBD that form 2 disulfide bonds. Our in silico modeling predicts that introduction of a fifth cysteine may disrupt normal disulfide bonding to cause poor receptor binding. In functional assays, the mutant-THPO-containing media shows two- to threefold reduced ability to sustain UT7-TPO cells, which require THPO for proliferation. Both parents and a sibling with heterozygous R17C change have reduced platelet counts, whereas a sibling with wild-type sequence has normal platelet count. Thus, the R17C partial loss-of-function allele results in aplastic anemia in the homozygous state and mild thrombocytopenia in the heterozygous state in our family. Together with the recent identification of THPO receptor (MPL) mutations and the effects of THPO agonists in aplastic anemia, our results have clinical implications in the diagnosis and treatment of patients with aplastic anemia and highlight a role for the THPO-MPL pathway in hematopoiesis in vivo.

  4. Phenotypic variability in patients with osteogenesis imperfecta caused by BMP1 mutations.

    PubMed

    Pollitt, Rebecca C; Saraff, Vrinda; Dalton, Ann; Webb, Emma A; Shaw, Nick J; Sobey, Glenda J; Mughal, M Zulf; Hobson, Emma; Ali, Farhan; Bishop, Nicholas J; Arundel, Paul; Högler, Wolfgang; Balasubramanian, Meena

    2016-12-01

    Osteogenesis Imperfecta (OI) is an inherited bone fragility disorder most commonly associated with autosomal dominant mutations in the type I collagen genes. Autosomal recessive mutations in a number of genes have also been described, including the BMP1 gene that encodes the mammalian Tolloid (mTLD) and its shorter isoform bone morphogenic protein-1 (BMP1). To date, less than 20 individuals with OI have been identified with BMP1 mutations, with skeletal phenotypes ranging from mild to severe and progressively deforming. In the majority of patients, bone fragility was associated with increased bone mineral density (BMD); however, the full range of phenotypes associated with BMP1 remains unclear. Here, we describe three children with mutations in BMP1 associated with a highly variable phenotype: a sibship homozygous for the c.2188delC mutation that affects only the shorter BMP1 isoform and a further patient who is compound heterozygous for a c.1293C>G nonsense mutation and a c.1148G>A missense mutation in the CUB1 domain. These individuals had recurrent fractures from early childhood, are hypermobile and have no evidence of dentinogenesis imperfecta. The homozygous siblings with OI had normal areal BMD by dual energy X-ray absorptiometry whereas the third patient presented with a high bone mass phenotype. Intravenous bisphosphonate therapy was started in all patients, but discontinued in two patients and reduced in another due to concerns about increasing bone stiffness leading to chalk-stick fractures. Given the association of BMP1-related OI with very high bone material density, concerns remain whether anti-resorptive therapy is indicated in this ultra-rare form of OI.© 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  5. Genetic heterogeneity and consanguinity lead to a "double hit": homozygous mutations of MYO7A and PDE6B in a patient with retinitis pigmentosa.

    PubMed

    Goldenberg-Cohen, Nitza; Banin, Eyal; Zalzstein, Yael; Cohen, Ben; Rotenstreich, Ygal; Rizel, Leah; Basel-Vanagaite, Lina; Ben-Yosef, Tamar

    2013-01-01

    Retinitis pigmentosa (RP), the most genetically heterogeneous disorder in humans, actually represents a group of pigmentary retinopathies characterized by night blindness followed by visual-field loss. RP can appear as either syndromic or nonsyndromic. One of the most common forms of syndromic RP is Usher syndrome, characterized by the combination of RP, hearing loss, and vestibular dysfunction. The underlying cause of the appearance of syndromic and nonsyndromic RP in three siblings from a consanguineous Israeli Muslim Arab family was studied with whole-genome homozygosity mapping followed by whole exome sequencing. THE FAMILY WAS FOUND TO SEGREGATE NOVEL MUTATIONS OF TWO DIFFERENT GENES: myosin VIIA (MYO7A), which causes type 1 Usher syndrome, and phosphodiesterase 6B, cyclic guanosine monophosphate-specific, rod, beta (PDE6B), which causes nonsyndromic RP. One affected child was homozygous for both mutations. Since the retinal phenotype seen in this patient results from overlapping pathologies, one might expect to find severe retinal degeneration. Indeed, he was diagnosed with RP based on an abnormal electroretinogram (ERG) at a young age (9 months). However, this early diagnosis may be biased, as two of his older siblings had already been diagnosed, leading to increased awareness. At the age of 32 months, he had relatively good vision with normal visual fields. Further testing of visual function and structure at different ages in the three siblings is needed to determine whether the two RP-causing genes mutated in this youngest sibling confer increased disease severity. This report further supports the genetic heterogeneity of RP, and demonstrates how consanguinity could increase intrafamilial clustering of multiple hereditary diseases. Moreover, this report provides a unique opportunity to study the clinical implications of the coexistence of pathogenic mutations in two RP-causative genes in a human patient.

  6. A novel splicing mutation in GALT gene causing Galactosemia in Ecuadorian family.

    PubMed

    De Lucca, M; Barba, C; Casique, L

    2017-07-01

    Classic Galactosemia (OMIM 230400) is an autosomal recessive disorder of galactose metabolism caused by mutations in the galactose-1-phosphate uridyl transferase (GALT) gene. This disease caused by the inability to metabolize galactose is potentially life-threatening but its pathophysiology has not been clearly defined. GALT gene presents high allelic heterogeneity and around 336 variations have been identified. Here, we report the case of a patient with Classic Galactosemia who was detected during a neonatal screening in Ecuador. Molecular study revealed a mutation in GALT gene intron 1, c.82+3A>G in homozygous condition, this mutation has not been previously reported. This gene variation was not found in any of the 119 healthy Ecuadorian individuals used as control. Furthermore, the mutation was the only alteration detected in the propositus's GALT after sequencing all exons and introns of this gene. In silico modeling predicted that the mutation was pathogenic. Copyright © 2017. Published by Elsevier B.V.

  7. Expanding the clinical and molecular spectrum of PRMT7 mutations: 3 additional patients and review.

    PubMed

    Agolini, E; Dentici, M L; Bellacchio, E; Alesi, V; Radio, F C; Torella, A; Musacchia, F; Tartaglia, M; Dallapiccola, B; Nigro, V; Digilio, M C; Novelli, A

    2018-03-01

    Protein arginine methyltransferase 7 (PRMT7) is a member of a family of enzymes that catalyze the transfer of methyl groups from S-adenosyl-l-methionine to nitrogen atoms on arginine residues. Arginine methylation is involved in multiple biological processes, such as signal transduction, mRNA splicing, transcriptional control, DNA repair, and protein translocation. Currently, 7 patients have been described harboring compound heterozygous or homozygous variants in the PRMT7 gene, causing a novel intellectual disability syndrome, known as SBIDDS syndrome (Short Stature, Brachydactyly, Intellectual Developmental Disability, and Seizures). We report on 3 additional patients from 2 consanguineous families with severe/moderate intellectual disability, short stature, brachydactyly and dysmorphisms. Exome sequencing revealed 2 novel homozygous mutations in PRMT7. Our findings expand the clinical and molecular spectrum of homozygous PRMT7 mutations, associated to the SBIDDS syndrome, showing a possible correlation between the type of mutation and the severity of the phenotype. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  8. Two novel disease-causing mutations in the CLRN1 gene in patients with Usher syndrome type 3

    PubMed Central

    García-García, Gema; Aparisi, María J.; Rodrigo, Regina; Sequedo, María D.; Espinós, Carmen; Rosell, Jordi; Olea, José L.; Mendívil, M. Paz; Ramos-Arroyo, María A; Ayuso, Carmen; Jaijo, Teresa; Aller, Elena

    2012-01-01

    Purpose To identify the genetic defect in Spanish families with Usher syndrome (USH) and probable involvement of the CLRN1 gene. Methods DNA samples of the affected members of our cohort of USH families were tested using an USH genotyping array, and/or genotyped with polymorphic markers specific for the USH3A locus. Based on these previous analyses and clinical findings, CLRN1 was directly sequenced in 17 patients susceptible to carrying mutations in this gene. Results Microarray analysis revealed the previously reported mutation p.Y63X in two unrelated patients, one of them homozygous for the mutation. After CLRN1 sequencing, we found two novel mutations, p.R207X and p.I168N. Both novel mutations segregated with the phenotype. Conclusions To date, 18 mutations in CLRN1 have been reported. In this work, we report two novel mutations and a third one previously identified in the Spanish USH sample. The prevalence of CLRN1 among our patients with USH is low. PMID:23304067

  9. G20210A prothrombin gene mutation identified in patients with venous leg ulcers.

    PubMed

    Jebeleanu, G; Procopciuc, L

    2001-01-01

    The G20210A mutation variant of prothrombin gene is the second most frequent mutation identified in patients with deep venous thrombosis, after factor V Leiden. The risk for developing deep venous thrombosis is high in patients identified as heterozygous for G20210A mutation. In order to identify this polymorphism in the gene coding prothrombin, the 345bp fragment in the 3'- untranslated region of the prothrombin gene was amplified using amplification by polymerase chain reaction and enzymatic digestion by HindIII (restriction endonuclease enzyme). The products of amplification and enzymatic's digestion were analized using agarose gel electrophoresis. We investigated 20 patients with venous leg ulcers and we found 2 heterozygous (10%) for G20210A mutation. None of the patients in the control group had G20210A mutation. Our study confirms the presence of G20210A mutation in the Romanian population. Our study also shows the link between venous leg ulcers and this polymorphism in the prothrombin gene.

  10. Homozygous variegate porphyria presenting with developmental and language delay in childhood.

    PubMed

    Pinder, V A E; Holden, S T; Deshpande, C; Siddiqui, A; Mellerio, J E; Wraige, E; Powell, A M

    2013-10-01

    Variegate porphyria is an autosomal dominant disorder that usually presents with photosensitivity and acute neurological crises in adulthood. It is caused by heterozygous mutations in the protoporphyrinogen oxidase gene (PPOX). A rarer variant, homozygous variegate porphyria (HVP), presents in childhood with recurrent skin blisters and scarring. More variable features of HVP are short stature, brachydactyly, nystagmus, epilepsy, developmental delay and mental retardation. We describe a child who presented with nystagmus, developmental delay and ataxia, combined with a photosensitive eruption. Analysis of porphyrins in plasma, urine and stool supported a clinical diagnosis of HVP. DNA from the patient showed that he is compound heterozygous for two novel missense mutations in the PPOX coding region: c.169G>C (p.Gly57Arg) and c.1259C>G (Pro420Arg). Interestingly, cranial magnetic resonance imaging showed an absence of myelin, a feature not previously reported in HVP, which expands the differential diagnosis of childhood hypomyelinating leucoencephalopathies. © 2013 British Association of Dermatologists.

  11. Novel mutations of endothelin-B receptor gene in Pakistani patients with Waardenburg syndrome.

    PubMed

    Jabeen, Raheela; Babar, Masroor Ellahi; Ahmad, Jamil; Awan, Ali Raza

    2012-01-01

    Mutations in EDNRB gene have been reported to cause Waardenburg-Shah syndrome (WS4) in humans. We investigated 17 patients with WS4 for identification of mutations in EDNRB gene using PCR and direct sequencing technique. Four genomic mutations were detected in four patients; a G to C transversion in codon 335 (S335C) in exon 5 and a transition of T to C in codon (S361L) in exon 5, a transition of A to G in codon 277 (L277L) in exon 4, a non coding transversion of T to A at -30 nucleotide position of exon 5. None of these mutations were found in controls. One of the patients harbored two novel mutations (S335C, S361L) in exon 5 and one in Intronic region (-30exon5 A>G). All of the mutations were homozygous and novel except the mutation observed in exon 4. In this study, we have identified 3 novel mutations in EDNRB gene associated with WS4 in Pakistani patients.

  12. A homozygous p53 R282W mutant human embryonic stem cell line generated using TALEN-mediated precise gene editing.

    PubMed

    Zhou, Ruoji; Xu, An; Wang, Donghui; Zhu, Dandan; Mata, Helen; Huo, Zijun; Tu, Jian; Liu, Mo; Mohamed, Alaa M T; Jewell, Brittany E; Gingold, Julian; Xia, Weiya; Rao, Pulivarthi H; Hung, Mien-Chie; Zhao, Ruiying; Lee, Dung-Fang

    2018-03-01

    The tumor suppressor gene TP53 is the most frequently mutated gene in human cancers. Many hot-spot mutations of TP53 confer novel functions not found in wild-type p53 and contribute to tumor development and progression. We report on the generation of a H1 human embryonic stem cell line carrying a homozygous TP53 R282W mutation using TALEN-mediated genome editing. The generated cell line demonstrates normal karyotype, maintains a pluripotent state, and is capable of generating a teratoma in vivo containing tissues from all three germ layers. Copyright © 2018 The Author(s). Published by Elsevier B.V. All rights reserved.

  13. A novel mutation in the EDAR gene causes severe autosomal recessive hypohidrotic ectodermal dysplasia.

    PubMed

    Henningsen, Emil; Svendsen, Mathias Tiedemann; Lildballe, Dorte Launholt; Jensen, Peter Kjestrup Axel

    2014-08-01

    We report on a 2-year-old girl presenting with a severe form of hypohidrotic ectodermal dysplasia (HED). The patient presented with hypotrichosis, anodontia, hypohidrosis, frontal bossing, prominent lips and ears, dry, pale skin, and dermatitis. The patient had chronic rhinitis with malodorous nasal discharge. The girl was the second born child of first-cousin immigrants from Northern Iraq. A novel homozygous mutation (c.84delC) in the EDAR gene was identified. This mutation most likely causes a frameshift in the protein product (p.S29fs*74). This results in abolition of all ectodysplasin-mediated NF-kB signalling. This complete loss-of-function mutation likely accounts for the severe clinical abnormalities in ectodermal structures in the described patient. © 2014 Wiley Periodicals, Inc.

  14. Monoallelic mutation analysis (MAMA) for identifying germline mutations.

    PubMed

    Papadopoulos, N; Leach, F S; Kinzler, K W; Vogelstein, B

    1995-09-01

    Dissection of germline mutations in a sensitive and specific manner presents a continuing challenge. In dominantly inherited diseases, mutations occur in only one allele and are often masked by the normal allele. Here we report the development of a sensitive and specific diagnostic strategy based on somatic cell hybridization termed MAMA (monoallelic mutation analysis). We have demonstrated the utility of this strategy in two different hereditary colorectal cancer syndromes, one caused by a defective tumour suppressor gene on chromosome 5 (familial adenomatous polyposis, FAP) and the other caused by a defective mismatch repair gene on chromosome 2 (hereditary non-polyposis colorectal cancer, HNPCC).

  15. Mutational signature analysis identifies MUTYH deficiency in colorectal cancers and adrenocortical carcinomas: Mutational signature associated with MUTYH deficiency in cancers

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pilati, Camilla; Shinde, Jayendra; Alexandrov, Ludmil B.

    Germline alterations in DNA repair genes are implicated in cancer predisposition and can result in characteristic mutational signatures. However, specific mutational signatures associated with base excision repair (BER) defects remain to be characterized. Here, by analysing a series of colorectal cancers (CRCs) using exome sequencing, we identified a particular spectrum of somatic mutations characterized by an enrichment of C > A transversions in NpCpA or NpCpT contexts in three tumours from a MUTYH-associated polyposis (MAP) patient and in two cases harbouring pathogenic germline MUTYH mutations. In two series of adrenocortical carcinomas (ACCs), we identified four tumours with a similar signaturemore » also presenting germline MUTYH mutations. Altogether, these findings demonstrate that MUTYH inactivation results in a particular mutational signature, which may serve as a useful marker of BER-related genomic instability in new cancer types.« less

  16. Mutational signature analysis identifies MUTYH deficiency in colorectal cancers and adrenocortical carcinomas: Mutational signature associated with MUTYH deficiency in cancers

    DOE PAGES

    Pilati, Camilla; Shinde, Jayendra; Alexandrov, Ludmil B.; ...

    2017-03-29

    Germline alterations in DNA repair genes are implicated in cancer predisposition and can result in characteristic mutational signatures. However, specific mutational signatures associated with base excision repair (BER) defects remain to be characterized. Here, by analysing a series of colorectal cancers (CRCs) using exome sequencing, we identified a particular spectrum of somatic mutations characterized by an enrichment of C > A transversions in NpCpA or NpCpT contexts in three tumours from a MUTYH-associated polyposis (MAP) patient and in two cases harbouring pathogenic germline MUTYH mutations. In two series of adrenocortical carcinomas (ACCs), we identified four tumours with a similar signaturemore » also presenting germline MUTYH mutations. Altogether, these findings demonstrate that MUTYH inactivation results in a particular mutational signature, which may serve as a useful marker of BER-related genomic instability in new cancer types.« less

  17. Homozygous Resistance to Thyroid Hormone β: Can Combined Antithyroid Drug and Triiodothyroacetic Acid Treatment Prevent Cardiac Failure?

    PubMed

    Moran, Carla; Habeb, Abdelhadi M; Kahaly, George J; Kampmann, Christoph; Hughes, Marina; Marek, Jan; Rajanayagam, Odelia; Kuczynski, Adam; Vargha-Khadem, Faraneh; Morsy, Mofeed; Offiah, Amaka C; Poole, Ken; Ward, Kate; Lyons, Greta; Halsall, David; Berman, Lol; Watson, Laura; Baguley, David; Mollon, John; Moore, Anthony T; Holder, Graham E; Dattani, Mehul; Chatterjee, Krishna

    2017-09-01

    Resistance to thyroid hormone β (RTH β ) due to homozygous THRB defects is exceptionally rare, with only five kindreds reported worldwide. Cardiac dysfunction, which can be life-threatening, is recognized in the disorder. Here we describe the clinical, metabolic, ophthalmic, and cardiac findings in a 9-year-old boy harboring a biallelic THRB mutation (R243Q), along with biochemical, physiologic, and cardiac responses to carbimazole and triiodothyroacetic acid (TRIAC) therapy. The patient exhibits recognized features (goiter, nonsuppressed thyroid-stimulating hormone levels, upper respiratory tract infections, hyperactivity, low body mass index) of heterozygous RTH β , with additional characteristics (dysmorphic facies, winging of scapulae) and more markedly elevated thyroid hormone levels, associated with the homozygous form of the disorder. Notably, an older sibling with similar clinical features and probable homozygous RTH β had died of cardiac failure at age 13 years. Features of early dilated cardiomyopathy in our patient prompted combination treatment with carbimazole and TRIAC. Careful titration of therapy limited elevation in TSH levels and associated increase in thyroid volume. Subsequently, sustained reduction in thyroid hormones with normal TSH levels was reflected in lower basal metabolic rate, gain of lean body mass, and improved growth and cardiac function. A combination of antithyroid drug and TRIAC therapy may prevent thyrotoxic cardiomyopathy and its decompensation in homozygous or even heterozygous RTH β in which life-threatening hyperthyroid features predominate.

  18. Two Independent Mutations in ADAMTS17 Are Associated with Primary Open Angle Glaucoma in the Basset Hound and Basset Fauve de Bretagne Breeds of Dog.

    PubMed

    Oliver, James A C; Forman, Oliver P; Pettitt, Louise; Mellersh, Cathryn S

    2015-01-01

    Mutations in ADAMTS10 (CFA20) have previously been associated with primary open angle glaucoma (POAG) in the Beagle and Norwegian Elkhound. The closely related gene, ADAMTS17, has also been associated with several different ocular phenotypes in multiple breeds of dog, including primary lens luxation and POAG. We investigated ADAMTS17 as a candidate gene for POAG in the Basset Hound and Basset Fauve de Bretagne dog breeds. We performed ADAMTS17 exon resequencing in three Basset Hounds and three Basset Fauve de Bretagne dogs with POAG. Identified variants were genotyped in additional sample cohorts of both breeds and dogs of other breeds to confirm their association with disease. All affected Basset Hounds were homozygous for a 19 bp deletion in exon 2 that alters the reading frame and is predicted to lead to a truncated protein. Fifty clinically unaffected Basset Hounds were genotyped for this mutation and all were either heterozygous or homozygous for the wild type allele. Genotyping of 223 Basset Hounds recruited for a different study revealed a mutation frequency of 0.081 and predicted frequency of affected dogs in the population to be 0.007. Based on the entire genotyping dataset the association statistic for the POAG-associated deletion was p = 1.26 x 10-10. All affected Basset Fauve de Bretagne dogs were homozygous for a missense mutation in exon 11 causing a glycine to serine amino acid substitution (G519S) in the disintegrin-like domain of ADAMTS17 which is predicted to alter protein function. Unaffected Basset Fauve de Bretagne dogs were either heterozygous for the mutation (5/24) or homozygous for the wild type allele (19/24). Based on the entire genotyping dataset the association statistic for the POAG-associated deletion was p = 2.80 x 10-7. Genotyping of 85 dogs of unrelated breeds and 90 dogs of related breeds for this variant was negative. This report documents strong associations between two independent ADAMTS17 mutations and POAG in two different

  19. Clinical profile and mutation analysis of xeroderma pigmentosum in Indian patients.

    PubMed

    Tamhankar, Parag M; Iyer, Shruti V; Ravindran, Shyla; Gupta, Neerja; Kabra, Madhulika; Nayak, Chitra; Kura, Mahendra; Sanghavi, Swapnil; Joshi, Rajesh; Chennuri, Vasundhara Sridhar; Khopkar, Uday

    2015-01-01

    Xeroderma pigmentosum (XP) is an autosomal recessive genetic disorder characterized by cutaneous and ocular photosensitivity and an increased risk of developing cutaneous neoplasms. Progressive neurological abnormalities develop in a quarter of XP patients. To study the clinical profile and perform a mutation analysis in Indian patients with xeroderma pigmentosum. Ten families with 13 patients with XP were referred to our clinic over 2 years. The genes XPA, XPB and XPC were sequentially analyzed till a pathogenic mutation was identified. Homozygous mutations in the XPA gene were seen in patients with moderate to severe mental retardation (6/10 families) but not in those without neurological features. Two unrelated families with a common family name and belonging to the same community from Maharashtra were found to have an identical mutation in the XPA gene, namely c.335_338delTTATinsCATAAGAAA (p.F112SfsX2). Testing of the XPC gene in two families with four affected children led to the identification of the novel mutations c.1243C>T or p.R415X and c.1677C>A or p.Y559X. In two families, mutations could not be identified in XPA, XPB and XPC genes. The sample size is small. Indian patients who have neurological abnormalities associated with XP should be screened for mutations in the XPA gene.

  20. Exome analysis identified a novel mutation in the RBP4 gene in a consanguineous pedigree with retinal dystrophy and developmental abnormalities.

    PubMed

    Cukras, Catherine; Gaasterland, Terry; Lee, Pauline; Gudiseva, Harini V; Chavali, Venkata R M; Pullakhandam, Raghu; Maranhao, Bruno; Edsall, Lee; Soares, Sandra; Reddy, G Bhanuprakash; Sieving, Paul A; Ayyagari, Radha

    2012-01-01

    Retinitis Pigmentosa (RP) is a common form of retinal degeneration characterized by photoreceptor degeneration and retinal pigment epithelium (RPE) atrophy causing loss of visual field and acuities. Exome sequencing identified a novel homozygous splice site variant (c.111+1G>A) in the gene encoding retinol binding protein 4 (RBP4). This change segregated with early onset, progressive, and severe autosomal recessive retinitis pigmentosa (arRP) in an eight member consanguineous pedigree of European ancestry. Additionally, one patient exhibited developmental abnormalities including patent ductus arteriosus and chorioretinal and iris colobomas. The second patient developed acne from young age and extending into the 5(th) decade. Both patients had undetectable levels of RBP4 in the serum suggesting that this mutation led to either mRNA or protein instability resulting in a null phenotype. In addition, the patients exhibited severe vitamin A deficiency, and diminished serum retinol levels. Circulating transthyretin levels were normal. This study identifies the RBP4 splice site change as the cause of RP in this pedigree. The presence of developmental abnormalities and severe acne in patients with retinal degeneration may indicate the involvement of genes that regulate vitamin A absorption, transport and metabolism.

  1. Exome Analysis Identified a Novel Mutation in the RBP4 Gene in a Consanguineous Pedigree with Retinal Dystrophy and Developmental Abnormalities

    PubMed Central

    Cukras, Catherine; Gaasterland, Terry; Lee, Pauline; Gudiseva, Harini V.; Chavali, Venkata R. M.; Pullakhandam, Raghu; Maranhao, Bruno; Edsall, Lee; Soares, Sandra; Reddy, G. Bhanuprakash; Sieving, Paul A.; Ayyagari, Radha

    2012-01-01

    Retinitis Pigmentosa (RP) is a common form of retinal degeneration characterized by photoreceptor degeneration and retinal pigment epithelium (RPE) atrophy causing loss of visual field and acuities. Exome sequencing identified a novel homozygous splice site variant (c.111+1G>A) in the gene encoding retinol binding protein 4 (RBP4). This change segregated with early onset, progressive, and severe autosomal recessive retinitis pigmentosa (arRP) in an eight member consanguineous pedigree of European ancestry. Additionally, one patient exhibited developmental abnormalities including patent ductus arteriosus and chorioretinal and iris colobomas. The second patient developed acne from young age and extending into the 5th decade. Both patients had undetectable levels of RBP4 in the serum suggesting that this mutation led to either mRNA or protein instability resulting in a null phenotype. In addition, the patients exhibited severe vitamin A deficiency, and diminished serum retinol levels. Circulating transthyretin levels were normal. This study identifies the RBP4 splice site change as the cause of RP in this pedigree. The presence of developmental abnormalities and severe acne in patients with retinal degeneration may indicate the involvement of genes that regulate vitamin A absorption, transport and metabolism. PMID:23189188

  2. Congenital myopathy is caused by mutation of HACD1

    PubMed Central

    Muhammad, Emad; Reish, Orit; Ohno, Yusuke; Scheetz, Todd; DeLuca, Adam; Searby, Charles; Regev, Miriam; Benyamini, Lilach; Fellig, Yakov; Kihara, Akio; Sheffield, Val C.; Parvari, Ruti

    2013-01-01

    Congenital myopathies are heterogeneous inherited diseases of muscle characterized by a range of distinctive histologic abnormalities. We have studied a consanguineous family with congenital myopathy. Genome-wide linkage analysis and whole-exome sequencing identified a homozygous non-sense mutation in 3-hydroxyacyl-CoA dehydratase 1 (HACD1) in affected individuals. The mutation results in non-sense mediated decay of the HACD1 mRNA to 31% of control levels in patient muscle and completely abrogates the enzymatic activity of dehydration of 3-hydroxyacyl-CoA, the third step in the elongation of very long-chain fatty acids (VLCFAs). We describe clinical findings correlated with a deleterious mutation in a gene not previously known to be associated with congenital myopathy in humans. We suggest that the mutation in the HACD1 gene causes a reduction in the synthesis of VLCFAs, which are components of membrane lipids and participants in physiological processes, leading to congenital myopathy. These data indicate that HACD1 is necessary for muscle function. PMID:23933735

  3. Glycogen branching enzyme (GBE1) mutation causing equine glycogen storage disease IV.

    PubMed

    Ward, Tara L; Valberg, Stephanie J; Adelson, David L; Abbey, Colette A; Binns, Matthew M; Mickelson, James R

    2004-07-01

    Comparative biochemical and histopathological evidence suggests that a deficiency in the glycogen branching enzyme, encoded by the GBE1 gene, is responsible for a recently identified recessive fatal fetal and neonatal glycogen storage disease (GSD) in American Quarter Horses termed GSD IV. We have now derived the complete GBE1 cDNA sequences for control horses and affected foals, and identified a C to A substitution at base 102 that results in a tyrosine (Y) to stop (X) mutation in codon 34 of exon 1. All 11 affected foals were homozygous for the X34 allele, their 11 available dams and sires were heterozygous, and all 16 control horses were homozygous for the Y34 allele. The previous findings of poorly branched glycogen, abnormal polysaccharide accumulation, lack of measurable GBE1 enzyme activity and immunodetectable GBE1 protein, coupled with the present observation of abundant GBE1 mRNA in affected foals, are all consistent with the nonsense mutation in the 699 amino acid GBE1 protein. The affected foal pedigrees have a common ancestor and contain prolific stallions that are likely carriers of the recessive X34 allele. Defining the molecular basis of equine GSD IV will allow for accurate DNA testing and the ability to prevent occurrence of this devastating disease affecting American Quarter Horses and related breeds.

  4. DCLRE1C (ARTEMIS) mutations causing phenotypes ranging from atypical severe combined immunodeficiency to mere antibody deficiency.

    PubMed

    Volk, Timo; Pannicke, Ulrich; Reisli, Ismail; Bulashevska, Alla; Ritter, Julia; Björkman, Andrea; Schäffer, Alejandro A; Fliegauf, Manfred; Sayar, Esra H; Salzer, Ulrich; Fisch, Paul; Pfeifer, Dietmar; Di Virgilio, Michela; Cao, Hongzhi; Yang, Fang; Zimmermann, Karin; Keles, Sevgi; Caliskaner, Zafer; Güner, S Ükrü; Schindler, Detlev; Hammarström, Lennart; Rizzi, Marta; Hummel, Michael; Pan-Hammarström, Qiang; Schwarz, Klaus; Grimbacher, Bodo

    2015-12-20

    Null mutations in genes involved in V(D)J recombination cause a block in B- and T-cell development, clinically presenting as severe combined immunodeficiency (SCID). Hypomorphic mutations in the non-homologous end-joining gene DCLRE1C (encoding ARTEMIS) have been described to cause atypical SCID, Omenn syndrome, Hyper IgM syndrome and inflammatory bowel disease-all with severely impaired T-cell immunity. By whole-exome sequencing, we investigated the molecular defect in a consanguineous family with three children clinically diagnosed with antibody deficiency. We identified perfectly segregating homozygous variants in DCLRE1C in three index patients with recurrent respiratory tract infections, very low B-cell numbers and serum IgA levels. In patients, decreased colony survival after irradiation, impaired proliferative response and reduced counts of naïve T cells were observed in addition to a restricted T-cell receptor repertoire, increased palindromic nucleotides in the complementarity determining regions 3 and long stretches of microhomology at switch junctions. Defective V(D)J recombination was complemented by wild-type ARTEMIS protein in vitro. Subsequently, homozygous or compound heterozygous DCLRE1C mutations were identified in nine patients from the same geographic region. We demonstrate that DCLRE1C mutations can cause a phenotype presenting as only antibody deficiency. This novel association broadens the clinical spectrum associated with ARTEMIS mutations. Clinicians should consider the possibility that an immunodeficiency with a clinically mild initial presentation could be a combined immunodeficiency, so as to provide appropriate care for affected patients. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  5. Identification and characterisation of mutations associated with von Willebrand disease in a Turkish patient cohort

    PubMed Central

    Hampshire, Daniel J.; Abuzenadah, Adel M.; Cartwright, Ashley; Al-Shammari, Nawal S.; Coyle, Rachael E.; Eckert, Michaela; Al-Buhairan, Ahlam M.; Messenger, Sarah L.; Budde, Ulrich; Gürsel, Türkiz; Ingerslev, Jørgen; Peake, Ian R.; Goodeve, Anne C.

    2014-01-01

    Summary Several cohort studies have investigated the molecular basis of von Willebrand disease (VWD); however these have mostly focused on European and North American populations. This study aimed to investigate mutation spectrum in 26 index cases (IC) from Turkey diagnosed with all three VWD types, the majority (73%) with parents who were knowingly related. IC were screened for mutations using multiplex ligation-dependent probe amplification and analysis of all von Willebrand factor gene (VWF) exons and exon/intron boundaries. Selected missense mutations were expressed in vitro. Candidate VWF mutations were identified in 25 of 26 IC and included propeptide missense mutations in four IC (two resulting in type 1 and two in recessive 2A), all influencing VWF expression in vitro. Four missense mutations, a nonsense mutation and a small in-frame insertion resulting in type 2A were also identified. Of 15 type 3 VWD IC, 13 were homozygous and two compound heterozygous for 14 candidate mutations predicted to result in lack of expression and two propeptide missense changes. Identification of intronic breakpoints of an exon 17–18 deletion suggested that the mutation resulted from non-homologous end joining. This study provides further insight into the pathogenesis of VWD in a population with a high degree of consanguineous partnerships. PMID:23702511

  6. Two common low density lipoprotein receptor gene mutations cause familial hypercholesterolemia in Afrikaners.

    PubMed

    Leitersdorf, E; Van der Westhuyzen, D R; Coetzee, G A; Hobbs, H H

    1989-09-01

    Familial hypercholesterolemia (FH), an autosomal dominant disease caused by mutations in the LDL receptor gene, is five times more frequent in the Afrikaner population of South Africa than it is in the population of the United States and Europe. It has been proposed that the high frequency is due to a founder effect. In this paper, we characterized 24 mutant LDL receptor alleles from 12 Afrikaner individuals homozygous for FH. We identified two mutations that together makeup greater than 95% of the mutant LDL receptor genes represented in our sample. Both mutations were basepair substitutions that result in single-amino acid changes. Each mutation can be detected readily with the polymerase chain reaction and restriction analysis. The finding of two common LDL receptor mutations in the Afrikaner FH homozygotes predicts that these mutations will predominate in the Afrikaner population and that the high frequency of FH is due to a founder effect. The increased incidence of ischemic heart disease in the Afrikaner population may in part be due to the high frequency of these two mutations in the LDL receptor gene.

  7. Homozygosity mapping on a single patient: identification of homozygous regions of recent common ancestry by using population data.

    PubMed

    Zhang, Lu; Yang, Wanling; Ying, Dingge; Cherny, Stacey S; Hildebrandt, Friedhelm; Sham, Pak Chung; Lau, Yu Lung

    2011-03-01

    Homozygosity mapping has played an important role in detecting recessive mutations using families of consanguineous marriages. However, detection of regions identical and homozygosity by descent (HBD) when family data are not available, or when relationships are unknown, is still a challenge. Making use of population data from high-density SNP genotyping may allow detection of regions HBD from recent common founders in singleton patients without genealogy information. We report a novel algorithm that detects such regions by estimating the population haplotype frequencies (HF) for an entire homozygous region. We also developed a simulation method to evaluate the probability of HBD and linkage to disease for a homozygous region by examining the best regions in unaffected controls from the host population. The method can be applied to diseases of Mendelian inheritance but can also be extended to complex diseases to detect rare founder mutations that affect a very small number of patients using either multiplex families or sporadic cases. Testing of the method on both real cases (singleton affected) and simulated data demonstrated its superb sensitivity and robustness under genetic heterogeneity. © 2011 Wiley-Liss, Inc.

  8. HMG CoA lyase deficiency: identification of five causal point mutations in codons 41 and 42, including a frequent Saudi Arabian mutation, R41Q.

    PubMed Central

    Mitchell, G A; Ozand, P T; Robert, M F; Ashmarina, L; Roberts, J; Gibson, K M; Wanders, R J; Wang, S; Chevalier, I; Plöchl, E; Miziorko, H

    1998-01-01

    The hereditary deficiency of 3-hydroxy-3-methylglutaryl (HMG) CoA lyase (HL; OMIM 246450 [http://www3.ncbi.nlm.nih. gov:80/htbin-post/Omim/dispmim?246450]) results in episodes of hypoketotic hypoglycemia and coma and is reported to be frequent and clinically severe in Saudi Arabia. We found genetic diversity among nine Saudi HL-deficient probands: six were homozygous for the missense mutation R41Q, and two were homozygous for the frameshift mutation F305fs(-2). In 32 non-Saudi HL-deficient probands, we found three R41Q alleles and also discovered four other deleterious point mutations in codons 41 and 42: R41X, D42E, D42G, and D42H. In purified mutant recombinant HL, all four missense mutations in codons 41 and 42 cause a marked decrease in HL activity. We developed a screening procedure for HL missense mutations that yields residual activity at levels comparable to those obtained using purified HL peptides. Codons 41 and 42 are important for normal HL catalysis and account for a disproportionate 21 (26%) of 82 of mutant alleles in our group of HL-deficient probands. PMID:9463337

  9. Targeted next generation sequencing of mucosal melanomas identifies frequent NF1 and RAS mutations.

    PubMed

    Cosgarea, Ioana; Ugurel, Selma; Sucker, Antje; Livingstone, Elisabeth; Zimmer, Lisa; Ziemer, Mirjana; Utikal, Jochen; Mohr, Peter; Pfeiffer, Christiane; Pföhler, Claudia; Hillen, Uwe; Horn, Susanne; Schadendorf, Dirk; Griewank, Klaus G; Roesch, Alexander

    2017-06-20

    Mucosal melanoma represents ~1% of all melanomas, frequently having a poor prognosis due to diagnosis at a late stage of disease. Mucosal melanoma differs from cutaneous melanoma not only in terms of poorer clinical outcome but also on the molecular level having e.g. less BRAF and more frequent KIT mutations than cutaneous melanomas. For the majority of mucosal melanomas oncogenic driver mutations remain unknown. In our study, 75 tumor tissues from patients diagnosed with mucosal melanoma were analyzed, applying a targeted next generation sequencing panel covering 29 known recurrently mutated genes in melanoma. NF1 and RAS mutations were identified as the most frequently mutated genes occurring in 18.3% and 16.9% of samples, respectively. Mutations in BRAF were identified in 8.4% and KIT in 7.0% of tumor samples. Our study identifies NF1 as the most frequently occurring driver mutation in mucosal melanoma. RAS alterations, consisting of NRAS and KRAS mutations, were the second most frequent mutation type. BRAF and KIT mutations were rare with frequencies below 10% each. Our data indicate that in mucosal melanomas RAS/NF1 alterations are frequent, implying a significant pathogenetic role for MAPK and potentially PI3K pathway activation in these tumors.

  10. Targeted next generation sequencing of mucosal melanomas identifies frequent NF1 and RAS mutations

    PubMed Central

    Cosgarea, Ioana; Ugurel, Selma; Sucker, Antje; Livingstone, Elisabeth; Zimmer, Lisa; Ziemer, Mirjana; Utikal, Jochen; Mohr, Peter; Pfeiffer, Christiane; Pföhler, Claudia; Hillen, Uwe; Horn, Susanne; Schadendorf, Dirk

    2017-01-01

    Purpose Mucosal melanoma represents ~1% of all melanomas, frequently having a poor prognosis due to diagnosis at a late stage of disease. Mucosal melanoma differs from cutaneous melanoma not only in terms of poorer clinical outcome but also on the molecular level having e.g. less BRAF and more frequent KIT mutations than cutaneous melanomas. For the majority of mucosal melanomas oncogenic driver mutations remain unknown. Experimental Design and Results In our study, 75 tumor tissues from patients diagnosed with mucosal melanoma were analyzed, applying a targeted next generation sequencing panel covering 29 known recurrently mutated genes in melanoma. NF1 and RAS mutations were identified as the most frequently mutated genes occurring in 18.3% and 16.9% of samples, respectively. Mutations in BRAF were identified in 8.4% and KIT in 7.0% of tumor samples. Conclusions Our study identifies NF1 as the most frequently occurring driver mutation in mucosal melanoma. RAS alterations, consisting of NRAS and KRAS mutations, were the second most frequent mutation type. BRAF and KIT mutations were rare with frequencies below 10% each. Our data indicate that in mucosal melanomas RAS/NF1 alterations are frequent, implying a significant pathogenetic role for MAPK and potentially PI3K pathway activation in these tumors. PMID:28380455

  11. Genetic heterogeneity and consanguinity lead to a “double hit”: Homozygous mutations of MYO7A and PDE6B in a patient with retinitis pigmentosa

    PubMed Central

    Goldenberg-Cohen, Nitza; Banin, Eyal; Zalzstein, Yael; Cohen, Ben; Rotenstreich, Ygal; Rizel, Leah; Basel-Vanagaite, Lina

    2013-01-01

    Purpose Retinitis pigmentosa (RP), the most genetically heterogeneous disorder in humans, actually represents a group of pigmentary retinopathies characterized by night blindness followed by visual-field loss. RP can appear as either syndromic or nonsyndromic. One of the most common forms of syndromic RP is Usher syndrome, characterized by the combination of RP, hearing loss, and vestibular dysfunction. Methods The underlying cause of the appearance of syndromic and nonsyndromic RP in three siblings from a consanguineous Israeli Muslim Arab family was studied with whole-genome homozygosity mapping followed by whole exome sequencing. Results The family was found to segregate novel mutations of two different genes: myosin VIIA (MYO7A), which causes type 1 Usher syndrome, and phosphodiesterase 6B, cyclic guanosine monophosphate-specific, rod, beta (PDE6B), which causes nonsyndromic RP. One affected child was homozygous for both mutations. Since the retinal phenotype seen in this patient results from overlapping pathologies, one might expect to find severe retinal degeneration. Indeed, he was diagnosed with RP based on an abnormal electroretinogram (ERG) at a young age (9 months). However, this early diagnosis may be biased, as two of his older siblings had already been diagnosed, leading to increased awareness. At the age of 32 months, he had relatively good vision with normal visual fields. Further testing of visual function and structure at different ages in the three siblings is needed to determine whether the two RP-causing genes mutated in this youngest sibling confer increased disease severity. Conclusions This report further supports the genetic heterogeneity of RP, and demonstrates how consanguinity could increase intrafamilial clustering of multiple hereditary diseases. Moreover, this report provides a unique opportunity to study the clinical implications of the coexistence of pathogenic mutations in two RP-causative genes in a human patient. PMID:23882135

  12. Gene mutations in children with chronic pancreatitis.

    PubMed

    Witt, H

    2001-01-01

    In the last few years, several genes have been identified as being associated with hereditary and idiopathic chronic pancreatitis (CP), i.e. PRSS1, CFTR and SPINK1. In this study, we investigated 164 unrelated children and adolescents with CP for mutations in disease-associated genes by direct DNA sequencing, SSCP, RFLP and melting curve analysis. In 15 patients, we detected a PRSS1 mutation (8 with A16V, 5 with R122H, 2 with N29I), and in 34 patients, a SPINK1 mutation (30 with N34S, 4 with others). SPINK1 mutations were predominantly found in patients without a family history (29/121). Ten patients were homozygous for N34S, SPINK1 mutations were most common in 'idiopathic' CP, whereas patients with 'hereditary' CP predominantly showed a PRSS1 mutation (R122H, N29I). In patients without a family history, the most common PRSS1 mutation was A16V (7/121). In conclusion, our data suggest that CP may be inherited in a dominant, recessive or multigenetic manner as a result of mutations in the above-mentioned or as yet unidentified genes. This challenges the concept of idiopathic CP as a nongenetic disorder and the differentiation between hereditary and idiopathic CP. Therefore, we propose to classify CP as either 'primary CP' (with or without a family history) or 'secondary CP' caused by toxic, metabolic or other factors.

  13. A recessive founder mutation in regulator of telomere elongation helicase 1, RTEL1, underlies severe immunodeficiency and features of Hoyeraal Hreidarsson syndrome.

    PubMed

    Ballew, Bari J; Joseph, Vijai; De, Saurav; Sarek, Grzegorz; Vannier, Jean-Baptiste; Stracker, Travis; Schrader, Kasmintan A; Small, Trudy N; O'Reilly, Richard; Manschreck, Chris; Harlan Fleischut, Megan M; Zhang, Liying; Sullivan, John; Stratton, Kelly; Yeager, Meredith; Jacobs, Kevin; Giri, Neelam; Alter, Blanche P; Boland, Joseph; Burdett, Laurie; Offit, Kenneth; Boulton, Simon J; Savage, Sharon A; Petrini, John H J

    2013-08-01

    Dyskeratosis congenita (DC) is a heterogeneous inherited bone marrow failure and cancer predisposition syndrome in which germline mutations in telomere biology genes account for approximately one-half of known families. Hoyeraal Hreidarsson syndrome (HH) is a clinically severe variant of DC in which patients also have cerebellar hypoplasia and may present with severe immunodeficiency and enteropathy. We discovered a germline autosomal recessive mutation in RTEL1, a helicase with critical telomeric functions, in two unrelated families of Ashkenazi Jewish (AJ) ancestry. The affected individuals in these families are homozygous for the same mutation, R1264H, which affects three isoforms of RTEL1. Each parent was a heterozygous carrier of one mutant allele. Patient-derived cell lines revealed evidence of telomere dysfunction, including significantly decreased telomere length, telomere length heterogeneity, and the presence of extra-chromosomal circular telomeric DNA. In addition, RTEL1 mutant cells exhibited enhanced sensitivity to the interstrand cross-linking agent mitomycin C. The molecular data and the patterns of inheritance are consistent with a hypomorphic mutation in RTEL1 as the underlying basis of the clinical and cellular phenotypes. This study further implicates RTEL1 in the etiology of DC/HH and immunodeficiency, and identifies the first known homozygous autosomal recessive disease-associated mutation in RTEL1.

  14. A Recessive Founder Mutation in Regulator of Telomere Elongation Helicase 1, RTEL1, Underlies Severe Immunodeficiency and Features of Hoyeraal Hreidarsson Syndrome

    PubMed Central

    Ballew, Bari J.; Joseph, Vijai; De, Saurav; Sarek, Grzegorz; Vannier, Jean-Baptiste; Stracker, Travis; Schrader, Kasmintan A.; Small, Trudy N.; O'Reilly, Richard; Manschreck, Chris; Harlan Fleischut, Megan M.; Zhang, Liying; Sullivan, John; Stratton, Kelly; Yeager, Meredith; Jacobs, Kevin; Giri, Neelam; Alter, Blanche P.; Boland, Joseph; Burdett, Laurie; Offit, Kenneth; Boulton, Simon J.

    2013-01-01

    Dyskeratosis congenita (DC) is a heterogeneous inherited bone marrow failure and cancer predisposition syndrome in which germline mutations in telomere biology genes account for approximately one-half of known families. Hoyeraal Hreidarsson syndrome (HH) is a clinically severe variant of DC in which patients also have cerebellar hypoplasia and may present with severe immunodeficiency and enteropathy. We discovered a germline autosomal recessive mutation in RTEL1, a helicase with critical telomeric functions, in two unrelated families of Ashkenazi Jewish (AJ) ancestry. The affected individuals in these families are homozygous for the same mutation, R1264H, which affects three isoforms of RTEL1. Each parent was a heterozygous carrier of one mutant allele. Patient-derived cell lines revealed evidence of telomere dysfunction, including significantly decreased telomere length, telomere length heterogeneity, and the presence of extra-chromosomal circular telomeric DNA. In addition, RTEL1 mutant cells exhibited enhanced sensitivity to the interstrand cross-linking agent mitomycin C. The molecular data and the patterns of inheritance are consistent with a hypomorphic mutation in RTEL1 as the underlying basis of the clinical and cellular phenotypes. This study further implicates RTEL1 in the etiology of DC/HH and immunodeficiency, and identifies the first known homozygous autosomal recessive disease-associated mutation in RTEL1. PMID:24009516

  15. Mutations in HPSE2 cause urofacial syndrome.

    PubMed

    Daly, Sarah B; Urquhart, Jill E; Hilton, Emma; McKenzie, Edward A; Kammerer, Richard A; Lewis, Malcolm; Kerr, Bronwyn; Stuart, Helen; Donnai, Dian; Long, David A; Burgu, Berk; Aydogdu, Ozgu; Derbent, Murat; Garcia-Minaur, Sixto; Reardon, Willie; Gener, Blanca; Shalev, Stavit; Smith, Rupert; Woolf, Adrian S; Black, Graeme C; Newman, William G

    2010-06-11

    Urinary voiding dysfunction in childhood, manifesting as incontinence, dysuria, and urinary frequency, is a common condition. Urofacial syndrome (UFS) is a rare autosomal recessive disease characterized by facial grimacing when attempting to smile and failure of the urinary bladder to void completely despite a lack of anatomical bladder outflow obstruction or overt neurological damage. UFS individuals often have reflux of infected urine from the bladder to the upper renal tract, with a risk of kidney damage and renal failure. Whole-genome SNP mapping in one affected individual defined an autozygous region of 16 Mb on chromosome 10q23-q24, within which a 10 kb deletion encompassing exons 8 and 9 of HPSE2 was identified. Homozygous exonic deletions, nonsense mutations, and frameshift mutations in five further unrelated families confirmed HPSE2 as the causative gene for UFS. Mutations were not identified in four additional UFS patients, indicating genetic heterogeneity. We show that HPSE2 is expressed in the fetal and adult central nervous system, where it might be implicated in controlling facial expression and urinary voiding, and also in bladder smooth muscle, consistent with a role in renal tract morphology and function. Our findings have broader implications for understanding the genetic basis of lower renal tract malformations and voiding dysfunction.

  16. Mutations in HPSE2 Cause Urofacial Syndrome

    PubMed Central

    Daly, Sarah B.; Urquhart, Jill E.; Hilton, Emma; McKenzie, Edward A.; Kammerer, Richard A.; Lewis, Malcolm; Kerr, Bronwyn; Stuart, Helen; Donnai, Dian; Long, David A.; Burgu, Berk; Aydogdu, Ozgu; Derbent, Murat; Garcia-Minaur, Sixto; Reardon, Willie; Gener, Blanca; Shalev, Stavit; Smith, Rupert; Woolf, Adrian S.; Black, Graeme C.; Newman, William G.

    2010-01-01

    Urinary voiding dysfunction in childhood, manifesting as incontinence, dysuria, and urinary frequency, is a common condition. Urofacial syndrome (UFS) is a rare autosomal recessive disease characterized by facial grimacing when attempting to smile and failure of the urinary bladder to void completely despite a lack of anatomical bladder outflow obstruction or overt neurological damage. UFS individuals often have reflux of infected urine from the bladder to the upper renal tract, with a risk of kidney damage and renal failure. Whole-genome SNP mapping in one affected individual defined an autozygous region of 16 Mb on chromosome 10q23-q24, within which a 10 kb deletion encompassing exons 8 and 9 of HPSE2 was identified. Homozygous exonic deletions, nonsense mutations, and frameshift mutations in five further unrelated families confirmed HPSE2 as the causative gene for UFS. Mutations were not identified in four additional UFS patients, indicating genetic heterogeneity. We show that HPSE2 is expressed in the fetal and adult central nervous system, where it might be implicated in controlling facial expression and urinary voiding, and also in bladder smooth muscle, consistent with a role in renal tract morphology and function. Our findings have broader implications for understanding the genetic basis of lower renal tract malformations and voiding dysfunction. PMID:20560210

  17. Neuropathology of the recessive A673V APP mutation: Alzheimer disease with distinctive features.

    PubMed

    Giaccone, Giorgio; Morbin, Michela; Moda, Fabio; Botta, Mario; Mazzoleni, Giulia; Uggetti, Andrea; Catania, Marcella; Moro, Maria Luisa; Redaelli, Veronica; Spagnoli, Alberto; Rossi, Roberta Simona; Salmona, Mario; Di Fede, Giuseppe; Tagliavini, Fabrizio

    2010-12-01

    Mutations of three different genes, encoding β-amyloid precursor protein (APP), presenilin 1 and presenilin 2 are associated with familial Alzheimer's disease (AD). Recently, the APP mutation A673V has been identified that stands out from all the genetic defects previously reported in these three genes, since it causes the disease only in the homozygous state (Di Fede et al. in Science 323:1473-1477, 2009). We here provide the detailed neuropathological picture of the proband of this family, who was homozygous for the APP A673V mutation and recently came to death. The brain has been studied by histological and immunohistochemical techniques, at the optical and ultrastructural levels. Cerebral Aβ accumulation and tau pathology were severe and extensive. Peculiar features were the configuration of the Aβ deposits that were of large size, mostly perivascular and exhibited a close correspondence between the pattern elicited by amyloid stainings and the labeling obtained with immunoreagents specific for Aβ40 or Aβ42. Moreover, Aβ deposition spared the neostriatum while deeply affecting the cerebellum, and therefore was not in compliance with the hierarchical topographical sequence of involvement documented in sporadic AD. Therefore, the neuropathological picture of familial AD caused by the APP recessive mutation A673V presents distinctive characteristics compared to sporadic AD or familial AD inherited as a dominant trait. Main peculiar features are the morphology, structural properties and composition of the Aβ deposits as well as their topographic distribution in the brain.

  18. Bilateral synergistic convergence associated with homozygous ROB03 mutation (p.Pro771Leu).

    PubMed

    Khan, Arif O; Oystreck, Darren T; Al-Tassan, Nada; Al-Sharif, Latifa; Bosley, Thomas M

    2008-12-01

    To document the phenotype and determine the genotype of a child with synergistic convergence. Interventional case report. Patient and nuclear family (7 members total). Ophthalmologic, neurologic, and radiologic examination of the proband; venous blood sampling for candidate gene testing of the proband; venous blood sampling for confirmatory testing in other family members. Clinical and radiologic observations in proband and candidate gene results. The proband, a 9-year-old girl, substituted convergence for horizontal gaze (synergistic convergence) since birth. She also had conjugate pendular nystagmus, asynchronous blinking, and high myopia. No family member had ophthalmologic or medical symptoms. Neuroradiologic imaging revealed hindbrain dysplasia and modest scoliosis. Sequencing of ROB03, the gene associated with horizontal gaze palsy and progressive scoliosis, revealed a novel missense mutation (p.Pro771Leu) that altered an evolutionarily conserved amino acid. Screening the family for this mutation confirmed that both parents were carriers and identified 2 sisters as carriers and 2 brothers as noncarriers. This is the second reported patient with synergistic convergence and the first associated with a documented pathologic genotype. Unlike the previously reported case (which occurred in the setting of the cranial dysinnervation disorder congenital fibrosis of the extraocular muscles), our patient presumably has a supranuclear cause. The author(s) have no proprietary or commercial interest in any materials discussed in this article.

  19. Leigh syndrome associated with mitochondrial complex I deficiency due to a novel mutation in the NDUFS1 gene.

    PubMed

    Martín, Miguel A; Blázquez, Alberto; Gutierrez-Solana, Luis G; Fernández-Moreira, Daniel; Briones, Paz; Andreu, Antoni L; Garesse, Rafael; Campos, Yolanda; Arenas, Joaquín

    2005-04-01

    Mutations in the nuclear-encoded subunits of complex I of the mitochondrial respiratory chain are a recognized cause of Leigh syndrome (LS). Recently, 6 mutations in the NDUFS1 gene were identified in 3 families. To describe a Spanish family with LS, complex I deficiency in muscle, and a novel mutation in the NDUFS1 gene. Using molecular genetic approaches, we identified the underlying molecular defect in a patient with LS with a complex I defect. The proband was a child who displayed the clinical features of LS. Muscle biochemistry results showed a complex I defect of the mitochondrial respiratory chain. Sequencing analysis of the mitochondrial DNA-encoded ND genes, the nuclear DNA-encoded NDUFV1, NDUFS1, NDUFS2, NDUFS4, NDUFS6, NDUFS7, NDUFS8, and NDUFAB1 genes, and the complex I assembly factor CIA30 gene revealed a novel homozygous L231V mutation (c.691C-->G) in the NDUFS1 gene. The parents were heterozygous carriers of the L231V mutation. Identifying nuclear mutations as a cause of respiratory chain disorders will enhance the possibility of prenatal diagnosis and help us understand how molecular defects can lead to complex I deficiency.

  20. Biallelic UFM1 and UFC1 mutations expand the essential role of ufmylation in brain development.

    PubMed

    Nahorski, Michael S; Maddirevula, Sateesh; Ishimura, Ryosuke; Alsahli, Saud; Brady, Angela F; Begemann, Anaïs; Mizushima, Tsunehiro; Guzmán-Vega, Francisco J; Obata, Miki; Ichimura, Yoshinobu; Alsaif, Hessa S; Anazi, Shams; Ibrahim, Niema; Abdulwahab, Firdous; Hashem, Mais; Monies, Dorota; Abouelhoda, Mohamed; Meyer, Brian F; Alfadhel, Majid; Eyaid, Wafa; Zweier, Markus; Steindl, Katharina; Rauch, Anita; Arold, Stefan T; Woods, C Geoffrey; Komatsu, Masaaki; Alkuraya, Fowzan S

    2018-06-02

    The post-translational modification of proteins through the addition of UFM1, also known as ufmylation, plays a critical developmental role as revealed by studies in animal models. The recent finding that biallelic mutations in UBA5 (the E1-like enzyme for ufmylation) cause severe early-onset encephalopathy with progressive microcephaly implicates ufmylation in human brain development. More recently, a homozygous UFM1 variant was proposed as a candidate aetiology of severe early-onset encephalopathy with progressive microcephaly. Here, we establish a locus for severe early-onset encephalopathy with progressive microcephaly based on two families, and map the phenotype to a novel homozygous UFM1 mutation. This mutation has a significantly diminished capacity to form thioester intermediates with UBA5 and with UFC1 (the E2-like enzyme for ufmylation), with resulting impaired ufmylation of cellular proteins. Remarkably, in four additional families where eight children have severe early-onset encephalopathy with progressive microcephaly, we identified two biallelic UFC1 mutations, which impair UFM1-UFC1 intermediate formation with resulting widespread reduction of cellular ufmylation, a pattern similar to that observed with UFM1 mutation. The striking resemblance between UFM1- and UFC1-related clinical phenotype and biochemical derangements strongly argues for an essential role for ufmylation in human brain development. The hypomorphic nature of UFM1 and UFC1 mutations and the conspicuous depletion of biallelic null mutations in the components of this pathway in human genome databases suggest that it is necessary for embryonic survival, which is consistent with the embryonic lethal nature of knockout models for the orthologous genes.

  1. Homozygous deletions at 3p12 in breast and lung cancer.

    PubMed

    Sundaresan, V; Chung, G; Heppell-Parton, A; Xiong, J; Grundy, C; Roberts, I; James, L; Cahn, A; Bench, A; Douglas, J; Minna, J; Sekido, Y; Lerman, M; Latif, F; Bergh, J; Li, H; Lowe, N; Ogilvie, D; Rabbitts, P

    1998-10-01

    We have constructed a physical map of the region homozygously deleted in the U2020 cell line at 3p12, including the location of putative CpG islands. Adjacent to one of these islands, we have identified and cloned a new gene (DUTT1) and used probes from this gene to detect two other homozygous deletions occurring in lung and breast carcinomas: the smallest deletion is within the gene itself and would result in a truncated protein. The DUTT1 gene is a member of the neural cell adhesion molecule family, although its widespread expression suggests it plays a less specialized role compared to other members of the family.

  2. A Novel Homozygous Mutation in SPTBN2 Leads to Spinocerebellar Ataxia in a Consanguineous Family: Report of a New Infantile-Onset Case and Brief Review of the Literature.

    PubMed

    Al-Muhaizea, Mohammad A; AlMutairi, Faten; Almass, Rawan; AlHarthi, Safinaz; Aldosary, Mazhor S; Alsagob, Maysoon; AlOdaib, Ali; Colak, Dilek; Kaya, Namik

    2018-06-01

    The objective of this study was the identification of likely genes and mutations associated with an autosomal recessive (AR) rare spinocerebellar ataxia (SCA) phenotype in two patients with infantile onset, from a consanguineous family. Using genome-wide SNP screening, autozygosity mapping, targeted Sanger sequencing and nextgen sequencing, family segregation analysis, and comprehensive neuropanel, we discovered a novel mutation in SPTBN2. Next, we utilized multiple sequence alignment of amino acids from various species as well as crystal structures provided by protein data bank (PDB# 1WYQ and 1WJM) to model the mutation site and its effect on β-III-spectrin. Finally, we used various bioinformatic classifiers to determine pathogenicity of the missense variant. A comprehensive clinical and diagnostic workup including radiological exams were performed on the patients as part of routine patient care. The homozygous missense variant (c.1572C>T; p.R414C) detected in exon 2 was fully segregated in the family and absent in a large ethnic cohort as well as publicly available data sets. Our comprehensive targeted sequencing approaches did not reveal any other likely candidate variants or mutations in both patients. The two male siblings presented with delayed motor milestones and cognitive and learning disability. Brain MRI revealed isolated cerebellar atrophy more marked in midline inferior vermis at ages of 3 and 6.5 years. Sequence alignments of the amino acids for β-III-spectrin indicated that the arginine at 414 is highly conserved among various species and located towards the end of first spectrin repeat domain. Inclusive bioinformatic analysis predicted that the variant is to be damaging and disease causing. In addition to the novel mutation, a brief literature review of the previously reported mutations as well as clinical comparison of the cases were also presented. Our study reviews the previously reported SPTBN2 mutations and cases. Moreover, the novel

  3. X-linked juvenile retinoschisis in a consanguineous family: phenotypic variability and report of a homozygous female patient.

    PubMed

    Gliem, Martin; Holz, Frank G; Stöhr, Heidi; Weber, Bernhard H F; Charbel Issa, Peter

    2014-12-01

    To describe the phenotypic variability in a consanguineous family with genetically confirmed X-linked retinoschisis. Five patients, including one homozygous female, were characterized by clinical examination, optical coherence tomography, fundus autofluorescence, mapping of macular pigment optical density, electroretinography, and DNA testing. The 36-year-old male index patient showed a ring of enhanced autofluorescence and outer retinal atrophy on optical coherence tomography. Electroretinography testing revealed a reduced a/b ratio. His mother presented with a central atrophic retina with markedly reduced autofluorescence signal and a surrounding ring of enhanced autofluorescence. The 40-year-old brother of the index patient and his 2 sons showed characteristic signs for X-linked retinoschisis, including retinal schisis and a reduced a/b ratio. Genetic testing revealed a c.293C>A mutation in the RS1 gene in all affected family members while the mother of the index patient was homozygous for this mutation. X-linked retinoschisis can present with a wide phenotypic variability. Here, detailed family history and genetic testing established the diagnosis of X-linked retinoschisis despite striking differences in phenotypic presentation in affected subjects, homozygosity of one affected female, and seemingly dominant inheritance in three subsequent generations because of multiple consanguinity.

  4. Different EGFR gene mutations in two patients with synchronous multiple lung cancers: A case report

    PubMed Central

    Sakai, Hiroki; Kimura, Hiroyuki; Tsuda, Masataka; Wakiyama, Yoichi; Miyazawa, Tomoyuki; Marushima, Hideki; Kojima, Koji; Hoshikawa, Masahiro; Takagi, Masayuki; Nakamura, Haruhiko

    2017-01-01

    Routine clinical and pathological evaluations to determine the relationship between different lesions are often not completely conclusive. Interestingly, detailed genetic analysis of tumor samples may provide important additional information and identify second primary lung cancers. In the present study, we report cases of two synchronous lung adenocarcinomas composed of two distinct pathological subtypes with different EGFR gene mutations: a homozygous deletion in exon 19 of the papillary adenocarcinoma subtype and a point mutation of L858R in exon 21 of the tubular adenocarcinoma. The present report highlights the clinical importance of molecular cancer biomarkers to guide management decisions in cases involving multiple lung tumors. PMID:29090842

  5. Permanent Neonatal Diabetes Caused by Dominant, Recessive, or Compound Heterozygous SUR1 Mutations with Opposite Functional Effects

    PubMed Central

    Ellard, Sian ; Flanagan, Sarah E. ; Girard, Christophe A. ; Patch, Ann-Marie ; Harries, Lorna W. ; Parrish, Andrew ; Edghill, Emma L. ; Mackay, Deborah J. G. ; Proks, Peter ; Shimomura, Kenju ; Haberland, Holger ; Carson, Dennis J. ; Shield, Julian P. H. ; Hattersley, Andrew T. ; Ashcroft, Frances M. 

    2007-01-01

    Heterozygous activating mutations in the KCNJ11 gene encoding the pore-forming Kir6.2 subunit of the pancreatic beta cell KATP channel are the most common cause of permanent neonatal diabetes (PNDM). Patients with PNDM due to a heterozygous activating mutation in the ABCC8 gene encoding the SUR1 regulatory subunit of the KATP channel have recently been reported. We studied a cohort of 59 patients with permanent diabetes who received a diagnosis before 6 mo of age and who did not have a KCNJ11 mutation. ABCC8 gene mutations were identified in 16 of 59 patients and included 8 patients with heterozygous de novo mutations. A recessive mode of inheritance was observed in eight patients with homozygous, mosaic, or compound heterozygous mutations. Functional studies of selected mutations showed a reduced response to ATP consistent with an activating mutation that results in reduced insulin secretion. A novel mutational mechanism was observed in which a heterozygous activating mutation resulted in PNDM only when a second, loss-of-function mutation was also present. PMID:17668386

  6. To pace or not to pace: a pilot study of four- and five-gaited Icelandic horses homozygous for the DMRT3 'Gait Keeper' mutation.

    PubMed

    Jäderkvist Fegraeus, K; Hirschberg, I; Árnason, T; Andersson, L; Velie, B D; Andersson, L S; Lindgren, G

    2017-12-01

    The Icelandic horse is a breed known mainly for its ability to perform the ambling four-beat gait 'tölt' and the lateral two-beat gait pace. The natural ability of the breed to perform these alternative gaits is highly desired by breeders. Therefore, the discovery that a nonsense mutation (C>A) in the DMRT3 gene was the main genetic factor for horses' ability to perform gaits in addition to walk, trot and canter was of great interest. Although several studies have demonstrated that homozygosity for the DMRT3 mutation is important for the ability to pace, only about 70% of the homozygous mutant (AA) Icelandic horses are reported to pace. The aim of the study was to genetically compare four- and five-gaited (i.e. horses with and without the ability to pace) AA Icelandic horses by performing a genome-wide association (GWA) analysis. All horses (n = 55) were genotyped on the 670K Axiom Equine Genotyping Array, and a GWA analysis was performed using the genabel package in r. No SNP demonstrated genome-wide significance, implying that the ability to pace goes beyond the presence of a single gene variant. Despite its limitations, the current study provides additional information regarding the genetic complexity of pacing ability in horses. However, to fully understand the genetic differences between four- and five-gaited AA horses, additional studies with larger sample materials and consistent phenotyping are needed. © 2017 Stichting International Foundation for Animal Genetics.

  7. Fanconi anemia founder mutation in Macedonian patients.

    PubMed

    Madjunkova, Svetlana; Kocheva, Svetlana A; Plaseska-Karanfilska, Dijana

    2014-01-01

    Fanconi anemia (FA) is a rare autosomal recessive disorder clinically characterized by developmental abnormalities, progressive bone marrow failure (BMF) and profound cancer predisposition. Approximately 65% of all affected individuals have mutation in the FANCA (Fanconi anemia complementation group A) gene. The mutation spectrum of the FANCA gene is highly heterogeneous. FA-A is usually associated with private FANCA mutations in individual families. We describe 3 unrelated patients with FA with a similar clinical presentation: BMF, renal anomalies and café-au-lait pigmentation without major skeletal abnormality. The molecular analysis of the FANCA gene using the FA MLPA kit P031-A2/P032 FANCA, showed homozygous deletion of exon 3 in all 3 patients. Molecular analysis of the flanking regions of exon 3 precisely defined unique deletion of 2,040 bp and duplication of C (1788_3828dupC). These are the first 3 patients homozygous for deletion of FANCA exon 3 described to date. Although not related, the patients originated from the same Gypsy-like ethnic population. We conclude that c.190-256_283 + 1680del2040 dupC mutation in the FANCA gene is a founder mutation in Macedonian FA patients of Gypsy-like ethnic origin. Our finding has very strong implications for these patients in formulating diagnostic and carrier-screening strategy for BMF and FA and to enable comprehensive genetic counseling. © 2013 S. Karger AG, Basel.

  8. Mutations in TULP1, NR2E3, and MFRP genes in Indian families with autosomal recessive retinitis pigmentosa

    PubMed Central

    Singh, Hardeep; Sahini, Nishika; Jalali, Subhadra; Mohan, Gayathri

    2012-01-01

    Purpose To identify genes underlying autosomal recessive retinitis pigmentosa (ARRP) by homozygosity mapping. Methods Families with ARRP were recruited after complete ophthalmic evaluation of all members and diagnosis of RP by predefined criteria. Genomic DNA from affected members of 26 families was genotyped on Illumina single nucleotide polymorphism (SNP) 6.0 K arrays with standard procedures. Genotypes were evaluated for homozygous regions that were common and concordant between affected members of each family. The genes mapping to homozygous intervals within these families were screened for pathogenic changes with PCR amplification and sequencing of coding regions. Cosegegration of sequence changes with disease was determined within each pedigree, and each variation was tested for presence in 100 unrelated normal controls. Results A genome-wide scan for homozygosity showed homozygous regions harboring the tubby like protein 1 gene (TULP1; chromosome 6) in one family, the nuclear receptor subfamily 2, group E, member 3 gene (NR2E3; chromosome 15) in three families, and the membrane frizzled-related protein gene (MFRP; chromosome 11) in one family. Screening of the three genes in the respective families revealed homozygous disease-causing mutations in three families. These included a missense mutation in TULP1, a deletion-cum-insertion in NR2E3, and a single base deletion in MFRP. Patients from all three families had a rod-cone type of dystrophy with night blindness initially. The NR2E3 and MFRP genes were associated with fundus features atypical of RP. Conclusions This study shows involvement of the TULP1, NR2E3, and MFRP genes in ARRP in Indian cases. Genome-wide screening with SNP arrays followed by a prioritized candidate gene evaluation is useful in identifying genes in these patients. PMID:22605927

  9. Targeted exome sequencing of Korean triple-negative breast cancer reveals homozygous deletions associated with poor prognosis of adjuvant chemotherapy-treated patients

    PubMed Central

    Jeong, Hae Min; Kim, Ryong Nam; Kwon, Mi Jeong; Oh, Ensel; Han, Jinil; Lee, Se Kyung; Choi, Jong-Sun; Park, Sara; Nam, Seok Jin; Gong, Gyung Yup; Nam, Jin Wu; Choi, Doo Ho; Lee, Hannah; Nam, Byung-Ho; Choi, Yoon-La; Shin, Young Kee

    2017-01-01

    Triple-negative breast cancer is characterized by the absence of estrogen and progesterone receptors and human epidermal growth factor receptor 2, and is associated with a poorer outcome than other subtypes of breast cancer. Moreover, there are no accurate prognostic genes or effective therapeutic targets, thereby necessitating continued intensive investigation. This study analyzed the genetic mutation landscape in 70 patients with triple-negative breast cancer by targeted exome sequencing of tumor and matched normal samples. Sequencing showed that more than 50% of these patients had deleterious mutations and homozygous deletions of DNA repair genes, such as ATM, BRCA1, BRCA2, WRN, and CHEK2. These findings suggested that a large number of patients with triple-negative breast cancer have impaired DNA repair function and that therefore a poly ADP-ribose polymerase inhibitor may be an effective drug in the treatment of this disease. Notably, homozygous deletion of three genes, EPHA5, MITF, and ACSL3, was significantly associated with an increased risk of recurrence or distant metastasis in adjuvant chemotherapy-treated patients. PMID:28977883

  10. Mipomersen: evidence-based review of its potential in the treatment of homozygous and severe heterozygous familial hypercholesterolemia.

    PubMed

    Parhofer, Klaus G

    2012-01-01

    Familial hypercholesterolemia (FH) is an autosomal-dominant inherited disease with a prevalence of one in 500 (heterozygous) to one in 1,000,000 (homozygous). Mutations of the low-density lipoprotein (LDL) receptor gene, the apolipoprotein B100 gene, or the PCSK9 gene may be responsible for the disease. The resulting LDL hypercholesterolemia results in premature atherosclerosis as early as childhood (homozygous FH) or in adulthood (heterozygous FH). Current treatment modalities include lifestyle modification, combination drug therapy (statin-based), and apheresis. Mipomersen is an antisense oligonucleotide which inhibits apolipoprotein B production independent of LDL receptor function and thus works in homozygous FH, heterozygous FH, and other forms of hypercholesterolemia. Mipomersen is given 200 mg/week subcutaneously. Phase III studies indicate that the LDL cholesterol concentration can be reduced by 25%-47%, lipoprotein(a) levels by 20%-40%, and triglyceride concentrations by approximately 10%. In general, mipomersen has no effect on high-density lipoprotein cholesterol concentrations. Although there is considerable interindividual variability, the observed lipid effects are largely independent of age, gender, concomitant statin therapy, and underlying dyslipoproteinemia. The most common side effects are injection site reactions (70%-100%), flu-like symptoms (29%-46%), and elevated transaminases associated with an increased liver fat content (6%-15%). Mipomersen may be an interesting addon drug in patients with heterozygous or homozygous FH not reaching treatment goals, either because baseline values are very high or because high-dose statins are not tolerated.

  11. Mipomersen: evidence-based review of its potential in the treatment of homozygous and severe heterozygous familial hypercholesterolemia

    PubMed Central

    Parhofer, Klaus G

    2012-01-01

    Familial hypercholesterolemia (FH) is an autosomal-dominant inherited disease with a prevalence of one in 500 (heterozygous) to one in 1,000,000 (homozygous). Mutations of the low-density lipoprotein (LDL) receptor gene, the apolipoprotein B100 gene, or the PCSK9 gene may be responsible for the disease. The resulting LDL hypercholesterolemia results in premature atherosclerosis as early as childhood (homozygous FH) or in adulthood (heterozygous FH). Current treatment modalities include lifestyle modification, combination drug therapy (statin-based), and apheresis. Mipomersen is an antisense oligonucleotide which inhibits apolipoprotein B production independent of LDL receptor function and thus works in homozygous FH, heterozygous FH, and other forms of hypercholesterolemia. Mipomersen is given 200 mg/week subcutaneously. Phase III studies indicate that the LDL cholesterol concentration can be reduced by 25%–47%, lipoprotein(a) levels by 20%–40%, and triglyceride concentrations by approximately 10%. In general, mipomersen has no effect on high-density lipoprotein cholesterol concentrations. Although there is considerable interindividual variability, the observed lipid effects are largely independent of age, gender, concomitant statin therapy, and underlying dyslipoproteinemia. The most common side effects are injection site reactions (70%–100%), flu-like symptoms (29%–46%), and elevated transaminases associated with an increased liver fat content (6%–15%). Mipomersen may be an interesting addon drug in patients with heterozygous or homozygous FH not reaching treatment goals, either because baseline values are very high or because high-dose statins are not tolerated. PMID:22701100

  12. Mutation Spectrum of GNE Myopathy in the Indian Sub-Continent.

    PubMed

    Bhattacharya, Sudha; Khadilkar, Satish V; Nalini, Atchayaram; Ganapathy, Aparna; Mannan, Ashraf U; Majumder, Partha P; Bhattacharya, Alok

    GNE myopathy is an adult onset recessive genetic disorder that affects distal muscles sparing the quadriceps. GNE gene mutations have been identified in GNE myopathy patients all over the world. Homozygosity is a common feature in GNE myopathy patients worldwide. The major objective of this study was to investigate the mutation spectrum of GNE myopathy in India in relation to the population diversity in the country. We have collated GNE mutation data of Indian GNE myopathy patients from published literature and from recently identified patients. We also used data of people of Indian subcontinent from 1000 genomes database, South Asian Genome database and Strand Life Science database to determine frequency of GNE mutations in the general population. A total of 67 GNE myopathy patients were studied, of whom 21% were homozygous for GNE variants, while the rest were compound heterozygous. Thirty-five different mutations in the GNE gene were recorded, of which 5 have not been reported earlier. The most frequent mutation was p.Val727Met (65%) found mainly in the heterozygous form. Another mutation, p.Ile618Thr was also common (16%) but was found mainly in patients from Rajasthan, while p.Val727Met was more widely distributed. The latter was also seen at a high frequency in general population of Indian subcontinent in all the databases. It was also present in Thailand but was absent in general population elsewhere in the world. p.Val727Met is likely to be a founder mutation of Indian subcontinent.

  13. Amelogenesis Imperfecta: 1 Family, 2 Phenotypes, and 2 Mutated Genes.

    PubMed

    Prasad, M K; Laouina, S; El Alloussi, M; Dollfus, H; Bloch-Zupan, A

    2016-12-01

    Amelogenesis imperfecta (AI) is a clinically and genetically heterogeneous group of diseases characterized by enamel defects. The authors have identified a large consanguineous Moroccan family segregating different clinical subtypes of hypoplastic and hypomineralized AI in different individuals within the family. Using targeted next-generation sequencing, the authors identified a novel heterozygous nonsense mutation in COL17A1 (c.1873C>T, p.R625*) segregating with hypoplastic AI and a novel homozygous 8-bp deletion in C4orf26 (c.39_46del, p.Cys14Glyfs*18) segregating with hypomineralized-hypoplastic AI in this family. This study highlights the phenotypic and genotypic heterogeneity of AI that can exist even within a single consanguineous family. Furthermore, the identification of novel mutations in COL17A1 and C4orf26 and their correlation with distinct AI phenotypes can contribute to a better understanding of the pathophysiology of AI and the contribution of these genes to amelogenesis. © International & American Associations for Dental Research 2016.

  14. p.H1069Q mutation in ATP7B and biochemical parameters of copper metabolism and clinical manifestation of Wilson's disease.

    PubMed

    Gromadzka, Graznya; Schmidt, Harmut H J; Genschel, Janine; Bochow, Bettina; Rodo, M; Tarnacka, Beatek; Litwin, Thomas; Chabik, Grzegorz; Członkowska, Anna

    2006-02-01

    We compared the effect of the p.H1069Q mutation and other non-p.H1069Q mutations in ATP7B on the phenotypic expression of Wilson's disease (WD), and assessed whether the clinical phenotype of WD in compound heterozygotes depends on the type of mutation coexisting with the p.H1069Q. One hundred forty-two patients with clinically, biochemically, and genetically diagnosed WD were studied. The mutational analysis of ATP7B was performed by direct sequencing. A total number of 26 mutations in ATP7B were identified. The p.His1069Gln was the most common mutation (allelic frequency: 72%). Seventy-three patients were homozygous for this mutation. Of compound heterozygotes, 37 had frameshift/nonsense mutation, and 20 had other missense mutation on one of their ATP7B alleles. Twelve patients had two non-p.H1069Q mutations. Patients homozygous for the p.H1069Q mutation had the less severe disturbances of copper metabolism and the latest presentation of first WD symptoms. The most severely disturbed copper metabolism and the earliest age at initial disease manifestation was noticed in non-p.H1069Q patients. In compound heterozygotes, the type of mutation coexisting with the p.H1069Q to a small extent influenced WD phenotype. The phenotype of WD varied considerably among patients with the same genotype. The p.H1069Q mutation is associated with late WD manifestation and with a mild disruption of copper metabolism. In compound heterozygotes, the phenotype of WD to a small extent depends on the type of mutation coexisting with the p.H1069Q. Besides genotype, additional modifying factors seem to determine WD manifestations. Copyright (c) 2005 Movement Disorder Society.

  15. A spectrum of novel NPHS1 and NPHS2 gene mutations in pediatric nephrotic syndrome patients from Pakistan.

    PubMed

    Abid, Aiysha; Khaliq, Shagufta; Shahid, Saba; Lanewala, Ali; Mubarak, Mohammad; Hashmi, Seema; Kazi, Javed; Masood, Tahir; Hafeez, Farkhanda; Naqvi, Syed Ali Anwar; Rizvi, Syed Adeebul Hasan; Mehdi, Syed Qasim

    2012-07-10

    Mutations in the NPHS1 and NPHS2 genes are among the main causes of early-onset and familial steroid resistant nephrotic syndrome respectively. This study was carried out to assess the frequencies of mutations in these two genes in a cohort of Pakistani pediatric NS patients. Mutation analysis was carried out by direct sequencing of the NPHS1 and NPHS2 genes in 145 nephrotic syndrome (NS) patients. This cohort included 36 samples of congenital or infantile onset NS cases and 39 samples of familial cases obtained from 30 families. A total of 7 homozygous (6 novel) mutations were found in the NPHS1 gene and 4 homozygous mutations in the NPHS2 gene. All mutations in the NPHS1 gene were found in the early onset cases. Of these, one patient has a family history of NS. Homozygous p.R229Q mutation in the NPHS2 gene was found in two children with childhood-onset NS. Our results show a low prevalence of disease causing mutations in the NPHS1 (22% early onset, 5.5% overall) and NPHS2 (3.3% early onset and 3.4% overall) genes in the Pakistani NS children as compared to the European populations. In contrast to the high frequency of the NPHS2 gene mutations reported for familial SRNS in Europe, no mutation was found in the familial Pakistani cases. To our knowledge, this is the first comprehensive screening of the NPHS1 and NPHS2 gene mutations in sporadic and familial NS cases from South Asia. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Four Novel p.N385K, p.V36A, c.1033–1034insT and c.1417–1418delCT Mutations in the Sphingomyelin Phosphodiesterase 1 (SMPD1) Gene in Patients with Types A and B Niemann-Pick Disease (NPD)

    PubMed Central

    Manshadi, Masoumeh Dehghan; Kamalidehghan, Behnam; Keshavarzi, Fatemeh; Aryani, Omid; Dadgar, Sepideh; Arastehkani, Ahoora; Tondar, Mahdi; Ahmadipour, Fatemeh; Meng, Goh Yong; Houshmand, Massoud

    2015-01-01

    Background: Types A and B Niemann-Pick disease (NPD) are autosomal-recessive lysosomal storage disorders caused by the deficient activity of acid sphingomyelinase due to mutations in the sphingomyelin phosphodiesterase 1 (SMPD1) gene. Methods: In order to determine the prevalence and distribution of SMPD1 gene mutations, the genomic DNA of 15 unrelated Iranian patients with types A and B NPD was examined using PCR, DNA sequencing and bioinformatics analysis. Results: Of 8 patients with the p.G508R mutation, 5 patients were homozygous, while the other 3 were heterozygous. One patient was heterozygous for both the p.N385K and p.G508R mutations. Another patient was heterozygous for both the p.A487V and p.G508R mutations. Two patients (one homozygous and one heterozygous) showed the p.V36A mutation. One patient was homozygous for the c.1033–1034insT mutation. One patient was homozygous for the c.573delT mutation, and 1 patient was homozygous for the c.1417–1418delCT mutation. Additionally, bioinformatics analysis indicated that two new p.V36A and p.N385K mutations decreased the acid sphingomyelinase (ASM) protein stability, which might be evidence to suggest the pathogenicity of these mutations. Conclusion: with detection of these new mutations, the genotypic spectrum of types A and B NPD is extended, facilitating the definition of disease-related mutations. However, more research is essential to confirm the pathogenic effect of these mutations. PMID:25811928

  17. Growth hormone receptor gene mutations in two Italian patients with Laron Syndrome.

    PubMed

    Fassone, L; Corneli, G; Bellone, S; Camacho-Hübner, C; Aimaretti, G; Cappa, M; Ubertini, G; Bona, G

    2007-05-01

    Laron Syndrome (LS) represents a condition characterized by GH insensitivity caused by molecular defects in the GH receptor (GHR) gene or in the post-receptor signalling pathway. We report the molecular characterization of two unrelated Italian girls from Sicily diagnosed with LS. The DNA sequencing of the GHR gene revealed the presence of different nonsense mutations, occurring in the same background haplotype. The molecular defects occurred in the extracellular domain of the GHR leading to a premature termination signal and to a truncated non-functional receptor. In one patient, a homozygous G to T transversion, in exon 6, led to the mutation GAA to TAA at codon 180 (E180X), while in the second patient a homozygous C to T transition in exon 7 was detected, causing the CGA to TAA substitution at codon 217 (R217X). Both probands presented the polymorphisms Gly168Gly and Ile544Leu in a homozygous state in exons 6 and 10, respectively. The E180X represents a novel defect of the GHR gene, while the R217X mutation has been previously reported in several patients from different ethnic backgrounds but all from countries located in the Mediterranean and Middle Eastern region.

  18. Novel mutations in the homogentisate 1,2 dioxygenase gene identified in Jordanian patients with alkaptonuria.

    PubMed

    Al-sbou, Mohammed

    2012-06-01

    This study was conducted to identify mutations in the homogentisate 1,2 dioxygenase gene (HGD) in alkaptonuria patients among Jordanian population. Blood samples were collected from four alkaptonuria patients, four carriers, and two healthy volunteers. DNA was isolated from peripheral blood. All 14 exons of the HGD gene were amplified using the polymerase chain reaction (PCR) technique. The PCR products were then purified and analyzed by sequencing. Five mutations were identified in our samples. Four of them were novel C1273A, T1046G, 551-552insG, T533G and had not been previously reported, and one mutation T847C has been described before. The types of mutations identified were two missense mutations, one splice site mutation, one frameshift mutation, and one polymorphism. We present the first molecular study of the HGD gene in Jordanian alkaptonuria patients. This study provides valuable information about the molecular basis of alkaptonuria in Jordanian population.

  19. Association of dilated cardiomyopathy with the striatin mutation genotype in boxer dogs.

    PubMed

    Meurs, K M; Stern, J A; Sisson, D D; Kittleson, M D; Cunningham, S M; Ames, M K; Atkins, C E; DeFrancesco, T; Hodge, T E; Keene, B W; Reina Doreste, Y; Leuthy, M; Motsinger-Reif, A A; Tou, S P

    2013-01-01

    Myocardial disease in the Boxer dog is characterized by 1 of 2 clinical presentations, dilated cardiomyopathy (DCM) characterized by ventricular systolic dysfunction, dilatation and tachyarrhythmias, and arrhythmogenic right ventricular cardiomyopathy (ARVC) characterized by ventricular tachyarrhythmias, syncope, and sudden death. Boxer ARVC has been associated with a deletion in the striatin gene in some families. We hypothesized that both presentations represent a single disease, and the development of DCM in the Boxer is associated with the striatin deletion. Thirty-three adult Boxer dogs with DCM, 29 adult Boxer dogs with the striatin deletion and ARVC, and 16 Boxers without cardiac disease. DNA samples were evaluated for the striatin deletion. Association of the deletion with the DCM phenotype was tested by a Fisher's exact test. T-tests were used to evaluate potential differences between the positive heterozygous and positive homozygous groups with DCM with regard to age, LVIDD, LVIDS, and FS%. Thirty of 33 dogs with DCM were positive for the striatin deletion. The striatin mutation and the homozygous genotype were strongly associated with the DCM phenotype (P < .001 and P = .005). There was no statistical difference between the heterozygous and homozygous groups with regard to age and echocardiographic measurements. This study demonstrates an association between DCM in the Boxer dog and the striatin mutation, particularly with the homozygous genotype. The observation that 3/33 dogs developed DCM and lacked the striatin mutation suggests that there is at least 1 other cause of DCM in the Boxer dog. Copyright © 2013 by the American College of Veterinary Internal Medicine.

  20. Autosomal Dominant Mutation in the Signal Peptide of Renin in a Kindred with Anemia, Hyperuricemia, and CKD

    PubMed Central

    Beck, Bodo B.; Trachtman, Howard; Gitman, Michael; Miller, Ilene; Sayer, John A.; Pannes, Andrea; Baasner, Anne; Hildebrandt, Friedhelm; Wolf, Matthias T.F.

    2012-01-01

    Homozygous or compound heterozygous Renin (REN) mutations cause renal tubular dysgenesis (RTD), which is characterized by death in utero due to renal failure and pulmonary hypoplasia. The phenotype resembles the fetopathy caused by angiotensin-converting enzyme inhibitor or angiotensin receptor blocker intake during pregnancy. Recently, heterozygous REN mutations were shown to result in early-onset hyperuricemia, anemia and chronic renal failure. So far, only three different heterozygous REN mutations were reported. We performed mutation analysis of the REN gene in 39 kindreds with hyperuricemia and chronic kidney disease (CKD) previously tested negative for mutations in the UMOD and HNF1β genes. We identified one kindred with a novel c.28T>C (p.W10R) REN mutation in the signal sequence, concluding that REN mutations are rare events in CKD patients. Affected individuals over four generations were identified carrying the novel REN mutation and were characterized by significant anemia, hyperuricemia and CKD. Anemia was severe and disproportional to the degree of renal impairment. Moreover all heterozygous REN mutations are localized in the signal sequence. Therefore, screening of the REN gene for CKD patients with hyperuricemia and anemia may be focusing on exon 1 sequencing, which encodes the signal peptide. PMID:21903317

  1. Distinct Brca1 Mutations Differentially Reduce Hematopoietic Stem Cell Function.

    PubMed

    Mgbemena, Victoria E; Signer, Robert A J; Wijayatunge, Ranjula; Laxson, Travis; Morrison, Sean J; Ross, Theodora S

    2017-01-24

    BRCA1 is a well-known DNA repair pathway component and a tissue-specific tumor suppressor. However, its role in hematopoiesis is uncertain. Here, we report that a cohort of patients heterozygous for BRCA1 mutations experienced more hematopoietic toxicity from chemotherapy than those with BRCA2 mutations. To test whether this reflects a requirement for BRCA1 in hematopoiesis, we generated mice with Brca1 mutations in hematopoietic cells. Mice homozygous for a null Brca1 mutation in the embryonic hematopoietic system (Vav1-iCre;Brca1 F22-24/F22-24 ) developed hematopoietic defects in early adulthood that included reduced hematopoietic stem cells (HSCs). Although mice homozygous for a huBRCA1 knockin allele (Brca1 BRCA1/BRCA1 ) were normal, mice with a mutant huBRCA1/5382insC allele and a null allele (Mx1-Cre;Brca1 F22-24/5382insC ) had severe hematopoietic defects marked by a complete loss of hematopoietic stem and progenitor cells. Our data show that Brca1 is necessary for HSC maintenance and normal hematopoiesis and that distinct mutations lead to different degrees of hematopoietic dysfunction. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  2. GeneChip{sup {trademark}} screening assay for cystic fibrosis mutations

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cronn, M.T.; Miyada, C.G.; Fucini, R.V.

    1994-09-01

    GeneChip{sup {trademark}} assays are based on high density, carefully designed arrays of short oligonucleotide probes (13-16 bases) built directly on derivatized silica substrates. DNA target sequence analysis is achieved by hybridizing fluorescently labeled amplification products to these arrays. Fluorescent hybridization signals located within the probe array are translated into target sequence information using the known probe sequence at each array feature. The mutation screening assay for cystic fibrosis includes sets of oligonucleotide probes designed to detect numerous different mutations that have been described in 14 exons and one intron of the CFTR gene. Each mutation site is addressed by amore » sub-array of at least 40 probe sequences, half designed to detect the wild type gene sequence and half designed to detect the reported mutant sequence. Hybridization with homozygous mutant, homozygous wild type or heterozygous targets results in distinctive hybridization patterns within a sub-array, permitting specific discrimination of each mutation. The GeneChip probe arrays are very small (approximately 1 cm{sup 2}). There miniature size coupled with their high information content make GeneChip probe arrays a useful and practical means for providing CF mutation analysis in a clinical setting.« less

  3. Exome sequencing of hepatocellular carcinomas identifies new mutational signatures and potential therapeutic targets

    DOE PAGES

    Schulze, Kornelius; Imbeaud, Sandrine; Letouzé, Eric; ...

    2015-03-30

    Our genomic analyses promise to improve tumor characterization to optimize personalized treatment for patients with hepatocellular carcinoma (HCC). Exome sequencing analysis of 243 liver tumors identified mutational signatures associated with specific risk factors, mainly combined alcohol and tobacco consumption and exposure to aflatoxin B1. We identified 161 putative driver genes associated with 11 recurrently altered pathways. Associations of mutations defined 3 groups of genes related to risk factors and centered on CTNNB1 (alcohol), TP53 (hepatitis B virus, HBV) and AXIN1. These analyses according to tumor stage progression identified TERT promoter mutation as an early event, whereasFGF3, FGF4, FGF19 or CCND1more » amplification and TP53 and CDKN2A alterations appeared at more advanced stages in aggressive tumors. In 28% of the tumors, we identified genetic alterations potentially targetable by US Food and Drug Administration (FDA)–approved drugs. Finally, we identified risk factor–specific mutational signatures and defined the extensive landscape of altered genes and pathways in HCC, which will be useful to design clinical trials for targeted therapy.« less

  4. Exome sequencing of hepatocellular carcinomas identifies new mutational signatures and potential therapeutic targets

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Schulze, Kornelius; Imbeaud, Sandrine; Letouzé, Eric

    Our genomic analyses promise to improve tumor characterization to optimize personalized treatment for patients with hepatocellular carcinoma (HCC). Exome sequencing analysis of 243 liver tumors identified mutational signatures associated with specific risk factors, mainly combined alcohol and tobacco consumption and exposure to aflatoxin B1. We identified 161 putative driver genes associated with 11 recurrently altered pathways. Associations of mutations defined 3 groups of genes related to risk factors and centered on CTNNB1 (alcohol), TP53 (hepatitis B virus, HBV) and AXIN1. These analyses according to tumor stage progression identified TERT promoter mutation as an early event, whereasFGF3, FGF4, FGF19 or CCND1more » amplification and TP53 and CDKN2A alterations appeared at more advanced stages in aggressive tumors. In 28% of the tumors, we identified genetic alterations potentially targetable by US Food and Drug Administration (FDA)–approved drugs. Finally, we identified risk factor–specific mutational signatures and defined the extensive landscape of altered genes and pathways in HCC, which will be useful to design clinical trials for targeted therapy.« less

  5. A novel FKRP-related muscular dystrophy founder mutation in South African Afrikaner patients with a phenotype suggestive of a dystrophinopathy.

    PubMed

    Mudau, M M; Essop, F; Krause, A

    2016-12-21

    Fukutin-related protein (FKRP) muscular dystrophy is an autosomal recessive disorder caused by mutations in the FKRP gene. The condition is often misdiagnosed as a dystrophinopathy. A previously unreported mutation, c.1100T>C in exon 4 of FKRP, had been identified in homozygous form in two white South African (SA) Afrikaner patients clinically diagnosed with a dystrophinopathy. To investigate whether the c.1100T>C mutation and the common European FKRP mutation c.826C>A are present in other patients of Afrikaner origin with suspected dystrophinopathy, and whether a founder haplotype exists. The c.1100T>C mutation was initially tested for using an amplification refractory mutation system technique in 45 white SA Afrikaner patients who had tested negative using multiplex ligation probe amplification screening for exonic deletions/duplications in the dystrophin gene. Sequencing analysis was used to confirm the c.1100T>C mutation and screen for the c.826C>A mutation. Two cohorts (each numbering 100) of Afrikaans and other white controls were screened for the c.1100T>C and c.826C>A mutations, respectively. Of the 45 patients, 8 patients (17.8%) were homozygous for c.1100T>C, 2 (4.4%) were compound heterozygotes for c.1100T>C and c.826C>A, and 1 (2.2%) was heterozygous for c.1100T>C with a second unidentified mutation. The c.1100T>C mutation was found in 1/100 controls, but no heterozygotes for the c.826C>A mutation were identified. Linked marker analysis for c.1100T>C showed a common haplotype, suggesting a probable founder mutation in the SA Afrikaner population. FKRP mutations may be relatively common in Afrikaners, and screening should be considered in patients who have a suggestive phenotype and test negative for a dystrophinopathy. This test will be useful for offering diagnostic, carrier and prenatal testing for affected individuals and their families. As FKRP muscular dystrophy is autosomal recessive in inheritance, the

  6. Mutations in ARL2BP, Encoding ADP-Ribosylation-Factor-Like 2 Binding Protein, Cause Autosomal-Recessive Retinitis Pigmentosa

    PubMed Central

    Davidson, Alice E.; Schwarz, Nele; Zelinger, Lina; Stern-Schneider, Gabriele; Shoemark, Amelia; Spitzbarth, Benjamin; Gross, Menachem; Laxer, Uri; Sosna, Jacob; Sergouniotis, Panagiotis I.; Waseem, Naushin H.; Wilson, Robert; Kahn, Richard A.; Plagnol, Vincent; Wolfrum, Uwe; Banin, Eyal; Hardcastle, Alison J.; Cheetham, Michael E.; Sharon, Dror; Webster, Andrew R.

    2013-01-01

    Retinitis pigmentosa (RP) is a genetically heterogeneous retinal degeneration characterized by photoreceptor death, which results in visual failure. Here, we used a combination of homozygosity mapping and exome sequencing to identify mutations in ARL2BP, which encodes an effector protein of the small GTPases ARL2 and ARL3, as causative for autosomal-recessive RP (RP66). In a family affected by RP and situs inversus, a homozygous, splice-acceptor mutation, c.101−1G>C, which alters pre-mRNA splicing of ARLBP2 in blood RNA, was identified. In another family, a homozygous c.134T>G (p.Met45Arg) mutation was identified. In the mouse retina, ARL2BP localized to the basal body and cilium-associated centriole of photoreceptors and the periciliary extension of the inner segment. Depletion of ARL2BP caused cilia shortening. Moreover, depletion of ARL2, but not ARL3, caused displacement of ARL2BP from the basal body, suggesting that ARL2 is vital for recruiting or anchoring ARL2BP at the base of the cilium. This hypothesis is supported by the finding that the p.Met45Arg amino acid substitution reduced binding to ARL2 and caused the loss of ARL2BP localization at the basal body in ciliated nasal epithelial cells. These data demonstrate a role for ARL2BP and ARL2 in primary cilia function and that this role is essential for normal photoreceptor maintenance and function. PMID:23849777

  7. Arrestin gene mutations in autosomal recessive retinitis pigmentosa.

    PubMed

    Nakazawa, M; Wada, Y; Tamai, M

    1998-04-01

    To assess the clinical and molecular genetic studies of patients with autosomal recessive retinitis pigmentosa associated with a mutation in the arrestin gene. Results of molecular genetic screening and case reports with DNA analysis and clinical features. University medical center. One hundred twenty anamnestically unrelated patients with autosomal recessive retinitis pigmentosa. DNA analysis was performed by single strand conformation polymorphism followed by nucleotide sequencing to search for a mutation in exon 11 of the arrestin gene. Clinical features were characterized by visual acuity slitlamp biomicroscopy, fundus examinations, fluorescein angiography, kinetic visual field testing, and electroretinography. We identified 3 unrelated patients with retinitis pigmentosa associated with a homozygous 1-base-pair deletion mutation in codon 309 of the arrestin gene designated as 1147delA. All 3 patients showed pigmentary retinal degeneration in the midperipheral area with or without macular involvement. Patient 1 had a sibling with Oguchi disease associated with the same mutation. Patient 2 demonstrated pigmentary retinal degeneration associated with a golden-yellow reflex in the peripheral fundus. Patients 1 and 3 showed features of retinitis pigmentosa without the golden-yellow fundus reflex. Although the arrestin 1147delA has been known as a frequent cause of Oguchi disease, this mutation also may be related to the pathogenesis of autosomal recessive retinitis pigmentosa. This phenomenon may provide evidence of variable expressivity of the mutation in the arrestin gene.

  8. Gene expression in hypothalamus, liver and adipose tissues and feed intake response to melanocortin-4 receptor (MC4R) agonist in pigs expressing (MC4R) mutations

    USDA-ARS?s Scientific Manuscript database

    Transcriptional profiling was used to identify genes and pathways that responded to intracerebroventricular (ICV) injection of melanocortin-4 receptor (MC4R) agonist, NDP-MSH, in pigs homozygous for the missense mutation in the MC4R, D298 allele (n = 12), N298 allele (n = 12) or heterozygous (n = 12...

  9. Mutations in PTRH2 cause novel infantile-onset multisystem disease with intellectual disability, microcephaly, progressive ataxia, and muscle weakness.

    PubMed

    Hu, Hao; Matter, Michelle L; Issa-Jahns, Lina; Jijiwa, Mayumi; Kraemer, Nadine; Musante, Luciana; de la Vega, Michelle; Ninnemann, Olaf; Schindler, Detlev; Damatova, Natalia; Eirich, Katharina; Sifringer, Marco; Schrötter, Sandra; Eickholt, Britta J; van den Heuvel, Lambert; Casamina, Chanel; Stoltenburg-Didinger, Gisela; Ropers, Hans-Hilger; Wienker, Thomas F; Hübner, Christoph; Kaindl, Angela M

    2014-12-01

    To identify the cause of a so-far unreported phenotype of infantile-onset multisystem neurologic, endocrine, and pancreatic disease (IMNEPD). We characterized a consanguineous family of Yazidian-Turkish descent with IMNEPD. The two affected children suffer from intellectual disability, postnatal microcephaly, growth retardation, progressive ataxia, distal muscle weakness, peripheral demyelinating sensorimotor neuropathy, sensorineural deafness, exocrine pancreas insufficiency, hypothyroidism, and show signs of liver fibrosis. We performed whole-exome sequencing followed by bioinformatic analysis and Sanger sequencing on affected and unaffected family members. The effect of mutations in the candidate gene was studied in wild-type and mutant mice and in patient and control fibroblasts. In a consanguineous family with two individuals with IMNEPD, we identified a homozygous frameshift mutation in the previously not disease-associated peptidyl-tRNA hydrolase 2 (PTRH2) gene. PTRH2 encodes a primarily mitochondrial protein involved in integrin-mediated cell survival and apoptosis signaling. We show that PTRH2 is highly expressed in the developing brain and is a key determinant in maintaining cell survival during human tissue development. Moreover, we link PTRH2 to the mTOR pathway and thus the control of cell size. The pathology suggested by the human phenotype and neuroimaging studies is supported by analysis of mutant mice and patient fibroblasts. We report a novel disease phenotype, show that the genetic cause is a homozygous mutation in the PTRH2 gene, and demonstrate functional effects in mouse and human tissues. Mutations in PTRH2 should be considered in patients with undiagnosed multisystem neurologic, endocrine, and pancreatic disease.

  10. Mutations in PTRH2 cause novel infantile-onset multisystem disease with intellectual disability, microcephaly, progressive ataxia, and muscle weakness

    PubMed Central

    Hu, Hao; Matter, Michelle L; Issa-Jahns, Lina; Jijiwa, Mayumi; Kraemer, Nadine; Musante, Luciana; de la Vega, Michelle; Ninnemann, Olaf; Schindler, Detlev; Damatova, Natalia; Eirich, Katharina; Sifringer, Marco; Schrötter, Sandra; Eickholt, Britta J; van den Heuvel, Lambert; Casamina, Chanel; Stoltenburg-Didinger, Gisela; Ropers, Hans-Hilger; Wienker, Thomas F; Hübner, Christoph; Kaindl, Angela M

    2014-01-01

    Objective To identify the cause of a so-far unreported phenotype of infantile-onset multisystem neurologic, endocrine, and pancreatic disease (IMNEPD). Methods We characterized a consanguineous family of Yazidian-Turkish descent with IMNEPD. The two affected children suffer from intellectual disability, postnatal microcephaly, growth retardation, progressive ataxia, distal muscle weakness, peripheral demyelinating sensorimotor neuropathy, sensorineural deafness, exocrine pancreas insufficiency, hypothyroidism, and show signs of liver fibrosis. We performed whole-exome sequencing followed by bioinformatic analysis and Sanger sequencing on affected and unaffected family members. The effect of mutations in the candidate gene was studied in wild-type and mutant mice and in patient and control fibroblasts. Results In a consanguineous family with two individuals with IMNEPD, we identified a homozygous frameshift mutation in the previously not disease-associated peptidyl-tRNA hydrolase 2 (PTRH2) gene. PTRH2 encodes a primarily mitochondrial protein involved in integrin-mediated cell survival and apoptosis signaling. We show that PTRH2 is highly expressed in the developing brain and is a key determinant in maintaining cell survival during human tissue development. Moreover, we link PTRH2 to the mTOR pathway and thus the control of cell size. The pathology suggested by the human phenotype and neuroimaging studies is supported by analysis of mutant mice and patient fibroblasts. Interpretation We report a novel disease phenotype, show that the genetic cause is a homozygous mutation in the PTRH2 gene, and demonstrate functional effects in mouse and human tissues. Mutations in PTRH2 should be considered in patients with undiagnosed multisystem neurologic, endocrine, and pancreatic disease. PMID:25574476

  11. Homozygosity Mapping and Candidate Prioritization Identify Mutations, Missed by Whole-Exome Sequencing, in SMOC2, Causing Major Dental Developmental Defects

    PubMed Central

    Bloch-Zupan, Agnès; Jamet, Xavier; Etard, Christelle; Laugel, Virginie; Muller, Jean; Geoffroy, Véronique; Strauss, Jean-Pierre; Pelletier, Valérie; Marion, Vincent; Poch, Olivier; Strahle, Uwe; Stoetzel, Corinne; Dollfus, Hélène

    2011-01-01

    Inherited dental malformations constitute a clinically and genetically heterogeneous group of disorders. Here, we report on a severe developmental dental defect that results in a dentin dysplasia phenotype with major microdontia, oligodontia, and shape abnormalities in a highly consanguineous family. Homozygosity mapping revealed a unique zone on 6q27-ter. The two affected children were found to carry a homozygous mutation in SMOC2. Knockdown of smoc2 in zebrafish showed pharyngeal teeth that had abnormalities reminiscent of the human phenotype. Moreover, smoc2 depletion in zebrafish affected the expression of three major odontogenesis genes: dlx2, bmp2, and pitx2. PMID:22152679

  12. Factor V Leiden, Prothrombin and MTHFR Mutation in Patients with Preeclamsia, Intrauterine Growth Restriction and Placental Abruption.

    PubMed

    Livrinova, Vesna; Lega, Marija Hadzi; Dimcheva, Anita Hristova; Samardziski, Igor; Isjanovska, Rozalinda

    2015-12-15

    Factor V Leiden, Prothrombin and MTHFR gene mutation, could have an influence in pregnancy with adverse outcome Preeclamsia, IUGR and Placental abruption. The aim of this study is to investigate the presence of above mentioned inherited thrombophilias and its statistical significance, distribution among the complicated and normal pregnancy, and relative risk for carrier of mutation to develop preeclampsia, IUGR and placental abruption. Prospective cohort study is implemented at University Clinic for Obstetric and Gynecology in Skopje, Republic of Macedonia. The study included 109 delivered patients: 40 with preeclapmsia, 22 with IUGR, 17 with placental abruption and 30 as control group with normal pregnancy. The amount of 3 ml venous blood has been used for detection of these point mutations using ThromboStrip -Opegen, QIAGEN kit manufactured for thrombotic risk. The highest frequency was found: in the group with preeclampsia 35% were MTHFR homozygous, IUGR -MTHFR heterozygous 45%, Placental abruption- 52.9% MTHFR heterozygous, and in the control group without thrombophilia 56.7%. There were combined thrombophilia in 3 patients. There aren`t statistical significance in presence of thrombophilia among groups (p > 0.05). Statistical significance (p < 0.05) was found between carriers of MTHFR homozygous in preeclampsia and group with placental abruption and control group. Relative risk in IUGR group for MTHFR homozygous was 5.54 (1.37mutation MTHFR homozygous could increase the risk for development of IUGR and mutation of Factor V Leiden for placental abruption. Further investigations with more patients are warranted.

  13. Factor V Leiden, Prothrombin and MTHFR Mutation in Patients with Preeclamsia, Intrauterine Growth Restriction and Placental Abruption

    PubMed Central

    Livrinova, Vesna; Lega, Marija Hadzi; Dimcheva, Anita Hristova; Samardziski, Igor; Isjanovska, Rozalinda

    2015-01-01

    BACKGROUND: Factor V Leiden, Prothrombin and MTHFR gene mutation, could have an influence in pregnancy with adverse outcome Preeclamsia, IUGR and Placental abruption. AIM: The aim of this study is to investigate the presence of above mentioned inherited thrombophilias and its statistical significance, distribution among the complicated and normal pregnancy, and relative risk for carrier of mutation to develop preeclampsia, IUGR and placental abruption. MATERIAL AND METHODS: Prospective cohort study is implemented at University Clinic for Obstetric and Gynecology in Skopje, Republic of Macedonia. The study included 109 delivered patients: 40 with preeclapmsia, 22 with IUGR, 17 with placental abruption and 30 as control group with normal pregnancy. The amount of 3 ml venous blood has been used for detection of these point mutations using ThromboStrip -Opegen, QIAGEN kit manufactured for thrombotic risk. RESULTS: The highest frequency was found: in the group with preeclampsia 35% were MTHFR homozygous, IUGR -MTHFR heterozygous 45%, Placental abruption- 52.9% MTHFR heterozygous, and in the control group without thrombophilia 56.7%. There were combined thrombophilia in 3 patients. There aren`t statistical significance in presence of thrombophilia among groups (p > 0.05). Statistical significance (p < 0.05) was found between carriers of MTHFR homozygous in preeclampsia and group with placental abruption and control group. Relative risk in IUGR group for MTHFR homozygous was 5.54 (1.37mutation MTHFR homozygous could increase the risk for development of IUGR and mutation of Factor V Leiden for placental abruption. Further investigations with more patients are warranted. PMID:27275292

  14. Meier–Gorlin syndrome genotype–phenotype studies: 35 individuals with pre-replication complex gene mutations and 10 without molecular diagnosis

    PubMed Central

    de Munnik, Sonja A; Bicknell, Louise S; Aftimos, Salim; Al-Aama, Jumana Y; van Bever, Yolande; Bober, Michael B; Clayton-Smith, Jill; Edrees, Alaa Y; Feingold, Murray; Fryer, Alan; van Hagen, Johanna M; Hennekam, Raoul C; Jansweijer, Maaike C E; Johnson, Diana; Kant, Sarina G; Opitz, John M; Ramadevi, A Radha; Reardon, Willie; Ross, Alison; Sarda, Pierre; Schrander-Stumpel, Constance T R M; Schoots, Jeroen; Temple, I Karen; Terhal, Paulien A; Toutain, Annick; Wise, Carol A; Wright, Michael; Skidmore, David L; Samuels, Mark E; Hoefsloot, Lies H; Knoers, Nine V A M; Brunner, Han G; Jackson, Andrew P; Bongers, Ernie M H F

    2012-01-01

    Meier–Gorlin syndrome (MGS) is an autosomal recessive disorder characterized by microtia, patellar aplasia/hypoplasia, and short stature. Recently, mutations in five genes from the pre-replication complex (ORC1, ORC4, ORC6, CDT1, and CDC6), crucial in cell-cycle progression and growth, were identified in individuals with MGS. Here, we report on genotype–phenotype studies in 45 individuals with MGS (27 females, 18 males; age 3 months–47 years). Thirty-five individuals had biallelic mutations in one of the five causative pre-replication genes. No homozygous or compound heterozygous null mutations were detected. In 10 individuals, no definitive molecular diagnosis was made. The triad of microtia, absent/hypoplastic patellae, and short stature was observed in 82% of individuals with MGS. Additional frequent clinical features were mammary hypoplasia (100%) and abnormal genitalia (42% predominantly cryptorchidism and hypoplastic labia minora/majora). One individual with ORC1 mutations only had short stature, emphasizing the highly variable clinical spectrum of MGS. Individuals with ORC1 mutations had significantly shorter stature and smaller head circumferences than individuals from other gene categories. Furthermore, compared with homozygous missense mutations, compound heterozygous mutations appeared to have a more severe effect on phenotype, causing more severe growth retardation in ORC4 and more frequently pulmonary emphysema in CDT1. A lethal phenotype was seen in four individuals with compound heterozygous ORC1 and CDT1 mutations. No other clear genotype–phenotype association was observed. Growth hormone and estrogen treatment may be of some benefit, respectively, to growth retardation and breast hypoplasia, though further studies in this patient group are needed. PMID:22333897

  15. Novel Tay-Sachs disease mutations from China.

    PubMed

    Akalin, N; Shi, H P; Vavougios, G; Hechtman, P; Lo, W; Scriver, C R; Mahuran, D; Kaplan, F

    1992-01-01

    We describe three HEXA mutations associated with infantile Tay-Sachs disease (TSD) in three unrelated nonconsanguineous Chinese families. Novel mutations were found in two of these families. The third is a previously reported mutation (G-->A transition at nt 1444) (Nakano et al., 1988). Direct sequencing of PCR products identified a novel insertion of an A after nt 547 in family 1. This change generates an early termination codon 6 bp downstream from the insertion site. Allele-specific oligonucleotide hybridization confirmed homozygosity in the proband. Single strand conformational polymorphism analysis and direct sequencing of amplified exon 13 revealed a T-->C transition at nt 1453 with the corresponding amino acid substitution W485R in the second family. This mutation creates an Fnu4HI restriction site. The proband is homozygous for this allele. When the site-specific mutagenized alpha cDNA carrying the T-->C transition at nt 1453 was expressed in COS 1 cells hexosaminidase S activity was not detectable above background. A G-->A transition at nt 1444 (exon 13) corresponding to the E482K substitution was found in the third family. This mutation occurs at a CpG dinucleotide. It has been reported in an Italian TSD proband and causes defective intracellular transport of the alpha-subunit from the rough endoplasmic reticulum to the Golgi apparatus.

  16. Deep mutational scanning identifies sites in influenza nucleoprotein that affect viral inhibition by MxA

    PubMed Central

    Ashenberg, Orr; Padmakumar, Jai

    2017-01-01

    The innate-immune restriction factor MxA inhibits influenza replication by targeting the viral nucleoprotein (NP). Human influenza virus is more resistant than avian influenza virus to inhibition by human MxA, and prior work has compared human and avian viral strains to identify amino-acid differences in NP that affect sensitivity to MxA. However, this strategy is limited to identifying sites in NP where mutations that affect MxA sensitivity have fixed during the small number of documented zoonotic transmissions of influenza to humans. Here we use an unbiased deep mutational scanning approach to quantify how all single amino-acid mutations to NP affect MxA sensitivity in the context of replication-competent virus. We both identify new sites in NP where mutations affect MxA resistance and re-identify mutations known to have increased MxA resistance during historical adaptations of influenza to humans. Most of the sites where mutations have the greatest effect are almost completely conserved across all influenza A viruses, and the amino acids at these sites confer relatively high resistance to MxA. These sites cluster in regions of NP that appear to be important for its recognition by MxA. Overall, our work systematically identifies the sites in influenza nucleoprotein where mutations affect sensitivity to MxA. We also demonstrate a powerful new strategy for identifying regions of viral proteins that affect inhibition by host factors. PMID:28346537

  17. Whole-exome sequencing identifies recurrent AKT1 mutations in sclerosing hemangioma of lung

    PubMed Central

    Jung, Seung-Hyun; Kim, Min Sung; Lee, Sung-Hak; Park, Hyun-Chun; Choi, Hyun Joo; Maeng, Leeso; Min, Ki Ouk; Kim, Jeana; Park, Tae In; Shin, Ok Ran; Kim, Tae-Jung; Xu, Haidong; Lee, Kyo Young; Kim, Tae-Min; Song, Sang Yong; Lee, Charles; Chung, Yeun-Jun; Lee, Sug Hyung

    2016-01-01

    Pulmonary sclerosing hemangioma (PSH) is a benign tumor with two cell populations (epithelial and stromal cells), for which genomic profiles remain unknown. We conducted exome sequencing of 44 PSHs and identified recurrent somatic mutations of AKT1 (43.2%) and β-catenin (4.5%). We used a second subset of 24 PSHs to confirm the high frequency of AKT1 mutations (overall 31/68, 45.6%; p.E17K, 33.8%) and recurrent β-catenin mutations (overall 3 of 68, 4.4%). Of the PSHs without AKT1 mutations, two exhibited AKT1 copy gain. AKT1 mutations existed in both epithelial and stromal cells. In two separate PSHs from one patient, we observed two different AKT1 mutations, indicating they were not disseminated but independent arising tumors. Because the AKT1 mutations were not found to co-occur with β-catenin mutations (or any other known driver alterations) in any of the PSHs studied, we speculate that this may be the single-most common driver alteration to develop PSHs. Our study revealed genomic differences between PSHs and lung adenocarcinomas, including a high rate of AKT1 mutation in PSHs. These genomic features of PSH identified in the present study provide clues to understanding the biology of PSH and for differential genomic diagnosis of lung tumors. PMID:27601661

  18. Hearing loss caused by a P2RX2 mutation identified in a MELAS family with a coexisting mitochondrial 3243AG mutation

    PubMed Central

    Moteki, Hideaki; Azaiez, Hela; Booth, Kevin T; Hattori, Mitsuru; Sato, Ai; Sato, Yoshihiko; Motobayashi, Mitsuo; Sloan, Christina M; Kolbe, Diana L; Shearer, A Eliot; Smith, Richard J H; Usami, Shin-ichi

    2015-01-01

    Objective We present a family with a mitochondrial DNA 3243A>G mutation resulting in MELAS, of which some members have hearing loss where a novel mutation in the P2RX2 gene was identified. Methods One hundred ninety-four (194) Japanese subjects from unrelated families were enrolled in the study. Targeted genomic enrichment and massively parallel sequencing of all known non-syndromic hearing loss genes were performed to identify the genetic causes of hearing loss. Results A novel mutation in the P2RX2 gene, that corresponded to c.601G>A (p.Asp201Tyr) was identified. Two patients carried the mutation, and had severe SNHL, while other members with MELAS (who did not carry the P2RX2 mutation) had normal hearing. Conclusion This is the first case report of a diagnosis of hearing loss caused by P2RX2 mutation in patients with MELAS. A potential explanation is that decreasing ATP production due to MELAS with mitochondrial 3243A>G mutation might suppress activation of P2X2 receptors. We also suggest that hearing loss caused by the P2RX2 mutation might be influenced by the decrease in ATP production due to MELAS, and that nuclear genetic factors may play a modifying role in mitochondrial dysfunction. PMID:25788561

  19. Molecular profiling of appendiceal epithelial tumors using massively parallel sequencing to identify somatic mutations.

    PubMed

    Liu, Xiaoying; Mody, Kabir; de Abreu, Francine B; Pipas, J Marc; Peterson, Jason D; Gallagher, Torrey L; Suriawinata, Arief A; Ripple, Gregory H; Hourdequin, Kathryn C; Smith, Kerrington D; Barth, Richard J; Colacchio, Thomas A; Tsapakos, Michael J; Zaki, Bassem I; Gardner, Timothy B; Gordon, Stuart R; Amos, Christopher I; Wells, Wendy A; Tsongalis, Gregory J

    2014-07-01

    Some epithelial neoplasms of the appendix, including low-grade appendiceal mucinous neoplasm and adenocarcinoma, can result in pseudomyxoma peritonei (PMP). Little is known about the mutational spectra of these tumor types and whether mutations may be of clinical significance with respect to therapeutic selection. In this study, we identified somatic mutations using the Ion Torrent AmpliSeq Cancer Hotspot Panel v2. Specimens consisted of 3 nonneoplastic retention cysts/mucocele, 15 low-grade mucinous neoplasms (LAMNs), 8 low-grade/well-differentiated mucinous adenocarcinomas with pseudomyxoma peritonei, and 12 adenocarcinomas with/without goblet cell/signet ring cell features. Barcoded libraries were prepared from up to 10 ng of extracted DNA and multiplexed on single 318 chips for sequencing. Data analysis was performed using Golden Helix SVS. Variants that remained after the analysis pipeline were individually interrogated using the Integrative Genomics Viewer. A single Janus kinase 3 (JAK3) mutation was detected in the mucocele group. Eight mutations were identified in the V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) and GNAS complex locus (GNAS) genes among LAMN samples. Additional gene mutations were identified in the AKT1 (v-akt murine thymoma viral oncogene homolog 1), APC (adenomatous polyposis coli), JAK3, MET (met proto-oncogene), phosphatidylinositol-4,5-bisphosphate 3-kinase (PIK3CA), RB1 (retinoblastoma 1), STK11 (serine/threonine kinase 11), and tumor protein p53 (TP53) genes. Among the PMPs, 6 mutations were detected in the KRAS gene and also in the GNAS, TP53, and RB1 genes. Appendiceal cancers showed mutations in the APC, ATM (ataxia telangiectasia mutated), KRAS, IDH1 [isocitrate dehydrogenase 1 (NADP+)], NRAS [neuroblastoma RAS viral (v-ras) oncogene homolog], PIK3CA, SMAD4 (SMAD family member 4), and TP53 genes. Our results suggest molecular heterogeneity among epithelial tumors of the appendix. Next generation sequencing efforts

  20. Mutations of the KISS1 gene in disorders of puberty.

    PubMed

    Silveira, L G; Noel, S D; Silveira-Neto, A P; Abreu, A P; Brito, V N; Santos, M G; Bianco, S D C; Kuohung, W; Xu, S; Gryngarten, M; Escobar, M E; Arnhold, I J P; Mendonca, B B; Kaiser, U B; Latronico, A C

    2010-05-01

    Kisspeptin, encoded by the KISS1 gene, is a key stimulatory factor of GnRH secretion and puberty onset. Inactivating mutations of its receptor (KISS1R) cause isolated hypogonadotropic hypogonadism (IHH). A unique KISS1R-activating mutation was described in central precocious puberty (CPP). Our objective was to investigate KISS1 mutations in patients with idiopathic CPP and normosmic IHH. Eighty-three children with CPP (77 girls) and 61 patients with IHH (40 men) were studied. The control group consisted of 200 individuals with normal pubertal development. The promoter region and the three exons of KISS1 were amplified and sequenced. Cells expressing KISS1R were stimulated with synthetic human wild-type or mutant kisspeptin-54 (kp54), and inositol phosphate accumulation was measured. In a second set of experiments, kp54 was preincubated in human serum before stimulation of the cells. Two novel KISS1 missense mutations, p.P74S and p.H90D, were identified in three unrelated children with idiopathic CPP. Both mutations were absent in 400 control alleles. The p.P74S mutation was identified in the heterozygous state in a boy who developed CPP at 1 yr of age. The p.H90D mutation was identified in the homozygous state in two unrelated girls with CPP. In vitro studies revealed that the capacity of the P74S and H90D mutants to stimulate IP production was similar to the wild type. After preincubation of wild-type and mutant kp54 in human serum, the capacity to stimulate signal transduction was significantly greater for P74S compared with the wild type, suggesting that the p.P74S variant is more stable. Only polymorphisms were found in the IHH group. Two KISS1 mutations were identified in unrelated patients with idiopathic CPP. The p.P74S variant was associated with higher kisspeptin resistance to degradation in comparison with the wild type, suggesting a role for this mutation in the precocious puberty phenotype.

  1. Mutation analysis of Leber congenital amaurosis‑associated genes in patients with retinitis pigmentosa.

    PubMed

    Shen, Tao; Guan, Liping; Li, Shiqiang; Zhang, Jianguo; Xiao, Xueshan; Jiang, Hui; Yang, Jianhua; Guo, Xiangming; Wang, Jun; Zhang, Qingjiong

    2015-03-01

    The genetic defects underlying approximately half of all retinitis pigmentosa (RP) cases are unknown. A number of genes responsible for Leber congenital amaurosis (LCA) may also cause RP when they are mutated. Our previous study revealed that variants in the most frequently mutated nine exons accounted for approximately half of the mutations detected in a cohort of patients with LCA. The aim of the present study was to detect mutations in LCA-associated genes in patients with RP using two different strategies. Sanger sequencing was used to screen mutations in the nine exons in 293 patients with RP and exome sequencing was used to detect variants in 12 LCA-associated genes in 157 of the 293 patients with RP and then to validate the variants by Sanger sequencing. Potential pathogenic mutations were identified in four patients with early onset RP, including homozygous CRB1 mutations in two patients, compound heterozygous CRB1 mutations in one patient and compound heterozygous CEP290 mutations in one patient. The present study indicated that mutations in CEP290 may also be associated with RP but not with LCA. With the exception of CEP290, the remaining 11 genes known to be associated with LCA but not with RP are unlikely to be a common cause of RP.

  2. Novel homozygous variants in ATCAY, MCOLN1, and SACS in complex neurological disorders.

    PubMed

    Manzoor, Humera; Brüggemann, Norbert; Hussain, Hafiz Muhammad Jafar; Bäumer, Tobias; Hinrichs, Frauke; Wajid, Muhammad; Münchau, Alexander; Naz, Sadaf; Lohmann, Katja

    2018-06-01

    Neurological disorders comprise a large group of clinically and genetically heterogeneous disorders, many of which have a genetic cause. In addition to a detailed neurological examination, exome sequencing is being increasingly used as a complementary diagnostic tool to identify the underlying genetic cause in patients with unclear, supposedly genetically determined disorders. To identify the genetic cause of a complex movement disorder in five consanguineous Pakistani families. We included five consanguineous Pakistani families with complex recessively inherited movement disorders. Clinical investigation including videotaping was carried out in a total of 59 family members (4-21 per family) and MRI in six patients. Exome sequencing was performed in 4-5 family members per pedigree to explore the underlying genetic cause. Patients presented a wide spectrum of neurological symptoms including ataxia and/or dystonia. We identified three novel homozygous, segregating variants in ATCAY (p.Pro200Profs*20), MCOLN1 (p.Ile184Thr), and SACS (p.Asn3040Lysfs*4) in three of the families. Thus, we were able to identify the likely cause of the disease in a considerable number of families (60%) with the relatively simple and nowadays widely available method of exome sequencing. Of note, close collaboration of neurologists and geneticists was instrumental for proper data interpretation. We expand the phenotypic, genotypic, and ethnical spectrum of mutations in these genes. Our findings alert neurologists that rare genetic causes should be considered in complex phenotypes regardless of ethnicity. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. New splicing-site mutations in the SURF1 gene in Leigh syndrome patients.

    PubMed

    Pequignot, M O; Desguerre, I; Dey, R; Tartari, M; Zeviani, M; Agostino, A; Benelli, C; Fouque, F; Prip-Buus, C; Marchant, D; Abitbol, M; Marsac, C

    2001-05-04

    The gene SURF1 encodes a factor involved in the biogenesis of cytochrome c oxidase, the last complex in the respiratory chain. Mutations of the SURF1 gene result in Leigh syndrome and severe cytochrome c oxidase deficiency. Analysis of seven unrelated patients with cytochrome c oxidase deficiency and typical Leigh syndrome revealed different SURF1 mutations in four of them. Only these four cases had associated demyelinating neuropathy. Three mutations were novel splicing-site mutations that lead to the excision of exon 6. Two different novel heterozygous mutations were found at the same guanine residue at the donor splice site of intron 6; one was a deletion, whereas the other was a transition [588+1G>A]. The third novel splicing-site mutation was a homozygous [516-2_516-1delAG] in intron 5. One patient only had a homozygous polymorphism in the middle of the intron 8 [835+25C>T]. Western blot analysis showed that Surf1 protein was absent in all four patients harboring mutations. Our studies confirm that the SURF1 gene is an important nuclear gene involved in the cytochrome c oxidase deficiency. We also show that Surf1 protein is not implicated in the assembly of other respiratory chain complexes or the pyruvate dehydrogenase complex.

  4. Two common low density lipoprotein receptor gene mutations cause familial hypercholesterolemia in Afrikaners.

    PubMed Central

    Leitersdorf, E; Van der Westhuyzen, D R; Coetzee, G A; Hobbs, H H

    1989-01-01

    Familial hypercholesterolemia (FH), an autosomal dominant disease caused by mutations in the LDL receptor gene, is five times more frequent in the Afrikaner population of South Africa than it is in the population of the United States and Europe. It has been proposed that the high frequency is due to a founder effect. In this paper, we characterized 24 mutant LDL receptor alleles from 12 Afrikaner individuals homozygous for FH. We identified two mutations that together makeup greater than 95% of the mutant LDL receptor genes represented in our sample. Both mutations were basepair substitutions that result in single-amino acid changes. Each mutation can be detected readily with the polymerase chain reaction and restriction analysis. The finding of two common LDL receptor mutations in the Afrikaner FH homozygotes predicts that these mutations will predominate in the Afrikaner population and that the high frequency of FH is due to a founder effect. The increased incidence of ischemic heart disease in the Afrikaner population may in part be due to the high frequency of these two mutations in the LDL receptor gene. Images PMID:2569482

  5. A novel homozygous no-stop mutation in G6PC gene from a Chinese patient with glycogen storage disease type Ia.

    PubMed

    Gu, Lei-Lei; Li, Xin-Hua; Han, Yue; Zhang, Dong-Hua; Gong, Qi-Ming; Zhang, Xin-Xin

    2014-02-25

    Glycogen storage disease type Ia (GSD-Ia) is an autosomal recessive genetic disorder resulting in hypoglycemia, hepatomegaly and growth retardation. It is caused by mutations in the G6PC gene encoding Glucose-6-phosphatase. To date, over 80 mutations have been identified in the G6PC gene. Here we reported a novel mutation found in a Chinese patient with abnormal transaminases, hypoglycemia, hepatomegaly and short stature. Direct sequencing of the coding region and splicing-sites in the G6PC gene revealed a novel no-stop mutation, p.*358Yext*43, leading to a 43 amino-acid extension of G6Pase. The expression level of mutant G6Pase transcripts was only 7.8% relative to wild-type transcripts. This mutation was not found in 120 chromosomes from 60 unrelated healthy control subjects using direct sequencing, and was further confirmed by digestion with Rsa I restriction endonuclease. In conclusion, we revealed a novel no-stop mutation in this study which expands the spectrum of mutations in the G6PC gene. The molecular genetic analysis was indispensable to the diagnosis of GSD-Ia for the patient. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Novel autosomal dominant TNNT1 mutation causing nemaline myopathy.

    PubMed

    Konersman, Chamindra G; Freyermuth, Fernande; Winder, Thomas L; Lawlor, Michael W; Lagier-Tourenne, Clotilde; Patel, Shailendra B

    2017-11-01

    Nemaline myopathy (NEM) is one of the three major forms of congenital myopathy and is characterized by diffuse muscle weakness, hypotonia, respiratory insufficiency, and the presence of nemaline rod structures on muscle biopsy. Mutations in troponin T1 (TNNT1) is 1 of 10 genes known to cause NEM. To date, only homozygous nonsense mutations or compound heterozygous truncating or internal deletion mutations in TNNT1 gene have been identified in NEM. This extended family is of historical importance as some members were reported in the 1960s as initial evidence that NEM is a hereditary disorder. Proband and extended family underwent Sanger sequencing for TNNT1. We performed RT-PCR and immunoblot on muscle to assess TNNT1 RNA expression and protein levels in proband and father. We report a novel heterozygous missense mutation of TNNT1 c.311A>T (p.E104V) that segregated in an autosomal dominant fashion in a large family residing in the United States. Extensive sequencing of the other known genes for NEM failed to identify any other mutant alleles. Muscle biopsies revealed a characteristic pattern of nemaline rods and severe myofiber hypotrophy that was almost entirely restricted to the type 1 fiber population. This novel mutation alters a residue that is highly conserved among vertebrates. This report highlights not only a family with autosomal dominant inheritance of NEM, but that this novel mutation likely acts via a dominant negative mechanism. © 2017 The Authors. Molecular Genetics & Genomic Medicine published by Wiley Periodicals, Inc.

  7. Analyses of MMP20 Missense Mutations in Two Families with Hypomaturation Amelogenesis Imperfecta.

    PubMed

    Kim, Youn Jung; Kang, Jenny; Seymen, Figen; Koruyucu, Mine; Gencay, Koray; Shin, Teo Jeon; Hyun, Hong-Keun; Lee, Zang Hee; Hu, Jan C-C; Simmer, James P; Kim, Jung-Wook

    2017-01-01

    Amelogenesis imperfecta is a group of rare inherited disorders that affect tooth enamel formation, quantitatively and/or qualitatively. The aim of this study was to identify the genetic etiologies of two families presenting with hypomaturation amelogenesis imperfecta. DNA was isolated from peripheral blood samples obtained from participating family members. Whole exome sequencing was performed using DNA samples from the two probands. Sequencing data was aligned to the NCBI human reference genome (NCBI build 37.2, hg19) and sequence variations were annotated with the dbSNP build 138. Mutations in MMP20 were identified in both probands. A homozygous missense mutation (c.678T>A; p.His226Gln) was identified in the consanguineous Family 1. Compound heterozygous MMP20 mutations (c.540T>A, p.Tyr180 * and c.389C>T, p.Thr130Ile) were identified in the non-consanguineous Family 2. Affected persons in Family 1 showed hypomaturation AI with dark brown discoloration, which is similar to the clinical phenotype in a previous report with the same mutation. However, the dentition of the Family 2 proband exhibited slight yellowish discoloration with reduced transparency. Functional analysis showed that the p.Thr130Ile mutant protein had reduced activity of MMP20, while there was no functional MMP20 in the Family 1 proband. These results expand the mutational spectrum of the MMP20 and broaden our understanding of genotype-phenotype correlations in amelogenesis imperfecta.

  8. PRSS1 and SPINK1 mutations in idiopathic chronic and recurrent acute pancreatitis.

    PubMed

    Pelaez-Luna, Mario; Robles-Diaz, Guillermo; Canizales-Quinteros, Samuel; Tusié-Luna, Maria T

    2014-09-07

    To identify gene mutations in PRSS1 and SPINK1 in individuals with early onset idiopathic chronic or recurrent acute pancreatitis. The cationic trypsinogen gene (PRSS1; exons 2 and 3) and the serine protease inhibitor Kazal 1 gene (SPINK1; exon 3) were selectively amplified and sequenced from blood samples of 19 patients admitted to the Pancreas Clinic at our institution with chronic pancreatitis and/or idiopathic recurrent acute pancreatitis that were diagnosed or with onset before age 35. Fifty healthy volunteers served as controls. Whole blood samples were collected and gene specific sequences were amplified by polymerase chain reaction (PCR). All PCR products were subsequently sequenced in order to identify the presence of any mutations. Nineteen patients with pancreatitis (14 males; median age 24 years, range 15-48 years) were included in this study, of which five showed the presence of gene mutations. Direct sequencing results indicated the presence of two previously unidentified mutations in exon 2 of PRSS1 (V39E and N42S) in two patients with recurrent acute pancreatitis. Two cases had the N34S SPINK1 mutation. Analysis of the relatives of one patient homozygous for this mutation showed that five of the six family members carried the N34S SPINK1 mutation. Of these members, three were healthy heterozygous carriers and two were homozygotes (one sibling had diabetes, the other was healthy). Another patient was heterozygous for a novel SPINK1 mutation located on exon 3 (V46D). All members from this patient's family had normal genotypes, indicating that it was a de novo mutation. No mutations in either gene were present in the control subjects. Two novel PRSS1 mutations and one novel SPINK1 mutation were identified in Mexican patients with early onset idiopathic recurrent acute pancreatitis.

  9. Craniofacial abnormalities in homozygous Small eye (Sey/Sey) embryos and newborn mice.

    PubMed

    Kaufman, M H; Chang, H H; Shaw, J P

    1995-06-01

    The Small eye (Sey) gene in the mouse is lethal in the homozygous state. It is located on chromosome 2, is a mutation in the Pax-6 gene, and is genetically homologous with the human aniridia 2 (AN2) gene mutation. Numerous studies over the last few years, using genetic and molecular biological approaches, have investigated both the location of the gene as well as its possible mode of action. In the homozygous state, the primary defect appears to be limited to the failure of differentiation of the presumptive lens and nasal placodes. Such mice therefore display a characteristic phenotype; they possess neither eyes nor any nasal derivatives. Their heterozygous (Sey/+) and normal (+/+) littermates may be distinguished before birth only by a detailed examination of their eyes. Few detailed morphological/histological studies have been undertaken to date in the Sey/Sey embryos and newborn, and in the present study we describe a variety of craniofacial abnormalities that have not previously been reported. We observed, with one exception, delayed closure of the palate, and the presence in 80% of mice of an abnormal complement of upper incisor teeth, so that 35% possessed 1 supernumerary tooth while 45% possessed 2 supernumerary teeth. In these mice, a total of either 3 or 4, rather than the normal complement of 2, upper incisor teeth were present. Possibly the most unexpected finding, however, was the presence of a median cartilaginous rod-like structure which protruded between the 2 maxillae to give the Alizarin red S and Alcian blue-stained 'cleared' skulls of the newborn mice a characteristic 'unicorn-like' appearance. While this structure appeared to be a rostral extension of the chondrocranium, its exact derivation is unclear.

  10. New mutation in the PTEN gene in a Brazilian patient with Cowden's syndrome.

    PubMed

    Lima, Erika U de; Soares, Iberê C; Danilovic, Debora L S; Marui, Suemi

    2012-11-01

    Cowden syndrome is characterized by hamartomatous polyps, trichilemmomas, increased risk of developing neoplasms, and is associated with germline mutations in the PTEN gene. We searched for germline mutations in PTEN in a 49-year-old female patient who presented trichilemmoma with previous history of breast carcinoma, and thyroidectomy for a thyroid nodule. We also searched for somatic mutations in breast and thyroid tumoral tissues. DNA was extracted from peripheral leukocytes, paraffin samples of breast carcinoma, and cytological smears of thyroid nodule fine-needle aspiration biopsy, whose final histopathological diagnosis was adenomatous goiter. PTEN was amplified and sequenced. We identified a novel mutation, due to a T>A inversion at position 159 and A>T inversion at position 160, leading to valine-to-aspartic acid substitution at position 53. The p.Val53Asp was also found in homozygous state in samples obtained from adenocarcinoma breast and thyroid biopsy, denoting loss of heterozygosity. Here, we demonstrated a novel germline mutation in PTEN, as well as somatic loss of the wild-type PTEN allele in breast and thyroid tumors in a patient with Cowden syndrome.

  11. Molecular and cellular characteristics of ABCA3 mutations associated with diffuse parenchymal lung diseases in children

    PubMed Central

    Flamein, Florence; Riffault, Laure; Muselet-Charlier, Céline; Pernelle, Julie; Feldmann, Delphine; Jonard, Laurence; Durand-Schneider, Anne-Marie; Coulomb, Aurore; Maurice, Michèle; Nogee, Lawrence M.; Inagaki, Nobuya; Amselem, Serge; Dubus, Jean Christophe; Rigourd, Virginie; Brémont, François; Marguet, Christophe; Brouard, Jacques; de Blic, Jacques; Clement, Annick; Epaud, Ralph; Guillot, Loïc

    2012-01-01

    ABCA3 (ATP-binding cassette subfamily A, member 3) is expressed in the lamellar bodies of alveolar type II cells and is crucial to pulmonary surfactant storage and homeostasis. ABCA3 gene mutations have been associated with neonatal respiratory distress (NRD) and pediatric interstitial lung disease (ILD). The objective of this study was to look for ABCA3 gene mutations in patients with severe NRD and/or ILD. The 30 ABCA3 coding exons were screened in 47 patients with severe NRD and/or ILD. ABCA3 mutations were identified in 10 out of 47 patients, including 2 homozygous, 5 compound heterozygous and 3 heterozygous patients. SP-B and SP-C expression patterns varied across patients. Among patients with ABCA3 mutations, five died shortly after birth and five developed ILD (including one without NRD). Functional studies of p.D253H and p.T1173R mutations revealed that p.D253H and p.T1173R induced abnormal lamellar bodies. Additionally, p.T1173R increased IL-8 secretion in vitro. In conclusion, we identified new ABCA3 mutations in patients with life-threatening NRD and/or ILD. Two mutations associated with ILD acted via different pathophysiological mechanisms despite similar clinical phenotypes. PMID:22068586

  12. [Homozygous familial hypercholesterolemia].

    PubMed

    Kayikçioğlu, Meral

    2014-10-01

    Familial hypercholesterolemia (FH) is caused by genetic deficiency of LDL receptors leading to extremely high cholesterol levels and atherosclerosis at early ages. For the prevention of early atherosclerotic cardiovascular events, effective reduction of LDL-cholesterol is necessary from the early ages. However, particularly in homozygous patients, it's almost impossible to achieve target LDL-cholesterol levels with antilipid agents including statin agents, due to the severe LDL receptor dysfunction. LDL apheresis is an effective treatment modality in severe AH patients. However, the invasive, chronic time consuming nature of this treatment decreases the compliance of these patients. Moreover, atherosclerosis progress in 25% of the patients undergoing regular and effective apheresis even though since early ages. Clinical data also indicate that there is still an unmet medical need for new effective treatments for AH patients. This review will address new therapeutic strategies targeting Apolipoprotein (Apo) B including MTTP inhibitor Lomitapideand oligonucleotide Mipomersen. As both agents are targeted against ApoB, they are expected to be effective even in receptor negative homozygous AH patients.

  13. Impact of glucocerebrosidase mutations on motor and nonmotor complications in Parkinson's disease.

    PubMed

    Oeda, Tomoko; Umemura, Atsushi; Mori, Yuko; Tomita, Satoshi; Kohsaka, Masayuki; Park, Kwiyoung; Inoue, Kimiko; Fujimura, Harutoshi; Hasegawa, Hiroshi; Sugiyama, Hiroshi; Sawada, Hideyuki

    2015-12-01

    Homozygous mutations of the glucocerebrosidase gene (GBA) cause Gaucher disease (GD), and heterozygous mutations of GBA are a major risk factor for Parkinson's disease (PD). This study examined the impact of GBA mutations on the longitudinal clinical course of PD patients by retrospective cohort design. GBA-coding regions were fully sequenced in 215 PD patients and GD-associated GBA mutations were identified in 19 (8.8%) PD patients. In a retrospective cohort study, time to develop dementia, psychosis, wearing-off, and dyskinesia were examined. Survival time analysis followed a maximum 12-year observation (median 6.0 years), revealing that PD patients with GD-associated mutations developed dementia and psychosis significantly earlier than those without mutations (p < 0.001 and p = 0.017, respectively). Adjusted hazard ratios of GBA mutations were 8.3 for dementia (p < 0.001) and 3.1 for psychosis (p = 0.002). No statistically significant differences were observed for wearing-off and dyskinesia between the groups. N-isopropyl-p[(123)I] iodoamphetamine single-photon emission tomography pixel-by-pixel analysis revealed that regional cerebral blood flow was reduced in the bilateral parietal cortex, including the precuneus of GD-associated mutant PD patients, compared with matched PD controls without mutations. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  14. Homozygous deficiency of ubiquitin-ligase ring-finger protein RNF168 mimics the radiosensitivity syndrome of ataxia-telangiectasia

    PubMed Central

    Devgan, S S; Sanal, O; Doil, C; Nakamura, K; Nahas, S A; Pettijohn, K; Bartek, J; Lukas, C; Lukas, J; Gatti, R A

    2011-01-01

    Maintaining genomic integrity is critical to avoid life-threatening disorders, such as premature aging, neurodegeneration and cancer. A multiprotein cascade operates at sites of DNA double-strand breaks (DSBs) to recognize, signal and repair damage. RNF168 (ring-finger nuclear factor) contributes to this emerging pathway of several E3 ubiquitin ligases that perform sequential ubiquitylations on damaged chromosomes, chromatin modifications essential for aggregation of repair complexes at the DSB sites. Here, we report the clinical and cellular phenotypes associated with a newly identified homozygous nonsense mutation in the RNF168 gene of a patient with a syndrome mimicking ataxia-telangiectasia. The mutation eliminated both of RNF168's ubiquitin-binding motifs, thus blocking progression of the ubiquitylation cascade and retention of repair proteins including tumor suppressors 53BP1 and BRCA1 at DSB sites, consistent with the observed defective DNA damage checkpoints/repair and pronounced radiosensitivity. Rapid screening for RNF168 pathway deficiency was achieved by scoring patients' lymphoblastoid cells for irradiation-induced nuclear foci containing 53BP1, a robust assay we propose for future diagnostic applications. The formation of radiation-induced DSB repair foci was rescued by ectopic expression of wild-type RNF168 in patient's cells, further causally linking the RNF168 mutation with the pathology. Clinically, this novel syndrome featured ataxia, telangiectasia, elevated alphafetoprotein, immunodeficiency, microcephaly and pulmonary failure and has implications for the differential diagnosis of autosomal recessive ataxias. PMID:21394101

  15. Pro416Arg cherubism mutation in Sh3bp2 knock-in mice affects osteoblasts and alters bone mineral and matrix properties

    PubMed Central

    Wang, Chiachien J.; Chen, I-Ping; Koczon-Jaremko, Boguslawa; Boskey, Adele L.; Ueki, Yasuyoshi; Kuhn, Liisa; Reichenberger, Ernst J.

    2010-01-01

    Cherubism is an autosomal dominant disorder in children characterized by unwarranted symmetrical bone resorption of the jaws with fibrous tissue deposition. Mutations causing cherubism have been identified in the adaptor protein SH3BP2. Knock-in mice with a Pro416Arg mutation in Sh3bp2 exhibit a generalized osteoporotic bone phenotype. In this study, we examined the effects of this “cherubism” mutation on spectroscopic indices of “bone quality” and on osteoblast differentiation. Fourier-transform infrared imaging (FTIRI) analysis of femurs from wild-type and Sh3bp2 knock-in mice showed decreased mineral content, decreased mineral crystallinity/crystal size, and increased collagen maturity in homozygous mutants. To assess osteoblast maturation in vivo, knock-in mice were crossed with transgenic mice over-expressing GFP driven by 3.6-kb or 2.3-kb Col1a1 promoter fragments. Reduced numbers of mature osteoblasts were observed in homozygous mice. Neonatal calvarial cultures, which were enriched for osteoblasts by depletion of hematopoietic cells (negative selection for Ter119- and CD45-positive cells) were investigated for osteoblast-specific gene expression and differentiation, which demonstrated that differentiation and mineralization in homozygous osteoblast cultures was impaired. Co-cultures with calvarial osteoblasts and bone marrow macrophages showed that mutant osteoblasts appear to increase osteoclastogenesis resulting in increased bone resorption on bone chips. In summary, the Sh3bp2 mutation in cherubism mice alters bone quality, reduces osteoblast function, and may contribute to excessive bone resorption by osteoclasts. Our data, together with previous osteoclast studies, demonstrate a critical role of Sh3bp2 in bone remodeling and osteoblast differentiation. PMID:20117257

  16. A novel mutation in NDUFS4 causes Leigh syndrome in an Ashkenazi Jewish family.

    PubMed

    Anderson, S L; Chung, W K; Frezzo, J; Papp, J C; Ekstein, J; DiMauro, S; Rubin, B Y

    2008-12-01

    Leigh syndrome is a neurodegenerative disorder of infancy or childhood generally due to mutations in nuclear or mitochondrial genes involved in mitochondrial energy metabolism. We performed linkage analysis in an Ashkenazi Jewish (AJ) family without consanguinity with three affected children. Linkage to microsatellite markers D5S1969 and D5S407 led to evaluation of the complex I gene NDUFS4, in which we identified a novel homozygous c.462delA mutation that disrupts the reading frame. The resulting protein lacks a cAMP-dependent protein kinase phosphorylation site required for activation of mitochondrial respiratory chain complex I. In a random sample of 5000 healthy AJ individuals, the carrier frequency of the NDUFS4 mutation c.462delA was 1 in 1000, suggesting that it should be considered in all AJ patients with Leigh syndrome.

  17. Novel SNP array analysis and exome sequencing detect a homozygous exon 7 deletion of MEGF10 causing early onset myopathy, areflexia, respiratory distress and dysphagia (EMARDD)

    PubMed Central

    Pierson, Tyler Mark; Markello, Thomas; Accardi, John; Wolfe, Lynne; Adams, David; Sincan, Murat; Tarazi, Noor M.; Fajardo, Karin Fuentes; Cherukuri, Praveen F.; Bajraktari, Ilda; Meilleur, Katy G.; Donkervoort, Sandra; Jain, Mina; Hu, Ying; Lehky, Tanya J.; Cruz, Pedro; Mullikin, James C.; Bonnemann, Carsten; Gahl, William A.; Boerkoel, Cornelius F.; Tifft, Cynthia J.

    2013-01-01

    Early-onset myopathy, areflexia, respiratory distress and dysphagia (EMARDD) is a myopathic disorder associated with mutations in MEGF10. By novel analysis of SNP array hybridization and exome sequence coverage, we diagnosed a 10-year old girl with EMARDD following identification of a novel homozygous deletion of exon 7 in MEGF10. In contrast to previously reported EMARDD patients, her weakness was more prominent proximally than distally, and involved her legs more than her arms. MRI of her pelvis and thighs showed muscle atrophy and fatty replacement. Ultrasound of several muscle groups revealed dense homogenous increases in echogenicity. Cloning and sequencing of the deletion breakpoint identified features suggesting the mutation arose by fork stalling and template switching. These findings constitute the first genomic deletion causing EMARDD, expand the clinical phenotype, and provide new insight into the pattern and histology of its muscular pathology. PMID:23453856

  18. A novel mutation in HSD11B2 causes apparent mineralocorticoid excess in an Omani kindred.

    PubMed

    Yau, Mabel; Azkawi, Hanan Said Al; Haider, Shozeb; Khattab, Ahmed; Badi, Maryam Al; Abdullah, Wafa; Senani, Aisha Al; Wilson, Robert C; Yuen, Tony; Zaidi, Mone; New, Maria I

    2016-07-01

    Apparent mineralocorticoid excess (AME) is a rare autosomal recessive genetic disorder causing severe hypertension in childhood due to a deficiency of 11β-hydroxysteroid dehydrogenase type 2 (11βHSD2), which is encoded by HSD11B2. Without treatment, chronic hypertension leads to early development of end-organ damage. Approximately 40 causative mutations in HSD11B2 have been identified in ∼100 AME patients worldwide. We have studied the clinical presentation, biochemical parameters, and molecular genetics in six patients from a consanguineous Omani family with AME. DNA sequence analysis of affected members of this family revealed homozygous c.799A>G mutations within exon 4 of HSD11B2, corresponding to a p.T267A mutation of 11βHSD2. The structural change and predicted consequences owing to the p.T267A mutation have been modeled in silico. We conclude that this novel mutation is responsible for AME in this family. © 2016 New York Academy of Sciences.

  19. Characteristic brain MRI findings in ataxia-neuropathy spectrum related to POLG mutation

    PubMed Central

    Henao, Adriana I; Pira, Sonia; Vargas, Sergio A; Montoya, Jorge; Castillo, Mauricio

    2016-01-01

    Patients with mutations in the polymerase gamma gene (POLG) may present with progressive ataxia and in such situations neuroimaging findings may suggest the diagnosis. Herein we report a patient with a POLG gene W748S homozygous mutation and characteristic lesions in the thalamus, cerebellum and inferior olivary nucleus seen on magnetic resonance imaging. PMID:26755490

  20. Characteristic brain MRI findings in ataxia-neuropathy spectrum related to POLG mutation.

    PubMed

    Henao, Adriana I; Pira, Sonia; Herrera, Diego A; Vargas, Sergio A; Montoya, Jorge; Castillo, Mauricio

    2016-02-01

    Patients with mutations in the polymerase gamma gene (POLG) may present with progressive ataxia and in such situations neuroimaging findings may suggest the diagnosis. Herein we report a patient with a POLG gene W748S homozygous mutation and characteristic lesions in the thalamus, cerebellum and inferior olivary nucleus seen on magnetic resonance imaging. © The Author(s) 2016.

  1. Muscle RAS oncogene homolog (MRAS) recurrent mutation in Borrmann type IV gastric cancer.

    PubMed

    Yasumoto, Makiko; Sakamoto, Etsuko; Ogasawara, Sachiko; Isobe, Taro; Kizaki, Junya; Sumi, Akiko; Kusano, Hironori; Akiba, Jun; Torimura, Takuji; Akagi, Yoshito; Itadani, Hiraku; Kobayashi, Tsutomu; Hasako, Shinichi; Kumazaki, Masafumi; Mizuarai, Shinji; Oie, Shinji; Yano, Hirohisa

    2017-01-01

    The prognosis of patients with Borrmann type IV gastric cancer (Type IV) is extremely poor. Thus, there is an urgent need to elucidate the molecular mechanisms underlying the oncogenesis of Type IV and to identify new therapeutic targets. Although previous studies using whole-exome and whole-genome sequencing have elucidated genomic alterations in gastric cancer, none has focused on comprehensive genetic analysis of Type IV. To discover cancer-relevant genes in Type IV, we performed whole-exome sequencing and genome-wide copy number analysis on 13 patients with Type IV. Exome sequencing identified 178 somatic mutations in protein-coding sequences or at splice sites. Among the mutations, we found a mutation in muscle RAS oncogene homolog (MRAS), which is predicted to cause molecular dysfunction. MRAS belongs to the Ras subgroup of small G proteins, which includes the prototypic RAS oncogenes. We analyzed an additional 46 Type IV samples to investigate the frequency of MRAS mutation. There were eight nonsynonymous mutations (mutation frequency, 17%), showing that MRAS is recurrently mutated in Type IV. Copy number analysis identified six focal amplifications and one homozygous deletion, including insulin-like growth factor 1 receptor (IGF1R) amplification. The samples with IGF1R amplification had remarkably higher IGF1R mRNA and protein expression levels compared with the other samples. This is the first report of MRAS recurrent mutation in human tumor samples. Our results suggest that MRAS mutation and IGF1R amplification could drive tumorigenesis of Type IV and could be new therapeutic targets. © 2016 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

  2. Mutations in ATP6V1B1 and ATP6V0A4 genes cause recessive distal renal tubular acidosis in Mexican families.

    PubMed

    Escobar, Laura I; Simian, Christopher; Treard, Cyrielle; Hayek, Donia; Salvador, Carolina; Guerra, Norma; Matos, Mario; Medeiros, Mara; Enciso, Sandra; Camargo, María Dolores; Vargas-Poussou, Rosa

    2016-05-01

    Autosomal recessive distal renal tubular acidosis (dRTA) is a rare disease characterized by a hyperchloremic metabolic acidosis with normal anion gap, hypokalemia, hypercalciuria, hypocitraturia, nephrocalcinosis, and conserved glomerular filtration rate. In some cases, neurosensorial deafness is associated. dRTA is developed during the first months of life and the main manifestations are failure to thrive, vomiting, dehydration, and anorexia. Nine unrelated families were studied: seven children, a teenager, and an adult with dRTA. Hearing was preserved in four children. Coding regions of the genes responsible for recessive dRTA were analysed by Sanger sequencing. Molecular defects were found in the genes ATP6V1B1 and ATP6V0A4. We identified three homozygous variants in ATP6V1B: a frameshift mutation (p.Ile386Hisfs*56), a nucleotide substitution in exon 10 (p.Pro346Arg), and a new splicing mutation in intron 5. Three patients were homozygous for one novel (p.Arg743Trp) and one known (p.Asp411Tyr) missense mutations in the ATP6V0A4 gene. Three patients were compound heterozygous: one proband displayed two novel mutations, the frameshift mutation p.Val52Metfs*25, and a large deletion of exons 18-21; two probands showed the missense mutation p.Asp411Tyr and as a second mutation, p.Arg194Ter and c.1691+2dup, respectively. ATP6V0A4 and ATP6V1B1 genes were involved in recessive dRTA of Mexican families. All ATP6V1B1 mutations detected were homozygous and all patients developed sensorineural hearing loss (SNHL) early in infancy. ATP6V0A4 mutations were found in one infant and three children without SNHL, and in one teenager and one adult with SNHL confirming the phenotypic variability in this trait. The mutation p.Asp411Tyr detected in four Mexican families was due to a founder effect. Screening of these mutations could provide a rapid and valuable tool for diagnosis of dRTA in this population.

  3. Inflammatory peeling skin syndrome caused a novel mutation in CDSN.

    PubMed

    Telem, Dana Fuchs; Israeli, Shirli; Sarig, Ofer; Sprecher, Eli

    2012-04-01

    Generalized peeling skin syndrome (PSS) is a rare autosomal recessive dermatosis manifesting with continuous exfoliation of the stratum corneum. The inflammatory (type B) subtype of PSS was recently found to be caused by deleterious mutations in the CDSN gene encoding corneodesmosin, a major component of desmosomal junctions in the uppermost layers of the epidermis. In the present study, we assessed a 10-month-old baby, who presented with generalized superficial peeling of the skin. Using PCR amplification and direct sequencing, we identified the third PSS-associated mutation in CDSN, a homozygous 4 bp duplication in the second exon of the gene (c.164_167dup GCCT; p.Thr57ProfsX6). These data further support the notion that corneodesmosin deficiency impairs cell-cell adhesion in the upper epidermis, paving the way for an abnormal inflammatory response due to epidermal barrier disruption.

  4. Autosomal recessive atrial dilated cardiomyopathy with standstill evolution associated with mutation of Natriuretic Peptide Precursor A.

    PubMed

    Disertori, Marcello; Quintarelli, Silvia; Grasso, Maurizia; Pilotto, Andrea; Narula, Nupoor; Favalli, Valentina; Canclini, Camilla; Diegoli, Marta; Mazzola, Silvia; Marini, Massimiliano; Del Greco, Maurizio; Bonmassari, Roberto; Masè, Michela; Ravelli, Flavia; Specchia, Claudia; Arbustini, Eloisa

    2013-02-01

    Atrial dilatation and atrial standstill are etiologically heterogeneous phenotypes with poorly defined nosology. In 1983, we described 8-years follow-up of atrial dilatation with standstill evolution in 8 patients from 3 families. We later identified 5 additional patients with identical phenotypes: 1 member of the largest original family and 4 unrelated to the 3 original families. All families are from the same geographic area in Northeast Italy. We followed up the 13 patients for up to 37 years, extended the clinical investigation and monitoring to living relatives, and investigated the genetic basis of the disease. The disease was characterized by: (1) clinical onset in adulthood; (2) biatrial dilatation up to giant size; (3) early supraventricular arrhythmias with progressive loss of atrial electric activity to atrial standstill; (4) thromboembolic complications; and (5) stable, normal left ventricular function and New York Heart Association functional class during the long-term course of the disease. By linkage analysis, we mapped a locus at 1p36.22 containing the Natriuretic Peptide Precursor A gene. By sequencing Natriuretic Peptide Precursor A, we identified a homozygous missense mutation (p.Arg150Gln) in all living affected individuals of the 6 families. All patients showed low serum levels of atrial natriuretic peptide. Heterozygous mutation carriers were healthy and demonstrated normal levels of atrial natriuretic peptide. Autosomal recessive atrial dilated cardiomyopathy is a rare disease associated with homozygous mutation of the Natriuretic Peptide Precursor A gene and characterized by extreme atrial dilatation with standstill evolution, thromboembolic risk, preserved left ventricular function, and severely decreased levels of atrial natriuretic peptide.

  5. Insights into Mutation Effect in Three Poikiloderma with Neutropenia Patients by Transcript Analysis and Disease Evolution of Reported Patients with the Same Pathogenic Variants.

    PubMed

    Colombo, Elisa A; Elcioglu, Nursel H; Graziano, Claudio; Farinelli, Pamela; Di Fede, Elisabetta; Neri, Iria; Facchini, Elena; Greco, Mariangela; Gervasini, Cristina; Larizza, Lidia

    2018-05-16

    Poikiloderma with neutropenia (PN) is a genodermatosis currently described in 77 patients, all presenting with early-onset poikiloderma, neutropenia, and several additional signs. Biallelic loss-of-function mutations in USB1 gene are detected in all molecularly tested patients but genotype-phenotype correlation remains elusive. Cancer predisposition is recognized among PN features and pathogenic variants found in patients who developed early in life myelodysplasia (n = 12), acute myeloid leukemia (n = 2), and squamous cell carcinoma (n = 2) should be kept into account in management and follow-up of novel patients. This will hopefully allow achieving data clustered on specific mutations relevant to oncological surveillance of the carrier patients. We describe the clinical features of three unreported PN patients and characterize their USB1 pathogenic variants by transcript analysis to get insights into the effect on the overall phenotype and disease evolution. A Turkish boy is homozygous for the c.531delA deletion, a recurrent mutation in Turkey; an adult Italian male is compound heterozygous for two nonsense mutations, c.243G>A and c.541C>T, while an Italian boy is homozygous for the splicing c.683_693+1del variant. The identified mutations have already been reported in PN patients who developed hematologic or skin cancer. Aberrant mRNAs of all four mutated alleles could be identified confirming that transcripts of USB1 main isoform either carrying stop codons or mis-spliced may at least partially escape nonsense-mediated decay. Our study addresses the need of gathering insights on genotype-phenotype correlations in newly described PN patients, by transcript analysis and information on disease evolution of reported patients with the same pathogenic variants.

  6. Absence of PITX3 mutation in a Tunisian family with congenital cataract and mental retardation

    PubMed Central

    Chograni, Manèl; Chaabouni, Myriam; Chelly, Imen; Helayem, Mohamed Bechir

    2010-01-01

    Purpose The PITX3 (pituitary homeobox 3) gene encodes for a homeobox bicoid-like transcription factor. When one allele is mutated, it leads to dominant cataract and anterior segment mesenchymal dysgenesis in humans. When both copies are mutated, homozygous mutation contributes to microphtalmia with brain malformations. In the current study, a family with autosomal recessive congenital cataract (ARCC) associated with mental retardation (MR) was examined to identify PITX3 mutations. Methods Sequencing of the PITX3 gene was performed on two affected and three unaffected members of the studied Tunisian family. The results were analyzed with Sequencing Analysis 5.2 and SeqScape. Results No mutation in the four exons of PITX3 was revealed. Two substitution polymorphisms, c.439C>T and c.930C>A, were detected in exons 3 and 4, respectively. These alterations did not segregate with the disease. Conclusions Although PITX3 was shown to be essential to normal embryonic eye and brain development in vertebrates, we report the absence of PITX3 mutations in a family presenting congenital cataract and mental retardation. PMID:20376326

  7. HSJ1-related hereditary neuropathies: novel mutations and extended clinical spectrum.

    PubMed

    Gess, Burkhard; Auer-Grumbach, Michaela; Schirmacher, Anja; Strom, Tim; Zitzelsberger, Manuela; Rudnik-Schöneborn, Sabine; Röhr, Dominik; Halfter, Hartmut; Young, Peter; Senderek, Jan

    2014-11-04

    To determine the nature and frequency of HSJ1 mutations in patients with hereditary motor and hereditary motor and sensory neuropathies. Patients were screened for mutations by genome-wide or targeted linkage and homozygosity studies, whole-exome sequencing, and Sanger sequencing. RNA and protein studies of skin fibroblasts were used for functional characterization. We describe 2 additional mutations in the HSJ1 gene in a cohort of 90 patients with autosomal recessive distal hereditary motor neuropathy (dHMN) and Charcot-Marie-Tooth disease type 2 (CMT2). One family with a dHMN phenotype showed the homozygous splice-site mutation c.229+1G>A, which leads to retention of intron 4 in the HSJ1 messenger RNA with a premature stop codon and loss of protein expression. Another family, presenting with a CMT2 phenotype, carried the homozygous missense mutation c.14A>G (p.Tyr5Cys). This mutation was classified as likely disease-related by several automatic algorithms for prediction of possible impact of an amino acid substitution on the structure and function of proteins. Both mutations cosegregated with autosomal recessive inheritance of the disease and were absent from the general population. Taken together, in our cohort of 90 probands, we confirm that HSJ1 mutations are a rare but detectable cause of autosomal recessive dHMN and CMT2. We provide clinical and functional information on an HSJ1 splice-site mutation and report the detailed phenotype of 2 patients with CMT2, broadening the phenotypic spectrum of HSJ1-related neuropathies. © 2014 American Academy of Neurology.

  8. Carriers of filaggrin gene (FLG) mutations avoid professional exposure to irritants in adulthood.

    PubMed

    Bandier, Josefine; Ross-Hansen, Katrine; Carlsen, Berit C; Menné, Torkil; Linneberg, Allan; Stender, Steen; Szecsi, Pal B; Meldgaard, Michael; Thyssen, Jacob P; Johansen, Jeanne D

    2013-12-01

    Loss-of-function mutations in the filaggrin gene (FLG) are associated with xerosis, atopic dermatitis, and early onset of hand eczema. Irritant exposure is a risk factor for occupational hand eczema, and FLG mutations increase the risk of occupational irritant contact dermatitis on the hands in hospital cohorts. It is unknown whether FLG mutations affect the level of irritant exposure. To evaluate whether exposure to occupational irritants was dependent on FLG mutations, atopic dermatitis, and age at hand eczema onset. Randomly chosen Danish adults completed a questionnaire on general health and occupational exposures. Genotyping for FLG mutations (R501X, 2282del4, and R2447X) and patch testing were performed. Overall, 38.7% of subjects reported present or previous occupational exposure to irritants. Among individuals who reported hand eczema onset before entering their work life, 50.6% (45/89) of FLG non-mutation carriers became exposed to irritants, as compared with 28.6% (4/14) of heterozygous and 0% (0/6) of homozygous mutation carriers (p = 0.006). Avoidance was conspicuous among mutation carriers reporting childhood hand eczema and atopic dermatitis (odds ratio 0.08, 95% confidence interval 0.01-0.65). Carriers of FLG mutations who have had hand eczema onset in childhood avoid occupational exposure to irritants; the association is most marked with homozygous mutation status combined with atopic dermatitis. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Targeted next generation sequencing identifies novel NOTCH3 gene mutations in CADASIL diagnostics patients.

    PubMed

    Maksemous, Neven; Smith, Robert A; Haupt, Larisa M; Griffiths, Lyn R

    2016-11-24

    Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a monogenic, hereditary, small vessel disease of the brain causing stroke and vascular dementia in adults. CADASIL has previously been shown to be caused by varying mutations in the NOTCH3 gene. The disorder is often misdiagnosed due to its significant clinical heterogeneic manifestation with familial hemiplegic migraine and several ataxia disorders as well as the location of the currently identified causative mutations. The aim of this study was to develop a new, comprehensive and efficient single assay strategy for complete molecular diagnosis of NOTCH3 mutations through the use of a custom next-generation sequencing (NGS) panel for improved routine clinical molecular diagnostic testing. Our custom NGS panel identified nine genetic variants in NOTCH3 (p.D139V, p.C183R, p.R332C, p.Y465C, p.C597W, p.R607H, p.E813E, p.C977G and p.Y1106C). Six mutations were stereotypical CADASIL mutations leading to an odd number of cysteine residues in one of the 34 NOTCH3 gene epidermal growth factor (EGF)-like repeats, including three new typical cysteine mutations identified in exon 11 (p.C597W; c.1791C>G); exon 18 (p.C977G; c.2929T>G) and exon 20 (p.Y1106C; c.3317A>G). Interestingly, a novel missense mutation in the CACNA1A gene was also identified in one CADASIL patient. All variants identified (novel and known) were further investigated using in silico bioinformatic analyses and confirmed through Sanger sequencing. NGS provides an improved and effective methodology for the diagnosis of CADASIL. The NGS approach reduced time and cost for comprehensive genetic diagnosis, placing genetic diagnostic testing within reach of more patients.

  10. Genetic Mapping of Glutaric Aciduria, Type 3, to Chromosome 7 and Identification of Mutations in C7orf10

    PubMed Central

    Sherman, Eric A.; Strauss, Kevin A.; Tortorelli, Silvia; Bennett, Michael J.; Knerr, Ina; Morton, D. Holmes; Puffenberger, Erik G.

    2008-01-01

    While screening Old Order Amish children for glutaric aciduria type 1 (GA1) between 1989 and 1993, we found three healthy children who excreted abnormal quantities of glutaric acid but low 3-hydroxyglutaric acid, a pattern consistent with glutaric aciduria type 3 (GA3). None of these children had the GCDH c.1262C→T mutation that causes GA1 among the Amish. Using single-nucleotide polymorphism (SNP) genotypes, we identified a shared homozygous 4.7 Mb region on chromosome 7. This region contained 25 genes including C7orf10, an open reading frame with a putative mitochondrial targeting sequence and coenzyme-A transferase domain. Direct sequencing of C7orf10 revealed that the three Amish individuals were homozygous for a nonsynonymous sequence variant (c.895C→T, Arg299Trp). We then sequenced three non-Amish children with GA3 and discovered two nonsense mutations (c.322C→T, Arg108Ter, and c.424C→T, Arg142Ter) in addition to the Amish mutation. Two pathogenic alleles were identified in each of the six patients. There was no consistent clinical phenotype associated with GA3. In affected individuals, urine molar ratios of glutarate to its derivatives (3-hydroxyglutarate, glutarylcarnitine, and glutarylglycine) were elevated, suggesting impaired formation of glutaryl-CoA. These observations refine our understanding of the lysine-tryptophan degradation pathway and have important implications for the pathophysiology of GA1. PMID:18926513

  11. Systematic analysis of mutation distribution in three dimensional protein structures identifies cancer driver genes.

    PubMed

    Fujimoto, Akihiro; Okada, Yukinori; Boroevich, Keith A; Tsunoda, Tatsuhiko; Taniguchi, Hiroaki; Nakagawa, Hidewaki

    2016-05-26

    Protein tertiary structure determines molecular function, interaction, and stability of the protein, therefore distribution of mutation in the tertiary structure can facilitate the identification of new driver genes in cancer. To analyze mutation distribution in protein tertiary structures, we applied a novel three dimensional permutation test to the mutation positions. We analyzed somatic mutation datasets of 21 types of cancers obtained from exome sequencing conducted by the TCGA project. Of the 3,622 genes that had ≥3 mutations in the regions with tertiary structure data, 106 genes showed significant skew in mutation distribution. Known tumor suppressors and oncogenes were significantly enriched in these identified cancer gene sets. Physical distances between mutations in known oncogenes were significantly smaller than those of tumor suppressors. Twenty-three genes were detected in multiple cancers. Candidate genes with significant skew of the 3D mutation distribution included kinases (MAPK1, EPHA5, ERBB3, and ERBB4), an apoptosis related gene (APP), an RNA splicing factor (SF1), a miRNA processing factor (DICER1), an E3 ubiquitin ligase (CUL1) and transcription factors (KLF5 and EEF1B2). Our study suggests that systematic analysis of mutation distribution in the tertiary protein structure can help identify cancer driver genes.

  12. Systematic analysis of mutation distribution in three dimensional protein structures identifies cancer driver genes

    PubMed Central

    Fujimoto, Akihiro; Okada, Yukinori; Boroevich, Keith A.; Tsunoda, Tatsuhiko; Taniguchi, Hiroaki; Nakagawa, Hidewaki

    2016-01-01

    Protein tertiary structure determines molecular function, interaction, and stability of the protein, therefore distribution of mutation in the tertiary structure can facilitate the identification of new driver genes in cancer. To analyze mutation distribution in protein tertiary structures, we applied a novel three dimensional permutation test to the mutation positions. We analyzed somatic mutation datasets of 21 types of cancers obtained from exome sequencing conducted by the TCGA project. Of the 3,622 genes that had ≥3 mutations in the regions with tertiary structure data, 106 genes showed significant skew in mutation distribution. Known tumor suppressors and oncogenes were significantly enriched in these identified cancer gene sets. Physical distances between mutations in known oncogenes were significantly smaller than those of tumor suppressors. Twenty-three genes were detected in multiple cancers. Candidate genes with significant skew of the 3D mutation distribution included kinases (MAPK1, EPHA5, ERBB3, and ERBB4), an apoptosis related gene (APP), an RNA splicing factor (SF1), a miRNA processing factor (DICER1), an E3 ubiquitin ligase (CUL1) and transcription factors (KLF5 and EEF1B2). Our study suggests that systematic analysis of mutation distribution in the tertiary protein structure can help identify cancer driver genes. PMID:27225414

  13. Isolated and Syndromic Retinal Dystrophy Caused by Biallelic Mutations in RCBTB1, a Gene Implicated in Ubiquitination.

    PubMed

    Coppieters, Frauke; Ascari, Giulia; Dannhausen, Katharina; Nikopoulos, Konstantinos; Peelman, Frank; Karlstetter, Marcus; Xu, Mingchu; Brachet, Cécile; Meunier, Isabelle; Tsilimbaris, Miltiadis K; Tsika, Chrysanthi; Blazaki, Styliani V; Vergult, Sarah; Farinelli, Pietro; Van Laethem, Thalia; Bauwens, Miriam; De Bruyne, Marieke; Chen, Rui; Langmann, Thomas; Sui, Ruifang; Meire, Françoise; Rivolta, Carlo; Hamel, Christian P; Leroy, Bart P; De Baere, Elfride

    2016-08-04

    Inherited retinal dystrophies (iRDs) are a group of genetically and clinically heterogeneous conditions resulting from mutations in over 250 genes. Here, homozygosity mapping and whole-exome sequencing (WES) in a consanguineous family revealed a homozygous missense mutation, c.973C>T (p.His325Tyr), in RCBTB1. In affected individuals, it was found to segregate with retinitis pigmentosa (RP), goiter, primary ovarian insufficiency, and mild intellectual disability. Subsequent analysis of WES data in different cohorts uncovered four additional homozygous missense mutations in five unrelated families in whom iRD segregates with or without syndromic features. Ocular phenotypes ranged from typical RP starting in the second decade to chorioretinal dystrophy with a later age of onset. The five missense mutations affect highly conserved residues either in the sixth repeat of the RCC1 domain or in the BTB1 domain. A founder haplotype was identified for mutation c.919G>A (p.Val307Met), occurring in two families of Mediterranean origin. We showed ubiquitous mRNA expression of RCBTB1 and demonstrated predominant RCBTB1 localization in human inner retina. RCBTB1 was very recently shown to be involved in ubiquitination, more specifically as a CUL3 substrate adaptor. Therefore, the effect on different components of the CUL3 and NFE2L2 (NRF2) pathway was assessed in affected individuals' lymphocytes, revealing decreased mRNA expression of NFE2L2 and several NFE2L2 target genes. In conclusion, our study puts forward mutations in RCBTB1 as a cause of autosomal-recessive non-syndromic and syndromic iRD. Finally, our data support a role for impaired ubiquitination in the pathogenetic mechanism of RCBTB1 mutations. Copyright © 2016 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  14. Characterization of Heterozygous HTRA1 Mutations in Taiwanese Patients With Cerebral Small Vessel Disease.

    PubMed

    Lee, Yi-Chung; Chung, Chih-Ping; Chao, Nai-Chen; Fuh, Jong-Ling; Chang, Feng-Chi; Soong, Bing-Wing; Liao, Yi-Chu

    2018-07-01

    Homozygous and compound heterozygous mutations in the high temperature requirement serine peptidase A1 gene ( HTRA1 ) cause cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy. However, heterozygous HTRA1 mutations were recently identified to be associated with autosomal dominant cerebral small vessel disease (SVD). The present study aims at investigating the clinical features, frequency, and spectrum of HTRA1 mutations in a Taiwanese cohort with SVD. Mutational analyses of HTRA1 were performed by Sanger sequencing in 222 subjects, selected from a cohort of 337 unrelated patients with SVD after excluding those harboring a NOTCH3 mutation. The influence of these mutations on HTRA1 protease activities was characterized. Seven novel heterozygous mutations in HTRA1 were identified, including p.Gly120Asp, p.Ile179Asn, p.Ala182Profs*33, p.Ile256Thr, p.Gly276Ala, p.Gln289Ter, and p.Asn324Thr, and each was identified in 1 single index patient. All mutations significantly compromise the HTRA1 protease activities. For the 7 index cases and another 2 affected siblings carrying a heterozygous HTRA1 mutation, the common clinical presentations include lacunar infarction, intracerebral hemorrhage, cognitive decline, and spondylosis at the fifth to sixth decade of life. Among the 9 patients, 4 have psychiatric symptoms as delusion, depression, and compulsive behavior, 3 have leukoencephalopathy in anterior temporal poles, and 2 patients have alopecia. Heterozygous HTRA1 mutations account for 2.08% (7 of 337) of SVD in Taiwan. The clinical and neuroradiological features of HTRA1 -related SVD and sporadic SVD are similar. These findings broaden the mutational spectrum of HTRA1 and highlight the pathogenic role of heterozygous HTRA1 mutations in SVD. © 2018 American Heart Association, Inc.

  15. Mutation in GM2A Leads to a Progressive Chorea-dementia Syndrome

    PubMed Central

    Salih, Mustafa A.; Seidahmed, Mohammed Z.; El Khashab, Heba Y.; Hamad, Muddathir H. A.; Bosley, Thomas M.; Burn, Sabrina; Myers, Angela; Landsverk, Megan L.; Crotwell, Patricia L.; Bilguvar, Kaya; Mane, Shrikant; Kruer, Michael C.

    2015-01-01

    Background The etiology of many cases of childhood-onset chorea remains undetermined, although advances in genomics are revealing both new disease-associated genes and variant phenotypes associated with known genes. Methods We report a Saudi family with a neurodegenerative course dominated by progressive chorea and dementia in whom we performed homozygosity mapping and whole exome sequencing. Results We identified a homozygous missense mutation in GM2A within a prominent block of homozygosity. This mutation is predicted to impair protein function. Discussion Although discovered more than two decades ago, to date, only five patients with this rare form of GM2 gangliosidosis have been reported. The phenotype of previously described GM2A patients has been typified by onset in infancy, profound hypotonia and impaired volitional movement, intractable seizures, hyperacusis, and a macular cherry red spot. Our findings expand the phenotypic spectrum of GM2A mutation-positive gangliosidosis to include generalized chorea without macular findings or hyperacusis and highlight how mutations in neurodegenerative disease genes may present in unexpected ways. PMID:26203402

  16. Disease-Associated Mutations in CEP120 Destabilize the Protein and Impair Ciliogenesis.

    PubMed

    Joseph, Nimesh; Al-Jassar, Caezar; Johnson, Christopher M; Andreeva, Antonina; Barnabas, Deepak D; Freund, Stefan M V; Gergely, Fanni; van Breugel, Mark

    2018-05-29

    Ciliopathies are a group of genetic disorders caused by a failure to form functional cilia. Due to a lack of structural information, it is currently poorly understood how ciliopathic mutations affect protein functionality to give rise to the underlying disease. Using X-ray crystallography, we show that the ciliopathy-associated centriolar protein CEP120 contains three C2 domains. The point mutations V194A and A199P, which cause Joubert syndrome (JS) and Jeune asphyxiating thoracic dystrophy (JATD), respectively, both reduce the thermostability of the second C2 domain by targeting residues that point toward its hydrophobic core. Genome-engineered cells homozygous for these mutations have largely normal centriole numbers but show reduced CEP120 levels, compromised recruitment of distal centriole markers, and deficient cilia formation. Our results provide insight into the disease mechanism of two ciliopathic mutations in CEP120, identify putative binding partners of CEP120 C2B, and suggest a complex genotype-phenotype relation of the CEP120 ciliopathy alleles. Copyright © 2018 MRC Laboratory of Molecular Biology. Published by Elsevier Inc. All rights reserved.

  17. HFE gene C282Y, H63D and S65C mutations frequency in the Transylvania region, Romania.

    PubMed

    Trifa, Adrian P; Popp, Radu A; Militaru, Mariela S; Farcaş, Marius F; Crişan, Tania O; Gana, Ionuţ; Cucuianu, Andrei; Pop, Ioan V

    2012-06-01

    HFE-associated haemochromatosis is one of the most frequent autosomal recessive disorders in the Caucasian population. Although most of the cases are homozygous individuals for the C282Y mutation, another two mutations, H63D and S65C, have been reported to be associated with milder forms of the disease. This study was a first attempt to evaluate the distribution of these HFE gene mutations in the Transylvania region. Two-hundred and twenty-five healthy, unrelated volunteers originating from the Transylvania region, Romania, were screened for the HFE gene C282Y, H63D and S65C mutations, using molecular genetics assays (Polymerase Chain Reaction-Restriction Fragments Length Polymorphism). For the C282Y mutation, 7 heterozygotes (3.1%) were found, but no homozygous individual. In the case of the H63D mutation, 40 heterozygotes (17.8%) and 4 homozygotes (1.75%) for the mutant allele were evidenced. We found a compound heterozygous genotype (C282Y/H63D) in one individual (0.45%). Thus, the allele frequencies of the C282Y and H63D were 1.75% and 10.9%, respectively. Three individuals (1.3%) were found to harbour the S65C mutation in a heterozygous state, but none in a homozygous state: the allele frequency of the mutant allele was 0.75%. The distribution of the HFE gene C282Y, H63D and S65C mutations found in our group matches the tendencies observed in other European countries: a decreasing gradient from Northern to Southern Europe for the C282Y mutation; high frequency for the H63D mutation, and low frequency for the S65C mutation in most of the countries.

  18. EDNRB mutations cause Waardenburg syndrome type II in the heterozygous state.

    PubMed

    Issa, Sarah; Bondurand, Nadege; Faubert, Emmanuelle; Poisson, Sylvain; Lecerf, Laure; Nitschke, Patrick; Deggouj, Naima; Loundon, Natalie; Jonard, Laurence; David, Albert; Sznajer, Yves; Blanchet, Patricia; Marlin, Sandrine; Pingault, Veronique

    2017-05-01

    Waardenburg syndrome (WS) is a genetic disorder characterized by sensorineural hearing loss and pigmentation anomalies. The clinical definition of four WS types is based on additional features due to defects in structures mostly arising from the neural crest, with type I and type II being the most frequent. While type I is tightly associated to PAX3 mutations, WS type II (WS2) remains partly enigmatic with mutations in known genes (MITF, SOX10) accounting for only 30% of the cases. We performed exome sequencing in a WS2 index case and identified a heterozygous missense variation in EDNRB. Interestingly, homozygous (and very rare heterozygous) EDNRB mutations are already described in type IV WS (i.e., in association with Hirschsprung disease [HD]) and heterozygous mutations in isolated HD. Screening of a WS2 cohort led to the identification of an overall of six heterozygous EDNRB variations. Clinical phenotypes, pedigrees and molecular segregation investigations unraveled a dominant mode of inheritance with incomplete penetrance. In parallel, cellular and functional studies showed that each of the mutations impairs the subcellular localization of the receptor or induces a defective downstream signaling pathway. Based on our results, we now estimate EDNRB mutations to be responsible for 5%-6% of WS2. © 2017 Wiley Periodicals, Inc.

  19. Myopathic mtDNA Depletion Syndrome Due to Mutation in TK2 Gene.

    PubMed

    Martín-Hernández, Elena; García-Silva, María Teresa; Quijada-Fraile, Pilar; Rodríguez-García, María Elena; Hernández-Laín, Aurelio; Coca-Robinot, David; Rivera, Henry; Fernández-Toral, Joaquín; Arenas, Joaquín; Martín, MiguelÁngel; Martínez-Azorín, Francisco

    2016-02-29

    Whole-exome sequencing (WES) was used to identify the disease gene(s) in a Spanish girl with failure to thrive, muscle weakness, mild facial weakness, elevated creatine kinase (CK), deficiency of mitochondrial complex III and depletion of mtDNA. With WES data, it was possible to get the whole mtDNA sequencing and discard any pathogenic variant in this genome. The analysis of whole exome uncovered a homozygous pathogenic mutation in Thymidine kinase 2 gene (TK2; NM_004614.4:c.323C>T, p.T108M). TK2 mutations have been identified mainly in patients with the myopathic form of mtDNA depletion syndromes (MDS). This patient presents an atypical TK2 related-myopathic form of MDS, because despite having a very low content of mtDNA (<20%), she presents a slower and less severe evolution of the disease. In conclusion, our data confirm the role of TK2 gene in MDS and expanded the phenotypic spectrum.

  20. Myopathic mtDNA Depletion Syndrome Due to Mutation in TK2 Gene.

    PubMed

    Martín-Hernández, Elena; García-Silva, María Teresa; Quijada-Fraile, Pilar; Rodríguez-García, María Elena; Rivera, Henry; Hernández-Laín, Aurelio; Coca-Robinot, David; Fernández-Toral, Joaquín; Arenas, Joaquín; Martín, Miguel A; Martínez-Azorín, Francisco

    2017-01-01

    Whole-exome sequencing was used to identify the disease gene(s) in a Spanish girl with failure to thrive, muscle weakness, mild facial weakness, elevated creatine kinase, deficiency of mitochondrial complex III and depletion of mtDNA. With whole-exome sequencing data, it was possible to get the whole mtDNA sequencing and discard any pathogenic variant in this genome. The analysis of whole exome uncovered a homozygous pathogenic mutation in thymidine kinase 2 gene ( TK2; NM_004614.4:c.323 C>T, p.T108M). TK2 mutations have been identified mainly in patients with the myopathic form of mtDNA depletion syndromes. This patient presents an atypical TK2-related myopathic form of mtDNA depletion syndromes, because despite having a very low content of mtDNA (<20%), she presents a slower and less severe evolution of the disease. In conclusion, our data confirm the role of TK2 gene in mtDNA depletion syndromes and expanded the phenotypic spectrum.

  1. [Identification of a HPGD mutation in three families affected with primary hypertrophic osteoarthropathy].

    PubMed

    Zhang, Wanying; Wang, Tao; Huang, Shuaiwu; Zhao, Xiuli

    2018-04-10

    To detect mutation of HPGD gene among three pedigrees affected with primary hypertrophic osteoarthropathy (PHO) by DNA sequencing and high-resolution melting (HRM) analysis. Genomic DNA was extracted from peripheral blood samples collected from the pedigrees. PCR and direct sequencing were carried out to identify potential mutations of the HPGD gene. Amplicons containing the mutation spot were generated by nested PCR. The products were then subjected to HRM analysis using the HR-1 instrument. Direct sequencing was carried out in family members and healthy individuals to confirm the result of HRM analysis. A homozygous mutation c.310_311delCT was detected in 2 affected probands, while a heterozygous mutation c.310_311delCT was detected in the third proband. HRM analysis of the fragments encompassing HPGD exon 3 showed 3 curve patterns representing three different genotypes, i.e., the wild type, the c.310_311delCT homozygote, and the c.310_311delCT heterozygote. Result of DNA sequencing was consistent with that of the HRM analysis and phenotype of the subjects. The c.310_311delCT mutation may be the most prevalent mutation among Chinese population. HRM analysis has provided an optimized method for genetic testing of HPGD mutation for its simplicity, rapid turnover and high sensitivity.

  2. Whole Exome Sequencing Identifies de Novo Mutations in GATA6 Associated with Congenital Diaphragmatic Hernia

    PubMed Central

    Yu, Lan; Bennett, James T.; Wynn, Julia; Carvill, Gemma L.; Cheung, Yee Him; Shen, Yufeng; Mychaliska, George B.; Azarow, Kenneth S.; Crombleholme, Timothy M.; Chung, Dai H.; Potoka, Douglas; Warner, Brad W.; Bucher, Brian; Lim, Foong-Yen; Pietsch, John; Stolar, Charles; Aspelund, Gudrun; Arkovitz, Marc S.; Mefford, Heather; Chung, Wendy K.

    2014-01-01

    Background Congenital diaphragmatic hernia (CDH) is a common birth defect affecting 1 in 3,000 births. It is characterized by herniation of abdominal viscera through an incompletely formed diaphragm. Although chromosomal anomalies and mutations in several genes have been implicated, the cause for most patients is unknown. Methods We used whole exome sequencing in two families with CDH and congenital heart disease, and identified mutations in GATA6 in both. Results In the first family, we identified a de novo missense mutation (c.1366C>T, p.R456C) in a sporadic CDH patient with tetralogy of Fallot. In the second, a nonsense mutation (c.712G>T, p.G238*) was identified in two siblings with CDH and a large ventricular septal defect. The G238* mutation was inherited from their mother, who was clinically affected with congenital absence of the pericardium, patent ductus arteriosus, and intestinal malrotation. Deep sequencing of blood and saliva derived DNA from the mother suggested somatic mosaicism as an explanation for her milder phenotype, with only approximately 15% mutant alleles. To determine the frequency of GATA6 mutations in CDH, we sequenced the gene in 378 patients with CDH. We identified one additional de novo mutation (c.1071delG, p.V358Cfs34*). Conclusions Mutations in GATA6 have been previously associated with pancreatic agenesis and congenital heart disease. We conclude that, in addition to the heart and the pancreas, GATA6 is involved in development of two additional organs, the diaphragm and the pericardium. In addition we have shown that de novo mutations can contribute to the development of CDH, a common birth defect. PMID:24385578

  3. Novel mutations in the USH1C gene in Usher syndrome patients.

    PubMed

    Aparisi, María José; García-García, Gema; Jaijo, Teresa; Rodrigo, Regina; Graziano, Claudio; Seri, Marco; Simsek, Tulay; Simsek, Enver; Bernal, Sara; Baiget, Montserrat; Pérez-Garrigues, Herminio; Aller, Elena; Millán, José María

    2010-12-31

    Usher syndrome type I (USH1) is an autosomal recessive disorder characterized by severe-profound sensorineural hearing loss, retinitis pigmentosa, and vestibular areflexia. To date, five USH1 genes have been identified. One of these genes is Usher syndrome 1C (USH1C), which encodes a protein, harmonin, containing PDZ domains. The aim of the present work was the mutation screening of the USH1C gene in a cohort of 33 Usher syndrome patients, to identify the genetic cause of the disease and to determine the relative involvement of this gene in USH1 pathogenesis in the Spanish population. Thirty-three patients were screened for mutations in the USH1C gene by direct sequencing. Some had already been screened for mutations in the other known USH1 genes (myosin VIIA [MYO7A], cadherin-related 23 [CDH23], protocadherin-related 15 [PCDH15], and Usher syndrome 1G [USH1G]), but no mutation was found. Two novel mutations were found in the USH1C gene: a non-sense mutation (p.C224X) and a frame-shift mutation (p.D124TfsX7). These mutations were found in a homozygous state in two unrelated USH1 patients. In the present study, we detected two novel pathogenic mutations in the USH1C gene. Our results suggest that mutations in USH1C are responsible for 1.5% of USH1 disease in patients of Spanish origin (considering the total cohort of 65 Spanish USH1 patients since 2005), indicating that USH1C is a rare form of USH in this population.

  4. Novel mutations in the USH1C gene in Usher syndrome patients

    PubMed Central

    Aparisi, María José; García-García, Gema; Jaijo, Teresa; Rodrigo, Regina; Graziano, Claudio; Seri, Marco; Simsek, Tulay; Simsek, Enver; Bernal, Sara; Baiget, Montserrat; Pérez-Garrigues, Herminio; Millán, José María

    2010-01-01

    Purpose Usher syndrome type I (USH1) is an autosomal recessive disorder characterized by severe-profound sensorineural hearing loss, retinitis pigmentosa, and vestibular areflexia. To date, five USH1 genes have been identified. One of these genes is Usher syndrome 1C (USH1C), which encodes a protein, harmonin, containing PDZ domains. The aim of the present work was the mutation screening of the USH1C gene in a cohort of 33 Usher syndrome patients, to identify the genetic cause of the disease and to determine the relative involvement of this gene in USH1 pathogenesis in the Spanish population. Methods Thirty-three patients were screened for mutations in the USH1C gene by direct sequencing. Some had already been screened for mutations in the other known USH1 genes (myosin VIIA [MYO7A], cadherin-related 23 [CDH23], protocadherin-related 15 [PCDH15], and Usher syndrome 1G [USH1G]), but no mutation was found. Results Two novel mutations were found in the USH1C gene: a non-sense mutation (p.C224X) and a frame-shift mutation (p.D124TfsX7). These mutations were found in a homozygous state in two unrelated USH1 patients. Conclusions In the present study, we detected two novel pathogenic mutations in the USH1C gene. Our results suggest that mutations in USH1C are responsible for 1.5% of USH1 disease in patients of Spanish origin (considering the total cohort of 65 Spanish USH1 patients since 2005), indicating that USH1C is a rare form of USH in this population. PMID:21203349

  5. A novel mutation in the AGXT gene causing primary hyperoxaluria type I: genotype-phenotype correlation.

    PubMed

    M'Dimegh, Saoussen; Aquaviva-Bourdain, Cécile; Omezzine, Asma; M'Barek, Ibtihel; Souche, Geneviéve; Zellama, Dorsaf; Abidi, Kamel; Achour, Abdelattif; Gargah, Tahar; Abroug, Saoussen; Bouslama, Ali

    2016-09-01

    Primary hyperoxaluria type I (PH1) is an autosomal recessive metabolic disorder caused by inherited mutations in the AGXT gene encoding liver peroxisomal alanine : glyoxylate aminotransferase (AGT) which is deficient or mistargeted to mitochondria. PH1 shows considerable phenotypic and genotypic heterogeneity. The incidence and severity of PH1 varies in different geographic regions. DNA samples of the affected members from two unrelated Tunisian families were tested by amplifying and sequencing each of the AGXT exons and intron-exon junctions. We identified a novel frameshift mutation in the AGXT gene, the c.406_410dupACTGC resulting in a truncated protein (p.Gln137Hisfs*19). It is found in homozygous state in two nonconsanguineous unrelated families from Tunisia. These molecular findings provide genotype/phenotype correlations in the intrafamilial phenotypic and permit accurate carrier detection, and prenatal diagnosis. The novel p.Gln137Hisfs*19 mutation detected in our study extend the spectrum of known AGXT gene mutations in Tunisia.

  6. Molecular genetics of cystinuria: Identification of four new mutations and seven polymorphisms, and evidence for genetic heterogeneity

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gasparini, P.; Bisceglia, L.; Notarangelo, A.

    A cystinuria disease gene (rBAT) has been recently identified, and some mutations causing the disease have been described. The frequency of these mutations has been investigated in a large sample of 51 Italian and Spanish cystinuric patients. In addition, to identify new mutated alleles, genomic DNA has been analyzed by an accurate and sensitive method able to detect nucleotide changes. Because of the lack of information available on the genomic structure of rBAT gene, the study was carried out using the sequence data so far obtained by us. More than 70% of the entire coding sequence and 8 intron-exon boundariesmore » have been analyzed. Four new mutations and seven intragenic polymorphisms have been detected. All mutations so far identified in rBAT belong only to cystinuria type I alleles, accounting for {approximately} 44% of all type I cystinuric chromosomes. Mutation M467T is the most common mutated allele in the Italian and Spanish populations. After analysis of 70% of the rBAT coding region, we have detected normal sequences in cystinuria type II and type III chromosomes. The presence of rBAT mutated alleles only in type I chromosomes of homozygous (type I/I) and heterozygous (type I/III) patients provides evidence for genetic heterogeneity where rBAT would be responsible only for type I cystinuria and suggests a complementation mechanism to explain the intermediate type I/type III phenotype. 25 refs., 1 fig., 3 tabs.« less

  7. Novel Mutations in HESX1 and PROP1 Genes in Combined Pituitary Hormone Deficiency.

    PubMed

    Avbelj Stefanija, Magdalena; Kotnik, Primož; Bratanič, Nina; Žerjav Tanšek, Mojca; Bertok, Sara; Bratina, Nataša; Battelino, Tadej; Trebušak Podkrajšek, Katarina

    2015-01-01

    The HESX1 gene is essential in forebrain development and pituitary organogenesis, and its mutations are the most commonly identified genetic cause of septo-optic dysplasia (SOD). The PROP1 gene is involved in anterior pituitary cell lineage specification and is commonly implicated in non-syndromic combined pituitary hormone deficiency (CPHD). We aimed to assess the involvement of HESX1 and PROP1 mutations in a cohort of patients with SOD and CPHD. Six patients with sporadic SOD and 16 patients with CPHD from 14 pedigrees were screened for mutations in HESX1 and PROP1 genes by exon sequencing. Half of the CPHD patients had variable associated clinical characteristics, such as hearing loss, orofacial cleft, kidney disorder or developmental delay. Novel variants were evaluated in silico and verified in SNP databases. A novel heterozygous p.Glu102Gly mutation in the HESX1 gene and a novel homozygous p.Arg121Thr mutation in the PROP1 gene were detected in 2 pedigrees with CPHD. A small previously reported deletion in PROP1 c.301_302delAG was detected in a separate patient with CPHD, in heterozygous state. No mutations were identified in patients with SOD. Our results expand the spectrum of mutations implicated in CPHD. The frequency of 15% of the PROP1 mutations in CPHD was low, likely due to the clinical heterogeneity of the cohort. © 2015 S. Karger AG, Basel.

  8. Whole-exome sequencing identifies novel MPL and JAK2 mutations in triple-negative myeloproliferative neoplasms

    PubMed Central

    Milosevic Feenstra, Jelena D.; Nivarthi, Harini; Gisslinger, Heinz; Leroy, Emilie; Rumi, Elisa; Chachoua, Ilyas; Bagienski, Klaudia; Kubesova, Blanka; Pietra, Daniela; Gisslinger, Bettina; Milanesi, Chiara; Jäger, Roland; Chen, Doris; Berg, Tiina; Schalling, Martin; Schuster, Michael; Bock, Christoph; Constantinescu, Stefan N.; Cazzola, Mario

    2016-01-01

    Essential thrombocythemia (ET) and primary myelofibrosis (PMF) are chronic diseases characterized by clonal hematopoiesis and hyperproliferation of terminally differentiated myeloid cells. The disease is driven by somatic mutations in exon 9 of CALR or exon 10 of MPL or JAK2-V617F in >90% of the cases, whereas the remaining cases are termed “triple negative.” We aimed to identify the disease-causing mutations in the triple-negative cases of ET and PMF by applying whole-exome sequencing (WES) on paired tumor and control samples from 8 patients. We found evidence of clonal hematopoiesis in 5 of 8 studied cases based on clonality analysis and presence of somatic genetic aberrations. WES identified somatic mutations in 3 of 8 cases. We did not detect any novel recurrent somatic mutations. In 3 patients with clonal hematopoiesis analyzed by WES, we identified a somatic MPL-S204P, a germline MPL-V285E mutation, and a germline JAK2-G571S variant. We performed Sanger sequencing of the entire coding region of MPL in 62, and of JAK2 in 49 additional triple-negative cases of ET or PMF. New somatic (T119I, S204F, E230G, Y591D) and 1 germline (R321W) MPL mutation were detected. All of the identified MPL mutations were gain-of-function when analyzed in functional assays. JAK2 variants were identified in 5 of 57 triple-negative cases analyzed by WES and Sanger sequencing combined. We could demonstrate that JAK2-V625F and JAK2-F556V are gain-of-function mutations. Our results suggest that triple-negative cases of ET and PMF do not represent a homogenous disease entity. Cases with polyclonal hematopoiesis might represent hereditary disorders. PMID:26423830

  9. Whole-exome sequencing identifies novel MPL and JAK2 mutations in triple-negative myeloproliferative neoplasms.

    PubMed

    Milosevic Feenstra, Jelena D; Nivarthi, Harini; Gisslinger, Heinz; Leroy, Emilie; Rumi, Elisa; Chachoua, Ilyas; Bagienski, Klaudia; Kubesova, Blanka; Pietra, Daniela; Gisslinger, Bettina; Milanesi, Chiara; Jäger, Roland; Chen, Doris; Berg, Tiina; Schalling, Martin; Schuster, Michael; Bock, Christoph; Constantinescu, Stefan N; Cazzola, Mario; Kralovics, Robert

    2016-01-21

    Essential thrombocythemia (ET) and primary myelofibrosis (PMF) are chronic diseases characterized by clonal hematopoiesis and hyperproliferation of terminally differentiated myeloid cells. The disease is driven by somatic mutations in exon 9 of CALR or exon 10 of MPL or JAK2-V617F in >90% of the cases, whereas the remaining cases are termed "triple negative." We aimed to identify the disease-causing mutations in the triple-negative cases of ET and PMF by applying whole-exome sequencing (WES) on paired tumor and control samples from 8 patients. We found evidence of clonal hematopoiesis in 5 of 8 studied cases based on clonality analysis and presence of somatic genetic aberrations. WES identified somatic mutations in 3 of 8 cases. We did not detect any novel recurrent somatic mutations. In 3 patients with clonal hematopoiesis analyzed by WES, we identified a somatic MPL-S204P, a germline MPL-V285E mutation, and a germline JAK2-G571S variant. We performed Sanger sequencing of the entire coding region of MPL in 62, and of JAK2 in 49 additional triple-negative cases of ET or PMF. New somatic (T119I, S204F, E230G, Y591D) and 1 germline (R321W) MPL mutation were detected. All of the identified MPL mutations were gain-of-function when analyzed in functional assays. JAK2 variants were identified in 5 of 57 triple-negative cases analyzed by WES and Sanger sequencing combined. We could demonstrate that JAK2-V625F and JAK2-F556V are gain-of-function mutations. Our results suggest that triple-negative cases of ET and PMF do not represent a homogenous disease entity. Cases with polyclonal hematopoiesis might represent hereditary disorders. © 2016 by The American Society of Hematology.

  10. Molecular analysis of congenital goitres with hypothyroidism caused by defective thyroglobulin synthesis. Identification of a novel c.7006C>T [p.R2317X] mutation and expression of minigenes containing nonsense mutations in exon 7.

    PubMed

    Machiavelli, Gloria A; Caputo, Mariela; Rivolta, Carina M; Olcese, María C; Gruñeiro-Papendieck, Laura; Chiesa, Ana; González-Sarmiento, Rogelio; Targovnik, Héctor M

    2010-01-01

    Thyroglobulin (TG) deficiency is an autosomal-recessive disorder that results in thyroid dyshormonogenesis. A number of distinct mutations have been identified as causing human hypothyroid goitre. The purpose of this study was to identify and characterize new mutations in the TG gene in an attempt to increase the understanding of the genetic mechanism responsible for this disorder. A total of six patients from four nonconsanguineous families with marked impairment of TG synthesis were studied. Single-strand conformation polymorphism (SSCP) analysis, sequencing of DNA, genotyping, expression of chimeric minigenes and bioinformatic analysis were performed. Four different inactivating TG mutations were identified: one novel mutation (c.7006C>T [p.R2317X]) and three previously reported (c.886C>T [p.R277X], c.6701C>A [p.A2215D] and c.6725G>A [p.R2223H]). Consequently, one patient carried a compound heterozygous for p.R2223H/p.R2317X mutations; two brothers showed a homozygous p.A2215D substitution and the remaining three patients, from two families with typical phenotype, had a single p.R277X mutated allele. We also showed functional evidences that premature stop codons inserted at different positions in exon 7, which disrupt exonic splicing enhancer (ESE) sequences, do not interfere with exon definition and processing. In this study, we have identified a novel nonsense mutation p.R2317X in the acetylcholinesterase homology domain of TG. We have also observed that nonsense mutations do not interfere with the pre-mRNA splicing of exon 7. The results are in accordance with previous observations confirming the genetic heterogeneity of TG defects.

  11. Recessive mutations in ELOVL4 cause ichthyosis, intellectual disability, and spastic quadriplegia.

    PubMed

    Aldahmesh, Mohammed A; Mohamed, Jawahir Y; Alkuraya, Hisham S; Verma, Ishwar C; Puri, Ratna D; Alaiya, Ayodele A; Rizzo, William B; Alkuraya, Fowzan S

    2011-12-09

    Very-long-chain fatty acids (VLCFAs) play important roles in membrane structure and cellular signaling, and their contribution to human health is increasingly recognized. Fatty acid elongases catalyze the first and rate-limiting step in VLCFA synthesis. Heterozygous mutations in ELOVL4, the gene encoding one of the elongases, are known to cause macular degeneration in humans and retinal abnormalities in mice. However, biallelic ELOVL4 mutations have not been observed in humans, and murine models with homozygous mutations die within hours of birth as a result of a defective epidermal water barrier. Here, we report on two human individuals with recessive ELOVL4 mutations revealed by a combination of autozygome analysis and exome sequencing. These individuals exhibit clinical features of ichthyosis, seizures, mental retardation, and spasticity-a constellation that resembles Sjögren-Larsson syndrome (SLS) but presents a more severe neurologic phenotype. Our findings identify recessive mutations in ELOVL4 as the cause of a neuro-ichthyotic disease and emphasize the importance of VLCFA synthesis in brain and cutaneous development. Copyright © 2011 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  12. Neuropathology of leukoencephalopathy with brainstem and spinal cord involvement and high lactate caused by a homozygous mutation of DARS2.

    PubMed

    Yamashita, Sumimasa; Miyake, Noriko; Matsumoto, Naomichi; Osaka, Hitoshi; Iai, Mizue; Aida, Noriko; Tanaka, Yukichi

    2013-04-01

    We diagnosed three siblings from consanguineous east Asian parents with leukoencephalopathy with brainstem and spinal cord involvement and high lactate (LBSL) from characteristic MRI, MRS findings and a homozygous mutation in the DARS2 gene. The neurological symptoms of the three patients consisted of psychomotor developmental delay, cerebellar ataxia since infancy, spasticity in the initial phase and peripheral neuropathy in later stages. Their mental development was delayed, but did not deteriorate. MRI signal abnormalities included the same abnormalities reported previously but tended to be more extensive. Signal abnormalities in the cerebral and cerebellar white matter were homogeneous and confluent from early stages. In addition, other tract such as the central tegmental tract was involved. Furthermore, an atrophic change in the cerebral white matter was observed on follow-up in one case. Two of the patients were autopsied and neuropathological findings revealed characteristic vacuolar changes in the white matter of the cerebrum, cerebellum and the nerve tracts of the brain stem and spinal cord. The central myelin sheath showed intralamellar splitting by electron microscopy. These findings were consistent to a spongy degeneration in the diffuse white matter of the brain, or spongiform leukoencephalopathy. In addition, peripheral nerves showed both axonal degeneration and abnormal myelin structures. We discussed the relationship between deficits in mitochondrial aspartyl-tRNA synthetase activity and the neuropathology observed. Copyright © 2012 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

  13. Common Variable Immunodeficiency Caused by FANC Mutations.

    PubMed

    Sekinaka, Yujin; Mitsuiki, Noriko; Imai, Kohsuke; Yabe, Miharu; Yabe, Hiromasa; Mitsui-Sekinaka, Kanako; Honma, Kenichi; Takagi, Masatoshi; Arai, Ayako; Yoshida, Kenichi; Okuno, Yusuke; Shiraishi, Yuichi; Chiba, Kenichi; Tanaka, Hiroko; Miyano, Satoru; Muramatsu, Hideki; Kojima, Seiji; Hira, Asuka; Takata, Minoru; Ohara, Osamu; Ogawa, Seishi; Morio, Tomohiro; Nonoyama, Shigeaki

    2017-07-01

    Common variable immunodeficiency (CVID) is the most common adult-onset primary antibody deficiency disease due to various causative genes. Several genes, which are known to be the cause of different diseases, have recently been reported as the cause of CVID in patients by performing whole exome sequencing (WES) analysis. Here, we found FANC gene mutations as a cause of adult-onset CVID in two patients. B cells were absent and CD4 + T cells were skewed toward CD45RO + memory T cells. T-cell receptor excision circles (TRECs) and signal joint kappa-deleting recombination excision circles (sjKRECs) were undetectable in both patients. Both patients had no anemia, neutropenia, or thrombocytopenia. Using WES, we identified compound heterozygous mutations of FANCE in one patient and homozygous mutation of FANCA in another patient. The impaired function of FANC protein complex was confirmed by a monoubiquitination assay and by chromosome fragility test. We then performed several immunological evaluations including quantitative lymphocyte analysis and TRECs/sjKRECs analysis for 32 individuals with Fanconi anemia (FA). In total, 22 FA patients (68.8%) were found to have immunological abnormalities, suggesting that such immunological findings may be common in FA patients. These data indicate that FANC mutations are involved in impaired lymphogenesis probably by the accumulation of DNA replication stress, leading to CVID. It is important to diagnose FA because it drastically changes clinical management. We propose that FANC mutations can cause isolated immunodeficiency in addition to bone marrow failure and malignancy.

  14. Whole exome sequencing reveals concomitant mutations of multiple FA genes in individual Fanconi anemia patients

    PubMed Central

    2014-01-01

    Background Fanconi anemia (FA) is a rare inherited genetic syndrome with highly variable clinical manifestations. Fifteen genetic subtypes of FA have been identified. Traditional complementation tests for grouping studies have been used generally in FA patients and in stepwise methods to identify the FA type, which can result in incomplete genetic information from FA patients. Methods We diagnosed five pediatric patients with FA based on clinical manifestations, and we performed exome sequencing of peripheral blood specimens from these patients and their family members. The related sequencing data were then analyzed by bioinformatics, and the FANC gene mutations identified by exome sequencing were confirmed by PCR re-sequencing. Results Homozygous and compound heterozygous mutations of FANC genes were identified in all of the patients. The FA subtypes of the patients included FANCA, FANCM and FANCD2. Interestingly, four FA patients harbored multiple mutations in at least two FA genes, and some of these mutations have not been previously reported. These patients’ clinical manifestations were vastly different from each other, as were their treatment responses to androstanazol and prednisone. This finding suggests that heterozygous mutation(s) in FA genes could also have diverse biological and/or pathophysiological effects on FA patients or FA gene carriers. Interestingly, we were not able to identify de novo mutations in the genes implicated in DNA repair pathways when the sequencing data of patients were compared with those of their parents. Conclusions Our results indicate that Chinese FA patients and carriers might have higher and more complex mutation rates in FANC genes than have been conventionally recognized. Testing of the fifteen FANC genes in FA patients and their family members should be a regular clinical practice to determine the optimal care for the individual patient, to counsel the family and to obtain a better understanding of FA pathophysiology

  15. Whole exome sequencing reveals concomitant mutations of multiple FA genes in individual Fanconi anemia patients.

    PubMed

    Chang, Lixian; Yuan, Weiping; Zeng, Huimin; Zhou, Quanquan; Wei, Wei; Zhou, Jianfeng; Li, Miaomiao; Wang, Xiaomin; Xu, Mingjiang; Yang, Fengchun; Yang, Yungui; Cheng, Tao; Zhu, Xiaofan

    2014-05-15

    Fanconi anemia (FA) is a rare inherited genetic syndrome with highly variable clinical manifestations. Fifteen genetic subtypes of FA have been identified. Traditional complementation tests for grouping studies have been used generally in FA patients and in stepwise methods to identify the FA type, which can result in incomplete genetic information from FA patients. We diagnosed five pediatric patients with FA based on clinical manifestations, and we performed exome sequencing of peripheral blood specimens from these patients and their family members. The related sequencing data were then analyzed by bioinformatics, and the FANC gene mutations identified by exome sequencing were confirmed by PCR re-sequencing. Homozygous and compound heterozygous mutations of FANC genes were identified in all of the patients. The FA subtypes of the patients included FANCA, FANCM and FANCD2. Interestingly, four FA patients harbored multiple mutations in at least two FA genes, and some of these mutations have not been previously reported. These patients' clinical manifestations were vastly different from each other, as were their treatment responses to androstanazol and prednisone. This finding suggests that heterozygous mutation(s) in FA genes could also have diverse biological and/or pathophysiological effects on FA patients or FA gene carriers. Interestingly, we were not able to identify de novo mutations in the genes implicated in DNA repair pathways when the sequencing data of patients were compared with those of their parents. Our results indicate that Chinese FA patients and carriers might have higher and more complex mutation rates in FANC genes than have been conventionally recognized. Testing of the fifteen FANC genes in FA patients and their family members should be a regular clinical practice to determine the optimal care for the individual patient, to counsel the family and to obtain a better understanding of FA pathophysiology.

  16. The glucokinase mutation p.T206P is common among MODY patients of Jewish Ashkenazi descent.

    PubMed

    Gozlan, Yael; Tenenbaum, Ariel; Shalitin, Shlomit; Lebenthal, Yael; Oron, Tal; Cohen, Ohad; Phillip, Moshe; Gat-Yablonski, Galia

    2012-09-01

    Maturity-onset diabetes of the young (MODY) is characterized by an autosomal dominant mode of inheritance; a primary defect in insulin secretion with non-ketotic hyperglycemia, age of onset under 25 yr; and lack of autoantibodies. Heterozygous mutations in glucokinase (GCK) are associated with mild fasting hyperglycemia and gestational diabetes mellitus while homozygous or compound heterozygous GCK mutations result in permanent neonatal diabetes mellitus. Given that both the Israeli-Arabic and the various Israeli-Jewish communities tend to maintain ethnic seclusion, we speculated that it would be possible to identify a relatively narrow spectrum of mutations in the Israeli population. To characterize the genetic basis of GCK-MODY in the different ethnic groups of the Israeli population. Patients with clinically identified GCK-MODY and their first degree family members. Molecular analysis of GCK was performed on genomic DNA using polymerase chain reaction, denaturing gradient gel electrophoresis (DGGE), and sequencing. Bioinformatic model was preformed using the NEST program. Mutations in GCK were identified in 25 families and were all family-specific, except c.616A>C. p.T206P. This mutation was identified in six unrelated families, all patients from a Jewish-Ashkenazi descent, thus indicating an ethno-genetic correlation. A simple, fast, and relatively cheap DGGE/restriction-digestion assay was developed. The high incidence of the mutant allele in GCK-MODY patients of Jewish-Ashkenazi descent suggests a founder effect. We propose that clinically identified GCK-MODY patients of Jewish-Ashkenazi origin be first tested for this mutation. © 2011 John Wiley & Sons A/S.

  17. Respiratory chain complex I deficiency due to NDUFA12 mutations as a new cause of Leigh syndrome.

    PubMed

    Ostergaard, Elsebet; Rodenburg, Richard J; van den Brand, Mariël; Thomsen, Lise Lykke; Duno, Morten; Batbayli, Mustafa; Wibrand, Flemming; Nijtmans, Leo

    2011-11-01

    This study investigated a girl with Leigh syndrome born to first-cousin parents of Pakistani descent with an isolated respiratory chain complex I deficiency in muscle and fibroblasts. Her early development was delayed, and from age 2 years she started losing motor abilities. Cerebral MRI showed basal ganglia lesions typical of Leigh syndrome. A genome-wide search for homozygosity was performed with the Affymetrix GeneChip 50K Xba array. The analysis revealed several homozygous regions. Three candidate genes were identified, and in one of the genes, NDUFA12, a homozygous c.178C→T mutation leading to a premature stop codon (p.Arg60X) was found. Western blot analysis showed absence of NDUFA12 protein in patient fibroblasts and functional complementation by a baculovirus system showed restoration of complex I activity. NDUFA12 mutations are apparently not a frequent cause of complex I deficiency, since mutations were not found by screening altogether 122 complex I deficient patients in two different studies. NDUFA12 encodes an accessory subunit of complex I and is a paralogue of NDUFAF2. Despite the complete absence of NDUFA12 protein, a fully assembled and enzymatically active complex I could be found, albeit in reduced amounts. This suggests that NDUFA12 is required either at a late step in the assembly of complex I, or in the stability of complex I.

  18. Targeted next-generation sequencing analysis identifies novel mutations in families with severe familial exudative vitreoretinopathy.

    PubMed

    Huang, Xiao-Yan; Zhuang, Hong; Wu, Ji-Hong; Li, Jian-Kang; Hu, Fang-Yuan; Zheng, Yu; Tellier, Laurent Christian Asker M; Zhang, Sheng-Hai; Gao, Feng-Juan; Zhang, Jian-Guo; Xu, Ge-Zhi

    2017-01-01

    Familial exudative vitreoretinopathy (FEVR) is a genetically and clinically heterogeneous disease, characterized by failure of vascular development of the peripheral retina. The symptoms of FEVR vary widely among patients in the same family, and even between the two eyes of a given patient. This study was designed to identify the genetic defect in a patient cohort of ten Chinese families with a definitive diagnosis of FEVR. To identify the causative gene, next-generation sequencing (NGS)-based target capture sequencing was performed. Segregation analysis of the candidate variant was performed in additional family members by using Sanger sequencing and quantitative real-time PCR (QPCR). Of the cohort of ten FEVR families, six pathogenic variants were identified, including four novel and two known heterozygous mutations. Of the variants identified, four were missense variants, and two were novel heterozygous deletion mutations [ LRP5 , c.4053 DelC (p.Ile1351IlefsX88); TSPAN12 , EX8Del]. The two novel heterozygous deletion mutations were not observed in the control subjects and could give rise to a relatively severe FEVR phenotype, which could be explained by the protein function prediction. We identified two novel heterozygous deletion mutations [ LRP5 , c.4053 DelC (p.Ile1351IlefsX88); TSPAN12 , EX8Del] using targeted NGS as a causative mutation for FEVR. These genetic deletion variations exhibit a severe form of FEVR, with tractional retinal detachments compared with other known point mutations. The data further enrich the mutation spectrum of FEVR and enhance our understanding of genotype-phenotype correlations to provide useful information for disease diagnosis, prognosis, and effective genetic counseling.

  19. Targeted next-generation sequencing analysis identifies novel mutations in families with severe familial exudative vitreoretinopathy

    PubMed Central

    Huang, Xiao-Yan; Zhuang, Hong; Wu, Ji-Hong; Li, Jian-Kang; Hu, Fang-Yuan; Zheng, Yu; Tellier, Laurent Christian Asker M.; Zhang, Sheng-Hai; Gao, Feng-Juan; Zhang, Jian-Guo

    2017-01-01

    Purpose Familial exudative vitreoretinopathy (FEVR) is a genetically and clinically heterogeneous disease, characterized by failure of vascular development of the peripheral retina. The symptoms of FEVR vary widely among patients in the same family, and even between the two eyes of a given patient. This study was designed to identify the genetic defect in a patient cohort of ten Chinese families with a definitive diagnosis of FEVR. Methods To identify the causative gene, next-generation sequencing (NGS)-based target capture sequencing was performed. Segregation analysis of the candidate variant was performed in additional family members by using Sanger sequencing and quantitative real-time PCR (QPCR). Results Of the cohort of ten FEVR families, six pathogenic variants were identified, including four novel and two known heterozygous mutations. Of the variants identified, four were missense variants, and two were novel heterozygous deletion mutations [LRP5, c.4053 DelC (p.Ile1351IlefsX88); TSPAN12, EX8Del]. The two novel heterozygous deletion mutations were not observed in the control subjects and could give rise to a relatively severe FEVR phenotype, which could be explained by the protein function prediction. Conclusions We identified two novel heterozygous deletion mutations [LRP5, c.4053 DelC (p.Ile1351IlefsX88); TSPAN12, EX8Del] using targeted NGS as a causative mutation for FEVR. These genetic deletion variations exhibit a severe form of FEVR, with tractional retinal detachments compared with other known point mutations. The data further enrich the mutation spectrum of FEVR and enhance our understanding of genotype–phenotype correlations to provide useful information for disease diagnosis, prognosis, and effective genetic counseling. PMID:28867931

  20. A Mismatch EndoNuclease Array-Based Methodology (MENA) for Identifying Known SNPs or Novel Point Mutations.

    PubMed

    Comeron, Josep M; Reed, Jordan; Christie, Matthew; Jacobs, Julia S; Dierdorff, Jason; Eberl, Daniel F; Manak, J Robert

    2016-04-05

    Accurate and rapid identification or confirmation of single nucleotide polymorphisms (SNPs), point mutations and other human genomic variation facilitates understanding the genetic basis of disease. We have developed a new methodology (called MENA (Mismatch EndoNuclease Array)) pairing DNA mismatch endonuclease enzymology with tiling microarray hybridization in order to genotype both known point mutations (such as SNPs) as well as identify previously undiscovered point mutations and small indels. We show that our assay can rapidly genotype known SNPs in a human genomic DNA sample with 99% accuracy, in addition to identifying novel point mutations and small indels with a false discovery rate as low as 10%. Our technology provides a platform for a variety of applications, including: (1) genotyping known SNPs as well as confirming newly discovered SNPs from whole genome sequencing analyses; (2) identifying novel point mutations and indels in any genomic region from any organism for which genome sequence information is available; and (3) screening panels of genes associated with particular diseases and disorders in patient samples to identify causative mutations. As a proof of principle for using MENA to discover novel mutations, we report identification of a novel allele of the beethoven (btv) gene in Drosophila, which encodes a ciliary cytoplasmic dynein motor protein important for auditory mechanosensation.