Rare Compound Heterozygous Frameshift Mutations in ALMS1 Gene Identified Through Exome Sequencing in a Taiwanese Patient With Alström Syndrome.

PubMed

Tsai, Meng-Che; Yu, Hui-Wen; Liu, Tsunglin; Chou, Yen-Yin; Chiou, Yuan-Yow; Chen, Peng-Chieh

2018-01-01

Alström syndrome (AS) is a rare autosomal recessive disorder that shares clinical features with other ciliopathy-related diseases. Genetic mutation analysis is often required in making differential diagnosis but usually costly in time and effort using conventional Sanger sequencing. Herein we describe a Taiwanese patient presenting cone-rod dystrophy and early-onset obesity that progressed to diabetes mellitus with marked insulin resistance during adolescence. Whole exome sequencing of the patient's genomic DNA identified a novel frameshift mutation in exons 15 (c.10290_10291delTA, p.Lys3431Serfs * 10) and a rare mutation in 16 (c.10823_10824delAG, p.Arg3609Alafs * 6) of ALMS1 gene. The compound heterozygous mutations were predicted to render truncated proteins. This report highlighted the clinical utility of exome sequencing and extended the knowledge of mutation spectrum in AS patients.

Truncating SLC5A7 mutations underlie a spectrum of dominant hereditary motor neuropathies

PubMed Central

Salter, Claire G.; Beijer, Danique; Hardy, Holly; Barwick, Katy E.S.; Bower, Matthew; Mademan, Ines; De Jonghe, Peter; Deconinck, Tine; Russell, Mark A.; McEntagart, Meriel M.; Chioza, Barry A.; Blakely, Randy D.; Chilton, John K.; De Bleecker, Jan; Baets, Jonathan; Baple, Emma L.

2018-01-01

Objective To identify the genetic cause of disease in 2 previously unreported families with forms of distal hereditary motor neuropathies (dHMNs). Methods The first family comprises individuals affected by dHMN type V, which lacks the cardinal clinical feature of vocal cord paralysis characteristic of dHMN-VII observed in the second family. Next-generation sequencing was performed on the proband of each family. Variants were annotated and filtered, initially focusing on genes associated with neuropathy. Candidate variants were further investigated and confirmed by dideoxy sequence analysis and cosegregation studies. Thorough patient phenotyping was completed, comprising clinical history, examination, and neurologic investigation. Results dHMNs are a heterogeneous group of peripheral motor neuron disorders characterized by length-dependent neuropathy and progressive distal limb muscle weakness and wasting. We previously reported a dominant-negative frameshift mutation located in the concluding exon of the SLC5A7 gene encoding the choline transporter (CHT), leading to protein truncation, as the likely cause of dominantly-inherited dHMN-VII in an extended UK family. In this study, our genetic studies identified distinct heterozygous frameshift mutations located in the last coding exon of SLC5A7, predicted to result in the truncation of the CHT C-terminus, as the likely cause of the condition in each family. Conclusions This study corroborates C-terminal CHT truncation as a cause of autosomal dominant dHMN, confirming upper limb predominating over lower limb involvement, and broadening the clinical spectrum arising from CHT malfunction. PMID:29582019

Two middle-age-onset hemochromatosis patients with heterozygous mutations in the hemojuvelin gene in a Chinese family.

PubMed

Li, Shufeng; Xue, Jun; Chen, Baojun; Wang, Qiwei; Shi, Minke; Xie, Xiaojing; Zhang, Liang

2014-04-01

Hereditary hemochromatosis is a disorder characterized by enhanced intestinal absorption of dietary iron. Here, we report a heterozygous genotype at two mutation sites in hemojuvelin (HJV) present in two brothers with middle-age-onset hemochromatosis in a Chinese family. To date, only homozygous or compound heterozygous states of HJV gene have been reported as associated with iron overload. However, the patients here were heterozygous for two mutations in one HJV allele in cis: a premature termination mutation (962G>A and 963C>A; C321X) and a mutation in the signal peptide (18G>C; Q6H). Previously unrecognized environmental or other genetic factors may have interacted with the heterozygous genotype in these patients.

Novel compound heterozygous mutations in the OTOF Gene identified by whole-exome sequencing in auditory neuropathy spectrum disorder.

PubMed

Tang, Fengzhu; Ma, Dengke; Wang, Yulan; Qiu, Yuecai; Liu, Fei; Wang, Qingqing; Lu, Qiutian; Shi, Min; Xu, Liang; Liu, Min; Liang, Jianping

2017-03-23

Many hearing-loss diseases are demonstrated to have Mendelian inheritance caused by mutations in single gene. However, many deaf individuals have diseases that remain genetically unexplained. Auditory neuropathy is a sensorineural deafness in which sounds are able to be transferred into the inner ear normally but the transmission of the signals from inner ear to auditory nerve and brain is injured, also known as auditory neuropathy spectrum disorder (ANSD). The pathogenic mutations of the genes responsible for the Chinese ANSD population remain poorly understood. A total of 127 patients with non-syndromic hearing loss (NSHL) were enrolled in Guangxi Zhuang Autonomous Region. A hereditary deafness gene mutation screening was performed to identify the mutation sites in four deafness-related genes (GJB2, GJB3, 12S rRNA, and SLC26A4). In addition, whole-exome sequencing (WES) was applied to explore unappreciated mutation sites in the cases with the singularity of its phenotype. Well-characterized mutations were found in only 8.7% (11/127) of the patients. Interestingly, two mutations in the OTOF gene were identified in two affected siblings with ANSD from a Chinese family, including one nonsense mutation c.1273C > T (p.R425X) and one missense mutation c.4994 T > C (p.L1665P). Furthermore, we employed Sanger sequencing to confirm the mutations in each subject. Two compound heterozygous mutations in the OTOF gene were observed in the two affected siblings, whereas the two parents and unaffected sister were heterozygous carriers of c.1273C > T (father and sister) and c.4994 T > C (mother). The nonsense mutation p.R425X, contributes to a premature stop codon, may result in a truncated polypeptide, which strongly suggests its pathogenicity for ANSD. The missense mutation p.L1665P results in a single amino acid substitution in a highly conserved region. Two mutations in the OTOF gene in the Chinese deaf population were recognized for the first time. These

Classical phenotype of Laron syndrome in a girl with a heterozygous mutation and heterozygous polymorphism of the growth hormone receptor gene.

PubMed

Shevah, Orit; Galli-Tsinopoulou, Assimina; Rubinstein, Menachem; Nousia-Arvanitakis, Sanda; Laron, Zvi

2004-03-01

We describe here a 19 month-old girl with classical Laron syndrome (LS). Molecular analysis of the GH receptor gene in the patient and her parents was performed. The patient was found to be heterozygous for a mutation in exon 4 (R43X) and heterozygous for a polymorphism in exon 6 (Gly168Gly). Her mother was also heterozygous for R43X but homozygous for the polymorphism. In the father, a heterozygous polymorphism was found. Contrary to previous assumptions that only homozygous patients express the typical phenotype, this patient shows all the classical features of LS, despite being a heterozygote for a pathological defect.

A heterozygous putative null mutation in ROM1 without a mutation in peripherin/RDS in a family with retinitis pigmentosa

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

Sakuma, Hitoshi; Inana, G.; Murakami, Akira

1995-05-20

ROM1 is a 351-amino-acid, 37-kDa outer segment membrane protein of rod photoreceptors. ROM1 is related to peripherin/RDS, another outer segment membrane protein found in both rods and cones. The precise function of ROM1 or peripherin/RDS is not known, but they have been suggested to play important roles in the function and/or structure of the rod photoreceptor outer segment disks. A recent report implicated ROM1 in disease by suggesting that RP can be caused by a heterozygous null mutation in ROM1 but only in combination with another heterozygous mutation in peripherin/RDS. Screening of the ROM1 gene using polymerase chain reaction amplification,more » denaturing gradient gel electrophoresis, and direct DNA sequencing identified the same heterozygous putative null mutation in a family with RP.« less

Prenatal diagnosis of fetal glutaric aciduria type 1 with rare compound heterozygous mutations in GCDH gene.

PubMed

Peng, Hsiu-Huei; Shaw, Sheng-Wen; Huang, Kuan-Gen

2018-02-01

Glutaric aciduria type 1 is a rare disease, with the estimated prevalence about 1 in 100,000 newborns. GCDH gene mutation can lead to glutaric acid and 3- OH glutaric acid accumulation, with clinical manifestation of neuronal damage, brain atrophy, microencephalic macrocephaly, decreased coordination of swallowing, poor muscle coordination, spasticity, and severe dystonic movement disorder. A 22-year-old female, Gravida 4 Para 2, is pregnancy at 13 weeks of gestational age. Her first child is normal, however, the second child was diagnosed as glutaric aciduria type I after birth. She came to our hospital for prenatal genetic counselling of her fetus at 13 weeks of gestational age. We performed GCDH gene mutation analysis of maternal blood showed IVS 3 + 1 G > A heterozygous mutation, GCDH gene mutation analysis of paternal blood showed c. 1240 G > A heterozygous mutation, and the second child has compound heterozygous IVS 3 + 1 G > A and c. 1240 G > A mutations. Later, we performed amniocentesis at 16 weeks of gestational age for chromosome study and GCDH gene mutation analysis for the fetus. The fetal chromosome study showed normal karyotype, however, GCDH gene mutation analysis showed compound heterozygous IVS 3 + 1 G > A and c. 1240 G > A mutations. The couple decided to termination of pregnancy thereafter. Glutaric acidemia type 1 is an autosomal recessive disorder because of pathogenic mutations in the GCDH gene. Early diagnosis and therapy of glutaric acidemia type 1 can reduce the risk of neuronal damage and acute dystonia. We report a case of prenatal diagnosis of fetal glutaric aciduria type 1 with rare compound heterozygous GCDH gene mutation at IVS 3 + 1 G > A and c. 1240 G > A mutations, which provide better genetic counselling for the couples. Copyright © 2018. Published by Elsevier B.V.

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

Short Stature, Accelerated Bone Maturation, and Early Growth Cessation Due to Heterozygous Aggrecan Mutations

PubMed Central

Nilsson, Ola; Guo, Michael H.; Dunbar, Nancy; Popovic, Jadranka; Flynn, Daniel; Jacobsen, Christina; Lui, Julian C.; Hirschhorn, Joel N.; Baron, Jeffrey

2014-01-01

Context: Many children with idiopathic short stature have a delayed bone age. Idiopathic short stature with advanced bone age is far less common. Objective: The aim was to identify underlying genetic causes of short stature with advanced bone age. Setting and Design: We used whole-exome sequencing to study three families with autosomal-dominant short stature, advanced bone age, and premature growth cessation. Results: Affected individuals presented with short stature [adult heights −2.3 to −4.2 standard deviation scores (SDS)] with histories of early growth cessation or childhood short stature (height SDS −1.9 to −3.5 SDS), advancement of bone age, and normal endocrine evaluations. Whole-exome sequencing identified novel heterozygous variants in ACAN, which encodes aggrecan, a proteoglycan in the extracellular matrix of growth plate and other cartilaginous tissues. The variants were present in all affected, but in no unaffected, family members. In Family 1, a novel frameshift mutation in exon 3 (c.272delA) was identified, which is predicted to cause early truncation of the aggrecan protein. In Family 2, a base-pair substitution was found in a highly conserved location within a splice donor site (c.2026+1G>A), which is also likely to alter the amino acid sequence of a large portion of the protein. In Family 3, a missense variant (c.7064T>C) in exon 14 affects a highly conserved residue (L2355P) and is strongly predicted to perturb protein function. Conclusions: Our study demonstrates that heterozygous mutations in ACAN can cause a mild skeletal dysplasia, which presents clinically as short stature with advanced bone age. The accelerating effect on skeletal maturation has not previously been noted in the few prior reports of human ACAN mutations. Our findings thus expand the spectrum of ACAN defects and provide a new molecular genetic etiology for the unusual child who presents with short stature and accelerated skeletal maturation. PMID:24762113

Heterozygous Mutations Causing Partial Prohormone Convertase 1 Deficiency Contribute to Human Obesity

PubMed Central

Creemers, John W.M.; Choquet, Hélène; Stijnen, Pieter; Vatin, Vincent; Pigeyre, Marie; Beckers, Sigri; Meulemans, Sandra; Than, Manuel E.; Yengo, Loïc; Tauber, Maithé; Balkau, Beverley; Elliott, Paul; Jarvelin, Marjo-Riitta; Van Hul, Wim; Van Gaal, Luc; Horber, Fritz; Pattou, François; Froguel, Philippe; Meyre, David

2012-01-01

Null mutations in the PCSK1 gene, encoding the proprotein convertase 1/3 (PC1/3), cause recessive monogenic early onset obesity. Frequent coding variants that modestly impair PC1/3 function mildly increase the risk for common obesity. The aim of this study was to determine the contribution of rare functional PCSK1 mutations to obesity. PCSK1 exons were sequenced in 845 nonconsanguineous extremely obese Europeans. Eight novel nonsynonymous PCSK1 mutations were identified, all heterozygous. Seven mutations had a deleterious effect on either the maturation or the enzymatic activity of PC1/3 in cell lines. Of interest, five of these novel mutations, one of the previously described frequent variants (N221D), and the mutation found in an obese mouse model (N222D), affect residues at or near the structural calcium binding site Ca-1. The prevalence of the newly identified mutations was assessed in 6,233 obese and 6,274 lean European adults and children, which showed that carriers of any of these mutations causing partial PCSK1 deficiency had an 8.7-fold higher risk to be obese than wild-type carriers. These results provide the first evidence of an increased risk of obesity in heterozygous carriers of mutations in the PCSK1 gene. Furthermore, mutations causing partial PCSK1 deficiency are present in 0.83% of extreme obesity phenotypes. PMID:22210313

Heterozygous mutations causing partial prohormone convertase 1 deficiency contribute to human obesity.

PubMed

Creemers, John W M; Choquet, Hélène; Stijnen, Pieter; Vatin, Vincent; Pigeyre, Marie; Beckers, Sigri; Meulemans, Sandra; Than, Manuel E; Yengo, Loïc; Tauber, Maithé; Balkau, Beverley; Elliott, Paul; Jarvelin, Marjo-Riitta; Van Hul, Wim; Van Gaal, Luc; Horber, Fritz; Pattou, François; Froguel, Philippe; Meyre, David

2012-02-01

Null mutations in the PCSK1 gene, encoding the proprotein convertase 1/3 (PC1/3), cause recessive monogenic early onset obesity. Frequent coding variants that modestly impair PC1/3 function mildly increase the risk for common obesity. The aim of this study was to determine the contribution of rare functional PCSK1 mutations to obesity. PCSK1 exons were sequenced in 845 nonconsanguineous extremely obese Europeans. Eight novel nonsynonymous PCSK1 mutations were identified, all heterozygous. Seven mutations had a deleterious effect on either the maturation or the enzymatic activity of PC1/3 in cell lines. Of interest, five of these novel mutations, one of the previously described frequent variants (N221D), and the mutation found in an obese mouse model (N222D), affect residues at or near the structural calcium binding site Ca-1. The prevalence of the newly identified mutations was assessed in 6,233 obese and 6,274 lean European adults and children, which showed that carriers of any of these mutations causing partial PCSK1 deficiency had an 8.7-fold higher risk to be obese than wild-type carriers. These results provide the first evidence of an increased risk of obesity in heterozygous carriers of mutations in the PCSK1 gene. Furthermore, mutations causing partial PCSK1 deficiency are present in 0.83% of extreme obesity phenotypes.

A novel loss-of-function heterozygous BRCA2 c.8946_8947delAG mutation found in a Chinese woman with family history of breast cancer.

PubMed

Ma, Jing; Yang, Jichun; Jian, Wenjing; Wang, Xianming; Xiao, Deyong; Xia, Wenjun; Xiong, Likuan; Ma, Duan

2017-04-01

Breast cancer is the most frequent female malignancy worldwide. Among them, some cases have hereditary susceptibility in two leading genes, BRCA1 and BRCA2. Heterozygous germ line mutations in them are related with increased risk of breast, ovarian and other cancer, following autosomal dominant inheritance mode. For purpose of early finding, early diagnosis and early treatment, mutation detecting of BRCA1/2 genes was performed in unselected 300 breast or ovarian patients and unaffected women using next-generation sequencing and then confirmed by Sanger sequencing. A non-previously reported heterozygous mutation c.8946_8947delAG (p.D2983FfsX34) of BRCA2 gene was identified in an unaffected Chinese woman with family history of breast cancer (her breast cancer mother, also carrying this mutation). The BRCA2-truncated protein resulted from the frame shift mutation was found to lose two putative nuclear localization signals and a Rad51-binding motif in the extreme C-terminal region by bioinformatic prediction. And then in vitro experiments showed that nearly all the mutant protein was unable to translocate to the nucleus to perform DNA repair activity. This novel mutant BRCA2 protein is dysfunction. We classify the mutation into disease causing and conclude that it is the risk factor for breast cancer in this family. So, conducting the same mutation test and providing genetic counseling for this family is practically meaningful and significant. Meanwhile, the identification of this new mutation enriches the Breast Cancer Information Core database, especially in China.

The risk for developing cancer in Israeli ATM, BLM, and FANCC heterozygous mutation carriers.

PubMed

Laitman, Yael; Boker-Keinan, Lital; Berkenstadt, Michal; Liphsitz, Irena; Weissglas-Volkov, Daphna; Ries-Levavi, Liat; Sarouk, Ifat; Pras, Elon; Friedman, Eitan

2016-03-01

Cancer risks in heterozygous mutation carriers of the ATM, BLM, and FANCC genes are controversial. To shed light on this issue, cancer rates were evaluated by cross referencing asymptomatic Israeli heterozygous mutation carriers in the ATM, BLM, and FANCC genes with cancer diagnoses registered at the Israeli National Cancer Registry (INCR). Comparison of observed to expected Standardized Incidence Rates (SIR) was performed. Overall, 474 individuals participated in the study: 378 females; 25 Arab and 31 Jewish ATM carriers, 152 BLM carriers, and 170 FANCC carriers (all Ashkenazim). Age range at genotyping was 19-53 years (mean + SD 30.6 + 5 years). In addition, 96 males were included; 5, 34, and 57 ATM, BLM, and FANCC mutation carriers, respectively. Over 5-16 years from genotyping (4721 person/years), 15 new cancers were diagnosed in mutation carriers: 5 breast, 4 cervical, 3 melanomas, and one each bone sarcoma, pancreatic, and colorectal cancer. No single cancer diagnosis was more prevalent then expected in all groups combined or per gene analyzed. Specifically breast cancer SIR was 0.02-0.77. We conclude that Israeli ATM, BLM, and FANCC heterozygous mutation carriers are not at an increased risk for developing cancer. Copyright © 2015 Elsevier Inc. All rights reserved.

PINK1 heterozygous mutations induce subtle alterations in dopamine-dependent synaptic plasticity

PubMed Central

Madeo, G.; Schirinzi, T.; Martella, G.; Latagliata, E.C.; Puglisi, F.; Shen, J.; Valente, E.M.; Federici, M.; Mercuri, N.B.; Puglisi-Allegra, S.; Bonsi, P.; Pisani, A.

2014-01-01

Background Homozygous or compound heterozygous mutations in the PTEN-induced kinase 1 (PINK1) gene are causative of autosomal recessive, early onset PD. Single heterozygous mutations have been repeatedly detected in a subset of patients as well as in non-affected subjects, and their significance has long been debated. Several neurophysiological studies from non-manifesting PINK1 heterozygotes have shown the existence of neural plasticity abnormalities, indicating the presence of specific endophenotypic traits in the heterozygous state. Methods In the present study, we performed a functional analysis of corticostriatal synaptic plasticity in heterozygous PINK1 knock-out (PINK1+/−) mice by a multidisciplinary approach. Results We found that, despite a normal motor behavior, repetitive activation of cortical inputs to striatal neurons failed to induce long-term potentiation (LTP), whereas long-term depression (LTD) was normal. Although nigral dopaminergic neurons exhibited normal morphological and electrophysiological properties with normal responses to dopamine receptor activation, we measured a significantly lower dopamine release in the striatum of PINK1+/−, compared to control mice, suggesting that a decrease in stimulus-evoked dopamine overflow acts as a major determinant for the LTP deficit. Accordingly, pharmacological agents capable of increasing the availability of dopamine in the synaptic cleft restored a normal LTP in heterozygous mice. Moreover, MAO-B inhibitors rescued a physiological LTP and a normal dopamine release. Conclusions Our results provide novel evidence for striatal plasticity abnormalities even in the heterozygous disease state. These alterations might be considered an endophenotype to this monogenic form of PD, and a valid tool to characterize early disease stage and design possible disease-modifying therapies. PMID:24167038

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/.

Heterozygous TGFBR2 mutations in Marfan syndrome

PubMed Central

Mizuguchi, Takeshi; Collod-Beroud, Gwenaëlle; Akiyama, Takushi; Abifadel, Marianne; Harada, Naoki; Morisaki, Takayuki; Allard, Delphine; Varret, Mathilde; Claustres, Mireille; Morisaki, Hiroko; Ihara, Makoto; Kinoshita, Akira; Yoshiura, Koh-ichiro; Junien, Claudine; Kajii, Tadashi; Jondeau, Guillaume; Ohta, Tohru; Kishino, Tatsuya; Furukawa, Yoichi; Nakamura, Yusuke; Niikawa, Norio; Boileau, Catherine; Matsumoto, Naomichi

2004-01-01

Marfan syndrome (MFS) is an extracellular matrix disorder with cardinal manifestations in the eye, skeleton, and cardiovascular systems and associated with defects in the fibrillin gene (FBN1) at 15q21.1 1. We previously mapped the second locus for MFS (MFS type 2, MFS2, OMIM *154705), at 3p24.2-p25 in a large French family (MS1)2. Identification of a 3p24.1 chromosomal breakpoint disrupting the TGF-beta receptor 2 gene (TGFBR2) in a Japanese MFS patient led us to consider TGFBR2 as the MSF2 gene. We found a Q508Q mutation of TGFBR2 that resulted in abnormal splicing and segregated with MFS2 in MS1. Three other missense mutations were found in four unrelated probands and were shown by luciferase-assays to lead to loss of function of the TGF-β signaling activity on extracellular matrix formation. These results show that heterozygous mutations in TGFBR2, a putative tumor suppressor gene implicated in several malignancies, are also associated with inherited connective-tissue disorders. PMID:15235604

Novel compound heterozygous mutations in SERPINH1 cause rare autosomal recessive osteogenesis imperfecta type X.

PubMed

Song, Y; Zhao, D; Xu, X; Lv, F; Li, L; Jiang, Y; Wang, O; Xia, W; Xing, X; Li, M

2018-03-09

We identified novel compound heterozygous mutations in SERPINH1 in a Chinese boy suffering from recurrent fractures, femoral deformities, and growth retardation, which resulted in extremely rare autosomal recessive OI type X. Long-term treatment of BPs was effective in increasing BMD Z-score, reducing fracture incidence and reshaping vertebrae compression. Osteogenesis imperfecta (OI) is a heritable bone disorder characterized by low bone mineral density, recurrent fractures, and progressive bone deformities. Mutation in serpin peptidase inhibitor clade H, member 1 (SERPINH1), which encodes heat shock protein 47 (HSP47), leads to rare autosomal recessive OI type X. We aimed to detect the phenotype and the pathogenic mutation of OI type X in a boy from a non-consanguineous Chinese family. We investigated the pathogenic mutations and analyzed their relationship with the phenotype in the patient using next-generation sequencing (NGS) and Sanger sequencing. Moreover, the efficacy of long-term bisphosphonate treatment in this patient was evaluated. The patient suffered from multiple fractures, low bone mass, and bone deformities in the femur, without dentinogenesis imperfecta or hearing loss. Compound heterozygous variants were found in SERPINH1 as follows: c.149 T>G in exon 2 and c.1214G>A in exon 5. His parents were heterozygous carriers of each of these mutations, respectively. Bisphosphonates could be helpful in increasing BMD Z-score, reducing bone fracture risk and reshaping the compressed vertebral bodies of this patient. We reported novel compound heterozygous mutations in SERPINH1 in a Chinese OI patient for the first time, which expanded the spectrum of phenotype and genotype of extremely rare OI type X.

A new compound heterozygous CFTR mutation in a Chinese family with cystic fibrosis.

PubMed

Xie, Yingjun; Huang, Xueqiong; Liang, Yujian; Xu, Lingling; Pei, Yuxin; Cheng, Yucai; Zhang, Lidan; Tang, Wen

2017-11-01

Cystic fibrosis (CF) is the most common autosomal recessive disease among Caucasians but is rarer in the Chinese population, because mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. To elucidate the causative role of a novel compound heterozygous mutation of CF. In this study, clinical samples were obtained from two siblings with recurrent airway infections, clubbed fingers, salt-sweat and failure to gain weight in a non-consanguineous Chinese family. Next-generation sequencing was performed on the 27 coding exons of CFTR in both children, with confirmation by Sanger sequencing. Next-generation sequencing showed the same compound heterozygous CFTR mutation (c.865A>T p.Arg289X and c.3651_3652insAAAT p.Tyr1219X) in both children. As this mutation is consistent with the clinical manifestations of CF and no other mutations were detected after scanning the gene sequence, we suggest that the CF phenotype is caused by compound heterozygosity for c.865A>T and c.3651_3652insAAAT. As c865A>T is not currently listed in the "Cystic Fibrosis Mutation Database", this information about CF in a Chinese population is of interest. © 2015 John Wiley & Sons Ltd.

Immune dysregulation in human subjects with heterozygous germline mutations in CTLA4

PubMed Central

Deenick, Elissa K.; Niemela, Julie E.; Avery, Danielle T.; Schickel, Jean-Nicolas; Tran, Dat Q.; Stoddard, Jennifer; Zhang, Yu; Frucht, David M.; Dumitriu, Bogdan; Scheinberg, Phillip; Folio, Les R.; Frein, Cathleen A.; Price, Susan; Koh, Christopher; Heller, Theo; Seroogy, Christine M.; Huttenlocher, Anna; Rao, V. Koneti; Su, Helen C.; Kleiner, David; Notarangelo, Luigi D.; Rampertaap, Yajesh; Olivier, Kenneth N.; McElwee, Joshua; Hughes, Jason; Pittaluga, Stefania; Oliveira, Joao B.; Meffre, Eric; Fleisher, Thomas A.; Holland, Steven M.; Lenardo, Michael J.; Tangye, Stuart G.; Uzel, Gulbu

2015-01-01

Cytotoxic T lymphocyte antigen–4 (CTLA-4) is an inhibitory receptor found on immune cells. The consequences of mutations in CTLA4 in humans are unknown. We identified germline heterozygous mutations in CTLA4 in subjects with severe immune dysregulation from four unrelated families. Whereas Ctla4 heterozygous mice have no obvious phenotype, human CTLA4 haploinsufficiency caused dysregulation of FoxP3+ regulatory T (Treg) cells, hyperactivation of effector T cells, and lymphocytic infiltration of target organs. Patients also exhibited progressive loss of circulating B cells, associated with an increase of predominantly autoreactive CD21lo B cells and accumulation of B cells in nonlymphoid organs. Inherited human CTLA4 haploinsufficiency demonstrates a critical quantitative role for CTLA-4 in governing T and B lymphocyte homeostasis. PMID:25213377

Truncating mutation in the NHS gene: phenotypic heterogeneity of Nance-Horan syndrome in an asian Indian family.

PubMed

Ramprasad, Vedam Lakshmi; Thool, Alka; Murugan, Sakthivel; Nancarrow, Derek; Vyas, Prateep; Rao, Srinivas Kamalakar; Vidhya, Authiappan; Ravishankar, Krishnamoorthy; Kumaramanickavel, Govindasamy

2005-01-01

A four-generation family containing eight affected males who inherited X-linked developmental lens opacity and microcornea was studied. Some members in the family had mild to moderate nonocular clinical features suggestive of Nance-Horan syndrome. The purpose of the study was to map genetically the gene in the large 57-live-member Asian-Indian pedigree. PCR-based genotyping was performed on the X-chromosome, by using fluorescent microsatellite markers (10-cM intervals). Parametric linkage analysis was performed by using two disease models, assuming either recessive or dominant X-linked transmission by the MLINK/ILINK and FASTLINK (version 4.1P) programs (http:www.hgmp.mrc.ac.uk/; provided in the public domain by the Human Genome Mapping Project Resources Centre, Cambridge, UK). The NHS gene at the linked region was screened for mutation. By fine mapping, the disease gene was localized to Xp22.13. Multipoint analysis placed the peak LOD of 4.46 at DSX987. The NHS gene mapped to this region. Mutational screening in all the affected males and carrier females (heterozygous form) revealed a truncating mutation 115C-->T in exon 1, resulting in conversion of glutamine to stop codon (Q39X), but was not observed in unaffected individuals and control subjects. conclusions. A family with X-linked Nance-Horan syndrome had severe ocular, but mild to moderate nonocular, features. The clinical phenotype of the truncating mutation (Q39X) in the NHS gene suggests allelic heterogeneity at the NHS locus or the presence of modifier genes. X-linked families with cataract should be carefully examined for both ocular and nonocular features, to exclude Nance-Horan syndrome. RT-PCR analysis did not suggest nonsense-mediated mRNA decay as the possible mechanism for clinical heterogeneity.

Short communication: novel truncating mutations in the CFTR gene causing a severe form of cystic fibrosis in Italian patients.

PubMed

Lenarduzzi, S; Morgutti, M; Crovella, S; Coiana, A; Rosatelli, M C

2014-11-14

Cystic fibrosis (CF) is a common recessive genetic disease caused by mutations in the gene encoding for the cystic fibrosis transmembrane conductance regulator (CFTR) protein. More than 1800 different mutations have been described to date. Here, we report 3 novel mutations in CFTR in 3 Italian CF patients. To detect and identify 36 frequent mutations in Caucasians, we used the INNO-LiPA CFTR19 and INNO-LiPA CFTR17+Tn Update kits (Innogenetics; Ghent, Belgium). Our first analysis did not reveal both of the responsible mutations; thus, direct sequencing of the CFTR gene coding region was performed. The 3 patients were compound heterozygous. In one allele, the F508del (c.1521_1523delCTT, p.PHE508del) mutation in exon 11 was observed in each case. For the second allele, in patient No.1, direct sequencing revealed an 11-base pair deletion (GAGGCGATACT) in exon 14 (c.2236_2246del; pGlu746Alafs*29). In patient No. 2, direct sequencing revealed a nonsense mutation at nucleotide 3892 (c.3892G>T) in exon 24. In patient No. 3, direct sequencing revealed a deletion of cytosine in exon 27 (c.4296delC; p.Asn1432Lysfs*16). These 3 novel mutations indicate the production of a truncated protein, which consequently results in a non-functional polypeptide.

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.

Novel germline PALB2 truncating mutations in African-American breast cancer patients

PubMed Central

Zheng, Yonglan; Zhang, Jing; Niu, Qun; Huo, Dezheng; Olopade, Olufunmilayo I.

2011-01-01

Background It has been demonstrated that PALB2 acts as a bridging molecule between the BRCA1 and BRCA2 proteins and is responsible for facilitating BRCA2-mediated DNA repair. Truncating mutations in the PALB2 gene have been reported to be enriched in Fanconi anemia and breast cancer patients in various populations. Methods We evaluated the contribution of PALB2 germline mutations in 279 African-American breast cancer patients including 29 patients with a strong family history, 29 patients with a moderate family history, 75 patients with a weak family history, and 146 non-familial or sporadic breast cancer cases. Results After direct sequencing of all the coding exons, exon/intron boundaries, 5′UTR and 3′UTR of PALB2, three (1.08%; 3 in 279) novel monoallelic truncating mutations were identified: c.758dupT (exon4), c.1479delC (exon4) and c.3048delT (exon 10); together with 50 sequence variants, 27 of which are novel. None of the truncating mutations were found in 262 controls from the same population. Conclusions PALB2 mutations are present in both familial and non-familial breast cancer among African-Americans. Rare PALB2 mutations account for a small but substantial proportion of breast cancer patients. PMID:21932393

Novel Compound Heterozygous Mutations Expand the Recognized Phenotypes of FARS2-Linked Disease.

PubMed

Walker, Melissa A; Mohler, Kyle P; Hopkins, Kyle W; Oakley, Derek H; Sweetser, David A; Ibba, Michael; Frosch, Matthew P; Thibert, Ronald L

2016-08-01

Mutations in mitochondrial aminoacyl-tRNA synthetases are an increasingly recognized cause of human diseases, often arising in individuals with compound heterozygous mutations and presenting with system-specific phenotypes, frequently neurologic. FARS2 encodes mitochondrial phenylalanyl transfer ribonucleic acid (RNA) synthetase (mtPheRS), perturbations of which have been reported in 6 cases of an infantile, lethal disease with refractory epilepsy and progressive myoclonus. Here the authors report the case of juvenile onset refractory epilepsy and progressive myoclonus with compound heterozygous FARS2 mutations. The authors describe the clinical course over 6 years of care at their institution and diagnostic studies including electroencephalogram (EEG), brain magnetic resonance imaging (MRI), serum and cerebrospinal fluid analyses, skeletal muscle biopsy histology, and autopsy gross and histologic findings, which include features shared with Alpers-Huttenlocher syndrome, Leigh syndrome, and a previously published case of FARS2 mutation associated infantile onset disease. The authors also present structure-guided analysis of the relevant mutations based on published mitochondrial phenylalanyl transfer RNA synthetase and related protein crystal structures as well as biochemical analysis of the corresponding recombinant mutant proteins. © The Author(s) 2016.

Variable expressivity of the phenotype in two families with brachydactyly type E, craniofacial dysmorphism, short stature and delayed bone age caused by novel heterozygous mutations in the PTHLH gene.

PubMed

Jamsheer, Aleksander; Sowińska-Seidler, Anna; Olech, Ewelina M; Socha, Magdalena; Kozłowski, Kazimierz; Pyrkosz, Antoni; Trzeciak, Tomasz; Materna-Kiryluk, Anna; Latos-Bieleńska, Anna

2016-05-01

Brachydactyly refers to shortening of digits due to hypoplasia or aplasia of bones forming the hands and/or feet. Isolated brachydactyly type E (BDE), which is characterized by shortened metacarpals and/or metatarsals, results in a small proportion of patients from HOXD13 or PTHLH mutations, although in the majority of cases molecular lesion remains unknown. BDE, like other brachydactylies, shows clinical heterogeneity with highly variable intrafamilial and interindividual expressivity. In this study, we investigated two Polish cases (one familial and one sporadic) presenting with BDE and additional symptoms due to novel PTHLH mutations. Apart from BDE, the affected family showed short stature, mild craniofacial dysmorphism and delayed bone age. Sanger sequencing of PTHLH revealed a novel heterozygous frameshift mutation c.258delC(p.N87Tfs*18) in two affected individuals and one relative manifesting mild brachydactyly. The sporadic patient, in addition to BDE, presented with craniofacial dysmorphism, normal stature and bone age, and was demonstrated to carry a de novo heterozygous c.166C>T(p.R56*) mutation. Our paper reports on the two novel truncating PTHLH variants, resulting in variable combination of BDE and other symptoms. Data shown here expand the knowledge on the phenotypic presentation of PTHLH mutations, highlighting significant clinical variability and incomplete penetrance of the PTHLH-related symptoms.

A novel heterozygous SOX2 mutation causing congenital bilateral anophthalmia, hypogonadotropic hypogonadism and growth hormone deficiency.

PubMed

Macchiaroli, Annamaria; Kelberman, Daniel; Auriemma, Renata Simona; Drury, Suzanne; Islam, Lily; Giangiobbe, Sara; Ironi, Gabriele; Lench, Nicholas; Sowden, Jane C; Colao, Annamaria; Pivonello, Rosario; Cavallo, Luciano; Gasperi, Maurizio; Faienza, Maria Felicia

2014-01-25

Heterozygous de novo mutations in SOX2 have been reported in approximately 10-20% of patients with unilateral or bilateral anophthalmia or microphthalmia. An additional phenotype of hypopituitarism, with anterior pituitary hypoplasia and hypogonadotropic hypogonadism, has been reported in patients carrying SOX2 alterations. We report a novel heterozygous mutation in the SOX2 gene in a male affected with congenital bilateral anophthalmia, hypogonadotrophic hypogonadism and growth hormone deficiency. The mutation we describe is a cytosine deletion in position 905 (c905delC) which causes frameshift and an aberrant C-terminal domain. Our report highlights the fact that subjects affected with eye anomalies and harboring SOX2 mutations are at high risk for gonadotropin deficiency, which has important implications for their clinical management. Copyright © 2013 Elsevier B.V. All rights reserved.

Late-onset nonketotic hyperglycinemia with a heterozygous novel point mutation of the GLDC gene.

PubMed

Brenton, J Nicholas; Rust, Robert S

2014-05-01

Atypical nonketotic hyperglycinemia is characterized by heterogeneous phenotypes that often include nonspecific behavioral problems, cognitive deficits, and developmental delays. We describe a girl with late-onset nonketotic hyperglycinemia presenting at 5 years of age with hypotonia, chorea, ataxia, and alterations in consciousness in the setting of febrile illness. Serum amino acid analysis was mildly elevated; however, urine amino acid analysis was instrumental in demonstrating marked hyperglycinuria. Mutation testing showed a heterozygous novel sequence change/point mutation in the glycine decarboxylase gene. This patient illustrates the importance of obtaining urine amino acids in individuals whose clinical manifestations are suspicious for any form of nonketotic hyperglycinemia, because this testing may provide more prominent evidence of elevations in glycine. She also illustrates the potential for a heterozygous mutation to result in manifestations of an atypical form of nonketotic hyperglycinemia. Copyright © 2014 Elsevier Inc. All rights reserved.

Atypical Progeroid Syndrome due to Heterozygous Missense LMNA Mutations

PubMed Central

Garg, Abhimanyu; Subramanyam, Lalitha; Agarwal, Anil K.; Simha, Vinaya; Levine, Benjamin; D'Apice, Maria Rosaria; Novelli, Giuseppe; Crow, Yanick

2009-01-01

Context: Hutchinson-Gilford progeria syndrome (HGPS) and mandibuloacral dysplasia are well-recognized allelic autosomal dominant and recessive progeroid disorders, respectively, due to mutations in lamin A/C (LMNA) gene. Heterozygous LMNA mutations have also been reported in a small number of patients with a less well-characterized atypical progeroid syndrome (APS). Objective: The objective of the study was to investigate the underlying genetic and molecular basis of the phenotype of patients presenting with APS. Results: We report 11 patients with APS from nine families, many with novel heterozygous missense LMNA mutations, such as, P4R, E111K, D136H, E159K, and C588R. These and previously reported patients now reveal a spectrum of clinical features including progeroid manifestations such as short stature, beaked nose, premature graying, partial alopecia, high-pitched voice, skin atrophy over the hands and feet, partial and generalized lipodystrophy with metabolic complications, and skeletal anomalies such as mandibular hypoplasia and mild acroosteolysis. Skin fibroblasts from these patients when assessed for lamin A/C expression using epifluorescence microscopy revealed variable nuclear morphological abnormalities similar to those observed in patients with HGPS. However, these nuclear abnormalities in APS patients could not be rescued with 48 h treatment with farnesyl transferase inhibitors, geranylgeranyl transferase inhibitors or trichostatin-A, a histone deacetylase inhibitor. Immunoblots of cell lysates from fibroblasts did not reveal prelamin A accumulation in any of these patients. Conclusions: APS patients have a few overlapping but some distinct clinical features as compared with HGPS and mandibuloacral dysplasia. The pathogenesis of clinical manifestations in APS patients seems not to be related to accumulation of mutant farnesylated prelamin A. PMID:19875478

Novel compound heterozygous mutations in MYO7A gene associated with autosomal recessive sensorineural hearing loss in a Chinese family.

PubMed

Ma, Yalin; Xiao, Yun; Zhang, Fengguo; Han, Yuechen; Li, Jianfeng; Xu, Lei; Bai, Xiaohui; Wang, Haibo

2016-04-01

Mutations in MYO7A gene have been reported to be associated with Usher Syndrome type 1B (USH1B) and nonsyndromic hearing loss (DFNB2, DFNA11). Most mutations in MYO7A gene caused USH1B, whereas only a few reported mutations led to DFNB2 and DFNA11. The current study was designed to investigate the mutations among a Chinese family with autosomal recessive hearing loss. In this study, we present the clinical, genetic and molecular characteristics of a Chinese family. Targeted capture of 127 known deafness genes and next-generation sequencing were employed to study the genetic causes of two siblings in the Chinese family. Sanger sequencing was employed to examine those variant mutations in the members of this family and other ethnicity-matched controls. We identified the novel compound heterozygous mutant alleles of MYO7A gene: a novel missense mutation c.3671C>A (p.A1224D) and a reported insert mutation c.390_391insC (p.P131PfsX9). Variants were further confirmed by Sanger sequencing. These two compound heterozygous variants were co-segregated with autosomal recessive hearing loss phenotype. The gene mutation analysis and protein sequence alignment further supported that the novel compound heterozygous mutations were pathogenic. The novel compound heterozygous mutations (c.3671C>A and c.390_391insC) in MYO7A gene identified in this study were responsible for the autosomal recessive sensorineural hearing loss of this Chinese family. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

PANRETINAL DEGENERATION ASSOCIATED WITH LONG-TERM HYDROXYCHLOROQUINE USE AND HETEROZYGOUS USH2A MUTATION.

PubMed

Katsman, Diana; Sanfilippo, Christian; Sarraf, David

2017-01-01

To report a case of bilateral panretinal degeneration in a patient with long-term hydroxychloroquine exposure and positive for a heterozygous mutation in the USH2A gene. Retrospective case report. Multimodal imaging including spectral-domain optical coherence tomography, fundus autofluorescence, and fluorescein angiography was performed and the results are presented. Electroretinography findings are also described. The authors report a 39-year-old patient with a history of hydroxychloroquine therapy for 20 years (cumulative dose of 2,774 g). Multimodal retinal imaging demonstrated bilateral paracentral outer retinal atrophy with spectral-domain optical coherence tomography and characteristic of hydroxychloroquine toxicity. Full-field electroretinography showed bilateral panretinal depression of the rod and cone responses. Mutational analysis revealed that the patient was a carrier for an autosomal recessive mutation in the USH2A gene. We report a case of panretinal degeneration but with features characteristic of hydroxychloroquine retinopathy in a patient who was found to be a heterozygous carrier of the USH2A gene, a cause of recessive retinitis pigmentosa without hearing loss. Carrier status for a retinal degenerative mutation may have rendered this patient more susceptible to the retinotoxic effects of long-term hydroxychloroquine therapy.

[A novel compound heterozygous mutation in ABCA3 gene in a child with diffuse parenchymal lung disease].

PubMed

Bao, Y M; Liu, X L; Liu, X L; Chen, J H; Zheng, Y J

2017-11-02

Objective: To summarize the clinical characteristics of the diffuse parenchymal lung diseases in a child caused by a novel compound heterozygous ABCA3 mutation and explore the association between the phenotype and ABCA3 mutation. Method: The clinical material of a patient diagnosed with diffuse parenchymal lung disease with ABCA3 mutation in December 2016 in Shenzhen Children's Hospital was analyzed. The information about ABCA3 gene mutation updated before April, 2017 was searched and collected from the gene databases (including 1000Genomes, HGMD, EXAC) and the literatures (including Wanfang Chinese database and Pubmed). Result: The girl was one year and nine months old. She presented with chronic cough, tachypnea, cyanosis and failure to thrive since she was one year and three months old. Her condition gradually deteriorated after she was empirically treated. Physical examination showed malnutrition, tachypnea and clubbed-fingers. Her high resolution computed tomography (HRCT) revealed diffused ground-glass opacities, thickened interlobular septum, and multiple subpleural small air-filled lung cysts. The second generation sequencing study identified a novel compound heterozygous mutation (c.1755delC+c.2890G>A) in her ABCA3 gene, which derived respectively from her parents and has not been reported in the database and the literatures mentioned above. Conclusion: c.1755delC+c.2890G>A is a new kind of compound heterozygous mutation in ABCA3, which can cause children's diffuse parenchymal lung disease. Its phenotype is related to its genotype.

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.

A novel heterozygous SOX2 mutation causing anophthalmia/microphthalmia with genital anomalies.

PubMed

Pedace, Lucia; Castori, Marco; Binni, Francesco; Pingi, Alberto; Grammatico, Barbara; Scommegna, Salvatore; Majore, Silvia; Grammatico, Paola

2009-01-01

Anophthalmia/microphthalmia is a rare developmental craniofacial defect, which recognizes a wide range of causes, including chromosomal abnormalities, single-gene mutations as well as environmental factors. Heterozygous mutations in the SOX2 gene are the most common monogenic form of anophthalmia/microphthalmia, as they are reported in up to 10-15% cases. Here, we describe a sporadic patient showing bilateral anophthalmia/microphthalmia and micropenis caused by a novel mutation (c.59_60insGG) in the SOX2 gene. Morphological and endocrinological evaluations excluded any anomaly of the hypothalamus-pituitary axis. Our finding supports the hypothesis that SOX2 is particularly prone to slipped-strand mispairing, which results in a high frequency of point deletions/insertions.

Heterozygous ABCC8 mutations are a cause of MODY.

PubMed

Bowman, P; Flanagan, S E; Edghill, E L; Damhuis, A; Shepherd, M H; Paisey, R; Hattersley, A T; Ellard, S

2012-01-01

The ABCC8 gene encodes the sulfonylurea receptor 1 (SUR1) subunit of the pancreatic beta cell ATP-sensitive potassium (K(ATP)) channel. Inactivating mutations cause congenital hyperinsulinism (CHI) and activating mutations cause transient neonatal diabetes (TNDM) or permanent neonatal diabetes (PNDM) that can usually be treated with sulfonylureas. Sulfonylurea sensitivity is also a feature of HNF1A and HNF4A MODY, but patients referred for genetic testing with clinical features of these types of diabetes do not always have mutations in the HNF1A/4A genes. Our aim was to establish whether mutations in the ABCC8 gene cause MODY that is responsive to sulfonylurea therapy. We sequenced the ABCC8 gene in 85 patients with a BMI <30 kg/m², no family history of neonatal diabetes and who were deemed sensitive to sulfonylureas by the referring clinician or were sulfonylurea-treated. All had tested negative for mutations in the HNF1A and HNF4A genes. ABCC8 mutations were found in seven of the 85 (8%) probands. Four patients were heterozygous for previously reported mutations and four novel mutations, E100K, G214R, Q485R and N1245D, were identified. Only four probands fulfilled MODY criteria, with two diagnosed after 25 years and one patient, who had no family history of diabetes, as a result of a proven de novo mutation. ABCC8 mutations can cause MODY in patients whose clinical features are similar to those with HNF1A/4A MODY. Therefore, sequencing of ABCC8 in addition to the known MODY genes should be considered if such features are present, to facilitate optimal clinical management of these patients.

A Novel Method to Screen for Dominant Negative ATM Mutations in Familial Breast Cancer

DTIC Science & Technology

2005-04-01

carry dominant negative mutation in ATM due to natural variation amongst LCLs. Microarrays have been performed to determine differences in gene expression... genes that are altered in their expression in ATMmutation carriers. The validation of this data in carriers of different ATM mutation indicated that the...heterozygous carriers of T727 1 G mutation display a gene expression phenotype that appears identical to carriers of protein truncating mutations in

Novel compound heterozygous Thyroglobulin mutations c.745+1G>A/c.7036+2T>A associated with congenital goiter and hypothyroidism in a Vietnamese family. Identification of a new cryptic 5' splice site in the exon 6.

PubMed

Citterio, Cintia E; Morales, Cecilia M; Bouhours-Nouet, Natacha; Machiavelli, Gloria A; Bueno, Elena; Gatelais, Frédérique; Coutant, Regis; González-Sarmiento, Rogelio; Rivolta, Carina M; Targovnik, Héctor M

2015-03-15

Several patients were identified with dyshormonogenesis caused by mutations in the thyroglobulin (TG) gene. These defects are inherited in an autosomal recessive manner and affected individuals are either homozygous or compound heterozygous for the mutations. The aim of the present study was to identify new TG mutations in a patient of Vietnamese origin affected by congenital hypothyroidism, goiter and low levels of serum TG. DNA sequencing identified the presence of compound heterozygous mutations in the TG gene: the maternal mutation consists of a novel c.745+1G>A (g.IVS6 + 1G>A), whereas the hypothetical paternal mutation consists of a novel c.7036+2T>A (g.IVS40 + 2T>A). The father was not available for segregation analysis. Ex-vivo splicing assays and subsequent RT-PCR analyses were performed on mRNA isolated from the eukaryotic-cells transfected with normal and mutant expression vectors. Minigene analysis of the c.745+1G>A mutant showed that the exon 6 is skipped during pre-mRNA splicing or partially included by use of a cryptic 5' splice site located to 55 nucleotides upstream of the authentic exon 6/intron 6 junction site. The functional analysis of c.7036+2T>A mutation showed a complete skipping of exon 40. The theoretical consequences of splice site mutations, predicted with the bioinformatics tool NNSplice, Fsplice, SPL, SPLM and MaxEntScan programs were investigated and evaluated in relation with the experimental evidence. These analyses predicted that both mutant alleles would result in the abolition of the authentic splice donor sites. The c.745+1G>A mutation originates two putative truncated proteins of 200 and 1142 amino acids, whereas c.7036+2T>A mutation results in a putative truncated protein of 2277 amino acids. In conclusion, we show that the c.745+1G>A mutation promotes the activation of a new cryptic donor splice site in the exon 6 of the TG gene. The functional consequences of these mutations could be structural changes in the protein

[A clinical and hereditary analysis of novel complex heterozygous KCNJ1 mutation in a Bartter syndrome type Ⅱ patient].

PubMed

Li, X Y; Jiang, Y; Xu, L J; Duan, L; Peng, X Y; Chen, L M; Xia, W B; Xing, X P

2017-10-01

Bartter syndrome (BS) is a hereditary condition transmitted as an autosomal recessive (Bartter type 1 to 4) or dominant trait (Bartter type 5). The disease associates hypokalemic alkalosis with varying degrees of hypercalciuria. Here we presented a case (BS type Ⅱ) of a 17 years old female presented with polyhydramnios, polyuria, nephrocalcinosis and hypokalemia, which was alleviated after treatment with celecoxib and vitamin D(3). DNA sequencing identified compound heterozygous KCNJ 1 gene mutations, c. 931C >T (p.R311W) and c. 445-446insCCTGAACAC (p.V149Afs, 150X), with the latter a novel mutation. Her father and mother were heterozygous carriers of c. 931C >T (p.R311W) and c. 445-446insCCTGAACAC (p.V149Afs, 150X), respectively. In conclusion, this case of BS type Ⅱ is caused by a novel compound heterozygous KCNJ 1 mutation. Further studies are needed to verify the effect of celecoxib in BS patients.

Novel CLCN7 compound heterozygous mutations in intermediate autosomal recessive osteopetrosis.

PubMed

Okamoto, Nana; Kohmoto, Tomohiro; Naruto, Takuya; Masuda, Kiyoshi; Komori, Takahide; Imoto, Issei

2017-01-01

Osteopetrosis is a heritable disorder of the skeleton that is characterized by increased bone density on radiographs caused by defects in osteoclast formation and function. Mutations in >10 genes are identified as causative for this clinically and genetically heterogeneous disease in humans. We report two novel missense variations in a compound heterozygous state in the CLCN7 gene, detected through targeted exome sequencing, in a 15-year-old Japanese female with intermediate autosomal recessive osteopetrosis.

Sector Retinitis Pigmentosa Associated With Novel Compound Heterozygous Mutations of CDH23.

PubMed

Branson, Sara V; McClintic, Jedediah I; Stamper, Tara H; Haldeman-Englert, Chad R; John, Vishak J

2016-02-01

Usher syndrome is an autosomal recessive condition characterized by retinitis pigmentosa (RP) and congenital hearing loss, with or without vestibular dysfunction. Allelic variants of CDH23 cause both Usher syndrome type 1D (USH1D) and a form of nonsyndromic hearing loss (DFNB12). The authors describe here a 34-year-old patient with congenital hearing loss and a new diagnosis of sector RP who was found to have two novel compound heterozygous mutations in CDH23, including one missense (c.8530C > A; p.Pro2844Thr) and one splice-site (c.5820 + 5G > A) mutation. This is the first report of sector RP associated with these types of mutations in CDH23. Copyright 2016, SLACK Incorporated.

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.

Novel compound heterozygous mutations in MYO7A Associated with Usher syndrome 1 in a Chinese family.

PubMed

Gao, Xue; Wang, Guo-Jian; Yuan, Yong-Yi; Xin, Feng; Han, Ming-Yu; Lu, Jing-Qiao; Zhao, Hui; Yu, Fei; Xu, Jin-Cao; Zhang, Mei-Guang; Dong, Jiang; Lin, Xi; Dai, Pu

2014-01-01

Usher syndrome is an autosomal recessive disease characterized by sensorineural hearing loss, age-dependent retinitis pigmentosa (RP), and occasionally vestibular dysfunction. The most severe form is Usher syndrome type 1 (USH1). Mutations in the MYO7A gene are responsible for USH1 and account for 29-55% of USH1 cases. Here, we characterized a Chinese family (no. 7162) with USH1. Combining the targeted capture of 131 known deafness genes, next-generation sequencing, and bioinformatic analysis, we identified two deleterious compound heterozygous mutations in the MYO7A gene: a reported missense mutation c.73G>A (p.G25R) and a novel nonsense mutation c.462C>A (p.C154X). The two compound variants are absent in 219 ethnicity-matched controls, co-segregates with the USH clinical phenotypes, including hearing loss, vestibular dysfunction, and age-dependent penetrance of progressive RP, in family 7162. Therefore, we concluded that the USH1 in this family was caused by compound heterozygous mutations in MYO7A.

A novel truncating mutation in FLNA causes periventricular nodular heterotopia, Ehlers-Danlos-like collagenopathy and macrothrombocytopenia.

PubMed

Ieda, Daisuke; Hori, Ikumi; Nakamura, Yuji; Ohshita, Hironori; Negishi, Yutaka; Shinohara, Tsutomu; Hattori, Ayako; Kato, Takenori; Inukai, Sachiko; Kitamura, Katsumasa; Kawai, Tomoki; Ohara, Osamu; Kunishima, Shinji; Saitoh, Shinji

2018-06-01

Filamin A (FLNA) is located in Xq28, and encodes the actin binding protein, filamin A. A mutation in FLNA is the most common cause of periventricular nodular heterotopia (PVNH), but a clear phenotype-genotype correlation has not been established. Indeed, some patients with a FLNA mutation have recently been shown to additionally have Ehlers-Danlos-like collagenopathy or macrothrombocytopenia. In an attempt to establish a clearer correlation between clinical symptoms and genotype, we have investigated a phenotype that involves thrombocytopenia in a patient with a truncation of the FLNA gene. We present the case of a 4-year-old girl who, at birth, showed a ventral hernia. At 2 months of age, she was diagnosed with patent ductus arteriosus (PDA) and aortic valve regurgitation. At 11 months, she underwent ligation of the PDA. She was also diagnosed with diaphragmatic eventration by a preoperative test. At 19 months, motor developmental delay was noted, and brain MRI revealed bilateral PVNH with mega cisterna magna. Presently, there is no evidence of epilepsy, intellectual disability or motor developmental delay. She has chronic, mild thrombocytopenia, and a platelet count that transiently decreases after viral infection. Dilation of the ascending aorta is progressing gradually. Genetic testing revealed a de novo nonsense heterozygous mutation in FLNA (NM_001456.3: c.1621G > T; p.Glu541Ter). Immunofluorescence staining of a peripheral blood smear showed a lack of filamin A expression in 21.1% of her platelets. These filamin A-negative platelets were slightly larger than her normal platelets. Our data suggests immunofluorescence staining of peripheral blood smears is a convenient diagnostic approach to identify patients with a FLNA mutation, which will facilitate further investigation of the correlation between FLNA mutations and patient phenotype. Copyright © 2018 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

Electroclinical presentation and genotype-phenotype relationships in patients with Unverricht-Lundborg disease carrying compound heterozygous CSTB point and indel mutations.

PubMed

Canafoglia, Laura; Gennaro, Elena; Capovilla, Giuseppe; Gobbi, Giuseppe; Boni, Antonella; Beccaria, Francesca; Viri, Maurizio; Michelucci, Roberto; Agazzi, Pamela; Assereto, Stefania; Coviello, Domenico A; Di Stefano, Maria; Rossi Sebastiano, Davide; Franceschetti, Silvana; Zara, Federico

2012-12-01

Unverricht-Lundborg disease (EPM1A) is frequently due to an unstable expansion of a dodecamer repeat in the CSTB gene, whereas other types of mutations are rare. EPM1A due to homozygous expansion has a rather stereotyped presentation with prominent action myoclonus. We describe eight patients with five different compound heterozygous CSTB point or indel mutations in order to highlight their particular phenotypical presentations and evaluate their genotype-phenotype relationships. We screened CSTB mutations by means of Southern blotting and the sequencing of the genomic DNA of each proband. CSTB messenger RNA (mRNA) aberrations were characterized by sequencing the complementary DNA (cDNA) of lymphoblastoid cells, and assessing the protein concentrations in the lymphoblasts. The patient evaluations included the use of a simplified myoclonus severity rating scale, multiple neurophysiologic tests, and electroencephalography (EEG)-polygraphic recordings. To highlight the particular clinical features and disease time-course in compound heterozygous patients, we compared some of their characteristics with those observed in a series of 40 patients carrying the common homozygous expansion mutation observed at the C. Besta Foundation, Milan, Italy. The eight compound heterozygous patients belong to six EPM1A families (out of 52; 11.5%) diagnosed at the Laboratory of Genetics of the Galliera Hospitals in Genoa, Italy. They segregated five different heterozygous point or indel mutations in association with the common dodecamer expansion. Four patients from three families had previously reported CSTB mutations (c.67-1G>C and c.168+1_18del); one had a novel nonsense mutation at the first exon (c.133C>T) leading to a premature stop codon predicting a short peptide; the other three patients from two families had a complex novel indel mutation involving the donor splice site of intron 2 (c.168+2_169+21delinsAA) and leading to an aberrant transcript with a partially retained intron

A novel RLBP1 gene geographical area-related mutation present in a young patient with retinitis punctata albescens.

PubMed

Scimone, Concetta; Donato, Luigi; Esposito, Teresa; Rinaldi, Carmela; D'Angelo, Rosalia; Sidoti, Antonina

2017-08-01

Autosomal recessive forms of retinitis punctata albescens (RPA) have been described. RPA is characterized by progressive retinal degeneration due to alteration in visual cycle and consequent deposit of photopigments in retinal pigment epithelium. Five loci have been linked to RPA onset. Among these, the retinaldehyde-binding protein 1 gene, RLBP1, is the most frequently involved and several founder mutations were reported. We report results of a genetic molecular investigation performed on a large Sicilian family in which appears a young woman with RPA. The proband is in homozygous condition for a novel RLBP1 single-pair deletion, and her healthy parents, both heterozygous, are not consanguineous. Thenovelc.398delC (p.P133Qfs*258) involves the exon 6 and leads to a premature stop codon, resulting in a truncated protein entirely missing of CRAL-TRIO lipid-binding domain. Pedigree analysis showed other non-consanguineous relatives heterozygous for the same mutation in the family. Extension of mutation research in the native town of the proband revealed its presence also in healthy subjects, in a heterozygous condition. A novel RLBP1 truncating mutation was detected in a young girl affected by RPA. Although her parents are not consanguineous, the mutation was observed in a homozygous condition. Being them native of the same small Sicilian town of Fiumedinisi, the hypothesis of a geographical area-related mutation was assessed and confirmed.

Novel CLCN7 compound heterozygous mutations in intermediate autosomal recessive osteopetrosis

PubMed Central

Okamoto, Nana; Kohmoto, Tomohiro; Naruto, Takuya; Masuda, Kiyoshi; Komori, Takahide; Imoto, Issei

2017-01-01

Osteopetrosis is a heritable disorder of the skeleton that is characterized by increased bone density on radiographs caused by defects in osteoclast formation and function. Mutations in >10 genes are identified as causative for this clinically and genetically heterogeneous disease in humans. We report two novel missense variations in a compound heterozygous state in the CLCN7 gene, detected through targeted exome sequencing, in a 15-year-old Japanese female with intermediate autosomal recessive osteopetrosis. PMID:28819563

A novel mutation in the MITF may be digenic with GJB2 mutations in a large Chinese family of Waardenburg syndrome type II.

PubMed

Yan, Xukun; Zhang, Tianyu; Wang, Zhengmin; Jiang, Yi; Chen, Yan; Wang, Hongyan; Ma, Duan; Wang, Lei; Li, Huawei

2011-12-20

Waardenburg syndrome type II (WS2) is associated with syndromic deafness. A subset of WS2, WS2A, accounting for approximately 15% of patients, is attributed to mutations in the microphthalmia-associated transcription factor (MITF) gene. We examined the genetic basis of WS2 in a large Chinese family. All 9 exons of the MITF gene, the single coding exon (exon 2) of the most common hereditary deafness gene GJB2 and the mitochondrial DNA (mtDNA) 12S rRNA were sequenced. A novel heterozygous mutation c.[742_743delAAinsT;746_747delCA] in exon 8 of the MITF gene co-segregates with WS2 in the family. The MITF mutation results in a premature termination codon and a truncated MITF protein with only 247 of the 419 wild type amino acids. The deaf proband had this MITF gene heterozygous mutation as well as a c.[109G>A]+[235delC] compound heterozygous pathogenic mutation in the GJB2 gene. No pathogenic mutation was found in mtDNA 12S rRNA in this family. Thus, a novel compound heterozygous mutation, c.[742_743delAAinsT;746_747delCA] in MITF exon 8 was the key genetic reason for WS2 in this family, and a digenic effect of MITF and GJB2 genes may contribute to deafness of the proband. Copyright © 2011. Published by Elsevier Ltd.

A novel heterozygous mutation in the Birt-Hogg-Dubé Syndrome.

PubMed

Gómez Rivas, Juan; Carrión, Diego M; Alonso Y Gregorio, Sergio; Álvarez-Maestro, Mario; Tabernero Gómez, Ángel; Cisneros Ledo, Jesus

2017-09-01

Our aim is to present a novel mutation of the Birt-Hogg-Dubé Syndrome. We present a case report of a 70-year-old male with three solid nodulary lesions of 4, 2.6, and 3 cm each in the right kidney, and two lesions of 1.5 and 1.3 cm in the left kidney. Needle biopsy was performed. The pathological analysis of right kidney lesions revealed a renal tumor suggestive of chromophobe renal cell carcinoma and medullar tumor with zones that suggested oncocytosis. Genetic test results were positive for a novel heterozygous mutation c.1198G>A; p.V400I in exon 11 of the FLCN gene. In patients presenting with bilateral multifocal renal tumors of oncocytic hybrid histology, Birt- Hogg-Dubé syndrome should be the first diagnosis in mind. The mutation found in this patient has not been previously described in the literature in the context of BHD.

Double heterozygous mutations of MITF and PAX3 result in Waardenburg syndrome with increased penetrance in pigmentary defects.

PubMed

Yang, T; Li, X; Huang, Q; Li, L; Chai, Y; Sun, L; Wang, X; Zhu, Y; Wang, Z; Huang, Z; Li, Y; Wu, H

2013-01-01

Waardenburg syndrome (WS) is characterized by sensorineural hearing loss and pigmentary defects of the hair, skin, and iris. Heterozygous mutations of MITF and its transactivator gene PAX3 are associated with Waardenburg syndrome type II (WS2) and type I (WS1), respectively. Most patients with MITF or PAX3 mutations, however, show variable penetrance of WS-associated phenotypes even within families segregating the same mutation, possibly mediated by genetic background or specific modifiers. In this study, we reported a rare Waardenburg syndrome simplex family in which a pair of WS parents gave birth to a child with double heterozygous mutations of MITF and PAX3. Compared to his parents who carried a single mutation in either MITF or PAX3, this child showed increased penetrance of pigmentary defects including white forelock, white eyebrows and eyelashes, and patchy facial depigmentation. This observation suggested that the expression level of MITF is closely correlated to the penetrance of WS, and variants in transcription regulator genes of MITF may modify the relevant clinical phenotypes. © 2012 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.

A novel truncation mutation in CRYBB1 associated with autosomal dominant congenital cataract with nystagmus.

PubMed

Rao, Yan; Dong, Sufang; Li, Zuhua; Yang, Guohua; Peng, Chunyan; Yan, Ming; Zheng, Fang

2017-01-01

To identify the potential candidate genes for a large Chinese family with autosomal dominant congenital cataract (ADCC) and nystagmus, and investigate the possible molecular mechanism underlying the role of the candidate genes in cataractogenesis. We combined the linkage analysis and direct sequencing for the candidate genes in the linkage regions to identify the causative mutation. The molecular and bio-functional properties of the proteins encoded by the candidate genes was further explored with biophysical and biochemical studies of the recombinant wild-type and mutant proteins. We identified a c. C749T (p.Q227X) transversion in exon 6 of CRYBB1 , a cataract-causative gene. This nonsense mutation changes a phylogenetically conserved glutamine to a stop codon and is predicted to truncate the C-terminus of the wild-type protein by 26 amino acids. Comparison of the biophysical and biochemical properties of the recombinant full-length and truncated βB1-crystallins revealed that the mutation led to the insolubility and the phase separation phenomenon of the truncated protein with a changed conformation. Meanwhile, the thermal stability of the truncated βB1-crystallin was significantly decreased, and the mutation diminished the chaperoning ability of αA-crystallin with the mutant under heating stress. Our findings highlight the importance of the C-terminus in βB1-crystallin in maintaining the crystalline function and stability, and provide a novel insight into the molecular mechanism underlying the pathogenesis of human autosomal dominant congenital cataract.

Rapid detection of translation-terminating mutations at the adenomatous polyposis coli (APC) gene by direct protein truncation test

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

Van Der Luut, R.; Khan, P.M.; Van Leeuwen, C.

Familial adenomatous polyposis (FAP) is usually associated with protein truncating mutations in the adenomatous polyposis coli (APC) gene. The APC mutations are known to play a major role in colorectal carcinogensis. For the identification of protein truncating mutations of the APC gene, the authors developed a rapid, sensitive, and direct screening procedure. The technique is based on the in vitro transcription and translation of the genomic PCR products and is called the protein truncation test. Samples of DNA from individual FAP patients, members of a FAP family, colorectal tumors, and colorectal tumor-derived cell lines were used to show the effectivenessmore » of this method. 9 refs., 2 figs.« less

Dental Abnormalities Caused by Novel Compound Heterozygous CTSK Mutations.

PubMed

Xue, Y; Wang, L; Xia, D; Li, Q; Gao, S; Dong, M; Cai, T; Shi, S; He, L; Hu, K; Mao, T; Duan, X

2015-05-01

Cathepsin K (CTSK) is an important protease responsible for degrading type I collagen, osteopontin, and other bone matrix proteins. The mutations in the CTSK gene can cause pycnodysostosis (OMIM 265800), a rare autosomal recessive bone dysplasia. Patients with pycnodysostosis have been reported to present specific dental abnormalities; however, whether these dental abnormalities are related to dysfunctional CTSK has never been reported. Here we investigated the histologic changes of cementum and alveolar bone in a pycnodysostosis patient, caused by novel compound heterozygous mutations in the CTSK gene (c.87 G>A p.W29X and c.848 A>G p.Y283C). The most impressive manifestations in tooth were extensive periradicular high-density clumps with unclear periodontal space by orthopantomography examination and micro-computed tomography scanning analysis. Hematoxylin/eosin and toluidine blue staining and atomic force microscopy analysis showed that the cementum became significantly thickened, softened, and full of cementocytes. The disorganized bone structure was the main character of alveolar bone. The p.W29X mutation may represent the loss-of-function allele with an earlier termination codon in the precursor CTSK polypeptide. Residue Y283 is highly conserved among papain-like cysteine proteases. Three-dimensional structure modeling analysis found that the loss of the hydroxybenzene residue in the Y283C mutation would interrupt the hydrogen network and possibly affect the self-cleavage of the CTSK enzyme. Furthermore, p.Y283C mutation did not affect the mRNA and protein levels of overexpressed CTSK in COS-7 system but did reduce CTSK enzyme activity. In conclusion, the histologic and ultrastructural changes of cementum and alveolar bone might be affected by CTSK mutation via reduction of its enzyme activity (clinical trial registration: ChiCTR-TNC-10000876). © International & American Associations for Dental Research 2015.

Prospective study on the potential of RAAS blockade to halt renal disease in Alport syndrome patients with heterozygous mutations.

PubMed

Stock, Johanna; Kuenanz, Johannes; Glonke, Niklas; Sonntag, Joseph; Frese, Jenny; Tönshoff, Burkhard; Höcker, Britta; Hoppe, Bernd; Feldkötter, Markus; Pape, Lars; Lerch, Christian; Wygoda, Simone; Weber, Manfred; Müller, Gerhard-Anton; Gross, Oliver

2017-01-01

Patients with autosomal or X-linked Alport syndrome (AS) with heterozygous mutations in type IV collagen genes have a 1-20 % risk of progressing to end-stage renal disease during their lifetime. We evaluated the long-term renal outcome of patients at risk of progressive disease (chronic kidney disease stages 1-4) with/without nephroprotective therapy. This was a prospective, non-interventional, observational study which included data from a 4-year follow-up of AS patients with heterozygous mutations whose datasets had been included in an analysis of the 2010 database of the European Alport Registry. Using Kaplan-Meier estimates and logrank tests, we prospectively analyzed the updated datasets of 52 of these patients and 13 new datasets (patients added to the Registry after 2011). The effects of therapy, extrarenal symptoms and inheritance pattern on renal outcome were analyzed. The mean prospective follow-up was 46 ± 10 months, and the mean time on therapy was 8.4 ± 4.4 (median 7; range 2-18) years. The time from the appearance of the first symptom to diagnosis was 8.1 ± 14.2 (range 0-52) years. At the time of starting therapy, 5.4 % of patients had an estimated glomerular filtration rate of <60 ml/min, 67.6 % had proteinuria and 27.0 % had microalbuminuria. Therapeutic strategies included angiotensin-converting enzymer inhibitors (97.1 %), angiotensin receptor antagonists (1 patient), dual therapy (11.8 %) and statins (8.8 %). Among patients included in the prospective dataset, prevented the need for dialysis. Among new patients, no patient at risk for renal failure progressed to the next disease stage after 4 years follow-up; three patients even regressed to a lower stage during therapy. Treatment with blockers of the renin-angiotensin-aldosterone system prevents progressive renal failure in AS patients with heterozygous mutations in the genes causing AS. Considerable numbers of aging AS patients on dialysis may have heterozygous mutations in these

Rad52 function prevents chromosome loss and truncation in Candida albicans

PubMed Central

Andaluz, E.; Bellido, A.; Gómez-Raja, J.; Selmecki, A.; Bouchonville, K.; Calderone, R.; Berman, J.; Larriba, G.

2013-01-01

Summary RAD52 is required for almost all recombination events in S. cerevisiae. We took advantage of the heterozygosity of HIS4 in the C. albicans SC5314 lineage to study the role of Rad52 in the genomic stability of this important fungal pathogen. The rate of loss of heterozygosity (LOH) at HIS4 in rad52-ΔΔ strains was ~10−3, at least 100-fold higher than in Rad52+ strains. LOH of whole chromosome 4 or truncation of the homologue that carries the functional HIS4 allele was detected in all 80 rad52-ΔΔ His auxotrophs (GLH –GL lab His−) obtained from six independent experiments. Isolates that had undergone whole chromosome LOH, presumably due to loss of chromosome, carried two copies of the remaining homolog. Isolates with truncations carried centric fragments of broken chromosomes healed by de novo telomere addition. GLH strains exhibited variable degrees of LOH across the genome, including two strains that became homozygous for all the heterozygous markers tested. In addition, GLH strains exhibited increased chromosomal instability (CIN), which was abolished by reintroduction of RAD52. CIN of GLH isolates is reminiscent of genomic alterations leading to cancer in human cells, and support the mutator hypothesis in which a mutator mutation or CIN phenotype facilitate more mutations/aneuploidies. PMID:21272099

Macrosomia and Hyperinsulinaemic Hypoglycaemia in Patients with Heterozygous Mutations in the HNF4A Gene

PubMed Central

Barrett, Timothy; Stals, Karen; Shield, Julian P; Ellard, Sian; Ferrer, Jorge; Hattersley, Andrew T

2007-01-01

Background Macrosomia is associated with considerable neonatal and maternal morbidity. Factors that predict macrosomia are poorly understood. The increased rate of macrosomia in the offspring of pregnant women with diabetes and in congenital hyperinsulinaemia is mediated by increased foetal insulin secretion. We assessed the in utero and neonatal role of two key regulators of pancreatic insulin secretion by studying birthweight and the incidence of neonatal hypoglycaemia in patients with heterozygous mutations in the maturity-onset diabetes of the young (MODY) genes HNF4A (encoding HNF-4α) and HNF1A/TCF1 (encoding HNF-1α), and the effect of pancreatic deletion of Hnf4a on foetal and neonatal insulin secretion in mice. Methods and Findings We examined birthweight and hypoglycaemia in 108 patients from families with diabetes due to HNF4A mutations, and 134 patients from families with HNF1A mutations. Birthweight was increased by a median of 790 g in HNF4A-mutation carriers compared to non-mutation family members (p < 0.001); 56% (30/54) of HNF4A-mutation carriers were macrosomic compared with 13% (7/54) of non-mutation family members (p < 0.001). Transient hypoglycaemia was reported in 8/54 infants with heterozygous HNF4A mutations, but was reported in none of 54 non-mutation carriers (p = 0.003). There was documented hyperinsulinaemia in three cases. Birthweight and prevalence of neonatal hypoglycaemia were not increased in HNF1A-mutation carriers. Mice with pancreatic β-cell deletion of Hnf4a had hyperinsulinaemia in utero and hyperinsulinaemic hypoglycaemia at birth. Conclusions HNF4A mutations are associated with a considerable increase in birthweight and macrosomia, and are a novel cause of neonatal hypoglycaemia. This study establishes a key role for HNF4A in determining foetal birthweight, and uncovers an unanticipated feature of the natural history of HNF4A-deficient diabetes, with hyperinsulinaemia at birth evolving to decreased insulin secretion and

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.

Novel compound heterozygous mutations in CNGA1in a Chinese family affected with autosomal recessive retinitis pigmentosa by targeted sequencing.

PubMed

Wang, Min; Gan, Dekang; Huang, Xin; Xu, Gezhi

2016-07-08

About 37 genes have been reported to be involved in autosomal recessive retinitis pigmentosa, a hereditary retinal disease. However, causative genes remain unclear in a lot of cases. Two sibs of a Chinese family with ocular disease were diagnosed in Eye and ENT Hospital of Fudan University. Targeted sequencing performed on proband to screen pathogenic mutations. PCR combined Sanger sequencing then performed on eight family members including two affected and six unaffected individuals to determine whether mutations cosegregate with disease. Two affected members exhibited clinical features that fit the criteria of autosomal recessive retinitis pigmentosa. Two heterozygous mutations (NM000087, p.Y82X and p.L89fs) in CNGA1 were revealed on proband. Affected members were compound heterozygotes for the two mutations whereas unaffected members either had no mutation or were heterozygote carriers for only one of the two mutations. That is, these mutations cosegregate with autosomal recessive retinitis pigmentosa. Compound heterozygous mutations (NM000087, p.Y82X and p.L89fs) in exon 6 of CNGA1are pathogenic mutations in this Chinese family. Of which, p.Y82X is firstly reported in patient with autosomal recessive retinitis pigmentosa.

Cancer-associated ASXL1 mutations may act as gain-of-function mutations of the ASXL1–BAP1 complex

PubMed Central

Balasubramani, Anand; Larjo, Antti; Bassein, Jed A.; Chang, Xing; Hastie, Ryan B.; Togher, Susan M.; Lähdesmäki, Harri; Rao, Anjana

2015-01-01

ASXL1 is the obligate regulatory subunit of a deubiquitinase complex whose catalytic subunit is BAP1. Heterozygous mutations of ASXL1 that result in premature truncations are frequent in myeloid leukemias and Bohring–Opitz syndrome. Here we demonstrate that ASXL1 truncations confer enhanced activity on the ASXL1–BAP1 complex. Stable expression of truncated, hyperactive ASXL1–BAP1 complexes in a haematopoietic precursor cell line results in global erasure of H2AK119Ub, striking depletion of H3K27me3, selective upregulation of a subset of genes whose promoters are marked by both H2AK119Ub and H3K4me3, and spontaneous differentiation to the mast cell lineage. These outcomes require the catalytic activity of BAP1, indicating that they are downstream consequences of H2AK119Ub erasure. In bone marrow precursors, expression of truncated ASXL1–BAP1 complex cooperates with TET2 loss-of-function to increase differentiation to the myeloid lineage in vivo. Our data raise the possibility that ASXL1 truncation mutations confer gain-of-function on the ASXL–BAP1 complex. PMID:26095772

Lifetime exercise intolerance with lactic acidosis as key manifestation of novel compound heterozygous ACAD9 mutations causing complex I deficiency.

PubMed

Schrank, Bertold; Schoser, Benedikt; Klopstock, Thomas; Schneiderat, Peter; Horvath, Rita; Abicht, Angela; Holinski-Feder, Elke; Augustis, Sarunas

2017-05-01

We report a 36-year-old female having lifetime exercise intolerance and lactic acidosis with nausea associated with novel compound heterozygous Acyl-CoA dehydrogenase 9 gene (ACAD9) mutations (p.Ala390Thr and p.Arg518Cys). ACAD9 is an assembly factor for the mitochondrial respiratory chain complex I. ACAD9 mutations are recognized as frequent causes of complex I deficiency. Our patient presented with exercise intolerance, rapid fatigue, and nausea since early childhood. Mild physical workload provoked the occurrence of nausea and vomiting repeatedly. Her neurological examination, laboratory findings and muscle biopsy demonstrated no abnormalities. A bicycle spiroergometry provoked significant lactic acidosis during and following exercise pointing towards a mitochondrial disorder. Subsequently, the analysis of respiratory chain enzyme activities in muscle revealed severe isolated complex I deficiency. Candidate gene sequencing revealed two novel heterozygous ACAD9 mutations. This patient report expands the mutational and phenotypic spectrum of diseases associated with mutations in ACAD9. Copyright © 2017 Elsevier B.V. All rights reserved.

A new compound heterozygous frameshift mutation in the type II 3{beta}-hydroxysteroid dehydrogenase 3{beta}-HSD gene causes salt-wasting 3{beta}-HSD deficiency congenital adrenal hyperplasia

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

Zhang, L.; Sakkal-Alkaddour, S.; Chang, Ying T.

1996-01-01

We report a new compound heterozygous frameshift mutation in the type II 3{Beta}-hydroxysteroid dehydrogenase (3{beta}-HSD) gene in a Pakistanian female child with the salt-wasting form of 3{Beta}-HSD deficiency congenital adrenal hyperplasia. The etiology for her congenital adrenal hyperplasia was not defined. Although the family history suggested possible 3{beta}-HSd deficiency disorder, suppressed adrenal function caused by excess glucocorticoid therapy in this child at 7 yr of age did not allow hormonal diagnosis. To confirm 3{beta}-HSD deficiency, we sequenced the type II 3{beta}-HSD gene in the patient, her family, and the parents of her deceased paternal cousins. The type II 3{beta}-HSD genemore » region of a putative promotor, exons I, II, III, and IV, and exon-intron boundaries were amplified by PCR and sequenced in all subjects. The DNA sequence of the child revealed a single nucleotide deletion at codon 318 [ACA(Thr){r_arrow}AA] in exon IV in one allele, and two nucleotide deletions at codon 273 [AAA(Lys){r_arrow}A] in exon IV in the other allele. The remaining gene sequences were normal. The codon 318 mutation was found in one allele from the father, brother, and parents of the deceased paternal cousins. The codon 273 mutation was found in one allele of the mother and a sister. These findings confirmed inherited 3{beta}-HSD deficiency in the child caused by the compound heterozygous type II 3{beta}-HSD gene mutation. Both codons at codons 279 and 367, respectively, are predicted to result in an altered and truncated type II 3{beta}-HSD protein, thereby causing salt-wasting 3{beta}-HSD deficiency in the patient. 21 refs., 2 figs., 1 tab.« less

A Japanese family with nonautoimmune hyperthyroidism caused by a novel heterozygous thyrotropin receptor gene mutation.

PubMed

Nakamura, Akie; Morikawa, Shuntaro; Aoyagi, Hayato; Ishizu, Katsura; Tajima, Toshihiro

2014-06-01

Hyperthyroidism caused by activating mutations of the thyrotropin receptor gene (TSHR) is rare in the pediatric population. We found a Japanese family with hyperthyroidism without autoantibody. DNA sequence analysis of TSHR was undertaken in this family. The functional consequences for the Gs-adenylyl cyclase and Gq/11-phospholipase C signaling pathways and cell surface expression of receptors were determined in vitro using transiently transfected human embryonic kidney 293 cells. We identified a heterozygous mutation (M453R) in exon 10 of TSHR. In this family, this mutation was found in all individuals who exhibited hyperthyroidism. The results showed that this mutation resulted in constitutive activation of the Gs-adenylyl cyclase system. However, this mutation also caused a reduction in the activation capacity of the Gq/11-phospholipase C pathway, compared with the wild type. We demonstrate that the M453R mutation is the cause of nonautoimmune hyperthyroidism.

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/

Novel compound heterozygous mutations in MYO7A in a Chinese family with Usher syndrome type 1

PubMed Central

Liu, Fei; Li, Pengcheng; Liu, Ying; Li, Weirong; Wong, Fulton; Du, Rong; Wang, Lei; Li, Chang; Jiang, Fagang; Tang, Zhaohui

2013-01-01

Purpose To identify the disease-causing mutation(s) in a Chinese family with autosomal recessive Usher syndrome type 1 (USH1). Methods An ophthalmic examination and an audiometric test were conducted to ascertain the phenotype of two affected siblings. The microsatellite marker D11S937, which is close to the candidate gene MYO7A (USH1B locus), was selected for genotyping. From the DNA of the proband, all coding exons and exon-intron boundaries of MYO7A were sequenced to identify the disease-causing mutation(s). Restriction fragment length polymorphism (RFLP) analysis was performed to exclude the alternative conclusion that the mutations are non-pathogenic rare polymorphisms. Results Based on severe hearing impairment, unintelligible speech, and retinitis pigmentosa, a clinical diagnosis of Usher syndrome type 1 was made. The genotyping results did not exclude the USH1B locus, which suggested that the MYO7A gene was likely the gene associated with the disease-causing mutation(s) in the family. With direct DNA sequencing of MYO7A, two novel compound heterozygous mutations (c.3742G>A and c.6051+1G>A) of MYO7A were identified in the proband. DNA sequence analysis and RFLP analysis of other family members showed that the mutations cosegregated with the disease. Unaffected members, including the parents, uncle, and sister of the proband, carry only one of the two mutations. The mutations were not present in the controls (100 normal Chinese subjects=200 chromosomes) according to the RFLP analysis. Conclusions In this study, we identified two novel mutations, c.3742G>A (p.E1248K) and c.6051+1G>A (donor splice site mutation in intron 44), of MYO7A in a Chinese non-consanguineous family with USH1. The mutations cosegregated with the disease and most likely cause the phenotype in the two affected siblings who carry these mutations compound heterozygously. Our finding expands the mutational spectrum of MYO7A. PMID:23559863

Novel compound heterozygous mutations in MYO7A in a Chinese family with Usher syndrome type 1.

PubMed

Liu, Fei; Li, Pengcheng; Liu, Ying; Li, Weirong; Wong, Fulton; Du, Rong; Wang, Lei; Li, Chang; Jiang, Fagang; Tang, Zhaohui; Liu, Mugen

2013-01-01

To identify the disease-causing mutation(s) in a Chinese family with autosomal recessive Usher syndrome type 1 (USH1). An ophthalmic examination and an audiometric test were conducted to ascertain the phenotype of two affected siblings. The microsatellite marker D11S937, which is close to the candidate gene MYO7A (USH1B locus), was selected for genotyping. From the DNA of the proband, all coding exons and exon-intron boundaries of MYO7A were sequenced to identify the disease-causing mutation(s). Restriction fragment length polymorphism (RFLP) analysis was performed to exclude the alternative conclusion that the mutations are non-pathogenic rare polymorphisms. Based on severe hearing impairment, unintelligible speech, and retinitis pigmentosa, a clinical diagnosis of Usher syndrome type 1 was made. The genotyping results did not exclude the USH1B locus, which suggested that the MYO7A gene was likely the gene associated with the disease-causing mutation(s) in the family. With direct DNA sequencing of MYO7A, two novel compound heterozygous mutations (c.3742G>A and c.6051+1G>A) of MYO7A were identified in the proband. DNA sequence analysis and RFLP analysis of other family members showed that the mutations cosegregated with the disease. Unaffected members, including the parents, uncle, and sister of the proband, carry only one of the two mutations. The mutations were not present in the controls (100 normal Chinese subjects=200 chromosomes) according to the RFLP analysis. In this study, we identified two novel mutations, c.3742G>A (p.E1248K) and c.6051+1G>A (donor splice site mutation in intron 44), of MYO7A in a Chinese non-consanguineous family with USH1. The mutations cosegregated with the disease and most likely cause the phenotype in the two affected siblings who carry these mutations compound heterozygously. Our finding expands the mutational spectrum of MYO7A.

Mutational analysis of AGXT in two Chinese families with primary hyperoxaluria type 1

PubMed Central

2014-01-01

Background Primary hyperoxaluria type 1 is a rare autosomal recessive disease of glyoxylate metabolism caused by a defect in the liver-specific peroxisomal enzyme alanine:glyoxylate aminotransferase (AGT) that leads to hyperoxaluria, recurrent urolithiasis, and nephrocalcinosis. Methods Two unrelated patients with recurrent urolithiasis, along with members of their families, exhibited mutations in the AGXT gene by PCR direct sequencing. Results Two heterozygous mutations that predict truncated proteins, p.S81X and p.S275delinsRAfs, were identified in one patient. The p.S81X mutation is novel. Two heterozygous missense mutations, p.M1T and p.I202N, were detected in another patient but were not identified in her sibling. These four mutations were confirmed to be of paternal and maternal origin. Conclusions These are the first cases of primary hyperoxaluria type 1 to be diagnosed by clinical manifestations and AGXT gene mutations in mainland China. The novel p.S81X and p.I202N mutations detected in our study extend the spectrum of known AGXT gene mutations. PMID:24934730

Mutational analysis of AGXT in two Chinese families with primary hyperoxaluria type 1.

PubMed

Li, Guo-min; Xu, Hong; Shen, Qian; Gong, Yi-nv; Fang, Xiao-yan; Sun, Li; Liu, Hai-mei; An, Yu

2014-06-17

Primary hyperoxaluria type 1 is a rare autosomal recessive disease of glyoxylate metabolism caused by a defect in the liver-specific peroxisomal enzyme alanine:glyoxylate aminotransferase (AGT) that leads to hyperoxaluria, recurrent urolithiasis, and nephrocalcinosis. Two unrelated patients with recurrent urolithiasis, along with members of their families, exhibited mutations in the AGXT gene by PCR direct sequencing. Two heterozygous mutations that predict truncated proteins, p.S81X and p.S275delinsRAfs, were identified in one patient. The p.S81X mutation is novel. Two heterozygous missense mutations, p.M1T and p.I202N, were detected in another patient but were not identified in her sibling. These four mutations were confirmed to be of paternal and maternal origin. These are the first cases of primary hyperoxaluria type 1 to be diagnosed by clinical manifestations and AGXT gene mutations in mainland China. The novel p.S81X and p.I202N mutations detected in our study extend the spectrum of known AGXT gene mutations.

Compound heterozygous TYK2 mutations underlie primary immunodeficiency with T-cell lymphopenia.

PubMed

Nemoto, Michiko; Hattori, Hiroyoshi; Maeda, Naoko; Akita, Nobuhiro; Muramatsu, Hideki; Moritani, Suzuko; Kawasaki, Tomonori; Maejima, Masami; Ode, Hirotaka; Hachiya, Atsuko; Sugiura, Wataru; Yokomaku, Yoshiyuki; Horibe, Keizo; Iwatani, Yasumasa

2018-05-03

Complete tyrosine kinase 2 (TYK2) deficiency has been previously described in patients with primary immunodeficiency diseases. The patients were infected with various pathogens, including mycobacteria and/or viruses, and one of the patients developed hyper-IgE syndrome. A detailed immunological investigation of these patients revealed impaired responses to type I IFN, IL-10, IL-12 and IL-23, which are associated with increased susceptibility to mycobacterial and/or viral infections. Herein, we report a recessive partial TYK2 deficiency in two siblings who presented with T-cell lymphopenia characterized by low naïve CD4 + T-cell counts and who developed Epstein-Barr virus (EBV)-associated B-cell lymphoma. Targeted exome-sequencing of the siblings' genomes demonstrated that both patients carried novel compound heterozygous mutations (c.209_212delGCTT/c.691C > T, p.Cys70Serfs*21/p.Arg231Trp) in the TYK2. The TYK2 protein levels were reduced by 35% in the T cells of the patient. Unlike the response under complete TYK2 deficiency, the patient's T cells responded normally to type I IFN, IL-6, IL-10 and IL-12, whereas the cells displayed an impaired response to IL-23. Furthermore, the level of STAT1 was low in the cells of the patient. These studies reveal a new clinical entity of a primary immunodeficiency with T-cell lymphopenia that is associated with compound heterozygous TYK2 mutations in the patients.

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.

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

Compound heterozygous mutations (p.Leu13Pro and p.Tyr294*) associated with factor VII deficiency cause impaired secretion through ineffective translocation and extensive intracellular degradation of factor VII.

PubMed

Suzuki, Keijiro; Sugawara, Takeshi; Ishida, Yoji; Suwabe, Akira

2013-02-01

Congenital coagulation factor VII (FVII) deficiency is a rare coagulation disease. We investigated the molecular mechanisms of this FVII deficiency in a patient with compound heterozygous mutations. A 22-year-old Japanese female was diagnosed with asymptomatic FVII deficiency. The FVII activity and antigen were greatly reduced (activity, 13.0%; antigen, 10.8%). We analyzed the F7 gene of this patient and characterized mutant FVII proteins using in vitro expression studies. Sequence analysis revealed that the patient was compound heterozygous with a point mutation (p.Leu13Pro) in the central hydrophobic core of the signal peptides and a novel non-sense mutation (p.Tyr294*) in the catalytic domain. Expression studies revealed that mutant FVII with p.Leu13Pro (FVII13P) showed less accumulation in the cells (17.5%) and less secretion into the medium (64.8%) than wild type showed. Truncated FVII resulting from p.Tyr294* (FVII294X) was also decreased in the cells (32.0%), but was not secreted into the medium. Pulse-chase experiments revealed that both mutants were extensively degraded intracellularly compared to wild type. The majority of FVII13P cannot translocate into endoplasmic reticulum (ER). However, a small amount of FVII13P was processed normally with post-translational modifications and was secreted into the medium. The fact that FVII294X was observed only in ER suggests that it is retained in ER. Proteasome apparently plays a central role in these degradations. These findings demonstrate that both mutant FVIIs impaired secretion through ineffective translocation to and retention in ER with extensive intracellular degradation, resulting in an insufficient phenotype. Copyright © 2012 Elsevier Ltd. All rights reserved.

Clinical Phenotype in a Toddler with a Novel Heterozygous Mutation of the Vitamin D Receptor.

PubMed

Brar, Preneet Cheema; Dingle, Elena; Pappas, John; Raisingani, Manish

2017-01-01

We present the clinical phenotype of a toddler who presented with vitamin D-resistant rickets, with one of the highest initial levels of alkaline phosphatase and parathyroid hormone (PTH) levels reported in the literature. The toddler had novel compound heterozygous mutations in the ligand-binding site of the vitamin D receptor and had an excellent response to calcitriol (1,25(OH)2D).

PPM1D Mosaic Truncating Variants in Ovarian Cancer Cases May Be Treatment-Related Somatic Mutations

PubMed Central

Pharoah, Paul D. P.; Song, Honglin; Dicks, Ed; Intermaggio, Maria P.; Harrington, Patricia; Baynes, Caroline; Alsop, Kathryn; Bogdanova, Natalia; Cicek, Mine S.; Cunningham, Julie M.; Fridley, Brooke L.; Gentry-Maharaj, Aleksandra; Hillemanns, Peter; Lele, Shashi; Lester, Jenny; McGuire, Valerie; Moysich, Kirsten B.; Poblete, Samantha; Sieh, Weiva; Sucheston-Campbell, Lara; Widschwendter, Martin; Whittemore, Alice S.; Dörk, Thilo; Menon, Usha; Odunsi, Kunle; Goode, Ellen L.; Karlan, Beth Y.; Bowtell, David D.; Gayther, Simon A.; Ramus, Susan J.

2016-01-01

Mosaic truncating mutations in the protein phosphatase, Mg2+/Mn2+-dependent, 1D (PPM1D) gene have recently been reported with a statistically significantly greater frequency in lymphocyte DNA from ovarian cancer case patients compared with unaffected control patients. Using massively parallel sequencing (MPS) we identified truncating PPM1D mutations in 12 of 3236 epithelial ovarian cancer (EOC) case patients (0.37%) but in only one of 3431 unaffected control patients (0.03%) (P = .001). All statistical tests were two-sided. A combination of Sanger sequencing, pyrosequencing, and MPS data suggested that 12 of the 13 mutations were mosaic. All mutations were identified in post-chemotherapy treatment blood samples from case patients (n = 1827) (average 1234 days post-treatment in carriers) rather than from cases collected pretreatment (less than 14 days after diagnosis, n = 1384) (P = .002). These data suggest that PPM1D variants in EOC cases are primarily somatic mosaic mutations caused by treatment and are not associated with germline predisposition to EOC. PMID:26823519

Targeted next-generation sequencing reveals that a compound heterozygous mutation in phosphodiesterase 6a gene leads to retinitis pigmentosa in a Chinese family.

PubMed

Zhang, Shanshan; Li, Jie; Li, Shujin; Yang, Yeming; Yang, Mu; Yang, Zhenglin; Zhu, Xianjun; Zhang, Lin

2018-04-25

Retinitis pigmentosa (RP) is a genetically heterogeneous disease with over 70 causative genes identified to date. However, approximately 40% of RP cases remain genetically unsolved, suggesting that many novel disease-causing mutations are yet to be identified. The purpose of this study is to identify the causative mutations of a Chinese RP family. Targeted next-generation sequencing (NGS) for a total of 163 genes which involved in inherited retinal disorders were used to screen the possible causative mutations. Sanger sequencing was used to verify the mutations. As results, we identified two heterozygous mutations: a splicing site mutation c.1407 + 1G>C and a nonsense mutation c. 1957C>T (p.R653X) in phosphodiesterase 6A (PDE6A) gene in the RP patient. These two mutations are inherited from his father and mother, respectively. Furthermore, these mutations are unique in our in-house database and are rare in human genome databases, implicating that these two mutations are pathological. By using targeted NGS method, we identified a compound heterozygous mutation in PDE6A gene that is associated with RP in a Chinese family.

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.

Clinical Phenotype in a Toddler with a Novel Heterozygous Mutation of the Vitamin D Receptor

PubMed Central

Dingle, Elena

2017-01-01

We present the clinical phenotype of a toddler who presented with vitamin D-resistant rickets, with one of the highest initial levels of alkaline phosphatase and parathyroid hormone (PTH) levels reported in the literature. The toddler had novel compound heterozygous mutations in the ligand-binding site of the vitamin D receptor and had an excellent response to calcitriol (1,25(OH)2D). PMID:28620554

Novel mutation of OCRL1 in Lowe syndrome.

PubMed

Liu, Ting; Yue, Zhihui; Wang, Haiyan; Tong, Huajuan; Sun, Liangzhong

2015-01-01

Lowe syndrome is a rare, X-linked recessive genetic disease with multi-organ involvement. The pathogenic gene is OCRL1. The authors analyzed the OCRL1 mutation and summarized the clinical features of a Chinese child with Lowe syndrome. The patient is a 3 year 7 mo-old boy. He presented with hypotonia at birth and gradually presented with bilateral congenital cataracts, psychomotor retardation, hypophosphatemic rickets and renal tubular function disorder. Sequence analysis of OCRL1 revealed a novel insertion mutation, c.2367insA (p. Ala813X), in exon 22. This mutation was suspected to cause a premature stop codon of OCRL1 and truncation of the OCRL1 protein. His mother, who carried a heterozygous mutation, had no sign of abnormality.

PTT analysis of polyps from FAP patients reveals a great majority of APC truncating mutations

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

Luijt, R.B. van der; Khan, P.M.; Tops, C.M.J.

The adenomatous polyposis coli (APC) gene plays an important role in colorectal carcinogenesis. Germline APC mutations are associated with familial adenomatous polyposis (FAP), an autosomal dominantly inherited predisposition to colorectal cancer, characterized by the development of numerous adenomatous polyps in the large intestine. In order to investigate whether somatic inactivation of the remaining APC allele is necessary for adenoma formation, we collected multiple adenomatous polyps from individual FAP patients and investigated the presence of somatic mutations in the APC gene. The analysis of somatic APC mutations in these tumor samples was performed using a rapid and sensitive assay, called themore » protein truncation test (PTT). Chain-terminating somatic APC mutations were detected in the great majority of the tumor samples investigated. As expected, these mutations were mainly located in the mutation cluster region (MCR) in exon 15. Our results confirm that somatic mutation of the second APC allele is required for adenoma formation in FAP. Interestingly, in the polyps investigated in our study, the second APC allele is somatically inactivated through point mutation leading to a stop codon rather than by loss of heterozygosity. The observation that somatic second hits in APC are required for tumor development in FAP is in apparent accordance with the Knudson hypothesis for classical tumor suppressor genes. However, it is yet unknown whether chain-terminating APC mutations lead to a truncated protein exerting a dominant-negative effect or whether these mutations result in a null allele. Further investigation of this important issue will hopefully provide a better understanding of the mechanism of action of the mutated APC alleles in colorectal carcinogenesis.« less

Frequent Truncating Mutation of TFAM Induces Mitochondrial DNA Depletion and Apoptotic Resistance in Microsatellite-Unstable Colorectal Cancer

PubMed Central

Guo, Jianhui; Zheng, Li; Liu, Wenyong; Wang, Xianshu; Wang, Zemin; Wang, Zehua; French, Amy J.; Kang, Dongchon; Chen, Lin; Thibodeau, Stephen N.; Liu, Wanguo

2013-01-01

The mitochondrial transcription factor A (TFAM) is required for mitochondrial DNA (mtDNA) replication and transcription. Disruption of TFAM results in heart failure and premature aging in mice. But very little is known about the role of TFAM in cancer development. Here, we report the identification of frequent frameshift mutations in the coding mononucleotide repeat of TFAM in sporadic colorectal cancer (CRC) cell lines and in primary tumors with microsatellite instability (MSI), but not in microsatellite stable (MSS) CRC cell lines and tumors. The presence of the TFAM truncating mutation, in CRC cells with MSI, reduced the TFAM protein level in vivo and in vitro and correlated with mtDNA depletion. Furthermore, forced overexpression of wild-type TFAM in RKO cells carrying a TFAM truncating mutation suppressed cell proliferation and inhibited RKO cell-induced xenograft tumor growth. Moreover, these cells showed more susceptibility to cisplatin-induced apoptosis due to an increase of cytochrome b (Cyt b) expression and its release from mitochondria. An interaction assay between TFAM and the heavy-strand promoter (HSP) of mitochondria revealed that mutant TFAM exhibited reduced binding to HSP, leading to reduction in Cyt b transcription. Collectively, these data provide evidence that a high incidence of TFAM truncating mutations leads to mitochondrial copy number reduction and mitochondrial instability, distinguishing most CRC with MSI from MSS CRC. These mutations may play an important role in tumorigenesis and cisplatin-induced apoptotic resistance of most microsatellite-unstable CRCs. PMID:21467167

[Infantile hypophosphatasia caused by a novel compound heterozygous mutation: a case report and pedigree analysis].

PubMed

Li, Deng-Feng; Lan, Dan; Zhong, Jing-Zi; Dewan, Roma Kajal; Xie, Yan-Shu; Yang, Ying

2017-05-01

This article reported the clinical features of one child with infantile hypophosphatasia (HPP) and his pedigree information. The proband was a 5-month-old boy with multiple skeletal dysplasia (koilosternia, bending deformity of both radii, and knock-knee deformity of both knees), feeding difficulty, reduction in body weight, developmental delay, recurrent pneumonia and respiratory failure, and a significant reduction in blood alkaline phosphatase. Among his parents, sister, uncle, and aunt (other family members did not cooperate with us in the examination), his parents and aunt had a slight reduction in alkaline phosphatase and his aunt had scoliosis; there were no other clinical phenotypes or abnormal laboratory testing results. His ALPL gene mutation came from c.228delG mutation in his mother and c.407G>A compound heterozygous mutation in his father. His aunt carried c.228delG mutation. The c.407G>A mutation had been reported as the pathogenic mutation of HPP, and c.228delG mutation was a novel pathogenic mutation. Hypophosphatasia is caused by ALPL gene mutation, and ALPL gene detection is an effective diagnostic method. This study expands the mutation spectrum of ALPL gene and provides a theoretical basis for genetic diagnosis of this disease.

PPM1D Mosaic Truncating Variants in Ovarian Cancer Cases May Be Treatment-Related Somatic Mutations.

PubMed

Pharoah, Paul D P; Song, Honglin; Dicks, Ed; Intermaggio, Maria P; Harrington, Patricia; Baynes, Caroline; Alsop, Kathryn; Bogdanova, Natalia; Cicek, Mine S; Cunningham, Julie M; Fridley, Brooke L; Gentry-Maharaj, Aleksandra; Hillemanns, Peter; Lele, Shashi; Lester, Jenny; McGuire, Valerie; Moysich, Kirsten B; Poblete, Samantha; Sieh, Weiva; Sucheston-Campbell, Lara; Widschwendter, Martin; Whittemore, Alice S; Dörk, Thilo; Menon, Usha; Odunsi, Kunle; Goode, Ellen L; Karlan, Beth Y; Bowtell, David D; Gayther, Simon A; Ramus, Susan J

2016-03-01

Mosaic truncating mutations in the protein phosphatase, Mg(2+)/Mn(2+)-dependent, 1D (PPM1D) gene have recently been reported with a statistically significantly greater frequency in lymphocyte DNA from ovarian cancer case patients compared with unaffected control patients. Using massively parallel sequencing (MPS) we identified truncating PPM1D mutations in 12 of 3236 epithelial ovarian cancer (EOC) case patients (0.37%) but in only one of 3431 unaffected control patients (0.03%) (P = .001). All statistical tests were two-sided. A combination of Sanger sequencing, pyrosequencing, and MPS data suggested that 12 of the 13 mutations were mosaic. All mutations were identified in post-chemotherapy treatment blood samples from case patients (n = 1827) (average 1234 days post-treatment in carriers) rather than from cases collected pretreatment (less than 14 days after diagnosis, n = 1384) (P = .002). These data suggest that PPM1D variants in EOC cases are primarily somatic mosaic mutations caused by treatment and are not associated with germline predisposition to EOC. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Combined pituitary hormone deficiency with unique pituitary dysplasia and morning glory syndrome related to a heterozygous PROKR2 mutation

PubMed Central

Asakura, Yumi; Muroya, Koji; Hanakawa, Junko; Sato, Takeshi; Aida, Noriko; Narumi, Satoshi; Hasegawa, Tomonobu; Adachi, Masanori

2015-01-01

Abstract Recent reports have indicated the role of the prokineticin receptor 2 gene (PROKR2) in the etiology of congenital hypopituitarism, including septo-optic dysplasia and Kallmann syndrome. In the present study, using next-generation targeted sequencing, we identified a novel heterozygous PROKR2 variant (c.742C>T; p.R248W) in a female patient who had combined pituitary hormone deficiency (CPHD), morning glory syndrome and a severely malformed pituitary gland. No other mutation was present in 27 genes related to hypogonadotropic hypogonadism, pituitary hormone deficiency and optic nerve malformation. The substituted amino acid was located on the third intracellular loop of the PROKR2 protein, which is a G protein-coupled receptor. Computational analyses with two programs (SIFT and PolyPhen-2) showed that the substitution was deleterious to PROKR2 function. The p.R248W mutation was transmitted from the patient’s mother, who had a slightly delayed menarche. Collectively, we provide further genetic evidence linking heterozygous PROKR2 mutations and the development of CPHD. PMID:25678757

Combined pituitary hormone deficiency with unique pituitary dysplasia and morning glory syndrome related to a heterozygous PROKR2 mutation.

PubMed

Asakura, Yumi; Muroya, Koji; Hanakawa, Junko; Sato, Takeshi; Aida, Noriko; Narumi, Satoshi; Hasegawa, Tomonobu; Adachi, Masanori

2015-01-01

Recent reports have indicated the role of the prokineticin receptor 2 gene (PROKR2) in the etiology of congenital hypopituitarism, including septo-optic dysplasia and Kallmann syndrome. In the present study, using next-generation targeted sequencing, we identified a novel heterozygous PROKR2 variant (c.742C>T; p.R248W) in a female patient who had combined pituitary hormone deficiency (CPHD), morning glory syndrome and a severely malformed pituitary gland. No other mutation was present in 27 genes related to hypogonadotropic hypogonadism, pituitary hormone deficiency and optic nerve malformation. The substituted amino acid was located on the third intracellular loop of the PROKR2 protein, which is a G protein-coupled receptor. Computational analyses with two programs (SIFT and PolyPhen-2) showed that the substitution was deleterious to PROKR2 function. The p.R248W mutation was transmitted from the patient's mother, who had a slightly delayed menarche. Collectively, we provide further genetic evidence linking heterozygous PROKR2 mutations and the development of CPHD.

Hypogonadism in a patient with two novel mutations of the luteinizing hormone β-subunit gene expressed in a compound heterozygous form.

PubMed

Basciani, Sabrina; Watanabe, Mikiko; Mariani, Stefania; Passeri, Marina; Persichetti, Agnese; Fiore, Daniela; Scotto d'Abusco, Anna; Caprio, Massimiliano; Lenzi, Andrea; Fabbri, Andrea; Gnessi, Lucio

2012-09-01

LH gene mutations are rare; only four mutations have been described. The affected individuals are hypogonadal. We describe the clinical features of a 31-yr-old man who presented with delayed puberty and azoospermia and was found to have hypogonadism associated with an absence of circulating LH. The patient had a 12-bp deletion in exon 2 in the LH β-subunit gene and a mutation of the 5' splice site IVS2+1G→T in the same gene present in a compound heterozygous state. The first mutation predicts a deletion of four leucines of the hydrophobic core of the signal peptide. The second mutation disrupts the splicing of mRNA, generating a gross abnormality in the processing. The patient's heterozygous parents were clinically normal. The phenotype of a 16-yr-old sister of the proband, carrying the same mutations, was characterized by normal pubertal development and oligomenorrhea. This report unravels two novel mutations of the LH gene critical for synthesis and activity of the LH molecule. The insight gained from the study is that normal pubertal maturation in women can occur in a state of LH deficiency, whereas LH is essential for maturation of Leydig cells and thus steroidogenesis, puberty, and spermatogenesis in man. These mutations should be considered in girls and boys with selective deficiency of LH.

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.

De Novo Truncating Mutations in the Last and Penultimate Exons of PPM1D Cause an Intellectual Disability Syndrome.

PubMed

Jansen, Sandra; Geuer, Sinje; Pfundt, Rolph; Brough, Rachel; Ghongane, Priyanka; Herkert, Johanna C; Marco, Elysa J; Willemsen, Marjolein H; Kleefstra, Tjitske; Hannibal, Mark; Shieh, Joseph T; Lynch, Sally Ann; Flinter, Frances; FitzPatrick, David R; Gardham, Alice; Bernhard, Birgitta; Ragge, Nicola; Newbury-Ecob, Ruth; Bernier, Raphael; Kvarnung, Malin; Magnusson, E A Helena; Wessels, Marja W; van Slegtenhorst, Marjon A; Monaghan, Kristin G; de Vries, Petra; Veltman, Joris A; Lord, Christopher J; Vissers, Lisenka E L M; de Vries, Bert B A

2017-04-06

Intellectual disability (ID) is a highly heterogeneous disorder involving at least 600 genes, yet a genetic diagnosis remains elusive in ∼35%-40% of individuals with moderate to severe ID. Recent meta-analyses statistically analyzing de novo mutations in >7,000 individuals with neurodevelopmental disorders highlighted mutations in PPM1D as a possible cause of ID. PPM1D is a type 2C phosphatase that functions as a negative regulator of cellular stress-response pathways by mediating a feedback loop of p38-p53 signaling, thereby contributing to growth inhibition and suppression of stress-induced apoptosis. We identified 14 individuals with mild to severe ID and/or developmental delay and de novo truncating PPM1D mutations. Additionally, deep phenotyping revealed overlapping behavioral problems (ASD, ADHD, and anxiety disorders), hypotonia, broad-based gait, facial dysmorphisms, and periods of fever and vomiting. PPM1D is expressed during fetal brain development and in the adult brain. All mutations were located in the last or penultimate exon, suggesting escape from nonsense-mediated mRNA decay. Both PPM1D expression analysis and cDNA sequencing in EBV LCLs of individuals support the presence of a stable truncated transcript, consistent with this hypothesis. Exposure of cells derived from individuals with PPM1D truncating mutations to ionizing radiation resulted in normal p53 activation, suggesting that p53 signaling is unaffected. However, a cell-growth disadvantage was observed, suggesting a possible effect on the stress-response pathway. Thus, we show that de novo truncating PPM1D mutations in the last and penultimate exons cause syndromic ID, which provides additional insight into the role of cell-cycle checkpoint genes in neurodevelopmental disorders. Copyright © 2017 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

[Novel CHST6 compound heterozygous mutations cause macular corneal dystrophy in a Chinese family].

PubMed

Qi, Yan-hua; Dang, Xiu-hong; Su, Hong; Zhou, Nan; Liang, Ting; Wang, Zheng; Huang, Shang-zhi

2010-02-01

The aim of this study was to identify mutations of CHST6 gene in a Chinese family with macular corneal dystrophy (MCD) and to investigate the histopathological changes of MCD. Corneal button of the proband was obtained from penetrating keratoplasty for the treatment of severe corneal dystrophy. The sections and ultrathin sections of this specimen were examined under light microscope and transmission electron microscope (TEM). Genomic DNA was extracted from leukocytes in peripheral blood from the family members. The coding region of CHST6 was amplified by polymerase chain reaction (PCR). The PCR products were analyzed by direct sequencing and restriction enzyme digestion. Histochemical study revealed positive results of colloidal iron stain. TEM revealed enlargement of smooth endoplasmic reticulum and the presence of intracytoplasmic vacuoles. Two mutations, Q298X Y358H, were identified in exon 3 of CHST6. Three patients were compound heterozygotes of these two mutations. The C892T transversion occurred at codon 298 turned the codon of glutamine to a stop codon; the T1072C transversion occurred at codon 358 caused a missense mutation, tyrosine to histidine. All six unaffected family members were heterozygotes. These two mutations were not detected in any of the 100 control subjects. The novel compound heterozygous mutation results in loss of CHST6 function and causes the occurrence of MCD. This is the first report of this gene mutation.

Phenotypic variation among familial hypercholesterolemics heterozygous for either one of two Afrikaner founder LDL receptor mutations.

PubMed

Kotze, M J; De Villiers, W J; Steyn, K; Kriek, J A; Marais, A D; Langenhoven, E; Herbert, J S; Graadt Van Roggen, J F; Van der Westhuyzen, D R; Coetzee, G A

1993-10-01

Two common founder-related gene mutations that affect the low-density lipoprotein receptor (LDLR) are responsible for approximately 80% of familial hypercholesterolemia (FH) in South African Afrikaners. The FH Afrikaner-1 (FH1) mutation (Asp206-->Glu) in exon 4 results in defective receptors with approximately 20% of normal activity, whereas the FH Afrikaner-2 (FH2) mutation (Val408-->Met) in exon 9 completely abolishes LDLR activity (< 2% normal activity). We analyzed the contribution of these mutations and other factors on the variation of hypercholesterolemia and clinical features in Afrikaner FH heterozygotes. The type of FH mutation, plasma triglyceride levels, and age of patients each contributed significantly to the variation in hypercholesterolemia, whereas smoking status, high-density lipoprotein cholesterol levels, and gender had no influence. Although all FH heterozygotes had frank hypercholesterolemia, patients with the FH1 mutation had significantly lower cholesterol levels than those with the FH2 mutation. FH1 heterozygotes also tended to have milder clinical features. The differences between the two FH groups could not be explained by a difference in the common apolipoprotein E variants. This study demonstrates that mutational heterogeneity in the LDLR gene influences the phenotypic expression of heterozygous FH.

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.

Clinical Features and Long-Term Outcome of Nephrotic Syndrome Associated with Heterozygous NPHS1 and NPHS2 Mutations

PubMed Central

Caridi, Gianluca; Gigante, Maddalena; Ravani, Pietro; Trivelli, Antonella; Barbano, Giancarlo; Scolari, Francesco; Dagnino, Monica; Murer, Luisa; Murtas, Corrado; Edefonti, Alberto; Allegri, Landino; Amore, Alessandro; Coppo, Rosanna; Emma, Francesco; De Palo, Tommaso; Penza, Rosa; Gesualdo, Loreto; Ghiggeri, Gian Marco

2009-01-01

Background and objectives: Mutations in nephrin (NPHS1) and podocin (NPHS2) genes represent a major cause of idiopathic nephrotic syndrome (NS) in children. It is not yet clear whether the presence of a single mutation acts as a modifier of the clinical course of NS. Design, setting, participants, & measurements: We reviewed the clinical features of 40 patients with NS associated with heterozygous mutations or variants in NPHS1 (n = 7) or NPHS2 (n = 33). Long-term renal survival probabilities were compared with those of a concurrent cohort with idiopathic NS. Results: Patients with a single mutation in NPHS1 received a diagnosis before those with potentially nongenetic NS and had a good response to therapies. Renal function was normal in all cases. For NPHS2, six patients had single heterozygous mutations, six had a p.P20L variant, and 21 had a p.R229Q variant. Age at diagnosis and the response to drugs were comparable in all NS subgroups. Overall, they had similar renal survival probabilities as non-NPHS1/NPHS2 cases (log-rank χ2 0.84, P = 0.656) that decreased in presence of resistance to therapy (P < 0.001) and in cases with renal lesions of glomerulosclerosis and IgM deposition (P < 0.001). Cox regression confirmed that the only significant predictor of dialysis was resistance to therapy. Conclusions: Our data indicate that single mutation or variant in NPHS1 and NPHS2 does not modify the outcome of primary NS. These patients should be treated following consolidated schemes and have good chances for a good long-term outcome. PMID:19406966

Autosomal-dominant Leber Congenital Amaurosis Caused by a Heterozygous CRX Mutation in a Father and Son.

PubMed

Arcot Sadagopan, Karthikeyan; Battista, Robert; Keep, Rosanne B; Capasso, Jenina E; Levin, Alex V

2015-06-01

Leber congenital amaurosis (LCA) is most often an autosomal recessive disorder. We report a father and son with autosomal dominant LCA due to a mutation in the CRX gene. DNA screening using an allele specific assay of 90 of the most common LCA-causing variations in the coding sequences of AIPL1, CEP290, CRB1, CRX, GUCY2D, RDH12 and RPE65 was performed on the father. Automated DNA sequencing of his son examining exon 3 of the CRX gene was subsequently performed. Both father and son have a heterozygous single base pair deletion of an adenine at codon 153 in the coding sequence of the CRX gene resulting in a frameshift mutation. Mutations involving the CRX gene may demonstrate an autosomal dominant inheritance pattern for LCA.

Novel and recurrent non-truncating mutations of the MITF basic domain: genotypic and phenotypic variations in Waardenburg and Tietz syndromes

PubMed Central

Léger, Sandy; Balguerie, Xavier; Goldenberg, Alice; Drouin-Garraud, Valérie; Cabot, Annick; Amstutz-Montadert, Isabelle; Young, Paul; Joly, Pascal; Bodereau, Virginie; Holder-Espinasse, Muriel; Jamieson, Robyn V; Krause, Amanda; Chen, Hongsheng; Baumann, Clarisse; Nunes, Luis; Dollfus, Hélène; Goossens, Michel; Pingault, Véronique

2012-01-01

The microphthalmia-associated transcription factor (MITF) is a basic helix-loop-helix leucine zipper transcription factor, which regulates melanocyte development and the biosynthetic melanin pathway. A notable relationship has been described between non-truncating mutations of its basic domain and Tietz syndrome, which is characterized by albinoid-like hypopigmentation of the skin and hair, rather than the patchy depigmentation seen in Waardenburg syndrome, and severe hearing loss. Twelve patients with new or recurrent non-truncating mutations of the MITF basic domain from six families were enrolled in this study. We observed a wide range of phenotypes and some unexpected features. All the patients had blue irides and pigmentation abnormalities that ranged from diffuse hypopigmentation to Waardenburg-like patches. In addition, they showed congenital complete hearing loss, diffuse hypopigmentation of the skin, freckling and ocular abnormalities, more frequently than patients with MITF mutations outside the basic domain. In conclusion, the non-truncating mutations of the basic domain do not always lead to Tietz syndrome but rather to a large range of phenotypes. Sun-exposed freckles are interestingly observed more frequently in Asian populations. This variability argues for the possible interaction with modifier loci. PMID:22258527

Biallelic PMS2 Mutation and Heterozygous DICER1 Mutation Presenting as Constitutional Mismatch Repair Deficiency With Corpus Callosum Agenesis: Case Report and Review of Literature.

PubMed

Cheyuo, Cletus; Radwan, Walid; Ahn, Janice; Gyure, Kymberly; Qaiser, Rabia; Tomboc, Patrick

2017-10-01

Constitutional mismatch repair deficiency syndrome is a cancer predisposition syndrome caused by autosomal recessive biallelic (homozygous) germline mutations in the mismatch repair genes (MLH1, MSH2, MSH6, and PMS2). The clinical spectrum includes neoplastic and non-neoplastic manifestations. We present the case of a 7-year-old boy who presented with T-lymphoblastic lymphoma and glioblastoma, together with non-neoplastic manifestations including corpus callosum agenesis, arachnoid cyst, developmental venous anomaly, and hydrocephalus. Gene mutation analysis revealed pathogenic biallelic mutations of PMS2 and heterozygous DICER1 variant predicted to be pathogenic. This report is the first to allude to a possible interaction of the mismatch repair system with DICER1 to cause corpus callosum agenesis.

Novel Compound Heterozygous Spatacsin Mutations in a Greek Kindred with Hereditary Spastic Paraplegia SPG11 and Dementia.

PubMed

Fraidakis, Matthew J; Brunetti, Maura; Blackstone, Craig; Filippi, Massimo; Chiò, Adriano

2016-01-01

SPG11 belongs to the autosomal recessive hereditary spastic paraplegias (HSP) and presents during childhood or puberty with a complex clinical phenotype encompassing learning difficulties, ataxia, peripheral neuropathy, amyotrophy, and mental retardation. We hereby present the case of a 30-year-old female patient with complex autosomal recessive HSP with thinning of the corpus callosum (TCC) and dementia that was compound heterozygous with two novel mutations in the SPG11 gene. Sequence analysis of the SPG11 gene revealed two novel mutations in a compound heterozygous state in the index patient (c.2431C>T/p.Gln811Ter and c.6755_6756insT/p.Glu2252Aspfs*88). MRI showed abnormal TCC, white matter (WM) hyperintensities periventricularly, and the 'ears of the lynx' sign. Diffusion tensor imaging showed a mild-to-moderate decrease in fractional anisotropy and an increase in mean diffusivity in WM compared to age-matched controls, while magnetic resonance spectroscopy showed abnormal findings in affected WM with a decrease in N-acetyl-aspartate in WM regions of interest. This is the first SPG11 kindred from the Greek population to be reported in the medical literature. © 2016 S. Karger AG, Basel.

Compound heterozygous PNPLA6 mutations cause Boucher-Neuhäuser syndrome with late-onset ataxia.

PubMed

Deik, A; Johannes, B; Rucker, J C; Sánchez, E; Brodie, S E; Deegan, E; Landy, K; Kajiwara, Y; Scelsa, S; Saunders-Pullman, R; Paisán-Ruiz, C

2014-12-01

PNPLA6 mutations, known to be associated with the development of motor neuron phenotypes, have recently been identified in families with Boucher-Neuhäuser syndrome. Boucher-Neuhäuser is a rare autosomal recessive syndrome characterized by the co-occurrence of cerebellar ataxia, hypogonadotropic hypogonadism, and chorioretinal dystrophy. Gait ataxia in Boucher-Neuhäuser usually manifests before early adulthood, although onset in the third or fourth decade has also been reported. However, given the recent identification of PNPLA6 mutations as the cause of this condition, the determining factors of age of symptom onset still need to be established. Here, we have identified a sporadic Boucher-Neuhäuser case with late-onset gait ataxia and relatively milder retinal changes due to compound heterozygous PNPLA6 mutations. Compound heterozygosity was confirmed by cloning and sequencing the patient's genomic DNA from coding exons 26-29. Furthermore, both mutations (one novel and one known) fell in the phospholipase esterase domain, where most pathogenic mutations seem to cluster. Taken together, we herein confirm PNPLA6 mutations as the leading cause of Boucher-Neuhäuser syndrome and suggest inquiring about a history of hypogonadism or visual changes in patients presenting with late-onset gait ataxia. We also advocate for neuroophthalmologic evaluation in suspected cases.

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

Tuning the free-energy landscape of a WW domain by temperature, mutation, and truncation

PubMed Central

Nguyen, Houbi; Jäger, Marcus; Moretto, Alessandro; Gruebele, Martin; Kelly, Jeffery W.

2003-01-01

The equilibrium unfolding of the Formin binding protein 28 (FBP) WW domain, a stable three-stranded β-sheet protein, can be described as reversible apparent two-state folding. Kinetics studied by laser temperature jump reveal a third state at temperatures below the midpoint of unfolding. The FBP free-energy surface can be tuned between three-state and two-state kinetics by changing the temperature, by truncation of the C terminus, or by selected point mutations. FBP WW domain is the smallest three-state folder studied to date and the only one that can be freely tuned between three-state and apparent two-state folding by several methods (temperature, truncation, and mutation). Its small size (28–37 residues), the availability of a quantitative reaction coordinate (φT), the fast folding time scale (10s of μs), and the tunability of the folding routes by small temperature or sequence changes make this system the ideal prototype for studying more subtle features of the folding free-energy landscape by simulations or analytical theory. PMID:12651955

Tuning the free-energy landscape of a WW domain by temperature, mutation, and truncation.

PubMed

Nguyen, Houbi; Jager, Marcus; Moretto, Alessandro; Gruebele, Martin; Kelly, Jeffery W

2003-04-01

The equilibrium unfolding of the Formin binding protein 28 (FBP) WW domain, a stable three-stranded beta-sheet protein, can be described as reversible apparent two-state folding. Kinetics studied by laser temperature jump reveal a third state at temperatures below the midpoint of unfolding. The FBP free-energy surface can be tuned between three-state and two-state kinetics by changing the temperature, by truncation of the C terminus, or by selected point mutations. FBP WW domain is the smallest three-state folder studied to date and the only one that can be freely tuned between three-state and apparent two-state folding by several methods (temperature, truncation, and mutation). Its small size (28-37 residues), the availability of a quantitative reaction coordinate (phi(T)), the fast folding time scale (10s of micros), and the tunability of the folding routes by small temperature or sequence changes make this system the ideal prototype for studying more subtle features of the folding free-energy landscape by simulations or analytical theory.

Probing the Effect of Two Heterozygous Mutations in Codon 723 of SLC26A4 on Deafness Phenotype Based on Molecular Dynamics Simulations.

PubMed

Yao, Jun; Qian, Xuli; Bao, Jingxiao; Wei, Qinjun; Lu, Yajie; Zheng, Heng; Cao, Xin; Xing, Guangqian

2015-06-02

A Chinese family was identified with clinical features of enlarged vestibular aqueduct syndrome (EVAS). The mutational analysis showed that the proband (III-2) had EVAS with bilateral sensorineural hearing loss and carried a rare compound heterozygous mutation of SLC26A4 (IVS7-2A>G, c.2167C>G), which was inherited from the same mutant alleles of IVS7-2A>G heterozygous father and c.2167C>G heterozygous mother. Compared with another confirmed pathogenic biallelic mutation in SLC26A4 (IVS7-2A>G, c.2168A>G), these two biallelic mutations shared one common mutant allele and the same codon of the other mutant allele, but led to different changes of amino acid (p.H723D, p.H723R) and both resulted in the deafness phenotype. Structure-modeling indicated that these two mutant alleles changed the shape of pendrin protein encoded by SLC26A4 with increasing randomness in conformation, and might impair pendrin's ability as an anion transporter. The molecular dynamics simulations also revealed that the stability of mutant pendrins was reduced with increased flexibility of backbone atoms, which was consistent with the structure-modeling results. These evidences indicated that codon 723 was a hot-spot region in SLC26A4 with a significant impact on the structure and function of pendrin, and acted as one of the genetic factors responsible for the development of hearing loss.

Follow-up Findings in a Turkish Girl with Pseudohypoparathyroidism Type Ia Caused by a Novel Heterozygous Mutation in the GNAS Gene.

PubMed

Şahin, Sezgin; Hiort, Olaf; Thiele, Susanne; Evliyaoğlu, Olcay; Tüysüz, Beyhan

2017-03-01

Pseudohypoparathyroidism type Ia (PHP-Ia) is characterized by multihormone resistance and an Albright hereditary osteodystrophy (AHO) phenotype. It is caused by heterozygous mutations in GNAS gene. Clinical and biochemical findings of a female PHP-Ia patient were evaluated from age of diagnosis (6.5 years) to 14.5 years of age. The patient had short stature, brachydactyly, and subcutaneous heterotopic ossifications. Serum calcium and phosphorus levels were normal, but parathyroid hormone levels were high. Based on the typical clinical findings of AHO phenotype and biochemical findings, she was diagnosed as having PHP-Ia. A novel heterozygous mutation (c.128T>C) was found in the GNAS gene. Follow-up examinations revealed resistance to thyroid-stimulating hormone and a bioinactive growth hormone. Clinicians should take into consideration PHP-Ia in patients referred with short stature, and patients with an AHO phenotype must be further evaluated for hormone resistance, GNAS gene mutation, Gsα activity. To our knowledge, this is the first case report describing bioinactive growth hormone in PHP-Ia.

A compound heterozygous mutation in SLC34A3 causes hereditary hypophosphatemic rickets with hypercalciuria in a Chinese patient.

PubMed

Chi, Yue; Zhao, Zhen; He, Xiaodong; Sun, Yue; Jiang, Yan; Li, Mei; Wang, Ou; Xing, Xiaoping; Sun, Andrew Y; Zhou, Xueying; Meng, Xunwu; Xia, Weibo

2014-02-01

Hereditary hypophosphatemic rickets with hypercalciuria (HHRH) is a rare metabolic disorder inherited in an autosomal recessive fashion and characterized by hypophosphatemia, short stature, rickets and/or osteomalacia, and secondary absorptive hypercalciuria. HHRH was recently mapped to chromosome 9q34, which contains the gene SLC34A3 which encodes the renal proximal tubular sodium-phosphate cotransporter NaPi-IIc. Here we describe a 29-year-old man with a history of childhood rickets who presented with increased renal phosphate clearance leading to hypophosphatemia, hypercalciuria, low serum parathyroid hormone (PTH), elevated serum 1,25-dihydroxyvitamin D (1,25(OH)2D) and recurrent nephrolithiasis. We performed a mutation analysis of SLC34A3 (exons and adjacent introns) of the proband and his parents to determine if there was a genetic contribution. The proband proved to be compound heterozygous for two missense mutations in SLC34A3: one novel mutation in exon 7 c.571G>C (p.G191R) and one previously identified mutation in exon 13 c.1402C>T (p.R468W). His parents were both asymptomatic heterozygous carriers of one of these two mutations. We also performed an oral phosphate loading test and compared serum phosphate, intact PTH, and intact fibroblast growth factor 23 (iFGF23) in this patient versus patients with other forms of hypophosphatemic rickets, the results of which further revealed that the mechanism of hypophosphatemia in HHRH is independent of FGF23. This is the first report of HHRH in the Chinese population. Our findings of the novel mutation in exon 7 add to the list of more than 20 reported mutations of SLC34A3. Copyright © 2013 Elsevier Inc. All rights reserved.

The heterozygous N291S mutation in the lipoprotein lipase gene impairs whole-body insulin sensitivity and affects a distinct set of plasma metabolites in humans.

PubMed

Berg, Sofia Mikkelsen; Havelund, Jesper; Hasler-Sheetal, Harald; Kruse, Vibeke; Pedersen, Andreas James Thestrup; Hansen, Aleksander Bill; Nybo, Mads; Beck-Nielsen, Henning; Højlund, Kurt; Færgeman, Nils Joakim

Mutations in the lipoprotein lipase gene causing decreased lipoprotein lipase activity are associated with surrogate markers of insulin resistance and the metabolic syndrome in humans. We investigated the hypothesis that a heterozygous lipoprotein lipase mutation (N291S) induces whole-body insulin resistance and alterations in the plasma metabolome. In 6 carriers of a heterozygous lipoprotein lipase mutation (N291S) and 11 age-matched and weight-matched healthy controls, we examined insulin sensitivity and substrate metabolism by euglycemic-hyperinsulinemic clamps combined with indirect calorimetry. Plasma samples were taken before and after the clamp (4 hours of physiological hyperinsulinemia), and metabolites were measured enzymatically or by gas chromatography-mass spectrometry. Compared with healthy controls, heterozygous carriers of a defective lipoprotein lipase allele had elevated fasting plasma levels triglycerides (P < .006), and markedly impaired insulin-stimulated glucose disposal rates (P < .024) and nonoxidative glucose metabolism (P < .015). Plasma metabolite profiling demonstrated lower circulating levels of pyruvic acid and α-tocopherol in the N291S carriers than in controls both before and after stimulation with insulin (all >1.5-fold change and P < .05). Heterozygous carriers with a defective lipoprotein lipase allele are less insulin sensitive and have increased plasma levels of nonesterified fatty acids and triglycerides. The heterozygous N291S carriers also have a distinct plasma metabolomic signature, which may serve as a diagnostic tool for deficient lipoprotein lipase activity and as a marker of lipid-induced insulin resistance. Copyright © 2017 National Lipid Association. Published by Elsevier Inc. All rights reserved.

Identification of FASTKD2 compound heterozygous mutations as the underlying cause of autosomal recessive MELAS-like syndrome.

PubMed

Yoo, Da Hye; Choi, Young-Chul; Nam, Da Eun; Choi, Sun Seong; Kim, Ji Won; Choi, Byung-Ok; Chung, Ki Wha

2017-07-01

Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) is a condition that affects many parts of the body, particularly the brain and muscles. This study examined a Korean MELAS-like syndrome patient with seizure, stroke-like episode, and optic atrophy. Target sequencing of whole mtDNA and 73 nuclear genes identified compound heterozygous mutations p.R205X and p.L255P in the FASTKD2. Each of his unaffected parents has one of the two mutations, and both mutations were not found in 302 controls. FASTKD2 encodes a FAS-activated serine-threonine (FAST) kinase domain 2 which locates in the mitochondrial inner compartment. A FASTKD2 nonsense mutation was once reported as the cause of a recessive infantile mitochondrial encephalomyopathy. The present case showed relatively mild symptoms with a late onset age, compared to a previous patient with FASTKD2 mutation, implicating an inter-allelic clinical heterogeneity. Because this study is the second report of an autosomal recessive mitochondrial encephalomyopathy patient with a FASTKD2 mutation, it will extend the phenotypic spectrum of the FASTKD2 mutation. Copyright © 2017. Published by Elsevier B.V.

Atypical generalized lipoatrophy and severe insulin resistance due to a heterozygous LMNA p.T10I mutation.

PubMed

Mory, Patricia B; Crispim, Felipe; Kasamatsu, Teresa; Gabbay, Monica A L; Dib, Sergio A; Moisés, Regina S

2008-11-01

Lipodystrophies are a group of heterogeneous disorders characterized by the loss of adipose tissue and metabolic complications. The main familial forms of lipodystrophy are Congenital Generalized Lipodystrophy and Familial Partial Lipodystrophy (FPLD). FPLD may result from mutations in the LMNA gene. Besides FPLD, mutations in LMNA have been shown to be responsible for other inherited diseases called laminopathies. Here we describe the case of a 15-year-old girl who was referred to our service due to diabetes mellitus and severe hypertriglyceridemia. Physical examination revealed generalized loss of subcutaneous fat, confirmed by DEXA (total body fat 8.6%). As the patient presented with pubertal-onset of generalized lipodystrophy and insulin resistance, molecular analysis of the LMNA gene was performed. We identified a heterozygous substitution in exon 1 (c.29C>T) predicting a p.T10I mutation. In summary, we describe an atypical phenotype of lipodistrophy associated with a de novo appearance of the p.T10I mutation in LMNA gene.

Heterozygous Germline Mutations in the CBL Tumor-Suppressor Gene Cause a Noonan Syndrome-like Phenotype

PubMed Central

Martinelli, Simone; De Luca, Alessandro; Stellacci, Emilia; Rossi, Cesare; Checquolo, Saula; Lepri, Francesca; Caputo, Viviana; Silvano, Marianna; Buscherini, Francesco; Consoli, Federica; Ferrara, Grazia; Digilio, Maria C.; Cavaliere, Maria L.; van Hagen, Johanna M.; Zampino, Giuseppe; van der Burgt, Ineke; Ferrero, Giovanni B.; Mazzanti, Laura; Screpanti, Isabella; Yntema, Helger G.; Nillesen, Willy M.; Savarirayan, Ravi; Zenker, Martin; Dallapiccola, Bruno; Gelb, Bruce D.; Tartaglia, Marco

2010-01-01

RAS signaling plays a key role in controlling appropriate cell responses to extracellular stimuli and participates in early and late developmental processes. Although enhanced flow through this pathway has been established as a major contributor to oncogenesis, recent discoveries have revealed that aberrant RAS activation causes a group of clinically related developmental disorders characterized by facial dysmorphism, a wide spectrum of cardiac disease, reduced growth, variable cognitive deficits, ectodermal and musculoskeletal anomalies, and increased risk for certain malignancies. Here, we report that heterozygous germline mutations in CBL, a tumor-suppressor gene that is mutated in myeloid malignancies and encodes a multivalent adaptor protein with E3 ubiquitin ligase activity, can underlie a phenotype with clinical features fitting or partially overlapping Noonan syndrome (NS), the most common condition of this disease family. Independent CBL mutations were identified in two sporadic cases and two families from among 365 unrelated subjects who had NS or suggestive features and were negative for mutations in previously identified disease genes. Phenotypic heterogeneity and variable expressivity were documented. Mutations were missense changes altering evolutionarily conserved residues located in the RING finger domain or the linker connecting this domain to the N-terminal tyrosine kinase binding domain, a known mutational hot spot in myeloid malignancies. Mutations were shown to affect CBL-mediated receptor ubiquitylation and dysregulate signal flow through RAS. These findings document that germline mutations in CBL alter development to cause a clinically variable condition that resembles NS and that possibly predisposes to malignancies. PMID:20619386

The use of high resolution melting analysis to detect Fabry mutations in heterozygous females via dry bloodspots.

PubMed

Tai, Chang-Long; Liu, Mei-Ying; Yu, Hsiao-Chi; Chiang, Chiang-Chuan; Chiang, Hung; Suen, Jeng-Hung; Kao, Shu-Min; Huang, Yu-Hsiu; Wu, Tina Jui-Ting; Yang, Chia-Feng; Tsai, Fang-Chih; Lin, Ching-Yuang; Chang, Jan-Gowth; Chen, Hong-Duo; Niu, Dau-Ming

2012-02-18

As an X-linked genetic disorder, Fabry disease was first thought to affect males only, and females were generally considered to be asymptomatic carriers. However, recent research suggests that female carriers of Fabry disease may still develop vital organ damage causing severe morbidity and mortality. In the previous newborn screening, from 299,007 newborns, we identified a total of 20 different Fabry mutations and 121 newborns with Fabry mutations. However, we found that most female carriers are not detected by enzyme assays. A streamlined method for high resolution melting (HRM) analysis was designed to screen for GLA gene mutations using a same PCR and melting program. Primer sets were designed to cover the 7 exons and the Chinese common intronic mutation, IVS4+919G>A of GLA gene. The HRM analysis was successful in identifying heterozygous and hemizygous patients with the 20 surveyed mutations. We were also successful in using this method to test dry blood spots of newborns afflicted with Fabry mutations without having to determine DNA concentration before PCR amplification. The results of this study show that HRM could be a reliable and sensitive method for use in the rapid screening of females for GLA mutations. Copyright © 2011 Elsevier B.V. All rights reserved.

Novel compound heterozygous mutations identified by whole exome sequencing in a Japanese patient with geroderma osteodysplastica.

PubMed

Takeda, Ryojun; Takagi, Masaki; Shinohara, Hiroyuki; Futagawa, Hiroshi; Narumi, Satoshi; Hasegawa, Tomonobu; Nishimura, Gen; Yoshihashi, Hiroshi

2017-12-01

Geroderma osteodysplastica (GO) is a subtype of cutis laxa syndrome characterized by congenital wrinkly skin, a prematurely aged face, extremely short stature, and osteoporosis leading to recurrent fractures. GO exhibits an autosomal recessive inheritance pattern and is caused by loss-of-function mutations in GORAB, which encodes a protein important for Golgi-related transport. Using whole exome sequencing, we identified novel compound heterozygous nonsense mutations in the GORAB in a GO patient. The patient was a 14-year-old Japanese boy. Wrinkled skin and joint laxity were present at birth. At 1 year of age, he was clinically diagnosed with cutis laxa syndrome based on recurrent long bone fractures and clinical features, including wrinkled skin, joint laxity, and a distinctive face. He did not show retarded gross motor and cognitive development. At 11 years of age, he was treated with oral bisphosphonate and vitamin D owing to recurrent multiple spontaneous fractures of the vertebral and extremity bones associated with a low bone mineral density (BMD). Bisphosphonate treatment improved his BMD and fracture rate. Whole exome sequencing revealed two novel compound heterozygous nonsense mutations in the GORAB gene (p.Arg60* and p.Gln124*), and the diagnosis of GO was established. GO is a rare connective tissue disorder. Approximately 60 cases have been described to date, and this is the first report of a patient from Japan. Few studies have reported the effects of bisphosphonate treatment in GO patients with recurrent spontaneous fractures. Based on this case study, we hypothesize that oral bisphosphonate and vitamin D are effective and safe treatment options for the management of recurrent fractures in GO patients. It is important to establish a precise diagnosis of GO to prevent recurrent fractures and optimize treatment plans. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Long-term response to growth hormone therapy in a patient with short stature caused by a novel heterozygous mutation in NPR2.

PubMed

Vasques, Gabriela A; Hisado-Oliva, Alfonso; Funari, Mariana F A; Lerario, Antonio M; Quedas, Elisangela P S; Solberg, Paulo; Heath, Karen E; Jorge, Alexander A L

2017-01-01

Heterozygous loss-of-function mutations in the natriuretic peptide receptor B gene (NPR2) are responsible for short stature in patients without a distinct phenotype. Some of these patients have been treated with recombinant human growth hormone (rhGH) therapy with a variable response. The proband was a healthy boy who presented at the age of 5.1 years with familial short stature (height SDS of -3.1). He had a prominent forehead, a depressed nasal bridge, centripetal fat distribution and a high-pitched voice resembling that of children with GH deficiency. His hormonal evaluation showed low insulin-like growth factor-1 (IGF-1) but a normal GH peak at a stimulation test. During the first year of rhGH treatment, his growth velocity increased from 3.4 to 10.4 cm/year (height SDS change of +1.1). At the last visit, he was 8.8 years old and still on treatment, his growth velocity was 6.4 cm/year and height SDS was -1.8. We identified through exome sequencing a novel heterozygous loss-of-function NPR2 mutation (c.2905G>C; p.Val969Leu). Cells cotransfected with the p.Val969Leu mutant showed a significant decrease in cyclic guanosine monophosphate (cGMP) production compared to the wild type (WT), suggesting a dominant negative effect. This case reveals a novel heterozygous loss-of-function NPR2 mutation responsible for familial short stature and the good response of rhGH therapy in this patient.

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.

A novel heterozygous germline deletion in MSH2 gene in a five generation Chinese family with Lynch syndrome

PubMed Central

Liang, Shengran; Ling, Chao; You, Yan; Xu, Lai; Zhong, Min-Er; Xiao, Yi; Qiu, Hui-Zhong; Lu, Jun-Yang; Banerjee, Santasree

2017-01-01

Lynch syndrome (LS) is one of the most common familial forms of colorectal cancer predisposing syndrome with an autosomal dominant mode of inheritance. LS is caused by the germline mutations in DNA mismatch repair (MMR) genes including MSH2, MLH1, MSH6 and PMS2. Clinically, LS is characterized by high incidence of early-onset colorectal cancer as well as endometrial, small intestinal and urinary tract cancers, usually occur in the third to fourth decade of the life. Here we describe a five generation Chinese family with LS clinically diagnosed according to the Amsterdam II criteria. Immuno-histochemical staining of MSH2 and MSH6 shows only foci nuclear positive on the surface of the tumor with strong expression of MLH1 and PMS2 with diffuse immunoreactivity. In order to dig into the molecular basis of this LS pedigree, we collected the proband's blood sample, extracted the genomic DNA and applied the genetic screening. As a result, we identified a novel heterozygous deletion in MSH2 gene by targeted next generation sequencing, which is also proved to be co-segregated among other affected family members by following validation. To our knowledge, this novel heterozygous deletion (c.1676_1679 delTAAA) in MSH2 gene causes frameshift mutation (p.Asn560Lysfs*29) and leads to the formation of a truncated MSH2 protein which is confirmed to be a deleterious mutation according to the variant interpretation guidelines of American College of Medical Genetics and Genomics (ACMG). Identification of novel DNA mismatch repair (MMR) gene mutations can definitely benefit to the clinical diagnosis and management. PMID:28903413

Heterozygous Mutations in BMP6 Pro-peptide Lead to Inappropriate Hepcidin Synthesis and Moderate Iron Overload in Humans.

PubMed

Daher, Raed; Kannengiesser, Caroline; Houamel, Dounia; Lefebvre, Thibaud; Bardou-Jacquet, Edouard; Ducrot, Nicolas; de Kerguenec, Caroline; Jouanolle, Anne-Marie; Robreau, Anne-Marie; Oudin, Claire; Le Gac, Gerald; Moulouel, Boualem; Loustaud-Ratti, Veronique; Bedossa, Pierre; Valla, Dominique; Gouya, Laurent; Beaumont, Carole; Brissot, Pierre; Puy, Hervé; Karim, Zoubida; Tchernitchko, Dimitri

2016-03-01

Hereditary hemochromatosis is a heterogeneous group of genetic disorders characterized by parenchymal iron overload. It is caused by defective expression of liver hepcidin, the main regulator of iron homeostasis. Iron stimulates the gene encoding hepcidin (HAMP) via the bone morphogenetic protein (BMP)6 signaling to SMAD. Although several genetic factors have been found to cause late-onset hemochromatosis, many patients have unexplained signs of iron overload. We investigated BMP6 function in these individuals. We sequenced the BMP6 gene in 70 consecutive patients with a moderate increase in serum ferritin and liver iron levels who did not carry genetic variants associated with hemochromatosis. We searched for BMP6 mutations in relatives of 5 probands and in 200 healthy individuals (controls), as well as in 2 other independent cohorts of hyperferritinemia patients. We measured serum levels of hepcidin by liquid chromatography-tandem mass spectrometry and analyzed BMP6 in liver biopsy specimens from patients by immunohistochemistry. The functions of mutant and normal BMP6 were assessed in transfected cells using immunofluorescence, real-time quantitative polymerase chain reaction, and immunoblot analyses. We identified 3 heterozygous missense mutations in BMP6 (p.Pro95Ser, p.Leu96Pro, and p.Gln113Glu) in 6 unrelated patients with unexplained iron overload (9% of our cohort). These mutations were detected in less than 1% of controls. p.Leu96Pro also was found in 2 patients from the additional cohorts. Family studies indicated dominant transmission. Serum levels of hepcidin were inappropriately low in patients. A low level of BMP6, compared with controls, was found in a biopsy specimen from 1 patient. In cell lines, the mutated residues in the BMP6 propeptide resulted in defective secretion of BMP6; reduced signaling via SMAD1, SMAD5, and SMAD8; and loss of hepcidin production. We identified 3 heterozygous missense mutations in BMP6 in patients with unexplained iron

Altered hippocampal replay is associated with memory impairment in mice heterozygous for the Scn2a gene.

PubMed

Middleton, Steven J; Kneller, Emily M; Chen, Shuo; Ogiwara, Ikuo; Montal, Mauricio; Yamakawa, Kazuhiro; McHugh, Thomas J

2018-06-04

An accumulating body of experimental evidence has implicated hippocampal replay occurring within sharp wave ripples (SPW-Rs) as crucial for learning and memory in healthy subjects. This raises speculation that neurological disorders impairing memory disrupt either SPW-Rs or their underlying neuronal activity. We report that mice heterozygous for the gene Scn2a, a site of frequent de novo mutations in humans with intellectual disability, displayed impaired spatial memory. While we observed no changes during encoding, to either single place cells or cell assemblies, we identified abnormalities restricted to SPW-R episodes that manifest as decreased cell assembly reactivation strengths and truncated hippocampal replay sequences. Our results suggest that alterations to hippocampal replay content may underlie disease-associated memory deficits.

Explosive mutation accumulation triggered by heterozygous human Pol ε proofreading-deficiency is driven by suppression of mismatch repair

PubMed Central

Campbell, Brittany B; Ungerleider, Nathan; Light, Nicholas; Wu, Tong; LeCompte, Kimberly G; Goksenin, A Yasemin; Bunnell, Bruce A; Tabori, Uri; Shlien, Adam

2018-01-01

Tumors defective for DNA polymerase (Pol) ε proofreading have the highest tumor mutation burden identified. A major unanswered question is whether loss of Pol ε proofreading by itself is sufficient to drive this mutagenesis, or whether additional factors are necessary. To address this, we used a combination of next generation sequencing and in vitro biochemistry on human cell lines engineered to have defects in Pol ε proofreading and mismatch repair. Absent mismatch repair, monoallelic Pol ε proofreading deficiency caused a rapid increase in a unique mutation signature, similar to that observed in tumors from patients with biallelic mismatch repair deficiency and heterozygous Pol ε mutations. Restoring mismatch repair was sufficient to suppress the explosive mutation accumulation. These results strongly suggest that concomitant suppression of mismatch repair, a hallmark of colorectal and other aggressive cancers, is a critical force for driving the explosive mutagenesis seen in tumors expressing exonuclease-deficient Pol ε. PMID:29488881

Explosive mutation accumulation triggered by heterozygous human Pol ε proofreading-deficiency is driven by suppression of mismatch repair.

PubMed

Hodel, Karl P; de Borja, Richard; Henninger, Erin E; Campbell, Brittany B; Ungerleider, Nathan; Light, Nicholas; Wu, Tong; LeCompte, Kimberly G; Goksenin, A Yasemin; Bunnell, Bruce A; Tabori, Uri; Shlien, Adam; Pursell, Zachary F

2018-02-28

Tumors defective for DNA polymerase (Pol) ε proofreading have the highest tumor mutation burden identified. A major unanswered question is whether loss of Pol ε proofreading by itself is sufficient to drive this mutagenesis, or whether additional factors are necessary. To address this, we used a combination of next generation sequencing and in vitro biochemistry on human cell lines engineered to have defects in Pol ε proofreading and mismatch repair. Absent mismatch repair, monoallelic Pol ε proofreading deficiency caused a rapid increase in a unique mutation signature, similar to that observed in tumors from patients with biallelic mismatch repair deficiency and heterozygous Pol ε mutations. Restoring mismatch repair was sufficient to suppress the explosive mutation accumulation. These results strongly suggest that concomitant suppression of mismatch repair, a hallmark of colorectal and other aggressive cancers, is a critical force for driving the explosive mutagenesis seen in tumors expressing exonuclease-deficient Pol ε. © 2018, Hodel et al.

A heterozygous mutation in RPGR associated with X-linked retinitis pigmentosa in a patient with Turner syndrome mosaicism (45,X/46,XX).

PubMed

Zhou, Qi; Yao, Fengxia; Wang, Feng; Li, Hui; Chen, Rui; Sui, Ruifang

2018-01-01

Turner syndrome with retinitis pigmentosa (RP) is rare, with only three cases reported based on clinical examination alone. We summarized the 4-year follow-up and molecular findings in a 28-year-old patient with Turner syndrome and the typical features of short stature and neck webbing, who also had X-linked RP. Her main complaints were night blindness and progressive loss of vision since the age of 9 years. Ophthalmologic examination, optical coherent tomographic imaging, and visual electrophysiology tests showed classic manifestations of RP. The karyotype of peripheral blood showed mosaicism (45,X [72%]/46,XX[28%]). A novel heterozygous frameshift mutation (c.2403_2406delAGAG, p.T801fsX812) in the RP GTPase regulator (RPGR) gene was detected using next generation sequencing and validated by Sanger sequencing. We believe that this is the first report of X-linked RP in a patient with Turner syndrome associated with mosaicism, and an RPGR heterozygous mutation. We hypothesize that X-linked RP in this woman is not related to Turner syndrome, but may be a manifestation of the lack of a normal paternal X chromosome with intact but mutated RPGR. © 2017 Wiley Periodicals, Inc.

Loss of MSH2 and MSH6 due to heterozygous germline defects in MSH3 and MSH6.

PubMed

Morak, Monika; Käsbauer, Sarah; Kerscher, Martina; Laner, Andreas; Nissen, Anke M; Benet-Pagès, Anna; Schackert, Hans K; Keller, Gisela; Massdorf, Trisari; Holinski-Feder, Elke

2017-10-01

Lynch Syndrome (LS) is the most common dominantly inherited colorectal cancer (CRC) predisposition and is caused by a heterozygous germline defect in one of the DNA mismatch repair (MMR) genes MLH1, MSH2, MSH6, or PMS2. High microsatellite instability (MSI-H) and loss of MMR protein expression in tumours reflecting a defective MMR are indicators for LS, as well as a positive family history of early onset CRC. MSH2 and MSH6 form a major functional heterodimer, and MSH3 is an alternative binding partner for MSH2. So far, the role of germline MSH3 variants remains unclear, as to our knowledge heterozygous truncating variants are not regarded causative for LS, but were detected in patients with CRC, and recently biallelic MSH3 defects have been identified in two patients with adenomatous polyposis. By gene screening we investigated the role of MSH3 in 11 LS patients with truncating MSH6 germline variants and an unexplained MSH2 protein loss in their corresponding MSI-H tumours. We report the first two LS patients harbouring heterozygous germline variants c.1035del and c.2732T>G in MSH3 coincidentally with truncating variants in MSH6. In the patient with truncating germline variants in MSH3 and MSH6, two additional somatic second hits in both genes abrogate all binding partners for the MSH2 protein which might subsequently be degraded. The clinical relevance of MSH3 germline variants is currently under re-evaluation, and heterozygous MSH3 defects alone do not seem to induce a LS phenotype, but might aggravate the MSH6 phenotype in affected family members.

Targeted exome sequencing identifies novel compound heterozygous mutations in P3H1 in a fetus with osteogenesis imperfecta type VIII.

PubMed

Huang, Yanru; Mei, Libin; Lv, Weigang; Li, Haoxian; Zhang, Rui; Pan, Qian; Tan, Hu; Guo, Jing; Luo, Xiaomei; Chen, Chen; Liang, Desheng; Wu, Lingqian

2017-01-01

Osteogenesis imperfecta (OI) is a highly clinically and genetically heterogeneous group of disorders. It is difficult to identify severe OI in the perinatal period. Here, a Chinese woman with a suspected history of fetal OI was referred to our institution at 19weeks of gestation, due to ultrasound inspection during antenatal screening, which revealed bulbous metaphyses, short humeri, and short thick bent femora in the fetus. Using targeted exome sequencing of 248 genes known to be involved in skeletal system diseases, we identified novel compound heterozygous mutation in the P3H1 gene in the fetus with OI type VIII: c.105_120del (p.D36Rfs*16) and c.2164C>T (p.Q722*). These two mutations were inherited from the father and mother, respectively. The mRNA level of P3H1 wasn't changed suggested that mRNA with this mutation escaped from nonsense-mediated RNA decay. Besides, the level of P3H1 was absence while the CRTAP was mildly decreased. In conclusion, our findings imply this novel compound heterozygous mutation as the molecular pathogenetic in a Chinese fetus with OI type VIII, and demonstrate that targeted next-generation sequencing (NGS) is an accurate, rapid, and cost-effective method in the genetic diagnosis of fetal skeletal dysplasia with genetic and clinical heterogeneity, especially for autosomal recessive skeletal disorders. Copyright © 2016 Elsevier B.V. All rights reserved.

De novo Uroplakin IIIa heterozygous mutations cause human renal adysplasia leading to severe kidney failure.

PubMed

Jenkins, Dagan; Bitner-Glindzicz, Maria; Malcolm, Sue; Hu, Chih-Chi A; Allison, Jennifer; Winyard, Paul J D; Gullett, Ambrose M; Thomas, David F M; Belk, Rachel A; Feather, Sally A; Sun, Tung-Tien; Woolf, Adrian S

2005-07-01

Human renal adysplasia usually occurs sporadically, and bilateral disease is the most common cause of childhood end-stage renal failure, a condition that is lethal without intervention using dialysis or transplantation. De novo heterozygous mutations in Uroplakin IIIa (UPIIIa) are reported in four of 17 children with kidney failure caused by renal adysplasia in the absence of an overt urinary tract obstruction. One girl and one boy in unrelated kindreds had a missense mutation at a CpG dinucleotide in the cytoplasmic domain of UPIIIa (Pro273Leu), both of whom had severe vesicoureteric reflux, and the girl had persistent cloaca; two other patients had de novo mutations in the 3' UTR (963 T-->G; 1003 T-->C), and they had renal adysplasia in the absence of any other anomaly. The mutations were absent in all sets of parents and in siblings, none of whom had radiologic evidence of renal adysplasia, and mutations were absent in two panels of 192 ethnically matched control chromosomes. UPIIIa was expressed in nascent urothelia in ureter and renal pelvis of human embryos, and it is suggested that perturbed urothelial differentiation may generate human kidney malformations, perhaps by altering differentiation of adjacent smooth muscle cells such that the metanephros is exposed to a functional obstruction of urine flow. With advances in renal replacement therapy, children with renal failure, who would otherwise have died, are surviving to adulthood. Therefore, although the mechanisms of action of the UPIIIa mutations have yet to be determined, these findings have important implications regarding genetic counseling of affected individuals who reach reproductive age.

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.

Effects of mutation, truncation, and temperature on the folding kinetics of a WW domain.

PubMed

Maisuradze, Gia G; Zhou, Rui; Liwo, Adam; Xiao, Yi; Scheraga, Harold A

2012-07-20

The purpose of this work is to show how mutation, truncation, and change of temperature can influence the folding kinetics of a protein. This is accomplished by principal component analysis of molecular-dynamics-generated folding trajectories of the triple β-strand WW domain from formin binding protein 28 (FBP28) (Protein Data Bank ID: 1E0L) and its full-size, and singly- and doubly-truncated mutants at temperatures below and very close to the melting point. The reasons for biphasic folding kinetics [i.e., coexistence of slow (three-state) and fast (two-state) phases], including the involvement of a solvent-exposed hydrophobic cluster and another delocalized hydrophobic core in the folding kinetics, are discussed. New folding pathways are identified in free-energy landscapes determined in terms of principal components for full-size mutants. Three-state folding is found to be a main mechanism for folding the FBP28 WW domain and most of the full-size and truncated mutants. The results from the theoretical analysis are compared to those from experiment. Agreements and discrepancies between the theoretical and experimental results are discussed. Because of its importance in understanding protein kinetics and function, the diffusive mechanism by which the FBP28 WW domain and its full-size and truncated mutants explore their conformational space is examined in terms of the mean-square displacement and principal component analysis eigenvalue spectrum analyses. Subdiffusive behavior is observed for all studied systems. Copyright © 2012. Published by Elsevier Ltd.

Effects of mutation, truncation and temperature on the folding kinetics of a WW domain

PubMed Central

Maisuradze, Gia G.; Zhou, Rui; Liwo, Adam; Xiao, Yi; Scheraga, Harold A.

2013-01-01

The purpose of this work is to show how mutation, truncation and change of temperature can influence the folding kinetics of a protein. This is accomplished by principal component analysis (PCA) of molecular dynamics (MD)-generated folding trajectories of the triple β-strand WW domain from the Formin binding protein 28 (FBP) [PDB: 1E0L] and its full-size, and singly- and doubly-truncated mutants at temperatures below and very close to the melting point. The reasons for biphasic folding kinetics [i.e., coexistence of slow (three-state) and fast (two-state) phases], including the involvement of a solvent-exposed hydrophobic cluster and another delocalized hydrophobic core in the folding kinetics, are discussed. New folding pathways are identified in free-energy landscapes determined in terms of principal components for full-size mutants. Three-state folding is found to be a main mechanism for folding FBP28 WW domain and most of the full-size and truncated mutants. The results from the theoretical analysis are compared to those from experiment. Agreements and discrepancies between the theoretical and experimental results are discussed. Because of its importance in understanding protein kinetics and function, the diffusive mechanism by which FBP28 WW domain and its full-size and truncated mutants explore their conformational space is examined in terms of the mean-square displacement, (MSD), and PCA eigenvalue spectrum analyses. Subdiffusive behavior is observed for all studied systems. PMID:22560992

A high frequency of distinct ATM gene mutations in ataxia-telangiectasia.

PubMed Central

Wright, J.; Teraoka, S.; Onengut, S.; Tolun, A.; Gatti, R. A.; Ochs, H. D.; Concannon, P.

1996-01-01

The clinical features of the autosomal recessive disorder ataxia-telangiectasia (AT) include a progressive cerebellar ataxia, hypersensitivity to ionizing radiation, and an increased susceptibility to malignancies. Epidemiological studies have suggested that AT heterozygotes may also be at increased risk for malignancy, possibly as a consequence of radiation exposure. A gene mutated in AT patients (ATM) has recently been isolated, making mutation screening in both patients and the general population possible. Because of the relatively large size of the ATM gene, the design of screening programs will depend on the types and distribution of mutations in the general population. In this report, we describe 30 mutations identified in a panel of unrelated AT patients and controls. Twenty-five of the 30 were distinct, and most patients were compound heterozygotes. The most frequently detected mutation was found in three different families and had previously been reported in five others. This corresponds to a frequency of 8% of all reported ATM mutations. Twenty-two of the alterations observed would be predicted to lead to protein truncation at sites scattered throughout the molecule. Two fibroblast cell lines, which displayed normal responses to ionizing radiation, also proved to be heterozygous for truncation mutations of ATM. These observations suggest that the carrier frequency of ATM mutations may be sufficiently high to make population screening practical. However, such screening may need to be done prospectively, that is, by searching for new mutations rather than by screening for just those already identified in AT families. PMID:8808599

Compound heterozygous mutations in SLC30A2/ZnT2 results in low milk zinc concentrations: a novel mechanism for zinc deficiency in a breast-fed infant.

PubMed

Itsumura, Naoya; Inamo, Yasuji; Okazaki, Fumiko; Teranishi, Fumie; Narita, Hiroshi; Kambe, Taiho; Kodama, Hiroko

2013-01-01

Zinc concentrations in breast milk are considerably higher than those of the maternal serum, to meet the infant's requirements for normal growth and development. Thus, effective mechanisms ensuring secretion of large amounts of zinc into the milk operate in mammary epithelial cells during lactation. ZnT2 was recently found to play an essential role in the secretion of zinc into milk. Heterozygous mutations of human ZnT2 (hZnT2), including H54R and G87R, in mothers result in low (>75% reduction) secretion of zinc into the breast milk, and infants fed on the milk develop transient neonatal zinc deficiency. We identified two novel missense mutations in the SLC30A2/ZnT2 gene in a Japanese mother with low milk zinc concentrations (>90% reduction) whose infant developed severe zinc deficiency; a T to C transition (c.454T>C) at exon 4, which substitutes a tryptophan residue with an arginine residue (W152R), and a C to T transition (c.887C>T) at exon 7, which substitutes a serine residue with a leucine residue (S296L). Biochemical characterization using zinc-sensitive DT40 cells indicated that the W152R mutation abolished the abilities to transport zinc and to form a dimer complex, indicating a loss-of-function mutation. The S296L mutation retained both abilities but was extremely destabilized. The two mutations were found on different alleles, indicating that the genotype of the mother with low milk zinc was compound heterozygous. These results show novel compound heterozygous mutations in the SLC30A2/ZnT2 gene causing zinc deficiency in a breast-fed infant.

Compound Heterozygous Mutations in SLC30A2/ZnT2 Results in Low Milk Zinc Concentrations: A Novel Mechanism for Zinc Deficiency in a Breast-Fed Infant

PubMed Central

Itsumura, Naoya; Inamo, Yasuji; Okazaki, Fumiko; Teranishi, Fumie; Narita, Hiroshi; Kambe, Taiho; Kodama, Hiroko

2013-01-01

Zinc concentrations in breast milk are considerably higher than those of the maternal serum, to meet the infant's requirements for normal growth and development. Thus, effective mechanisms ensuring secretion of large amounts of zinc into the milk operate in mammary epithelial cells during lactation. ZnT2 was recently found to play an essential role in the secretion of zinc into milk. Heterozygous mutations of human ZnT2 (hZnT2), including H54R and G87R, in mothers result in low (>75% reduction) secretion of zinc into the breast milk, and infants fed on the milk develop transient neonatal zinc deficiency. We identified two novel missense mutations in the SLC30A2/ZnT2 gene in a Japanese mother with low milk zinc concentrations (>90% reduction) whose infant developed severe zinc deficiency; a T to C transition (c.454T>C) at exon 4, which substitutes a tryptophan residue with an arginine residue (W152R), and a C to T transition (c.887C>T) at exon 7, which substitutes a serine residue with a leucine residue (S296L). Biochemical characterization using zinc-sensitive DT40 cells indicated that the W152R mutation abolished the abilities to transport zinc and to form a dimer complex, indicating a loss-of-function mutation. The S296L mutation retained both abilities but was extremely destabilized. The two mutations were found on different alleles, indicating that the genotype of the mother with low milk zinc was compound heterozygous. These results show novel compound heterozygous mutations in the SLC30A2/ZnT2 gene causing zinc deficiency in a breast-fed infant. PMID:23741301

Novel autosomal recessive gene mutations in aquaporin-2 in two Chinese congenital nephrogenic diabetes insipidus pedigrees

PubMed Central

Cen, Jing; Nie, Min; Duan, Lian; Gu, Feng

2015-01-01

Recent evidence has linked novel mutations in the arginine vasopressin receptor 2 gene (AVPR2) and aquaporin-2 gene (AQP2) present in Southeast Asian populations to congenital nephrogenic diabetes insipidus (NDI). To investigate mutations in 2 distinct Chinese pedigrees with NDI patients, clinical data, laboratory findings, and genomic DNA sequences from peripheral blood leukocytes were analyzed in two 5.5- and 8-year-old boys (proband 1 and 2, respectively) and their first-degree relatives. Water intake, urinary volume, body weight and medication use were recorded. Mutations in coding regions and intron-exon borders of both AQP2 and AVPR2 gene were sequenced. Three mutations in AQP2 were detected, including previously reported heterozygous frameshift mutation (c.127_128delCA, p.Gln43Aspfs ×63) inherited from the mother, a novel frameshift mutation (c.501_502insC, p.Val168Argfs ×30, inherited from the father) in proband 1 and a novel missense mutation (c. 643G>A, p. G215S), inherited from both parents in proband 2. In family 2 both parents and one sister were heterozygous carriers of the novel missense mutation. Neither pedigree exhibited mutation in the AVPR2 gene. The patient with truncated AQP2 may present with much more severe NDI manifestations. Identification of these novel AQP2 gene mutations expands the AQP2 genotypic spectrum and may contribute to etiological diagnosis and genetic counseling. PMID:26064258

Severe Early-Onset Combined Immunodeficiency due to Heterozygous Gain-of-Function Mutations in STAT1.

PubMed

Baris, Safa; Alroqi, Fayhan; Kiykim, Ayca; Karakoc-Aydiner, Elif; Ogulur, Ismail; Ozen, Ahmet; Charbonnier, Louis-Marie; Bakır, Mustafa; Boztug, Kaan; Chatila, Talal A; Barlan, Isil B

2016-10-01

Loss and gain-of-function (GOF) mutations in human signal transducer and activator of transcription 1 (STAT1) lead to distinct phenotypes. Although recurrent infections are common to both types of STAT1 mutations, GOF mutations are distinguished by chronic mucocutaneous candidiasis and autoimmunity. However, the clinical spectra of STAT1 GOF mutations continue to expand. We here describe two patients with STAT1 GOF mutations presenting early in life with combined immunodeficiency (CID). Clinical data and laboratory findings including immunophenotyping, level of interferon (IFN)-γ/IL-17(+) T cells, interferon-induced STAT1 phosphorylation, and JAK inhibitor assays were evaluated. Sequencing of STAT1 gene was performed by Sanger sequencer. Patient 1 (P1) had persistent oral candidiasis and cytomegalovirus (CMV) infection since 2 months of age and later developed cavitary lung lesions due to Mycobacterium tuberculosis. Patient 2 (P2) presented with oral candidiasis and recurrent pneumonia at 4 months of age and subsequently developed CMV pneumonitis. Both patients suffered heterozygous missense mutations in STAT1, leading to deleterious amino acid substitutions in the DNA binding domain (P1: c.1154C > T; p.T385M; P2. c.971G > T; p.C324F). Circulating CD4(+) T cells of both patients exhibited increased interferon-γ and decreased IL-17 expression as compared to controls. They also exhibited increased IFN-β and -γ-induced STAT1 phosphorylation that was reversed upon treatment with the JAK kinase inhibitor ruxolitinib. STAT1 GOF mutations may present early in life with CID, consistent with the clinical heterogeneity of the disease. JAK kinase inhibitors may potentially be useful in some patients as adjunct therapy pending definitive treatment with bone marrow transplantation.

DNA hypermethylation and X chromosome inactivation are major determinants of phenotypic variation in women heterozygous for G6PD mutations.

PubMed

Wang, Jin; Xiao, Qi-Zhi; Chen, You-Ming; Yi, Sheng; Liu, Dun; Liu, Yan-Hui; Zhang, Cui-Mei; Wei, Xiao-Feng; Zhou, Yu-Qiu; Zhong, Xing-Ming; Zhao, Cun-You; Xiong, Fu; Wei, Xiang-Cai; Xu, Xiang-Min

2014-12-01

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked incompletely dominant enzyme deficiency that results from G6PD gene mutations. Women heterozygous for G6PD mutations exhibit variation in the loss of enzyme activity but the cause of this phenotypic variation is unclear. We determined DNA methylation and X-inactivation patterns in 71 G6PD-deficient female heterozygotes and 68 G6PD non-deficient controls with the same missense mutations (G6PD Canton c.1376G>T or Kaiping c.1388G>A) to correlate determinants with variable phenotypes. Specific CpG methylations within the G6PD promoter were significantly higher in G6PD-deficient heterozygotes than in controls. Preferential X-inactivation of the G6PD wild-type allele was determined in heterozygotes. The incidence of preferential X-inactivation was 86.2% in the deficient heterozygote group and 31.7% in the non-deficient heterozygote group. A significant negative correlation was observed between X-inactivation ratios of the wild-type allele and G6PD/6-phosphogluconate dehydrogenase (6PGD) ratios in heterozygous G6PD Canton (r=-0.657, p<0.001) or Kaiping (r=-0.668, p<0.001). Multivariate logistic regression indicated that heterozygotes with hypermethylation of specific CpG sites in the G6PD promoter and preferential X-inactivation of the wild-type allele were at risk of enzyme deficiency. Copyright © 2014 Elsevier Inc. All rights reserved.

Diversified clinical presentations associated with a novel sal-like 4 gene mutation in a Chinese pedigree with Duane retraction syndrome.

PubMed

Yang, Ming-ming; Ho, Mary; Lau, Henry H W; Tam, Pancy O S; Young, Alvin L; Pang, Chi Pui; Yip, Wilson W K; Chen, LiJia

2013-01-01

To determine the underlying genetic cause of Duane retraction syndrome (DRS) in a non-consanguineous Chinese Han family. Detailed ophthalmic and physical examinations were performed on all members from a pedigree with DRS. All exons and their adjacent splicing junctions of the sal-like 4 (SALL4) gene were amplified with polymerase chain reaction and analyzed with direct sequencing in all the recruited family members and 200 unrelated control subjects. Clinical examination revealed a broad spectrum of phenotypes in the DRS family. Mutation analysis of SALL4 identified a novel heterozygous duplication mutation, c.1919dupT, which was completely cosegregated with the disease in the family and absent in controls. This mutation was predicted to cause a frameshift, introducing a premature stop codon, when translated, resulting in a truncated SALL4 protein, i.e., p.Met640IlefsX25. Bioinformatics analysis showed that the affected region of SALL4 shared a highly conserved sequence across different species. Diversified clinical manifestations were observed in the c.1919dupT carriers of the family. We identified a novel truncating mutation in the SALL4 gene that leads to diversified clinical features of DRS in a Chinese family. This mutation is predicted to result in a truncated SALL4 protein affecting two functional domains and cause disease development due to haploinsufficiency through nonsense-mediated mRNA decay.

[Identification of novel compound heterozygous mutations of USH2A gene in a family with Usher syndrome type II].

PubMed

Jiang, Haiou; Ge, Chuanqin; Wang, Yiwang; Tang, Genyun; Quan, Qingli

2015-06-01

To identify potential mutations in a Chinese family with Usher syndrome type II. Genomic DNA was obtained from two affected and four unaffected members of the family and subjected to amplification of the entire coding sequence and splicing sites of USH2A gene. Mutation detection was conducted by direct sequencing of the PCR products. A total of 100 normal unrelated individuals were used as controls. The patients were identified to be a compound heterozygote for two mutations: c.8272G>T (p.E2758X) in exon 42 from his mother and c.12376-12378ACT>TAA(p.T4126X) in exon 63 of the USH2A gene from his father. Both mutations were not found in either of the two unaffected family members or 100 unrelated controls, and had completely co-segregated with the disease phenotype in the family. Neither mutation has been reported in the HGMD database. The novel compound heterozygous mutations c.8272G>T and c.12376-12378ACT>TAA within the USH2A gene may be responsible for the disease. This result may provide new clues for molecular diagnosis of this disease.

Screening for duplications, deletions and a common intronic mutation detects 35% of second mutations in patients with USH2A monoallelic mutations on Sanger sequencing.

PubMed

Steele-Stallard, Heather B; Le Quesne Stabej, Polona; Lenassi, Eva; Luxon, Linda M; Claustres, Mireille; Roux, Anne-Francoise; Webster, Andrew R; Bitner-Glindzicz, Maria

2013-08-08

Usher Syndrome is the leading cause of inherited deaf-blindness. It is divided into three subtypes, of which the most common is Usher type 2, and the USH2A gene accounts for 75-80% of cases. Despite recent sequencing strategies, in our cohort a significant proportion of individuals with Usher type 2 have just one heterozygous disease-causing mutation in USH2A, or no convincing disease-causing mutations across nine Usher genes. The purpose of this study was to improve the molecular diagnosis in these families by screening USH2A for duplications, heterozygous deletions and a common pathogenic deep intronic variant USH2A: c.7595-2144A>G. Forty-nine Usher type 2 or atypical Usher families who had missing mutations (mono-allelic USH2A or no mutations following Sanger sequencing of nine Usher genes) were screened for duplications/deletions using the USH2A SALSA MLPA reagent kit (MRC-Holland). Identification of USH2A: c.7595-2144A>G was achieved by Sanger sequencing. Mutations were confirmed by a combination of reverse transcription PCR using RNA extracted from nasal epithelial cells or fibroblasts, and by array comparative genomic hybridisation with sequencing across the genomic breakpoints. Eight mutations were identified in 23 Usher type 2 families (35%) with one previously identified heterozygous disease-causing mutation in USH2A. These consisted of five heterozygous deletions, one duplication, and two heterozygous instances of the pathogenic variant USH2A: c.7595-2144A>G. No variants were found in the 15 Usher type 2 families with no previously identified disease-causing mutations. In 11 atypical families, none of whom had any previously identified convincing disease-causing mutations, the mutation USH2A: c.7595-2144A>G was identified in a heterozygous state in one family. All five deletions and the heterozygous duplication we report here are novel. This is the first time that a duplication in USH2A has been reported as a cause of Usher syndrome. We found that 8 of

A novel truncating AIP mutation, p.W279*, in a familial isolated pituitary adenoma (FIPA) kindred.

PubMed

Cansu, Güven Barış; Taşkıran, Bengür; Trivellin, Giampaolo; Faucz, Fabio R; Stratakis, Constantine A

2016-07-01

Familial isolated pituitary adenomas (FIPA) constitute 2-3% of pituitary tumours. AIP is the most commonly mutated gene in FIPA. We herein report a novel germline mutation of the AIP gene in a family with FIPA. We present two patients, a father and his 12-year-old daughter, diagnosed clinically and using laboratory measures with acromegaly-gigantism. Both underwent transsphenoidal hypophyseal surgery for macroadenomas. We initially detected a novel heterozygous germline AIP mutation, c.836G>A (p.W279*), in the father's DNA. We then found the same mutation in his affected daughter. Pituitary adenomas associated with AIP mutations mostly present as FIPA (68%) at an early age (78% occur at <30 years old). They are often growth hormone (GH) - or prolactin - secreting macroadenomas (88%) that have already extended beyond the sella at the time of diagnosis. Acromegalic cases are resistant to somatostatin analogues and multimodal management is frequently essential to control the disease. Our patients had normalized GH/IGF-1 values soon after surgery, although enough time may not have elapsed to reach final cure. While penetrance of the disease can be as low as 10% in FIPA, especially children and young patients with somatotropinoma and prolactinoma should be surveyed for inactivating mutations or deletions in AIP. Determining the causative mutations may be of assistance in early diagnosis, treatment success, and genetic counseling.

Truncating mutations of MAGEL2 cause Prader-Willi phenotypes and autism.

PubMed

Schaaf, Christian P; Gonzalez-Garay, Manuel L; Xia, Fan; Potocki, Lorraine; Gripp, Karen W; Zhang, Baili; Peters, Brock A; McElwain, Mark A; Drmanac, Radoje; Beaudet, Arthur L; Caskey, C Thomas; Yang, Yaping

2013-11-01

Prader-Willi syndrome (PWS) is caused by the absence of paternally expressed, maternally silenced genes at 15q11-q13. We report four individuals with truncating mutations on the paternal allele of MAGEL2, a gene within the PWS domain. The first subject was ascertained by whole-genome sequencing analysis for PWS features. Three additional subjects were identified by reviewing the results of exome sequencing of 1,248 cases in a clinical laboratory. All four subjects had autism spectrum disorder (ASD), intellectual disability and a varying degree of clinical and behavioral features of PWS. These findings suggest that MAGEL2 is a new gene causing complex ASD and that MAGEL2 loss of function can contribute to several aspects of the PWS phenotype.

Canine MPV17 truncation without clinical manifestations

PubMed Central

Hänninen, Reetta L.; Ahonen, Saija; Màrquez, Merce; Myöhänen, Maarit J.; Hytönen, Marjo K.; Lohi, Hannes

2015-01-01

ABSTRACT Mitochondrial DNA depletion syndromes (MDS) are often serious autosomal recessively inherited disorders characterized by tissue-specific mtDNA copy number reduction. Many genes, including MPV17, are associated with the hepatocerebral form of MDS. MPV17 encodes for a mitochondrial inner membrane protein with a poorly characterized function. Several MPV17 mutations have been reported in association with a heterogeneous group of early-onset manifestations, including liver disease and neurological problems. Mpv17-deficient mice present renal and hearing defects. We describe here a MPV17 truncation mutation in dogs. We found a 1-bp insertion in exon 4 of the MPV17 gene, resulting in a frameshift and early truncation of the encoded protein. The mutation halves MPV17 expression in the lymphocytes of the homozygous dogs and the truncated protein is not translated in transfected cells. The insertion mutation is recurrent and exists in many unrelated breeds, although is highly enriched in the Boxer breed. Unexpectedly, despite the truncation of MPV17, we could not find any common phenotypes in the genetically affected dogs. The lack of observable phenotype could be due to a late onset, mild symptoms or potential tissue-specific compensatory mechanisms. This study suggests species-specific differences in the manifestation of the MPV17 defects and establishes a novel large animal model to further study MPV17 function and role in mitochondrial biology. PMID:26353863

Behavioral and Electrophysiological Characterization of Dyt1 Heterozygous Knockout Mice

PubMed Central

Yokoi, Fumiaki; Chen, Huan-Xin; Dang, Mai Tu; Cheetham, Chad C.; Campbell, Susan L.; Roper, Steven N.; Sweatt, J. David; Li, Yuqing

2015-01-01

DYT1 dystonia is an inherited movement disorder caused by mutations in DYT1 (TOR1A), which codes for torsinA. Most of the patients have a trinucleotide deletion (ΔGAG) corresponding to a glutamic acid in the C-terminal region (torsinAΔE). Dyt1 ΔGAG heterozygous knock-in (KI) mice, which mimic ΔGAG mutation in the endogenous gene, exhibit motor deficits and deceased frequency of spontaneous excitatory post-synaptic currents (sEPSCs) and normal theta-burst-induced long-term potentiation (LTP) in the hippocampal CA1 region. Although Dyt1 KI mice show decreased hippocampal torsinA levels, it is not clear whether the decreased torsinA level itself affects the synaptic plasticity or torsinAΔE does it. To analyze the effect of partial torsinA loss on motor behaviors and synaptic transmission, Dyt1 heterozygous knock-out (KO) mice were examined as a model of a frame-shift DYT1 mutation in patients. Consistent with Dyt1 KI mice, Dyt1 heterozygous KO mice showed motor deficits in the beam-walking test. Dyt1 heterozygous KO mice showed decreased hippocampal torsinA levels lower than those in Dyt1 KI mice. Reduced sEPSCs and normal miniature excitatory post-synaptic currents (mEPSCs) were also observed in the acute hippocampal brain slices from Dyt1 heterozygous KO mice, suggesting that the partial loss of torsinA function in Dyt1 KI mice causes action potential-dependent neurotransmitter release deficits. On the other hand, Dyt1 heterozygous KO mice showed enhanced hippocampal LTP, normal input-output relations and paired pulse ratios in the extracellular field recordings. The results suggest that maintaining an appropriate torsinA level is important to sustain normal motor performance, synaptic transmission and plasticity. Developing therapeutics to restore a normal torsinA level may help to prevent and treat the symptoms in DYT1 dystonia. PMID:25799505

Behavioral and electrophysiological characterization of Dyt1 heterozygous knockout mice.

PubMed

Yokoi, Fumiaki; Chen, Huan-Xin; Dang, Mai Tu; Cheetham, Chad C; Campbell, Susan L; Roper, Steven N; Sweatt, J David; Li, Yuqing

2015-01-01

DYT1 dystonia is an inherited movement disorder caused by mutations in DYT1 (TOR1A), which codes for torsinA. Most of the patients have a trinucleotide deletion (ΔGAG) corresponding to a glutamic acid in the C-terminal region (torsinA(ΔE)). Dyt1 ΔGAG heterozygous knock-in (KI) mice, which mimic ΔGAG mutation in the endogenous gene, exhibit motor deficits and deceased frequency of spontaneous excitatory post-synaptic currents (sEPSCs) and normal theta-burst-induced long-term potentiation (LTP) in the hippocampal CA1 region. Although Dyt1 KI mice show decreased hippocampal torsinA levels, it is not clear whether the decreased torsinA level itself affects the synaptic plasticity or torsinA(ΔE) does it. To analyze the effect of partial torsinA loss on motor behaviors and synaptic transmission, Dyt1 heterozygous knock-out (KO) mice were examined as a model of a frame-shift DYT1 mutation in patients. Consistent with Dyt1 KI mice, Dyt1 heterozygous KO mice showed motor deficits in the beam-walking test. Dyt1 heterozygous KO mice showed decreased hippocampal torsinA levels lower than those in Dyt1 KI mice. Reduced sEPSCs and normal miniature excitatory post-synaptic currents (mEPSCs) were also observed in the acute hippocampal brain slices from Dyt1 heterozygous KO mice, suggesting that the partial loss of torsinA function in Dyt1 KI mice causes action potential-dependent neurotransmitter release deficits. On the other hand, Dyt1 heterozygous KO mice showed enhanced hippocampal LTP, normal input-output relations and paired pulse ratios in the extracellular field recordings. The results suggest that maintaining an appropriate torsinA level is important to sustain normal motor performance, synaptic transmission and plasticity. Developing therapeutics to restore a normal torsinA level may help to prevent and treat the symptoms in DYT1 dystonia.

A novel heterozygous intronic mutation in POU1F1 is associated with combined pituitary hormone deficiency.

PubMed

Takagi, Masaki; Kamasaki, Hotaka; Yagi, Hiroko; Fukuzawa, Ryuji; Narumi, Satoshi; Hasegawa, Tomonobu

2017-02-27

POU class 1 homeobox 1 (POU1F1) regulates pituitary cell-specific gene expression of somatotropes, lactotropes, and thyrotropes. In humans, two POU1F1 isoforms (long and short isoform), which are generated by the alternative use of the splice acceptor site for exon 2, have been identified. To date, more than 30 POU1F1 mutations in patients with combined pituitary hormone deficiency (CPHD) have been described. All POU1F1 variants reported to date affect both the short and long isoforms of the POU1F1 protein; therefore, it is unclear at present whether a decrease in the function of only one of these two isoforms is sufficient for disease onset in humans. Here, we described a sibling case of CPHD carrying a heterozygous mutation in intron 1 of POU1F1. In vitro experiments showed that this mutation resulted in exon 2-skipping of only in the short isoform of POU1F1, while the long isoform remained intact. This result strongly suggests the possibility, for the first time, that isolated mutations in the short isoform of POU1F1 could be sufficient for induction of POU1F1-related CPHD. This finding improves our understanding of the molecular mechanisms, and developmental course associated with mutations in POU1F1.

Two novel compound heterozygous mutations in the BCKDHB gene that cause the intermittent form of maple syrup urine disease.

PubMed

Guo, Yi; Liming, Liu; Jiang, Li

2015-12-01

Intermittent maple syrup urine disease (MSUD) is a potentially life-threatening metabolic disorder caused by a deficiency of branched chain α-ketoacid dehydrogenase (BCKD) complex. In contrast to classic MSUD, children with the intermittent form usually have an atypical clinical manifestation. Here, we describe the presenting symptoms and clinical course of a Chinese boy with intermittent MSUD. Mutation analysis identified two previously unreported mutations in exon 7 of the BCKDHB gene: c.767A > G (p.Y256C) and c.768C > G (p.Y256X); the parents were each heterozygous for one of these mutations. In silico analysis predicted Y256C probably affects protein structure; Y256X leads to a premature stop codon. This case demonstrates intermittent MSUD should be suspected in cases with symptoms of recurrent encephalopathy, especially ataxia or marked drowsiness, which usually present after the neonatal period and in conjunction with infection. symmetrical basal ganglia damage but normal myelination in the posterior limb will assist differential diagnosis; alloisoleucine is a useful diagnostic marker and mutation analysis may be of prognostic value. These novel mutations Y256C and Y256X result in the clinical manifestation of a variant form of MSUD, expanding the mutation spectrum of this disease.

A novel pathogenic mutation of the CYP27B1 gene in a patient with vitamin D-dependent rickets type 1: a case report.

PubMed

Babiker, Amir M I; Al Gadi, Iman; Al-Jurayyan, Nasir A M; Al Nemri, Abdulrahman M H; Al Haboob, Ali Abdu N; Al Boukai, Ahmed Amer; Al Zahrani, Ali; Habib, Hanan Ahmed

2014-11-05

Rickets can occur due to Vitamin D deficiency or defects in its metabolism. Three rare genetic types of rickets with different alterations of genes have been reported, including: Vitamin D dependent rickets type 1, Vitamin D dependent rickets type 2 or also known as Vitamin D resistant rickets and 25 hydroxylase deficiency rickets. Vitamin D dependent rickets type 1 is inherited in an autosomal recessive pattern, and is caused by mutations in the CYP27B1 gene encoding the 1α-hydroxylase enzyme. We report here a new mutation in CYP27B1, which lead to Vitamin D dependent rickets type 1. We report on a 13-month-old Arabic Saudi girl with Vitamin D dependent rickets type 1 presented with multiple fractures and classic features of rickets. A whole exome sequencing identified a novel pathogenic missense mutation (CYP27B1:Homozygous c.1510C > T(p.Q504X)) which results in a protein truncating alteration. Both parents are heterozygous carriers of the mutation. Based on data search in Human Gene Mutation Database, 63 CYP27B1 alterations were reported: only 28.6% are protein truncating (5 nonsense, 13 frameshift insertions/deletions, 0 gross deletions), while 61.9% are non-truncating (38 missense, 1 small in-frame insertions/deletion), and 9.5% are possible protein-truncating (5 splice, 1 regulatory). The deleterious effect of this alteration, which was the only mutation detected in the CYP27B1 common gene of Vitamin D dependent rickets type 1 in the proband, and its autosomal recessive inheritance fashion, both support a pathogenic nature of this mutation as the cause of Vitamin D dependent rickets type 1.

Rapid identification of mutations in the IDS gene of Hunter patients: Analysis of mRNA by the protein truncation test

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

Hogervorst, F.B.L.; Tuijn, A.C. van der; Ommen, G.J.B. van

Hunter syndrome is an X-linked recessive disorder constituting phenotypes ranging from mild to severe. The gene affected in Hunter syndrome is iduronate-2-sulfatase (IDS). The identification of mutations leading to a defective enzyme could be of benefit for the diagnosis and prognosis of patients. At this moment a variety of mutations have been found, including large deletions and base substitutions. We have previously described a method, designated the protein truncation test (PTT), for the detection of mutations leading to premature translation termination. The method combines reverse transcription and PCR (RT-PCR) with in vitro transcript/translation of the products generated. To facilitate amore » PTT analysis, the forward primer is modified by addition of a T7 promoter sequence and an in-frame protein translation initiation sequence. In our department the method has been successfully applied for DMD and FAP. Here we report on the PTT analysis of 8 Hunter patients, all of them without major gene alterations as determined by Southern analysis. Total RNA was isolated from cultured skin fibroblasts or peripheral blood lymphocytes. PTT analysis revealed 4 novel mutations in the IDS gene: two missense mutations and two frameshift mutations (splice donor site alteration in intron 6 and a 13 bp deletion in exon 9). Furthermore, PTT proved to be a simple method to identify carriers. Currently, we use the generated RT-PCR products of the remaining patients for automated sequence analysis. PTT may be of great value in screening disorders in which affected genes give rise to truncated protein products.« less

[Molecular characterization of heterozygous beta-thalassemia in Lanzarote, Spain].

PubMed

Calvo-Villas, José Manuel; de la Iglesia Iñigo, Silvia; Ropero Gradilla, Paloma; Zapata Ramos, María Francisca; Cuesta Tovar, Jorge; Sicilia Guillén, Francisco

2008-04-05

The aim of this study was to determine the molecular defects of heterozygous beta thalassaemia and to ascertain their distribution in Lanzarote. Molecular characterization was achieved by real time polymerase chain reaction (RT-PCR LightCycler, Roche), PCR-ARMS (PCR-amplification reaction mutations system) and DNA sequencing on an automated DNA sequencer. Two hundred forty-three heterozygous beta thalassaemia carriers were included between July 1991 and February 2007. RT-PCR detected the molecular defect in 81% of the beta thalassaemia chromosomes analyzed [113 codon CD 39 (C --> T); 41 IVS-1-nt-110 (G --> A), 25 IVS 1-nt-1 (G --> A) and 19 IVS 1-nt-6 (T --> C)]. The remaining 12 molecular defects included the deletion 619 bp (7.8%) and the mutations -28 (A --> G), IVS1-nt-2 (T --> G), CD 41/42 (-TTCT), CD 8/9 (+G), CD 51 (-C), CD 22 (G --> T) and CD 24 (T --> A), CD 67 (-TG) and the novel mutation CD 20/21-TGGA. The distribution of the mutations is similar to that found in the Mediterranean area. The increasing migratory flow received in the Canary Islands may explain the emergence of new mutations not reported before in our area.

Exome sequencing reveals two novel compound heterozygous XYLT1 mutations in a Polish patient with Desbuquois dysplasia type 2 and growth hormone deficiency.

PubMed

Jamsheer, Aleksander; Olech, Ewelina M; Kozłowski, Kazimierz; Niedziela, Marek; Sowińska-Seidler, Anna; Obara-Moszyńska, Monika; Latos-Bieleńska, Anna; Karczewski, Marek; Zemojtel, Tomasz

2016-07-01

Desbuquois dysplasia type 2 (DBQD2) is a rare recessively inherited skeletal genetic disorder characterized by severe prenatal and postnatal growth retardation, generalized joint laxity with dislocation of large joints and facial dysmorphism. The condition was recently described to result from autosomal recessive mutations in XYLT1, encoding the enzyme xylosyltransferase-1. In this paper, we report on a Polish patient with DBQD2 who presented with severe short stature of prenatal onset, joint laxity, psychomotor retardation and multiple radiological abnormalities including short metacarpals, advanced bone age and exaggerated trochanters. Endocrinological examinations revealed that sleep-induced growth hormone (GH) release and GH peak in clonidine- and glucagon-induced provocative tests as well as insulin-like growth factor 1 (IGF-1) and IGF-binding protein-3 levels were all markedly decreased, confirming deficiency of GH secretion. Bone age, unlikely to GH deficiency, was significantly advanced. To establish the diagnosis at a molecular level, we performed whole-exome sequencing and bioinformatic analysis in the index patient, which revealed compound heterozygous XYLT1 mutations: c.595C>T(p.Gln199*) and c.1651C>T(p.Arg551Cys), both of which are novel. Sanger sequencing showed that the former mutation was inherited from the healthy mother, whereas the latter one most probably occurred de novo. Our study describes the first case of DBQD2 resulting from compound heterozygous XYLT1 mutation, expands the mutational spectrum of the disease and provides evidence that the severe growth retardation and microsomia observed in DBQD2 patients may result not only from the skeletal dysplasia itself but also from GH and IGF-1 deficiency.

Whole-exome sequencing identifies novel compound heterozygous mutations in USH2A in Spanish patients with autosomal recessive retinitis pigmentosa.

PubMed

Méndez-Vidal, Cristina; González-Del Pozo, María; Vela-Boza, Alicia; Santoyo-López, Javier; López-Domingo, Francisco J; Vázquez-Marouschek, Carmen; Dopazo, Joaquin; Borrego, Salud; Antiñolo, Guillermo

2013-01-01

Retinitis pigmentosa (RP) is an inherited retinal dystrophy characterized by extreme genetic and clinical heterogeneity. Thus, the diagnosis is not always easily performed due to phenotypic and genetic overlap. Current clinical practices have focused on the systematic evaluation of a set of known genes for each phenotype, but this approach may fail in patients with inaccurate diagnosis or infrequent genetic cause. In the present study, we investigated the genetic cause of autosomal recessive RP (arRP) in a Spanish family in which the causal mutation has not yet been identified with primer extension technology and resequencing. We designed a whole-exome sequencing (WES)-based approach using NimbleGen SeqCap EZ Exome V3 sample preparation kit and the SOLiD 5500×l next-generation sequencing platform. We sequenced the exomes of both unaffected parents and two affected siblings. Exome analysis resulted in the identification of 43,204 variants in the index patient. All variants passing filter criteria were validated with Sanger sequencing to confirm familial segregation and absence in the control population. In silico prediction tools were used to determine mutational impact on protein function and the structure of the identified variants. Novel Usher syndrome type 2A (USH2A) compound heterozygous mutations, c.4325T>C (p.F1442S) and c.15188T>G (p.L5063R), located in exons 20 and 70, respectively, were identified as probable causative mutations for RP in this family. Family segregation of the variants showed the presence of both mutations in all affected members and in two siblings who were apparently asymptomatic at the time of family ascertainment. Clinical reassessment confirmed the diagnosis of RP in these patients. Using WES, we identified two heterozygous novel mutations in USH2A as the most likely disease-causing variants in a Spanish family diagnosed with arRP in which the cause of the disease had not yet been identified with commonly used techniques. Our data

Whole-exome sequencing identifies novel compound heterozygous mutations in USH2A in Spanish patients with autosomal recessive retinitis pigmentosa

PubMed Central

Méndez-Vidal, Cristina; González-del Pozo, María; Vela-Boza, Alicia; Santoyo-López, Javier; López-Domingo, Francisco J.; Vázquez-Marouschek, Carmen; Dopazo, Joaquin; Borrego, Salud

2013-01-01

Purpose Retinitis pigmentosa (RP) is an inherited retinal dystrophy characterized by extreme genetic and clinical heterogeneity. Thus, the diagnosis is not always easily performed due to phenotypic and genetic overlap. Current clinical practices have focused on the systematic evaluation of a set of known genes for each phenotype, but this approach may fail in patients with inaccurate diagnosis or infrequent genetic cause. In the present study, we investigated the genetic cause of autosomal recessive RP (arRP) in a Spanish family in which the causal mutation has not yet been identified with primer extension technology and resequencing. Methods We designed a whole-exome sequencing (WES)-based approach using NimbleGen SeqCap EZ Exome V3 sample preparation kit and the SOLiD 5500×l next-generation sequencing platform. We sequenced the exomes of both unaffected parents and two affected siblings. Exome analysis resulted in the identification of 43,204 variants in the index patient. All variants passing filter criteria were validated with Sanger sequencing to confirm familial segregation and absence in the control population. In silico prediction tools were used to determine mutational impact on protein function and the structure of the identified variants. Results Novel Usher syndrome type 2A (USH2A) compound heterozygous mutations, c.4325T>C (p.F1442S) and c.15188T>G (p.L5063R), located in exons 20 and 70, respectively, were identified as probable causative mutations for RP in this family. Family segregation of the variants showed the presence of both mutations in all affected members and in two siblings who were apparently asymptomatic at the time of family ascertainment. Clinical reassessment confirmed the diagnosis of RP in these patients. Conclusions Using WES, we identified two heterozygous novel mutations in USH2A as the most likely disease-causing variants in a Spanish family diagnosed with arRP in which the cause of the disease had not yet been identified with

A Novel Heterozygous Mutation in the T-box Protein 4 Gene in an Adult Case of Small Patella Syndrome.

PubMed

Oda, Tomoyuki; Matsushita, Masaki; Ono, Yohei; Kitoh, Hiroshi; Sakai, Tadahiro

2018-01-01

Small patella syndrome (SPS) is a rare skeletal dysplasia relating to the T-box protein 4 (TBX4) gene, which regulates the development of lower extremities. Patients typically present with recurrent patellar dislocation (RPD) in childhood or adolescence, leading to a diagnosis of SPS and subsequent treatment to improve activity levels. However, those with mild symptoms may not be diagnosed when young and present later after skeletal maturation, which might compromise treatment options. Further understanding of genetic mutations of SPS could possibly help early diagnosis and following adequate surgical treatment. In this case report, we present a surgically treated adult female case of RPD associated with SPS, carrying a novel heterozygous mutation in the TBX4 gene. A 19-year-old female presented with persistent right knee pain after an atraumatic episode ofpatellar dislocation during walking. The patient had a history of recurrent patella instability of the right knee with an onset at the age of 8 years due to a minor trauma. Patellar apprehension sign was positive bilaterally. There was radiological evidence of bilateral small patellae, hypoplastic femoral trochlea, and tibial tuberosity. A direct sequencing of the coding regions in the TBX4 gene had confirmed the diagnosis of SPS. A novel heterozygous mutation (p.L39PfsX35) was found in the patient and her father. Surgical treatment was indicated and the patient underwent an isolated medial patellofemoral ligament (MPFL) reconstruction while no distal realignment osteotomy was performed due to hypoplastic tibial tuberosity. Excellent subjective and objective outcomes were obtained at 1 year postoperatively. To the best of our knowledge, this is the first reported SPS case with a novel mutation in the TBX4 gene in an Asian population. While a satisfying short-term outcome was obtained by an isolated MPFL reconstruction, early genetic diagnosis in childhood with adequate surgical treatment (e.g., Roux

Identification of a novel heterozygous missense mutation in the CACNA1F gene in a chinese family with retinitis pigmentosa by next generation sequencing.

PubMed

Zhou, Qi; Cheng, Jingliang; Yang, Weichan; Tania, Mousumi; Wang, Hui; Khan, Md Asaduzzaman; Duan, Chengxia; Zhu, Li; Chen, Rui; Lv, Hongbin; Fu, Junjiang

2015-01-01

Retinitis pigmentosa (RP) is an inherited retinal degenerative disease, which is clinically and genetically heterogeneous, and the inheritance pattern is complex. In this study, we have intended to study the possible association of certain genes with X-linked RP (XLRP) in a Chinese family. A Chinese family with RP was recruited, and a total of seven individuals were enrolled in this genetic study. Genomic DNA was isolated from peripheral leukocytes, and used for the next generation sequencing (NGS). The affected individual presented the clinical signs of XLRP. A heterozygous missense mutation (c.1555C>T, p.R519W) was identified by NGS in exon 13 of the CACNA1F gene on X chromosome, and was confirmed by Sanger sequencing. It showed perfect cosegregation with the disease in the family. The mutation at this position in the CACNA1F gene of RP was found novel by database searching. By using NGS, we have found a novel heterozygous missense mutation (c.1555C>T, p.R519W) in CACNA1F gene, which is probably associated with XLRP. The findings might provide new insights into the cause and diagnosis of RP, and have implications for genetic counseling and clinical management in this family.

Identification of a Novel Heterozygous Missense Mutation in the CACNA1F Gene in a Chinese Family with Retinitis Pigmentosa by Next Generation Sequencing

PubMed Central

Tania, Mousumi; Wang, Hui; Khan, Md. Asaduzzaman; Duan, Chengxia; Zhu, Li; Chen, Rui; Lv, Hongbin

2015-01-01

Background. Retinitis pigmentosa (RP) is an inherited retinal degenerative disease, which is clinically and genetically heterogeneous, and the inheritance pattern is complex. In this study, we have intended to study the possible association of certain genes with X-linked RP (XLRP) in a Chinese family. Methods. A Chinese family with RP was recruited, and a total of seven individuals were enrolled in this genetic study. Genomic DNA was isolated from peripheral leukocytes, and used for the next generation sequencing (NGS). Results. The affected individual presented the clinical signs of XLRP. A heterozygous missense mutation (c.1555C>T, p.R519W) was identified by NGS in exon 13 of the CACNA1F gene on X chromosome, and was confirmed by Sanger sequencing. It showed perfect cosegregation with the disease in the family. The mutation at this position in the CACNA1F gene of RP was found novel by database searching. Conclusion. By using NGS, we have found a novel heterozygous missense mutation (c.1555C>T, p.R519W) in CACNA1F gene, which is probably associated with XLRP. The findings might provide new insights into the cause and diagnosis of RP, and have implications for genetic counseling and clinical management in this family. PMID:26075273

Heterozygous p.Asp50Asn mutation in the GJB2 gene in two Cameroonian patients with keratitis-ichthyosis-deafness (KID) syndrome.

PubMed

Wonkam, Ambroise; Noubiap, Jean Jacques N; Bosch, Jason; Dandara, Collet; Toure, Geneviève Bengono

2013-08-07

Keratitis-Ichthyosis-Deafness (KID) syndrome (OMIM 148210) is a congenital ectodermal defect that consists of an atypical ichthyosiform erythroderma associated with congenital sensorineural deafness. KID appears to be genetically heterogeneous and most cases are caused by GJB2 mutations. Mutations in African patients have been rarely described. We report on two unrelated Cameroonian individuals affected with sporadic KID, presenting with the classic phenotypic triad. The two patients were heterozygous for the most frequent p.Asp50Asn mutation. This first report in patients from sub-Saharan African origin supports the hypothesis that the occurrence of KID due to p.Asp50Asn mutation in GJB2 seems not to be population specific. Our finding has implication in medical genetic practice, specifically in the molecular diagnosis of KID in Africans. These cases also reveal and emphasize the urgent need to develop appropriate policies to care for patients with rare/orphan diseases in Sub-Saharan Africa, as many of these cases become more and more recognizable.

Novel Compound Heterozygous CLCNKB Gene Mutations (c.1755A>G/ c.848_850delTCT) Cause Classic Bartter Syndrome.

PubMed

Wang, Chunli; Chen, Ying; Zheng, Bixia; Zhu, Mengshu; Fan, Jia; Wang, Juejin; Jia, Zhanjun; Huang, Songming; Zhang, Aihua

2018-02-14

Inactivated variants in CLCNKB gene encoding the basolateral chloride channel ClC-Kb cause classic Bartter syndrome characterized by hypokalemic metabolic alkalosis and hyperreninemic hyperaldosteronism. Here we identified two cBS siblings presenting hypokalemia in a Chinese family due to novel compound heterozygous CLCNKB mutations (c.848_850delTCT/c.1755A>G). Compound heterozygosity was confirmed by amplifying and sequencing the patient's genomic DNA. The synonymous mutation c.1755A>G (Thr585Thr) was located at +2bp from the 5' splice donor site in exon 15, further transcript analysis demonstrated that this single nucleotide mutation causes exclusion of exon 15 in the cDNA from the proband and his mother. Furthermore, we investigated the expression and protein trafficking change of c.848_850delTCT (TCT) and exon 15 deletion（E15）mutation in vitro. The E15 mutation markedly decreased the expression of ClC-Kb and resulted in a low-molecular-weight band (~55kD) trapping in the endoplasmic reticulum, while the TCT mutant only decreased the total and plasma membrane ClC-Kb protein expression but did not affect the subcellular localization. Finally, we studied the physiological functions of mutations by using whole-cell patch clamp and found that E15 or TCT mutation decreased the current of ClC-Kb/barttin channel. These results suggested that the compound defective mutations of CLCNKB gene are the molecular mechanism of the two cBS siblings.

Two truncating USH3A mutations, including one novel, in a German family with Usher syndrome.

PubMed

Ebermann, Inga; Wilke, Robert; Lauhoff, Thomas; Lübben, Dirk; Zrenner, Eberhart; Bolz, Hanno Jörn

2007-08-30

To identify the genetic defect in a German family with Usher syndrome (USH) and linkage to the USH3A locus. DNA samples of five family members (both parents and the three patients) were genotyped with polymorphic microsatellite markers specific for eight USH genes. Three affected family members underwent detailed ocular and audiologic characterization. Symptoms in the patients were compatible with Usher syndrome and show intrafamilial variation, for both hearing loss (ranging from severe to profound with non-linear progression) and vision. Genotyping of microsatellite markers for the different USH loci was in line with a defect in the USH3A gene on chromosome 3q25. Sequence analysis of the USH3A gene revealed two truncating mutations; c.149_152delCAGGinsTGTCCAAT, which has been described previously, and a novel mutation, c.502_503insA, segregating with the phenotype. To date, only 11 USH3A mutations have been described. This is the first description of a German family with USH due to USH3A mutations, including one novel. Our findings indicate that also in the Central European population, USH3A mutations should be considered in cases of USH.

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.

Heterozygous defects in PAX6 gene and congenital hypopituitarism.

PubMed

Takagi, Masaki; Nagasaki, Keisuke; Fujiwara, Ikuma; Ishii, Tomohiro; Amano, Naoko; Asakura, Yumi; Muroya, Koji; Hasegawa, Yukihiro; Adachi, Masanori; Hasegawa, Tomonobu

2015-01-01

The prevalence of congenital hypopituitarism (CH) attributable to known transcription factor mutations appears to be rare and other causative genes for CH remain to be identified. Due to the sporadic occurrence of CH, de novo chromosomal rearrangements could be one of the molecular mechanisms participating in its etiology, especially in syndromic cases. To identify the role of copy number variations (CNVs) in the etiology of CH and to identify novel genes implicated in CH. We enrolled 88 (syndromic: 30; non-syndromic: 58) Japanese CH patients. We performed an array comparative genomic hybridization screening in the 30 syndromic CH patients. For all the 88 patients, we analyzed PAX6 by PCR-based sequencing. We identified one heterozygous 310-kb deletion of the PAX6 enhancer region in one patient showing isolated GH deficiency (IGHD), cleft palate, and optic disc cupping. We also identified one heterozygous 6.5-Mb deletion encompassing OTX2 in a patient with bilateral anophthalmia and multiple pituitary hormone deficiency. We identified a novel PAX6 mutation, namely p.N116S in one non-syndromic CH patient showing IGHD. The p.N116S PAX6 was associated with an impairment of the transactivation capacities of the PAX6-binding elements. This study showed that heterozygous PAX6 mutations are associated with CH patients. PAX6 mutations may be associated with diverse clinical features ranging from severely impaired ocular and pituitary development to apparently normal phenotype. Overall, this study identified causative CNVs with a possible role in the etiology of CH in <10% of syndromic CH patients. © 2015 European Society of Endocrinology.

Identification of 99 novel mutations in a worldwide cohort of 1,056 patients with a nephronophthisis-related ciliopathy.

PubMed

Halbritter, Jan; Porath, Jonathan D; Diaz, Katrina A; Braun, Daniela A; Kohl, Stefan; Chaki, Moumita; Allen, Susan J; Soliman, Neveen A; Hildebrandt, Friedhelm; Otto, Edgar A

2013-08-01

Nephronophthisis-related ciliopathies (NPHP-RC) are autosomal-recessive cystic kidney diseases. More than 13 genes are implicated in its pathogenesis to date, accounting for only 40 % of all cases. High-throughput mutation screenings of large patient cohorts represent a powerful tool for diagnostics and identification of novel NPHP genes. We here performed a new high-throughput mutation analysis method to study 13 established NPHP genes (NPHP1-NPHP13) in a worldwide cohort of 1,056 patients diagnosed with NPHP-RC. We first applied multiplexed PCR-based amplification using Fluidigm Access-Array™ technology followed by barcoding and next-generation resequencing on an Illumina platform. As a result, we established the molecular diagnosis in 127/1,056 independent individuals (12.0 %) and identified a single heterozygous truncating mutation in an additional 31 individuals (2.9 %). Altogether, we detected 159 different mutations in 11 out of 13 different NPHP genes, 99 of which were novel. Phenotypically most remarkable were two patients with truncating mutations in INVS/NPHP2 who did not present as infants and did not exhibit extrarenal manifestations. In addition, we present the first case of Caroli disease due to mutations in WDR19/NPHP13 and the second case ever with a recessive mutation in GLIS2/NPHP7. This study represents the most comprehensive mutation analysis in NPHP-RC patients, identifying the largest number of novel mutations in a single study worldwide.

Convergent Evolution of Slick Coat in Cattle through Truncation Mutations in the Prolactin Receptor.

PubMed

Porto-Neto, Laercio R; Bickhart, Derek M; Landaeta-Hernandez, Antonio J; Utsunomiya, Yuri T; Pagan, Melvin; Jimenez, Esbal; Hansen, Peter J; Dikmen, Serdal; Schroeder, Steven G; Kim, Eui-Soo; Sun, Jiajie; Crespo, Edward; Amati, Norman; Cole, John B; Null, Daniel J; Garcia, Jose F; Reverter, Antonio; Barendse, William; Sonstegard, Tad S

2018-01-01

Evolutionary adaptations are occasionally convergent solutions to the same problem. A mutation contributing to a heat tolerance adaptation in Senepol cattle, a New World breed of mostly European descent, results in the distinct phenotype known as slick, where an animal has shorter hair and lower follicle density across its coat than wild type animals. The causal variant, located in the 11 th exon of prolactin receptor , produces a frameshift that results in a truncated protein. However, this mutation does not explain all cases of slick coats found in criollo breeds. Here, we obtained genome sequences from slick cattle of a geographically distinct criollo breed, namely Limonero, whose ancestors were originally brought to the Americas by the Spanish. These data were used to identify new causal alleles in the 11 th exon of the prolactin receptor , two of which also encode shortened proteins that remove a highly conserved tyrosine residue. These new mutations explained almost 90% of investigated cases of animals that had slick coats, but which also did not carry the Senepol slick allele. These results demonstrate convergent evolution at the molecular level in a trait important to the adaptation of an animal to its environment.

Convergent Evolution of Slick Coat in Cattle through Truncation Mutations in the Prolactin Receptor

PubMed Central

Porto-Neto, Laercio R.; Bickhart, Derek M.; Landaeta-Hernandez, Antonio J.; Utsunomiya, Yuri T.; Pagan, Melvin; Jimenez, Esbal; Hansen, Peter J.; Dikmen, Serdal; Schroeder, Steven G.; Kim, Eui-Soo; Sun, Jiajie; Crespo, Edward; Amati, Norman; Cole, John B.; Null, Daniel J.; Garcia, Jose F.; Reverter, Antonio; Barendse, William; Sonstegard, Tad S.

2018-01-01

Evolutionary adaptations are occasionally convergent solutions to the same problem. A mutation contributing to a heat tolerance adaptation in Senepol cattle, a New World breed of mostly European descent, results in the distinct phenotype known as slick, where an animal has shorter hair and lower follicle density across its coat than wild type animals. The causal variant, located in the 11th exon of prolactin receptor, produces a frameshift that results in a truncated protein. However, this mutation does not explain all cases of slick coats found in criollo breeds. Here, we obtained genome sequences from slick cattle of a geographically distinct criollo breed, namely Limonero, whose ancestors were originally brought to the Americas by the Spanish. These data were used to identify new causal alleles in the 11th exon of the prolactin receptor, two of which also encode shortened proteins that remove a highly conserved tyrosine residue. These new mutations explained almost 90% of investigated cases of animals that had slick coats, but which also did not carry the Senepol slick allele. These results demonstrate convergent evolution at the molecular level in a trait important to the adaptation of an animal to its environment. PMID:29527221

Nonsense mutations in the PAX3 gene cause Waardenburg syndrome type I in two Chinese patients.

PubMed

Yang, Shu-Zhi; Cao, Ju-Yang; Zhang, Rui-Ning; Liu, Li-Xian; Liu, Xin; Zhang, Xin; Kang, Dong-Yang; Li, Mei; Han, Dong-Yi; Yuan, Hui-Jun; Yang, Wei-Yan

2007-01-05

Waardenburg syndrome type I (WS1) is an autosomal dominant disorder characterized by sensorineural hearing loss, pigmental abnormalities of the eye, hair and skin, and dystopia canthorum. The gene mainly responsible for WS1 is PAX3 which is involved in melanocytic development and survival. Mutations of PAX3 have been reported in familiar or sporadic patients with WS1 in several populations of the world except Chinese. In order to explore the genetic background of Chinese WS1 patients, a mutation screening of PAX3 gene was carried out in four WS1 pedigrees. A questionnaire survey and comprehensive clinical examination were conducted in four Chinese pedigrees of WS1. Genomic DNA from each patient and their family members was extracted and exons of PAX3 were amplified by PCR. PCR fragments were ethanol-purified and sequenced in both directions on an ABI_Prism 3100 DNA sequencer with the BigDye Terminator Cycle Sequencing Ready Reaction Kit. The sequences were obtained and aligned to the wild type sequence of PAX3 with the GeneTool program. Two nonsense PAX3 mutations have been found in the study population. One is heterozygous for a novel nonsense mutation S209X. The other is heterozygous for a previously reported mutation in European population R223X. Both mutations create stop codons leading to truncation of the PAX3 protein. This is the first demonstration of PAX3 mutations in Chinese WS1 patients and one of the few examples of an identical mutation of PAX3 occurred in different populations.

A novel heterozygous RIT1 mutation in a patient with Noonan syndrome, leukopenia, and transient myeloproliferation-a review of the literature.

PubMed

Nemcikova, Michaela; Vejvalkova, Sarka; Fencl, Filip; Sukova, Martina; Krepelova, Anna

2016-04-01

Noonan syndrome (NS) is a genetic condition presenting with typical facies, cardiac defects, short stature, variable developmental deficit, cryptorchidism, skeletal, and other abnormalities. Germline mutations in genes involved in the RAS/MAPK signaling have been discovered to underlie NS. Recently, missense mutations in RIT1 have been reported as causative for individuals with clinical signs of NS. We report on a 2.5-year-old boy with NS phenotype with a novel heterozygous change in the RIT1 gene. The patient was born prematurely from pregnancy monitored for polyhydramnios. At 7 months of age, non-immune neutropenia and splenomegaly have been observed. During the severe pneumonia at 10 months, significant progression of hepatosplenomegaly, leukopenia with monocytosis (15-29 %), and thrombocytopenia occurred. Bone marrow evaluation showed myeloid hyperplasia and monocytosis, suggestive of myeloproliferative syndrome. Clinical phenotype (facial dysmorphism, soft hair, short neck, broad chest, widely spaced nipples, mild pectus carinatum, deep palmar creases, unilateral cryptorchidism), and moderate pulmonary valve stenosis with mild psychomotor delay were indicative of NS. DNA analysis identified a de novo heterozygous variant c.69A >T, p.(Lys23Asn) in exon 2 of the RIT1 gene, presumed to be causative. We present a patient with a clinical suspicion of NS carrying a novel substitution in RIT1 and hematologic findings not being observed in RIT1 positive patients to date. Thus, the case broadens variability of hematologic symptoms in RIT1 positive NS individuals. • Noonan syndrome is a common genetically heterogeneous disorder of autosomal dominant inheritance characterized by craniofacial dysmorphism, short stature, congenital heart defects, variable cognitive deficit, and other anomalies. What is new: • We report on a 2.5-year-old male patient with clinical signs of NS and hematologic abnormalities, in whom a novel heterozygous substitution in RIT1 with probable

Andermann syndrome can be a phenocopy of hereditary motor and sensory neuropathy--report of a discordant sibship with a compound heterozygous mutation of the KCC3 gene.

PubMed

Rudnik-Schöneborn, S; Hehr, U; von Kalle, T; Bornemann, A; Winkler, J; Zerres, K

2009-06-01

Andermann syndrome is a rare autosomal recessive disorder characterized by agenesis of the corpus callosum (ACC), progressive motor-sensory neuropathy, mental retardation and facial features. We report on two siblings with the clinical picture of a demyelinating hereditary motor and sensory neuropathy (HMSN), where only the presence of ACC in the younger brother pointed to the diagnosis of Andermann syndrome. Mutation analysis of the KCC3 (SLC12A6) gene showed a compound heterozygous mutation; a maternal missense mutation c.1616G>A (p.G539D) and a paternal splice mutation c.1118+1G>A in both siblings. We hypothesize that mutations of the KCC3 gene may result in non-syndromic childhood onset HMSN.

Heterozygous Null Bone Morphogenetic Protein Receptor Type 2 Mutations Promote SRC Kinase-dependent Caveolar Trafficking Defects and Endothelial Dysfunction in Pulmonary Arterial Hypertension*

PubMed Central

Prewitt, Allison R.; Ghose, Sampa; Frump, Andrea L.; Datta, Arumima; Austin, Eric D.; Kenworthy, Anne K.; de Caestecker, Mark P.

2015-01-01

Hereditary pulmonary arterial hypertension (HPAH) is a rare, fatal disease of the pulmonary vasculature. The majority of HPAH patients inherit mutations in the bone morphogenetic protein type 2 receptor gene (BMPR2), but how these promote pulmonary vascular disease is unclear. HPAH patients have features of pulmonary endothelial cell (PEC) dysfunction including increased vascular permeability and perivascular inflammation associated with decreased PEC barrier function. Recently, frameshift mutations in the caveolar structural protein gene Caveolin-1 (CAV-1) were identified in two patients with non-BMPR2-associated HPAH. Because caveolae regulate endothelial function and vascular permeability, we hypothesized that defects in caveolar function might be a common mechanism by which BMPR2 mutations promote pulmonary vascular disease. To explore this, we isolated PECs from mice carrying heterozygous null Bmpr2 mutations (Bmpr2+/−) similar to those found in the majority of HPAH patients. We show that Bmpr2+/− PECs have increased numbers and intracellular localization of caveolae and caveolar structural proteins CAV-1 and Cavin-1 and that these defects are reversed after blocking endocytosis with dynasore. SRC kinase is also constitutively activated in Bmpr2+/− PECs, and localization of CAV-1 to the plasma membrane is restored after treating Bmpr2+/− PECs with the SRC kinase inhibitor 3-(4-chlorophenyl)-1-(1,1-dimethylethyl)-1H-pyrazolo[3,4-d]pyrimidin-4-amine (PP2). Late outgrowth endothelial progenitor cells isolated from HPAH patients show similar increased activation of SRC kinase. Moreover, Bmpr2+/− PECs have impaired endothelial barrier function, and barrier function is restored after treatment with PP2. These data suggest that heterozygous null BMPR2 mutations promote SRC-dependent caveolar trafficking defects in PECs and that this may contribute to pulmonary endothelial barrier dysfunction in HPAH patients. PMID:25411245

Novel GATAD2B loss-of-function mutations cause intellectual disability in two unrelated cases.

PubMed

Luo, Xiaomei; Zou, Yongyi; Tan, Bo; Zhang, Yue; Guo, Jing; Zeng, Lanlan; Zhang, Rui; Tan, Hu; Wei, Xianda; Hu, Yiqiao; Zheng, Yu; Liang, Desheng; Wu, Lingqian

2017-04-01

GATA zinc finger domain-containing 2B (GATAD2B) is a subunit of the methyl-CpG-binding protein-1 complex (MECP1), which deacetylates methylated nucleosomes and regresses transcriptional activity. Recently, GATAD2B has been elucidated as a candidate gene in patients with intellectual disability (ID). In this study, we identified two novel heterozygous frameshift mutations of GATAD2B in two unrelated ID cases through next-generation sequencing (NGS). Both of the mutations c.80_81insGATGT and c.552_555delGAAA cause truncated proteins that might be detrimental to neurodevelopment. We performed western blotting and observed a reduction in the target protein compared with normal controls. This is the first report of GATAD2B in Chinese ID patients. Our findings will broaden the spectrum of GATAD2B mutations and facilitate genetic diagnosis and counseling.

Truncated C-terminus of fibrillin-1 induces Marfanoid-progeroid-lipodystrophy (MPL) syndrome in rabbit.

PubMed

Chen, Mao; Yao, Bing; Yang, Qiangbing; Deng, Jichao; Song, Yuning; Sui, Tingting; Zhou, Lina; Yao, HaoBing; Xu, Yuanyuan; Ouyang, Hongsheng; Pang, Daxin; Li, Zhanjun; Lai, Liangxue

2018-04-09

Various clinical differences have been observed between patients with the FBN1 gene mutation and those with the classical Marfan phenotype. Although FBN1 knockout (KO) or dominant-negative mutant mice are widely used as an animal model for Marfan syndrome (MFS), these mice cannot recapitulate the genotype/phenotype relationship of Marfanoid-progeroid-lipodystrophy (MPL) syndrome, which is caused by a mutation in the C-terminus of fibrillin-1, the penultimate exon of the FBN1 gene. Here, we describe the generation of a rabbit MPL model with C-terminal truncation of fibrillin-1 using a CRISPR/Cas9 system. FBN1 heterozygous ( FBN1 Het) rabbits faithfully recapitulated the phenotypes of MFS, including muscle wasting and impaired connective tissue, ocular syndrome and aortic dilation. Moreover, skin symptoms, lipodystrophy, growth retardation and dysglycemia were also seen in these FBN1 Het rabbits, and have not been reported in other animal models. In conclusion, this novel rabbit model mimics the histopathological changes and functional defects of MPL syndrome, and could become a valuable model for studies of pathogenesis and drug screening for MPL syndrome. © 2018. Published by The Company of Biologists Ltd.

A novel germline inactivating mutation in the CASR gene in an Italian kindred affected by familial hypocalciuric hypercalcemia.

PubMed

Falchetti, Alberto; Gozzini, Alessia; Terranegra, Annalisa; Soldati, Laura; Vezzoli, Giuseppe; Leoncini, Gigliola; Giusti, Francesca; Franceschelli, Francesco; Masi, Laura; Tanini, Annalisa; Cavalli, Loredana; Brandi, Maria Luisa

2012-05-01

Familial hypocalciuric hypercalcemia (FHH) syndrome is a rare benign condition, inherited as an autosomal dominant trait, in which inactivating mutations of the calcium-sensing receptor (CASR) gene affects the body's ability to regulate calcium homeostasis. Its outcome is featured by increased levels of serum calcium, moderate hypophosphatemia, and inadequately normal or elevated circulating parathyroid hormone levels. Affected patients are mostly asymptomatic and do not benefit from surgical resection of their mildly enlarged parathyroids. We evaluated for hypercalcemia an Italian family that was identified via a young adult male proband referred to our center for parathyroidectomy. The patients and the family members were evaluated both biochemically and genetically as suspected FHH subjects. An in vitro functional study was performed by site-directed mutagenesis, and CASR activity was monitored by measuring intracellular calcium ([Ca(2)(+)](i)). The patient had a novel germline heterozygous CASR mutation (c.361_364GATT; p.D121del/fsX122). The mutation caused a premature stop codon at codon 122, exiting a truncated protein. The biochemical phenotype of all family members carrying the heterozygous deletion was concordant with classic FHH syndrome. Our findings confirm the role of CASR gene mutational analysis to offer a valuable addition for the recognition of FHH in hypercalcemic patients not yet characterized for a positive familial history of hypercalcemia, the only condition that identifies CASR gene mutations in hypercalcemia.

Tietz/Waardenburg type 2A syndrome associated with posterior microphthalmos in two unrelated patients with novel MITF gene mutations.

PubMed

Cortés-González, Vianney; Zenteno, Juan Carlos; Guzmán-Sánchez, Martín; Giordano-Herrera, Verónica; Guadarrama-Vallejo, Dalia; Ruíz-Quintero, Narlly; Villanueva-Mendoza, Cristina

2016-12-01

Tietz syndrome and Waardenburg syndrome type 2A are allelic conditions caused by MITF mutations. Tietz syndrome is inherited in an autosomal dominant pattern and is characterized by congenital deafness and generalized skin, hair, and eye hypopigmentation, while Waardenburg syndrome type 2A typically includes variable degrees of sensorineural hearing loss and patches of de-pigmented skin, hair, and irides. In this paper, we report two unrelated families with MITF mutations. The first family showed an autosomal dominant pattern and variable expressivity. The second patient was isolated. MITF gene analysis in the first family demonstrated a c.648A>C heterozygous mutation in exon 8 c.648A>C; p. (R216S), while in the isolated patient, an apparently de novo heterozygous c.1183_1184insG truncating mutation was demonstrated in exon 10. All patients except one had bilateral reduced ocular anteroposterior axial length and a high hyperopic refractive error corresponding to posterior microphthalmos, features that have not been described as part of the disease. Our results suggest that posterior microphthalmos might be part of the clinical characteristics of Tietz/Waardenburg syndrome type 2A and expand both the clinical and molecular spectrum of the disease. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Case-control analysis of truncating mutations in DNA damage response genes connects TEX15 and FANCD2 with hereditary breast cancer susceptibility.

PubMed

Mantere, Tuomo; Tervasmäki, Anna; Nurmi, Anna; Rapakko, Katrin; Kauppila, Saila; Tang, Jiangbo; Schleutker, Johanna; Kallioniemi, Anne; Hartikainen, Jaana M; Mannermaa, Arto; Nieminen, Pentti; Hanhisalo, Riitta; Lehto, Sini; Suvanto, Maija; Grip, Mervi; Jukkola-Vuorinen, Arja; Tengström, Maria; Auvinen, Päivi; Kvist, Anders; Borg, Åke; Blomqvist, Carl; Aittomäki, Kristiina; Greenberg, Roger A; Winqvist, Robert; Nevanlinna, Heli; Pylkäs, Katri

2017-04-06

Several known breast cancer susceptibility genes encode proteins involved in DNA damage response (DDR) and are characterized by rare loss-of-function mutations. However, these explain less than half of the familial cases. To identify novel susceptibility factors, 39 rare truncating mutations, identified in 189 Northern Finnish hereditary breast cancer patients in parallel sequencing of 796 DDR genes, were studied for disease association. Mutation screening was performed for Northern Finnish breast cancer cases (n = 578-1565) and controls (n = 337-1228). Mutations showing potential cancer association were analyzed in additional Finnish cohorts. c.7253dupT in TEX15, encoding a DDR factor important in meiosis, associated with hereditary breast cancer (p = 0.018) and likely represents a Northern Finnish founder mutation. A deleterious c.2715 + 1G > A mutation in the Fanconi anemia gene, FANCD2, was over two times more common in the combined Finnish hereditary cohort compared to controls. A deletion (c.640_644del5) in RNF168, causative for recessive RIDDLE syndrome, had high prevalence in majority of the analyzed cohorts, but did not associate with breast cancer. In conclusion, truncating variants in TEX15 and FANCD2 are potential breast cancer risk factors, warranting further investigations in other populations. Furthermore, high frequency of RNF168 c.640_644del5 indicates the need for its testing in Finnish patients with RIDDLE syndrome symptoms.

Viable phenotype of ILNEB syndrome without nephrotic impairment in siblings heterozygous for unreported integrin alpha3 mutations.

PubMed

Colombo, Elisa Adele; Spaccini, Luigina; Volpi, Ludovica; Negri, Gloria; Cittaro, Davide; Lazarevic, Dejan; Zirpoli, Salvatore; Farolfi, Andrea; Gervasini, Cristina; Cubellis, Maria Vittoria; Larizza, Lidia

2016-10-07

Integrin α3 (ITGA3) gene mutations are associated with Interstitial Lung disease, Nephrotic syndrome and Epidermolysis bullosa (ILNEB syndrome). To date only six patients are reported: all carried homozygous ITGA3 mutations and presented a dramatically severe phenotype leading to death before age 2 years, from multi-organ failure due to interstitial lung disease and congenital nephrotic syndrome. The involvement of skin and cutaneous adnexa was variable with sparse hair and nail dysplasia combined or not to skin lesions ranging from skin fragility to epidermolysis bullosa-like blistering. We report on two siblings of 13 and 9 years born to non-consanguineous healthy parents, who display growth delay, severe pulmonary fibrosis with fatigue, dyspnea on exertion and wheezing, atrophic skin with erythematosus lesions, rare eyelashes/eyebrows and pachyonychia. By exome sequencing, we identified two unreported ITGA3 missense mutations, c.373G>A (p.(G125R)) in exon 3 and c.821G>A (p.(R274Q)) in exon 6, affecting highly conserved residues in the integrin α3 extracellular N-terminal β-propeller domain. Homology modelling of α3β1 heterodimer fragment, encompassing the mutation sites, showed that G125 plays a pivotal structural role in the β-propeller, while R274 might prevent the interaction between integrin and urokinase complex. We report a variant of ILNEB syndrome in two siblings differing from the previously reported patients in the lack of nephrotic impairment and survival beyond childhood. Our siblings are the first reported compound heterozygous for ITGA3 mutations; this state as well as the hypomorphic nature of their p.(R274Q) mutation likely account for their survival.

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

Hypomorphic NOTCH3 mutation in an Italian family with CADASIL features.

PubMed

Moccia, Marcello; Mosca, Lorena; Erro, Roberto; Cervasio, Mariarosaria; Allocca, Roberto; Vitale, Carmine; Leonardi, Antonio; Caranci, Ferdinando; Del Basso-De Caro, Maria Laura; Barone, Paolo; Penco, Silvana

2015-01-01

The cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL) is because of NOTCH3 mutations affecting the number of cysteine residues. In this view, the role of atypical NOTCH3 mutations is still debated. Therefore, we investigated a family carrying a NOTCH3 nonsense mutation, with dominantly inherited recurrent cerebrovascular disorders. Among 7 family members, 4 received a clinical diagnosis of CADASIL. A heterozygous truncating mutation in exon 3 (c.307C>T, p.Arg103X) was found in the 4 clinically affected subjects and in one 27-year old lady, only complaining of migraine with aura. Magnetic resonance imaging scans found typical signs of small-vessel disease in the 4 affected subjects, supporting the clinical diagnosis. Skin biopsies did not show the typical granular osmiophilic material, but only nonspecific signs of vascular damage, resembling those previously described in Notch3 knockout mice. Interestingly, messenger RNA (mRNA) analysis supports the hypothesis of an atypical NOTCH3 mutation, suggesting a nonsense-mediated mRNA decay. In conclusion, the present study broadens the spectrum of CADASIL mutations, and, therefore, opens new insights about Notch3 signaling. Copyright © 2015 Elsevier Inc. All rights reserved.

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

Early-Onset X-Linked Retinitis Pigmentosa in a Heterozygous Female Harboring an Intronic Donor Splice Site Mutation in the Retinitis Pigmentosa GTPase Regulator Gene.

PubMed

Shifera, Amde Selassie; Kay, Christine Nichols

2015-01-01

To report a heterozygous female presenting with an early-onset and severe form of X-linked retinitis pigmentosa (XLRP). This is a case series presenting the clinical findings in a heterozygous female with XLRP and two of her family members. Fundus photography, fundus autofluorescence, ocular coherence tomography, and visual perimetry are presented. The proband reported here is a heterozygous female who presented at the age of 8 years with an early onset and aggressive form of XLRP. The patient belongs to a four-generation family with a total of three affected females and four affected males. The patient was initially diagnosed with retinitis pigmentosa (RP) at the age of 4 years. Genetic testing identified a heterozygous donor splice site mutation in intron 1 (IVS1 + 1G > A) of the retinitis pigmentosa GTPase regulator gene. The father of the proband was diagnosed with RP when he was a young child. The sister of the proband, evaluated at the age of 6 years, showed macular pigmentary changes. Although carriers of XLRP are usually asymptomatic or have a mild disease of late onset, the proband presented here exhibited an early-onset, aggressive form of the disease. It is not clear why some carrier females manifest a severe phenotype. A better understanding of the genetic processes involved in the penetrance and expressivity of XLRP in heterozygous females could assist in providing the appropriate counseling to affected families.

SLC1A4 mutations cause a novel disorder of intellectual disability, progressive microcephaly, spasticity and thin corpus callosum.

PubMed

Heimer, G; Marek-Yagel, D; Eyal, E; Barel, O; Oz Levi, D; Hoffmann, C; Ruzzo, E K; Ganelin-Cohen, E; Lancet, D; Pras, E; Rechavi, G; Nissenkorn, A; Anikster, Y; Goldstein, D B; Ben Zeev, B

2015-10-01

Two unrelated patients, presenting with significant global developmental delay, severe progressive microcephaly, seizures, spasticity and thin corpus callosum (CC) underwent trio whole-exome sequencing. No candidate variant was found in any known genes related to the phenotype. However, crossing the data of the patients illustrated that they both manifested pathogenic variants in the SLC1A4 gene which codes the ASCT1 transporter of serine and other neutral amino acids. The Ashkenazi patient is homozygous for a deleterious missense c.766G>A, p.(E256K) mutation whereas the Ashkenazi-Iraqi patient is compound heterozygous for this mutation and a nonsense c.945delTT, p.(Leu315Hisfs*42) mutation. Structural prediction demonstrates truncation of significant portion of the protein by the nonsense mutation and speculates functional disruption by the missense mutation. Both mutations are extremely rare in general population databases, however, the missense mutation was found in heterozygous mode in 1:100 Jewish Ashkenazi controls suggesting a higher carrier rate among Ashkenazi Jews. We conclude that SLC1A4 is the disease causing gene of a novel neurologic disorder manifesting with significant intellectual disability, severe postnatal microcephaly, spasticity and thin CC. The role of SLC1A4 in the serine transport from astrocytes to neurons suggests a possible pathomechanism for this disease and implies a potential therapeutic approach. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Heterozygous p.Asp50Asn mutation in the GJB2 gene in two Cameroonian patients with keratitis-ichthyosis-deafness (KID) syndrome

PubMed Central

2013-01-01

Background Keratitis-Ichthyosis-Deafness (KID) syndrome (OMIM 148210) is a congenital ectodermal defect that consists of an atypical ichthyosiform erythroderma associated with congenital sensorineural deafness. KID appears to be genetically heterogeneous and most cases are caused by GJB2 mutations. Mutations in African patients have been rarely described. Case presentation We report on two unrelated Cameroonian individuals affected with sporadic KID, presenting with the classic phenotypic triad. The two patients were heterozygous for the most frequent p.Asp50Asn mutation. This first report in patients from sub-Saharan African origin supports the hypothesis that the occurrence of KID due to p.Asp50Asn mutation in GJB2 seems not to be population specific. Conclusions Our finding has implication in medical genetic practice, specifically in the molecular diagnosis of KID in Africans. These cases also reveal and emphasize the urgent need to develop appropriate policies to care for patients with rare/orphan diseases in Sub-Saharan Africa, as many of these cases become more and more recognizable. PMID:23924173

Dominant mutations in KAT6A cause intellectual disability with recognizable syndromic features.

PubMed

Tham, Emma; Lindstrand, Anna; Santani, Avni; Malmgren, Helena; Nesbitt, Addie; Dubbs, Holly A; Zackai, Elaine H; Parker, Michael J; Millan, Francisca; Rosenbaum, Kenneth; Wilson, Golder N; Nordgren, Ann

2015-03-05

Through a multi-center collaboration study, we here report six individuals from five unrelated families, with mutations in KAT6A/MOZ detected by whole-exome sequencing. All five different de novo heterozygous truncating mutations were located in the C-terminal transactivation domain of KAT6A: NM_001099412.1: c.3116_3117 delCT, p.(Ser1039∗); c.3830_3831insTT, p.(Arg1278Serfs∗17); c.3879 dupA, p.(Glu1294Argfs∗19); c.4108G>T p.(Glu1370∗) and c.4292 dupT, p.(Leu1431Phefs∗8). An additional subject with a 0.23 MB microdeletion including the entire KAT6A reading frame was identified with genome-wide array comparative genomic hybridization. Finally, by detailed clinical characterization we provide evidence that heterozygous mutations in KAT6A cause a distinct intellectual disability syndrome. The common phenotype includes hypotonia, intellectual disability, early feeding and oromotor difficulties, microcephaly and/or craniosynostosis, and cardiac defects in combination with subtle facial features such as bitemporal narrowing, broad nasal tip, thin upper lip, posteriorly rotated or low-set ears, and microretrognathia. The identification of human subjects complements previous work from mice and zebrafish where knockouts of Kat6a/kat6a lead to developmental defects. Copyright © 2015 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

A heterozygous IDH1R132H/WT mutation induces genome-wide alterations in DNA methylation.

PubMed

Duncan, Christopher G; Barwick, Benjamin G; Jin, Genglin; Rago, Carlo; Kapoor-Vazirani, Priya; Powell, Doris R; Chi, Jen-Tsan; Bigner, Darell D; Vertino, Paula M; Yan, Hai

2012-12-01

Monoallelic point mutations of the NADP(+)-dependent isocitrate dehydrogenases IDH1 and IDH2 occur frequently in gliomas, acute myeloid leukemias, and chondromas, and display robust association with specific DNA hypermethylation signatures. Here we show that heterozygous expression of the IDH1(R132H) allele is sufficient to induce the genome-wide alterations in DNA methylation characteristic of these tumors. Using a gene-targeting approach, we knocked-in a single copy of the most frequently observed IDH1 mutation, R132H, into a human cancer cell line and profiled changes in DNA methylation at over 27,000 CpG dinucleotides relative to wild-type parental cells. We find that IDH1(R132H/WT) mutation induces widespread alterations in DNA methylation, including hypermethylation of 2010 and hypomethylation of 842 CpG loci. We demonstrate that many of these alterations are consistent with those observed in IDH1-mutant and G-CIMP+ primary gliomas and can segregate IDH wild-type and mutated tumors as well as those exhibiting the G-CIMP phenotype in unsupervised analysis of two primary glioma cohorts. Further, we show that the direction of IDH1(R132H/WT)-mediated DNA methylation change is largely dependent upon preexisting DNA methylation levels, resulting in depletion of moderately methylated loci. Additionally, whereas the levels of multiple histone H3 and H4 methylation modifications were globally increased, consistent with broad inhibition of histone demethylation, hypermethylation at H3K9 in particular accompanied locus-specific DNA hypermethylation at several genes down-regulated in IDH1(R132H/WT) knock-in cells. These data provide insight on epigenetic alterations induced by IDH1 mutations and support a causal role for IDH1(R132H/WT) mutants in driving epigenetic instability in human cancer cells.

Heterozygous familial hypercholesterolemia: an underrecognized cause of early cardiovascular disease.

PubMed

Yuan, George; Wang, Jian; Hegele, Robert A

2006-04-11

Heterozygous familial hypercholesterolemia (HeFH) is a monogenic disorder that affects about 1 in 500 people, with a higher prevalence in certain subpopulations such as people of Quebecois, Christian Lebanese and Dutch South Afrikaner extraction. HeFH is characterized by cholesterol deposits affecting the corneas, eyelids and extensor tendons; elevated plasma concentrations of low-density lipoprotein (LDL) cholesterol; and accelerated vascular disease, especially coronary artery disease (CAD). Although HeFH is genetically heterogeneous, it is most often caused by heterozygous mutations in the LDLR gene encoding the LDL receptor. We describe a man who was diagnosed with HeFH after he had a myocardial infarction at 33 years of age. By DNA sequence analysis, he was found to have a heterozygous splicing mutation in his LDLR gene. This discovery expanded the growing mutational spectrum in patients with HeFH in Ontario. Given that HeFH is a treatable cause of early vascular disease, it is important that this condition be recognized, diagnosed and treated in affected patients; but as yet, there is no consensus on the best approach. Diagnostic criteria based on family history and clinical presentation have been proposed for patients with suspected HeFH. Biochemical or molecular screening might be considered to detect new cases of HeFH in populations with a relatively high HeFH prevalence and a relatively small number of possible causative mutations. So far, however, the most cost-effective and efficient systematic strategy to detect previously undiagnosed cases of HeFH is still cascade testing: clinical and biochemical screening of close relatives of the proband patient diagnosed with HeFH. Pharmacologic treatment of HeFH is cost-effective.

Heterozygous familial hypercholesterolemia: an underrecognized cause of early cardiovascular disease

PubMed Central

Yuan, George; Wang, Jian; Hegele, Robert A.

2006-01-01

Heterozygous familial hypercholesterolemia (HeFH) is a monogenic disorder that affects about 1 in 500 people, with a higher prevalence in certain subpopulations such as people of Quebecois, Christian Lebanese and Dutch South Afrikaner extraction. HeFH is characterized by cholesterol deposits affecting the corneas, eyelids and extensor tendons; elevated plasma concentrations of low-density lipoprotein (LDL) cholesterol; and accelerated vascular disease, especially coronary artery disease (CAD). Although HeFH is genetically heterogeneous, it is most often caused by heterozygous mutations in the LDLR gene encoding the LDL receptor. We describe a man who was diagnosed with HeFH after he had a myocardial infarction at 33 years of age. By DNA sequence analysis, he was found to have a heterozygous splicing mutation in his LDLR gene. This discovery expanded the growing mutational spectrum in patients with HeFH in Ontario. Given that HeFH is a treatable cause of early vascular disease, it is important that this condition be recognized, diagnosed and treated in affected patients; but as yet, there is no consensus on the best approach. Diagnostic criteria based on family history and clinical presentation have been proposed for patients with suspected HeFH. Biochemical or molecular screening might be considered to detect new cases of HeFH in populations with a relatively high HeFH prevalence and a relatively small number of possible causative mutations. So far, however, the most cost-effective and efficient systematic strategy to detect previously undiagnosed cases of HeFH is still cascade testing: clinical and biochemical screening of close relatives of the proband patient diagnosed with HeFH. Pharmacologic treatment of HeFH is cost-effective. PMID:16606962

Dent Disease in Chinese Children and Findings from Heterozygous Mothers: Phenotypic Heterogeneity, Fetal Growth, and 10 Novel Mutations.

PubMed

Li, Fucheng; Yue, Zhihui; Xu, Tingting; Chen, Minghui; Zhong, Liangying; Liu, Ting; Jing, Xiangyi; Deng, Jia; Hu, Bin; Liu, Yuling; Wang, Haiyan; Lai, Kar N; Sun, Liangzhong; Liu, Jinsong; Maxwell, Patrick H; Wang, Yiming

2016-07-01

To characterize the phenotypes of Dent disease in Chinese children and their heterozygous mothers and to establish genetic diagnoses. Using a modified protocol, we screened 1288 individuals with proteinuria. A diagnosis of Dent disease was established in 19 boys from 16 families by the presence of loss of function/deleterious mutations in CLCN5 or OCRL1. We also analyzed 16 available patients' mothers and examined their pregnancy records. We detected 14 loss of function/deleterious mutations of CLCN5 in 15 boys and 2 mutations of OCRL1 in 4 boys. Of the patients, 16 of 19 had been wrongly diagnosed with other diseases and 11 of 19 had incorrect or unnecessary treatment. None of the patients, but 6 of 14 mothers, had nephrocalcinosis or nephrolithiasis at diagnosis. Of the patients, 8 of 14 with Dent disease 1 were large for gestational age (>90th percentile); 8 of 15 (53.3%) had rickets. We also present predicted structural changes for 4 mutant proteins. Pediatric Dent disease often is misdiagnosed; genetic testing achieves a correct diagnosis. Nephrocalcinosis or nephrolithiasis may not be sensitive diagnostic criteria. We identified 10 novel mutations in CLCN5 and OCRL1. The possibility that altered CLCN5 function could affect fetal growth and a possible link between a high rate of rickets and low calcium intake are discussed. Copyright © 2016 Elsevier Inc. All rights reserved.

Epitope-positive truncating MLH1 mutation and loss of PMS2: implications for IHC-directed genetic testing for Lynch syndrome.

PubMed

Zighelboim, Israel; Powell, Matthew A; Babb, Sheri A; Whelan, Alison J; Schmidt, Amy P; Clendenning, Mark; Senter, Leigha; Thibodeau, Stephen N; de la Chapelle, Albert; Goodfellow, Paul J

2009-01-01

We assessed mismatch repair by immunohistochemistry (IHC) and microsatellite instability (MSI) analysis in an early onset endometrial cancer and a sister's colon cancer. We demonstrated high-level MSI and normal expression for MLH1, MSH2 and MSH6. PMS2 failed to stain in both tumors, strongly implicating a PMS2 defect. This family did not meet clinical criteria for Lynch syndrome. However, early onset endometrial cancers in the proband and her sister, a metachronous colorectal cancer in the sister as well as MSI in endometrial and colonic tumors suggested a heritable mismatch repair defect. PCR-based direct exonic sequencing and multiplex ligation-dependent probe amplification (MLPA) were undertaken to search for PMS2 mutations in the germline DNA from the proband and her sister. No mutation was identified in the PMS2 gene. However, PMS2 exons 3, 4, 13, 14, 15 were not evaluated by MLPA and as such, rearrangements involving those exons cannot be excluded. Clinical testing for MLH1 and MSH2 mutation revealed a germline deletion of MLH1 exons 14 and 15. This MLH1 germline deletion leads to an immunodetectable stable C-terminal truncated MLH1 protein which based on the IHC staining must abrogate PMS2 stabilization. To the best of our knowledge, loss of PMS2 in MLH1 truncating mutation carriers that express MLH1 in their tumors has not been previously reported. This family points to a potential limitation of IHC-directed gene testing for suspected Lynch syndrome and the need to consider comprehensive MLH1 testing for individuals whose tumors lack PMS2 but for whom PMS2 mutations are not identified.

Identification of two novel compound heterozygous mutations of ADGRV1 in a Chinese family with Usher syndrome type IIC.

PubMed

Zhang, Nian; Wang, Juan; Liu, Shuting; Liu, Mugen; Jiang, Fagang

2018-08-01

To describe the clinical and genetic findings in a Chinese family with three sibs diagnosed with Usher syndrome type IIC. Four members received ophthalmic and otologic tests to ascertain the clinical characteristics. According to the clinical phenotype, we focused attention on a total of 658 genes associated with them. We screened the possible pathogenic mutation sites, used Sanger to exclude the false positive and verified whether there were co-segregated among the family members. Typical fundus features found in the proband supported the diagnosis of retinitis pigmentosa (RP). Audiometric test indicated moderate to severe sensorineural hearing impairment while the vestibular function was normal. Whole-exome sequencing identified the presence of two novel compound heterozygous mutations in ADGRV1, a known gene responsible for Usher syndrome type IIC. Mutationc.15008delG/p.Gly5003AlafsTer13 was inherited from the mother while c.18383_18386dupACAG/p.His6130GlnfsTer84 was inherited from the father, and they were co-segregated with the disease phenotype in the family. The mutations found in our study not only broaden the mutation spectrum of ADGRV1, but also provide assistances for future genetic diagnosis and treatment for Usher syndrome patients.

Heterozygous RTEL1 variants in bone marrow failure and myeloid neoplasms

PubMed Central

Marsh, Judith C. W.; Gutierrez-Rodrigues, Fernanda; Cooper, James; Jiang, Jie; Gandhi, Shreyans; Kajigaya, Sachiko; Feng, Xingmin; Ibanez, Maria del Pilar F.; Donaires, Flávia S.; Lopes da Silva, João P.; Li, Zejuan; Das, Soma; Ibanez, Maria; Smith, Alexander E.; Lea, Nicholas; Best, Steven; Ireland, Robin; Kulasekararaj, Austin G.; McLornan, Donal P.; Pagliuca, Anthony; Callebaut, Isabelle; Young, Neal S.; Calado, Rodrigo T.; Townsley, Danielle M.

2018-01-01

Biallelic germline mutations in RTEL1 (regulator of telomere elongation helicase 1) result in pathologic telomere erosion and cause dyskeratosis congenita. However, the role of RTEL1 mutations in other bone marrow failure (BMF) syndromes and myeloid neoplasms, and the contribution of monoallelic RTEL1 mutations to disease development are not well defined. We screened 516 patients for germline mutations in telomere-associated genes by next-generation sequencing in 2 independent cohorts; one constituting unselected patients with idiopathic BMF, unexplained cytopenia, or myeloid neoplasms (n = 457) and a second cohort comprising selected patients on the basis of the suspicion of constitutional/familial BMF (n = 59). Twenty-three RTEL1 variants were identified in 27 unrelated patients from both cohorts: 7 variants were likely pathogenic, 13 were of uncertain significance, and 3 were likely benign. Likely pathogenic RTEL1 variants were identified in 9 unrelated patients (7 heterozygous and 2 biallelic). Most patients were suspected to have constitutional BMF, which included aplastic anemia (AA), unexplained cytopenia, hypoplastic myelodysplastic syndrome, and macrocytosis with hypocellular bone marrow. In the other 18 patients, RTEL1 variants were likely benign or of uncertain significance. Telomeres were short in 21 patients (78%), and 3′ telomeric overhangs were significantly eroded in 4. In summary, heterozygous RTEL1 variants were associated with marrow failure, and telomere length measurement alone may not identify patients with telomere dysfunction carrying RTEL1 variants. Pathogenicity assessment of heterozygous RTEL1 variants relied on a combination of clinical, computational, and functional data required to avoid misinterpretation of common variants. PMID:29344583

Heterozygous RTEL1 variants in bone marrow failure and myeloid neoplasms.

PubMed

Marsh, Judith C W; Gutierrez-Rodrigues, Fernanda; Cooper, James; Jiang, Jie; Gandhi, Shreyans; Kajigaya, Sachiko; Feng, Xingmin; Ibanez, Maria Del Pilar F; Donaires, Flávia S; Lopes da Silva, João P; Li, Zejuan; Das, Soma; Ibanez, Maria; Smith, Alexander E; Lea, Nicholas; Best, Steven; Ireland, Robin; Kulasekararaj, Austin G; McLornan, Donal P; Pagliuca, Anthony; Callebaut, Isabelle; Young, Neal S; Calado, Rodrigo T; Townsley, Danielle M; Mufti, Ghulam J

2018-01-09

Biallelic germline mutations in RTEL1 (regulator of telomere elongation helicase 1) result in pathologic telomere erosion and cause dyskeratosis congenita. However, the role of RTEL1 mutations in other bone marrow failure (BMF) syndromes and myeloid neoplasms, and the contribution of monoallelic RTEL1 mutations to disease development are not well defined. We screened 516 patients for germline mutations in telomere-associated genes by next-generation sequencing in 2 independent cohorts; one constituting unselected patients with idiopathic BMF, unexplained cytopenia, or myeloid neoplasms (n = 457) and a second cohort comprising selected patients on the basis of the suspicion of constitutional/familial BMF (n = 59). Twenty-three RTEL1 variants were identified in 27 unrelated patients from both cohorts: 7 variants were likely pathogenic, 13 were of uncertain significance, and 3 were likely benign. Likely pathogenic RTEL1 variants were identified in 9 unrelated patients (7 heterozygous and 2 biallelic). Most patients were suspected to have constitutional BMF, which included aplastic anemia (AA), unexplained cytopenia, hypoplastic myelodysplastic syndrome, and macrocytosis with hypocellular bone marrow. In the other 18 patients, RTEL1 variants were likely benign or of uncertain significance. Telomeres were short in 21 patients (78%), and 3' telomeric overhangs were significantly eroded in 4. In summary, heterozygous RTEL1 variants were associated with marrow failure, and telomere length measurement alone may not identify patients with telomere dysfunction carrying RTEL1 variants. Pathogenicity assessment of heterozygous RTEL1 variants relied on a combination of clinical, computational, and functional data required to avoid misinterpretation of common variants.

Identification of a novel truncating PALB2 mutation and analysis of its contribution to early-onset breast cancer in French-Canadian women.

PubMed

Foulkes, William D; Ghadirian, Parviz; Akbari, Mohammed Reza; Hamel, Nancy; Giroux, Sylvie; Sabbaghian, Nelly; Darnel, Andrew; Royer, Robert; Poll, Aletta; Fafard, Eve; Robidoux, André; Martin, Ginette; Bismar, Tarek A; Tischkowitz, Marc; Rousseau, Francois; Narod, Steven A

2007-01-01

PALB2 has recently been identified as a breast cancer susceptibility gene. PALB2 mutations are rare causes of hereditary breast cancer but may be important in countries such as Finland where a founder mutation is present. We sought to estimate the contribution of PALB2 mutations to the burden of breast cancer in French Canadians from Quebec. We screened all coding exons of PALB2 in a sample of 50 French-Canadian women diagnosed with either early-onset breast cancer or familial breast cancer at a single Montreal hospital. The genetic variants identified in this sample were then studied in 356 additional women with breast cancer diagnosed before age 50 and in 6,448 newborn controls. We identified a single protein-truncating mutation in PALB2 (c.2323 C>T, resulting in Q775X) in 1 of the 50 high-risk women. This variant was present in 2 of 356 breast cancer cases and in none of 6,440 newborn French-Canadian controls (P = 0.003). We also identified two novel new non-synonymous single nucleotide polymorphisms in exon 4 of PALB2 (c.5038 A>G [I76V] and c.5156 G>T [G115V]). G115V was found in 1 of 356 cases and in 15 of 6,442 controls (P = 0.6). The I76V variant was not identified in either the extended case series or the controls. We have identified a novel truncating mutation in PALB2. The mutation was found in approximately 0.5% of unselected French-Canadian women with early-onset breast cancer and appears to have a single origin. Although mutations are infrequent, PALB2 can be added to the list of breast cancer susceptibility genes for which founder mutations have been identified in the French-Canadian population.

Identification of a novel truncating PALB2 mutation and analysis of its contribution to early-onset breast cancer in French-Canadian women

PubMed Central

Foulkes, William D; Ghadirian, Parviz; Akbari, Mohammed Reza; Hamel, Nancy; Giroux, Sylvie; Sabbaghian, Nelly; Darnel, Andrew; Royer, Robert; Poll, Aletta; Fafard, Eve; Robidoux, André; Martin, Ginette; Bismar, Tarek A; Tischkowitz, Marc; Rousseau, Francois; Narod, Steven A

2007-01-01

Background PALB2 has recently been identified as a breast cancer susceptibility gene. PALB2 mutations are rare causes of hereditary breast cancer but may be important in countries such as Finland where a founder mutation is present. We sought to estimate the contribution of PALB2 mutations to the burden of breast cancer in French Canadians from Quebec. Methods We screened all coding exons of PALB2 in a sample of 50 French-Canadian women diagnosed with either early-onset breast cancer or familial breast cancer at a single Montreal hospital. The genetic variants identified in this sample were then studied in 356 additional women with breast cancer diagnosed before age 50 and in 6,448 newborn controls. Results We identified a single protein-truncating mutation in PALB2 (c.2323 C>T, resulting in Q775X) in 1 of the 50 high-risk women. This variant was present in 2 of 356 breast cancer cases and in none of 6,440 newborn French-Canadian controls (P = 0.003). We also identified two novel new non-synonymous single nucleotide polymorphisms in exon 4 of PALB2 (c.5038 A>G [I76V] and c.5156 G>T [G115V]). G115V was found in 1 of 356 cases and in 15 of 6,442 controls (P = 0.6). The I76V variant was not identified in either the extended case series or the controls. Conclusion We have identified a novel truncating mutation in PALB2. The mutation was found in approximately 0.5% of unselected French-Canadian women with early-onset breast cancer and appears to have a single origin. Although mutations are infrequent, PALB2 can be added to the list of breast cancer susceptibility genes for which founder mutations have been identified in the French-Canadian population. PMID:18053174

Laboratory and Genetic Investigation of Mutations Accounting for Congenital Fibrinogen Disorders.

PubMed

Neerman-Arbez, Marguerite; de Moerloose, Philippe; Casini, Alessandro

2016-06-01

Congenital fibrinogen disorders are classified into two types of plasma fibrinogen defects: type I (quantitative fibrinogen deficiencies), that is, hypofibrinogenemia or afibrinogenemia, in which there are low or absent plasma fibrinogen antigen levels, respectively, and type II (qualitative fibrinogen deficiencies), that is, dysfibrinogenemia or hypodysfibrinogenemia, in which there are normal or reduced antigen levels associated with disproportionately low functional activity. These disorders are caused by mutations in the three fibrinogen-encoding genes FGA, FGB, and FGG. Afibrinogenemia is associated with mild to severe bleeding, whereas hypofibrinogenemia is often asymptomatic. For these quantitative disorders, the majority of mutations prevent protein production. However, in some cases, missense or late-truncating nonsense mutations allow synthesis of the mutant fibrinogen chain, but intracellular fibrinogen assembly and/or secretion are impaired. Qualitative fibrinogen disorders are associated with bleeding, thrombosis, or both thrombosis and bleeding, but many dysfibrinogenemias are asymptomatic. The majority of cases are caused by heterozygous missense mutations. Here, we review the laboratory and genetic diagnosis of fibrinogen gene anomalies with an updated discussion of causative mutations identified. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

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

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

Neutropenia-associated ELANE mutations disrupting translation initiation produce novel neutrophil elastase isoforms

PubMed Central

Tidwell, Timothy; Wechsler, Jeremy; Nayak, Ramesh C.; Trump, Lisa; Salipante, Stephen J.; Cheng, Jerry C.; Donadieu, Jean; Glaubach, Taly; Corey, Seth J.; Grimes, H. Leighton; Lutzko, Carolyn; Cancelas, Jose A.

2014-01-01

Hereditary neutropenia is usually caused by heterozygous germline mutations in the ELANE gene encoding neutrophil elastase (NE). How mutations cause disease remains uncertain, but two hypotheses have been proposed. In one, ELANE mutations lead to mislocalization of NE. In the other, ELANE mutations disturb protein folding, inducing an unfolded protein response in the endoplasmic reticulum (ER). In this study, we describe new types of mutations that disrupt the translational start site. At first glance, they should block translation and are incompatible with either the mislocalization or misfolding hypotheses, which require mutant protein for pathogenicity. We find that start-site mutations, instead, force translation from downstream in-frame initiation codons, yielding amino-terminally truncated isoforms lacking ER-localizing (pre) and zymogen-maintaining (pro) sequences, yet retain essential catalytic residues. Patient-derived induced pluripotent stem cells recapitulate hematopoietic and molecular phenotypes. Expression of the amino-terminally deleted isoforms in vitro reduces myeloid cell clonogenic capacity. We define an internal ribosome entry site (IRES) within ELANE and demonstrate that adjacent mutations modulate IRES activity, independently of protein-coding sequence alterations. Some ELANE mutations, therefore, appear to cause neutropenia via the production of amino-terminally deleted NE isoforms rather than by altering the coding sequence of the full-length protein. PMID:24184683

Molecular Genetics of the Usher Syndrome in Lebanon: Identification of 11 Novel Protein Truncating Mutations by Whole Exome Sequencing

PubMed Central

Reddy, Ramesh; Fahiminiya, Somayyeh; El Zir, Elie; Mansour, Ahmad; Megarbane, Andre; Majewski, Jacek; Slim, Rima

2014-01-01

Background Usher syndrome (USH) is a genetically heterogeneous condition with ten disease-causing genes. The spectrum of genes and mutations causing USH in the Lebanese and Middle Eastern populations has not been described. Consequently, diagnostic approaches designed to screen for previously reported mutations were unlikely to identify the mutations in 11 unrelated families, eight of Lebanese and three of Middle Eastern origins. In addition, six of the ten USH genes consist of more than 20 exons, each, which made mutational analysis by Sanger sequencing of PCR-amplified exons from genomic DNA tedious and costly. The study was aimed at the identification of USH causing genes and mutations in 11 unrelated families with USH type I or II. Methods Whole exome sequencing followed by expanded familial validation by Sanger sequencing. Results We identified disease-causing mutations in all the analyzed patients in four USH genes, MYO7A, USH2A, GPR98 and CDH23. Eleven of the mutations were novel and protein truncating, including a complex rearrangement in GPR98. Conclusion Our data highlight the genetic diversity of Usher syndrome in the Lebanese population and the time and cost-effectiveness of whole exome sequencing approach for mutation analysis of genetically heterogeneous conditions caused by large genes. PMID:25211151

Molecular genetics of the Usher syndrome in Lebanon: identification of 11 novel protein truncating mutations by whole exome sequencing.

PubMed

Reddy, Ramesh; Fahiminiya, Somayyeh; El Zir, Elie; Mansour, Ahmad; Megarbane, Andre; Majewski, Jacek; Slim, Rima

2014-01-01

Usher syndrome (USH) is a genetically heterogeneous condition with ten disease-causing genes. The spectrum of genes and mutations causing USH in the Lebanese and Middle Eastern populations has not been described. Consequently, diagnostic approaches designed to screen for previously reported mutations were unlikely to identify the mutations in 11 unrelated families, eight of Lebanese and three of Middle Eastern origins. In addition, six of the ten USH genes consist of more than 20 exons, each, which made mutational analysis by Sanger sequencing of PCR-amplified exons from genomic DNA tedious and costly. The study was aimed at the identification of USH causing genes and mutations in 11 unrelated families with USH type I or II. Whole exome sequencing followed by expanded familial validation by Sanger sequencing. We identified disease-causing mutations in all the analyzed patients in four USH genes, MYO7A, USH2A, GPR98 and CDH23. Eleven of the mutations were novel and protein truncating, including a complex rearrangement in GPR98. Our data highlight the genetic diversity of Usher syndrome in the Lebanese population and the time and cost-effectiveness of whole exome sequencing approach for mutation analysis of genetically heterogeneous conditions caused by large genes.

Heterozygous M1V variant of ELA-2 gene mutation associated with G-CSF refractory severe congenital neutropenia.

PubMed

Setty, Bhuvana A; Yeager, Nicholas D; Bajwa, Rajinder P

2011-09-01

Severe congenital neutropenia is an autosomal recessive disorder characterized by maturation arrest at the promyelocyte/myelocyte phase in the bone marrow, absolute neutrophil count <0.5 × 10(9) /L and recurrent bacterial infections. Homozygous mutations of either HAX-1 or ELA-2 have been described. We report the case of a premature male infant with congenital neutropenia, associated with multiple infections, refractory to treatment with granulocyte colony stimulating factor who subsequently underwent matched sibling donor stem-cell transplant. He was found to be heterozygous for the M1V variant of the ELA-2 gene that we postulate to be causative for his severe neutropenia Copyright © 2011 Wiley-Liss, Inc.

Truncating mutations of HIBCH tend to cause severe phenotypes in cases with HIBCH deficiency: a case report and brief literature review.

PubMed

Tan, Hu; Chen, Xin; Lv, Weigang; Linpeng, Siyuan; Liang, Desheng; Wu, Lingqian

2018-04-27

3-hydroxyisobutryl-CoA hydrolase (HIBCH) deficiency is a rare inborn error of valine metabolism characterized by neurodegenerative symptoms and caused by recessive mutations in the HIBCH gene. In this study, utilizing whole exome sequencing, we identified two novel splicing mutations of HIBCH (c.304+3A>G; c.1010_1011+3delTGGTA) in a Chinese patient with characterized neurodegenerative features of HIBCH deficiency and bilateral syndactyly which was not reported in previous studies. Functional tests showed that both of these two mutations destroyed the normal splicing and reduced the expression of HIBCH protein. Through a literature review, a potential phenotype-genotype correlation was found that patients carrying truncating mutations tended to have more severe phenotypes compared with those with missense mutations. Our findings would widen the mutation spectrum of HIBCH causing HIBCH deficiency and the phenotypic spectrum of the disease. The potential genotype-phenotype correlation would be profitable for the treatment and management of patients with HIBCH deficiency.

Identification of ALK germline mutation (3605delG) in pediatric anaplastic medulloblastoma.

PubMed

Coco, Simona; De Mariano, Marilena; Valdora, Francesca; Servidei, Tiziana; Ridola, Vita; Andolfo, Immacolata; Oberthuer, André; Tonini, Gian Paolo; Longo, Luca

2012-10-01

The anaplastic lymphoma kinase (ALK) gene has been found either rearranged or mutated in several neoplasms such as anaplastic large-cell lymphoma, non-small-cell lung cancer, neuroblastoma and anaplastic thyroid cancer. Medulloblastoma (MB) is an embryonic pediatric cancer arising from nervous system, a tissue in which ALK is expressed during embryonic development. We performed an ALK mutation screening in 52 MBs and we found a novel heterozygous germline deletion of a single base in exon 23 (3605delG) in a case with marked anaplasia. This G deletion results in a frameshift mutation producing a premature stop codon in exon 25 of ALK tyrosine kinase domain. We also screened three human MB cell lines without finding any mutation of ALK gene. Quantitative expression analysis of 16 out of 52 samples showed overexpression of ALK mRNA in three MBs. In the present study, we report the first mutation of ALK found in MB. Moreover, a deletion of ALK gene producing a stop codon has not been detected in human tumors up to now. Further investigations are now required to elucidate whether the truncated form of ALK may have a role in signal transduction.

Mutations in POGLUT1, Encoding Protein O-Glucosyltransferase 1, Cause Autosomal-Dominant Dowling-Degos Disease

PubMed Central

Basmanav, F. Buket; Oprisoreanu, Ana-Maria; Pasternack, Sandra M.; Thiele, Holger; Fritz, Günter; Wenzel, Jörg; Größer, Leopold; Wehner, Maria; Wolf, Sabrina; Fagerberg, Christina; Bygum, Anette; Altmüller, Janine; Rütten, Arno; Parmentier, Laurent; El Shabrawi-Caelen, Laila; Hafner, Christian; Nürnberg, Peter; Kruse, Roland; Schoch, Susanne; Hanneken, Sandra; Betz, Regina C.

2014-01-01

Dowling-Degos disease (DDD) is an autosomal-dominant genodermatosis characterized by progressive and disfiguring reticulate hyperpigmentation. We previously identified loss-of-function mutations in KRT5 but were only able to detect pathogenic mutations in fewer than half of our subjects. To identify additional causes of DDD, we performed exome sequencing in five unrelated affected individuals without mutations in KRT5. Data analysis identified three heterozygous mutations from these individuals, all within the same gene. These mutations, namely c.11G>A (p.Trp4∗), c.652C>T (p.Arg218∗), and c.798-2A>C, are within POGLUT1, which encodes protein O-glucosyltransferase 1. Further screening of unexplained cases for POGLUT1 identified six additional mutations, as well as two of the above described mutations. Immunohistochemistry of skin biopsies of affected individuals with POGLUT1 mutations showed significantly weaker POGLUT1 staining in comparison to healthy controls with strong localization of POGLUT1 in the upper parts of the epidermis. Immunoblot analysis revealed that translation of either wild-type (WT) POGLUT1 or of the protein carrying the p.Arg279Trp substitution led to the expected size of about 50 kDa, whereas the c.652C>T (p.Arg218∗) mutation led to translation of a truncated protein of about 30 kDa. Immunofluorescence analysis identified a colocalization of the WT protein with the endoplasmic reticulum and a notable aggregating pattern for the truncated protein. Recently, mutations in POFUT1, which encodes protein O-fucosyltransferase 1, were also reported to be responsible for DDD. Interestingly, both POGLUT1 and POFUT1 are essential regulators of Notch activity. Our results furthermore emphasize the important role of the Notch pathway in pigmentation and keratinocyte morphology. PMID:24387993

Identification a nonsense mutation of APC gene in Chinese patients with familial adenomatous polyposis.

PubMed

Li, Haishan; Zhang, Lingling; Jiang, Quan; Shi, Zhenwang; Tong, Hanxing

2017-04-01

Familial adenomatous polyposis (FAP; Mendelian of Inherintance in Man ID, 175100) is a rare autosomal dominant disorder characterized by the development of numerous adenomatous polyps throughout the colon and rectum associated with an increased risk of colorectal cancer. FAP is at time accompanied with certain extraintestinal manifestations such as congenital hypertrophy of the retinal pigment epithelium, dental disorders and desmoid tumors. It is caused by mutations in the adenomatous polyposis coli ( APC ) gene. The present study reported on a Chinese family with FAP. Polymerase chain reaction and direct sequencing of the full coding sequence of the APC gene were performed to identify the mutation in this family. A nonsense mutation of the APC gene was identified in this pedigree. It is a heterozygous G>T substitution at position 2,971 in exon 15 of the APC gene, which formed a premature stop codon at amino acid residue 991 (p.Glu991*). The resulting truncated protein lacked 1,853 amino acids. The present study expanded the database on APC gene mutations in FAP and enriched the spectrum of known germline mutations of the APC gene. Prophylactic proctocolectomy may be considered as a possible treatment for carriers of the mutation.

Thiamine responsive megaloblastic anemia: a novel SLC19A2 compound heterozygous mutation in two siblings.

PubMed

Mozzillo, Enza; Melis, Daniela; Falco, Mariateresa; Fattorusso, Valentina; Taurisano, Roberta; Flanagan, Sarah E; Ellard, Sian; Franzese, Adriana

2013-08-01

Thiamine responsive megaloblastic anemia (TRMA) is an autosomal recessive disease caused by loss of function mutations in the SLC19A2 gene. TRMA is characterized by anemia, deafness, and diabetes. In some cases, optic atrophy or more rarely retinitis pigmentosa is noted. We now report two sisters, the eldest of which presented to a different hospital during childhood with sensorineural deafness, which was treated with a hearing prosthesis, insulin requiring diabetes, retinitis pigmentosa, optic atrophy, and macrocytic anemia. These features initially suggested a clinical diagnosis of Wolfram syndrome (WS). Therapy with thiamine was initiated which resulted in the resolution of the anemia. The younger sister, who was affected with sensorineural deafness, was referred to our hospital for non-autoimmune diabetes. She was found to have macrocytosis and ocular abnormalities. Because a diagnosis of TRMA was suspected, therapy with insulin and thiamine was started. Sequencing analysis of the SLC19A2 gene identified a compound heterozygous mutation p.Y81X/p.L457X (c.242insA/c.1370delT) in both sisters. Non-autoimmune diabetes associated with deafness and macrocytosis, without anemia, suggests a diagnosis of TRMA. Patients clinically diagnosed with WS with anemia and/or macrocytosis should be reevaluated for TRMA. © 2012 John Wiley & Sons A/S.

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

C-terminally truncated form of αB-crystallin is associated with IDH1 R132H mutation in anaplastic astrocytoma.

PubMed

Avliyakulov, Nuraly K; Rajavel, Kavitha S; Le, Khanh Minh T; Guo, Lea; Mirsadraei, Leili; Yong, William H; Liau, Linda M; Li, Sichen; Lai, Albert; Nghiemphu, Phioanh L; Cloughesy, Timothy F; Linetsky, Michael; Haykinson, Michael J; Pope, Whitney B

2014-03-01

Malignant gliomas are the most common human primary brain tumors. Point mutation of amino acid arginine 132 to histidine (R132H) in the IDH1 protein leads to an enzymatic gain-of-function and is thought to promote gliomagenesis. Little is known about the downstream effects of the IDH1 mutation on protein expression and how and whether changes in protein expression are involved in tumor formation or propagation. In the current study, we used 2D DIGE (difference gel electrophoresis) and mass spectrometry to analyze differences in protein expression between IDH1(R132H) mutant and wild type anaplastic (grade III) astrocytoma from human brain cancer tissues. We show that expression levels of many proteins are altered in IDH1(R132H) mutant anaplastic astrocytoma. Some of the most over-expressed proteins in the mutants include several forms of αB-crystallin, a small heat-shock and anti-apoptotic protein. αB-crystallin proteins are elevated up to 22-fold in IDH1(R132H) mutant tumors, and αB-crystallin expression appears to be controlled at the post-translational level. We identified the most abundant form of αB-crystallin as a low molecular weight species that is C-terminally truncated. We also found that overexpression of αB-crystallin can be induced by transfecting U251 human glioblastoma cell lines with the IDH1(R132H) mutation. In conclusion, the association of a C-terminally truncated form of αB-crystallin protein with the IDH1(R132H) mutation is a novel finding that could impact apoptosis and stress response in IDH1 mutant glioma.

A POT1 mutation implicates defective telomere end fill-in and telomere truncations in Coats plus

PubMed Central

Takai, Hiroyuki; Jenkinson, Emma; Kabir, Shaheen; Babul-Hirji, Riyana; Najm-Tehrani, Nasrin; Chitayat, David A.; Crow, Yanick J.; de Lange, Titia

2016-01-01

Coats plus (CP) can be caused by mutations in the CTC1 component of CST, which promotes polymerase α (polα)/primase-dependent fill-in throughout the genome and at telomeres. The cellular pathology relating to CP has not been established. We identified a homozygous POT1 S322L substitution (POT1CP) in two siblings with CP. POT1CP induced a proliferative arrest that could be bypassed by telomerase. POT1CP was expressed at normal levels, bound TPP1 and telomeres, and blocked ATR signaling. POT1CP was defective in regulating telomerase, leading to telomere elongation rather than the telomere shortening observed in other telomeropathies. POT1CP was also defective in the maintenance of the telomeric C strand, causing extended 3′ overhangs and stochastic telomere truncations that could be healed by telomerase. Consistent with shortening of the telomeric C strand, metaphase chromosomes showed loss of telomeres synthesized by leading strand DNA synthesis. We propose that CP is caused by a defect in POT1/CST-dependent telomere fill-in. We further propose that deficiency in the fill-in step generates truncated telomeres that halt proliferation in cells lacking telomerase, whereas, in tissues expressing telomerase (e.g., bone marrow), the truncations are healed. The proposed etiology can explain why CP presents with features distinct from those associated with telomerase defects (e.g., dyskeratosis congenita). PMID:27013236

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.

[Mutation screening of MITF gene in patients with Waardenburg syndrome type 2].

PubMed

Chen, Jing; Yang, Shu-Zhi; Liu, Jun; Han, Bing; Wang, Guo-Jian; Zhang, Xin; Kang, Dong-Yang; Dai, Pu; Young, Wie-Yen; Yuan, Hui-Jun

2008-04-01

Warrgenburg syndrome type 2 (WS2) is the most common autosomal dominantly-inherited syndrome with hearing loss. MITF (microphthalmia associated transcription factor)is a basic-helix-loop-helix-luecine zipper (bHLHZip) factor which regulates expression of tyrosinase, and is involved in melanocyte differentiation. Mutations in MITF associated with WS2 have been identified in some but not all affected families. Here, we report a three-generation Chinese family with a point mutation in the MITF gene causing WS2. The proband exhibits congenital severe sensorineural hearing loss, heterochromia iridis and facial freckles. One of family members manifests sensorineural deafness, and the other patients show premature greying or/and freckles. This mutation, heterozygous deletion c.639delA, creates a stop codon in exon 7 and is predicted to result in a truncated protein lacking normal interaction with its target DNA motif. This mutation is a novel mutation and the third case identified in exon 7 of MITF in WS2. Though there is only one base pair distance between this novel mutation and the other two documented cases and similar amino acids change, significant difference is seen in clinical phenotype, which suggests genetic background may play an important role.

Novel compound heterozygous DPH1 mutations in a patient with the unique clinical features of airway obstruction and external genital abnormalities.

PubMed

Nakajima, Junya; Oana, Shingo; Sakaguchi, Tomohiro; Nakashima, Mitsuko; Numabe, Hironao; Kawashima, Hisashi; Matsumoto, Naomichi; Miyake, Noriko

2018-04-01

The diphthamide biosynthesis 1 (DPH1) gene encodes one of the essential components of the enzyme catalyzing the first step of diphthamide formation on eukaryotic elongation factor 2 (EEF2). Diphthamide is the posttranslationally modified histidine residue on EEF2 that promotes protein chain elongation in the ribosome. DPH1 defects result in a failure of protein synthesis involving EEF2, leading to growth defects, embryonic lethality, and cell death. In humans, DPH1 mutations cause developmental delay with a short stature, dysmorphic features, and sparse hair, and are inherited in an autosomal recessive manner (MIM#616901). To date, only two homozygous missense mutations in DPH1 (c.17T>A, p.Met6Lys and c.701T>C, p.Leu234Pro) have been reported. We used WES to identify novel compound heterozygous mutations in DPH1 (c.289delG, p.Glu97Lysfs*8 and c.491T>C, p.Leu164Pro) in a patient from a nonconsanguineous family presenting with intellectual disability, a short stature, craniofacial abnormalities, and external genital abnormalities. The clinical phenotype of all patients with DPH1 mutations, including the current patient, revealed core features, although the external genital anomaly was newly recognized in our case.

Truncating mutations in TAF4B and ZMYND15 causing recessive azoospermia.

PubMed

Ayhan, Özgecan; Balkan, Mahmut; Guven, Ayse; Hazan, Renin; Atar, Murat; Tok, Atalay; Tolun, Aslıhan

2014-04-01

Azoospermia is the absence of a measurable level of spermatozoa in the semen. It affects approximately 1% of all men, and the genetic basis of the majority of idiopathic cases is unknown. We investigated two unrelated consanguineous families with idiopathic azoospermia. In family 1, there were three azoospermic brothers and one oligozoospermic brother; and in family 2, there were three azoospermic brothers. Testis biopsy in the brothers in family 2 had led to the diagnosis of maturation arrest in the spermatid stage. Candidate disease loci were found via linkage mapping using data from single nucleotide polymorphism genome scans. Exome sequencing was applied to find the variants at the loci. We identified two candidate loci in each family and homozygous truncating mutations p.R611X in TAF4B in family 1 and p.K507Sfs*3 in ZMYND15 in family 2. We did not detect any mutations in these genes in a cohort of 45 azoospermic and 15 oligozoospermic men. Expression studies for ZMYND15 showed that the highest expression was in the testis. Both genes are known to have roles in spermatogenesis in mice but neither has been studied in humans. To our knowledge, they are the first genes identified for recessive idiopathic spermatogenic failure in men. Assuming that recessive genes for isolated azoospermia are as numerous in men as in mice, each gene is possibly responsible for only a small fraction of all cases.

A combination of two truncating mutations in USH2A causes more severe and progressive hearing impairment in Usher syndrome type IIa.

PubMed

Hartel, Bas P; Löfgren, Maria; Huygen, Patrick L M; Guchelaar, Iris; Lo-A-Njoe Kort, Nicole; Sadeghi, Andre M; van Wijk, Erwin; Tranebjærg, Lisbeth; Kremer, Hannie; Kimberling, William J; Cremers, Cor W R J; Möller, Claes; Pennings, Ronald J E

2016-09-01

Usher syndrome is an inherited disorder that is characterized by hearing impairment (HI), retinitis pigmentosa, and in some cases vestibular dysfunction. Usher syndrome type IIa is caused by mutations in USH2A. HI in these patients is highly heterogeneous and the present study evaluates the effects of different types of USH2A mutations on the audiometric phenotype. Data from two large centres of expertise on Usher Syndrome in the Netherlands and Sweden were combined in order to create a large combined sample of patients to identify possible genotype-phenotype correlations. A retrospective study on HI in 110 patients (65 Dutch and 45 Swedish) genetically diagnosed with Usher syndrome type IIa. We used methods especially designed for characterizing and testing differences in audiological phenotype between patient subgroups. These methods included Age Related Typical Audiograms (ARTA) and a method to evaluate the difference in the degree of HI developed throughout life between subgroups. Cross-sectional linear regression analysis of last-visit audiograms for the best hearing ear demonstrated a gradual decline of hearing over decades. The congenital level of HI was in the range of 16-33 dB at 0.25-0.5 kHz, and in the range of 51-60 dB at 1-8 kHz. The annual threshold deterioration was in the range of 0.4-0.5 dB/year at 0.25-2 kHz and in the range of 0.7-0.8 dB/year at 4-8 kHz. Patients with two truncating mutations, including homozygotes for the common c.2299delG mutation, developed significantly more severe HI throughout life than patients with one truncating mutation combined with one nontruncating mutation, and patients with two nontruncating mutations. The results have direct implications for patient counselling in terms of prognosis of hearing and may serve as baseline measures for future (genetic) therapeutic interventions. Copyright © 2016 Elsevier B.V. All rights reserved.

Identification of compound heterozygous patients with primary hyperoxaluria type 1: clinical evaluations and in silico investigations.

PubMed

Kanoun, Houda; Jarraya, Faiçal; Maalej, Bayen; Lahiani, Amina; Mahfoudh, Hichem; Makni, Fatma; Hachicha, Jamil; Fakhfakh, Faiza

2017-10-02

Primary hyperoxaluria type 1 (PH1) is an autosomal recessive inherited disorder of glyoxylate metabolism in which excessive oxalates are formed by the liver and excreted by the kidneys. Calcium oxalate crystallizes in the urine, leading to urolithiasis, nephrocalcinosis, and consequent renal failure if treatment is not initiated promptly. Mutations in the AGXT gene which encodes the hepatic peroxisomal enzyme alanine:glyoxylate aminotransferase are responsible of PH1. In the present work, we aimed to analyze AGXT gene and in silico investigations performed in four patients with PH1 among two non consanguineous families. Exhaustive gene sequencing was performed after PCR amplification of coding exons and introns boundaries. Bioinformatic tools were used to predict the impact of AGXT variants on gene expression as well as on the protein structure and function. Direct sequencing of all exons of AGXT gene revealed the emergence of multiple mutations in compound heterozygous state in the two studied families. Two patients were compound heterozygous for the c.731 T > C, c.32C > T, c.1020A > G and c.33_34insC and presented clinically with recurrent urinary tract infection, multiple urolithiasis and nephrocalcinosis under the age of 1 year and a persistent hyperoxaluria at the age of diagnosis. The two other patients presenting a less severe phenotypes were heterozygous for c.731 T > C and homozygous for the c.32C > T and c.1020A > G or compound heterozygous for c.26C > A and c.65A > G variants. In Summary, we provided relevance regarding the compound heterozygous mutations in non consanguineous PH1 families with variable severity.

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.

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.

Antisense Oligonucleotide-Based Splicing Correction in Individuals with Leber Congenital Amaurosis due to Compound Heterozygosity for the c.2991+1655A>G Mutation in CEP290.

PubMed

Duijkers, Lonneke; van den Born, L Ingeborgh; Neidhardt, John; Bax, Nathalie M; Pierrache, Laurence H M; Klevering, B Jeroen; Collin, Rob W J; Garanto, Alejandro

2018-03-07

Leber congenital amaurosis (LCA) is a rare inherited retinal disorder affecting approximately 1:50,000 people worldwide. So far, mutations in 25 genes have been associated with LCA, with CEP290 (encoding the Centrosomal protein of 290 kDa) being the most frequently mutated gene. The most recurrent LCA-causing CEP290 mutation, c.2991+1655A>G, causes the insertion of a pseudoexon into a variable proportion of CEP290 transcripts. We previously demonstrated that antisense oligonucleotides (AONs) have a high therapeutic potential for patients homozygously harbouring this mutation, although to date, it is unclear whether rescuing one single allele is enough to restore CEP290 function. Here, we assessed the AON efficacy at RNA, protein and cellular levels in samples that are compound heterozygous for this mutation, together with a protein-truncating mutation in CEP290 . We demonstrate that AONs can efficiently restore splicing and increase protein levels. However, due to a high variability in ciliation among the patient-derived cell lines, the efficacy of the AONs was more difficult to assess at the cellular level. This observation points towards the importance of the severity of the second allele and possibly other genetic variants present in each individual. Overall, AONs seem to be a promising tool to treat CEP290 -associated LCA, not only in homozygous but also in compound heterozygous carriers of the c.2991+1655A>G variant.

Identification of the first nonsense CDSN mutation with expression of a truncated protein causing peeling skin syndrome type B.

PubMed

Mallet, A; Kypriotou, M; George, K; Leclerc, E; Rivero, D; Mazereeuw-Hautier, J; Serre, G; Huber, M; Jonca, N; Hohl, D

2013-12-01

Peeling skin disease (PSD), a generalized inflammatory form of peeling skin syndrome, is caused by autosomal recessive nonsense mutations in the corneodesmosin gene (CDSN). To investigate a novel mutation in CDSN. A 50-year-old white woman showed widespread peeling with erythema and elevated serum IgE. DNA sequencing, immunohistochemistry, Western blot and real-time polymerase chain reaction analyses of skin biopsies were performed in order to study the genetics and to characterize the molecular profile of the disease. Histology showed hyperkeratosis and acanthosis of the epidermis, and inflammatory infiltrates in the dermis. DNA sequencing revealed a homozygous mutation leading to a premature termination codon in CDSN: p.Gly142*. Protein analyses showed reduced expression of a 16-kDa corneodesmosin mutant in the upper epidermal layers, whereas the full-length protein was absent. These results are interesting regarding the genotype-phenotype correlations in diseases caused by CDSN mutations. The PSD-causing CDSN mutations identified heretofore result in total corneodesmosin loss, suggesting that PSD is due to full corneodesmosin deficiency. Here, we show for the first time that a mutant corneodesmosin can be stably expressed in some patients with PSD, and that this truncated protein is very probably nonfunctional. © 2013 British Association of Dermatologists.

Loss of function mutations in EPHB4 are responsible for vein of Galen aneurysmal malformation.

PubMed

Vivanti, Alexandre; Ozanne, Augustin; Grondin, Cynthia; Saliou, Guillaume; Quevarec, Loic; Maurey, Helène; Aubourg, Patrick; Benachi, Alexandra; Gut, Marta; Gut, Ivo; Martinovic, Jelena; Sénat, Marie Victoire; Tawk, Marcel; Melki, Judith

2018-04-01

See Meschia (doi:10.1093/brain/awy066) for a scientific commentary on this article.Vein of Galen aneurysmal malformation is a congenital anomaly of the cerebral vasculature representing 30% of all paediatric vascular malformations. We conducted whole exome sequencing in 19 unrelated patients presenting this malformation and subsequently screened candidate genes in a cohort of 32 additional patients using either targeted exome or Sanger sequencing. In a cohort of 51 patients, we found five affected individuals with heterozygous mutations in EPHB4 including de novo frameshift (p.His191Alafs*32) or inherited deleterious splice or missense mutations predicted to be pathogenic by in silico tools. Knockdown of ephb4 in zebrafish embryos leads to specific anomalies of dorsal cranial vessels including the dorsal longitudinal vein, which is the orthologue of the median prosencephalic vein and the embryonic precursor of the vein of Galen. This model allowed us to investigate EPHB4 loss-of-function mutations in this disease by the ability to rescue the brain vascular defect in knockdown zebrafish co-injected with wild-type, but not truncated EPHB4, mimicking the p.His191Alafs mutation. Our data showed that in both species, loss of function mutations of EPHB4 result in specific and similar brain vascular development anomalies. Recently, EPHB4 germline mutations have been reported in non-immune hydrops fetalis and in cutaneous capillary malformation-arteriovenous malformation. Here, we show that EPHB4 mutations are also responsible for vein of Galen aneurysmal malformation, indicating that heterozygous germline mutations of EPHB4 result in a large clinical spectrum. The identification of EPHB4 pathogenic mutations in patients presenting capillary malformation or vein of Galen aneurysmal malformation should lead to careful follow-up of pregnancy of carriers for early detection of anomaly of the cerebral vasculature in order to propose optimal neonatal care. Endovascular

Integrated allelic, transcriptional, and phenomic dissection of the cardiac effects of titin truncations in health and disease

PubMed Central

Roberts, Angharad M.; Ware, James S.; Herman, Daniel S.; Schafer, Sebastian; Baksi, John; Bick, Alexander G.; Buchan, Rachel J.; Walsh, Roddy; John, Shibu; Wilkinson, Samuel; Mazzarotto, Francesco; Felkin, Leanne E.; Gong, Sungsam; MacArthur, Jacqueline A.L.; Cunningham, Fiona; Flannick, Jason; Gabriel, Stacey B.; Altshuler, David M.; Macdonald, Peter S.; Heinig, Matthias; Keogh, Anne M.; Hayward, Christopher S.; Banner, Nicholas R.; Pennell, Dudley J.; O’Regan, Declan; San, Tan Ru; de Marvao, Antonio; Dawes, Timothy J. W.; Gulati, Ankur; Birks, Emma J.; Yacoub, Magdi H.; Radke, Michael; Gotthardt, Michael; Wilson, James G.; O’Donnell, Christopher J.; Prasad, Sanjay K.; Barton, Paul J.R.; Fatkin, Diane; Hubner, Norbert; Seidman, J. G.; Seidman, Christine E.; Cook, Stuart A.

2015-01-01

The recent discovery of heterozygous human mutations that truncate full-length titin (TTN, an abundant structural, sensory, and signaling filament in muscle) as a common cause of end-stage dilated cardiomyopathy (DCM) provides new prospects for improving heart failure management. However, realization of this opportunity has been hindered by the burden of TTN truncating variants (TTNtv) in the general population and uncertainty about their consequences in health or disease. To elucidate the effects of TTNtv, we coupled TTN gene sequencing with cardiac phenotyping in 5,267 individuals across the spectrum of cardiac physiology, and integrated these data with RNA and protein analyses of human heart tissues. We report diversity of TTN isoform expression in the heart, define the relative inclusion of TTN exons in different isoforms, and demonstrate that these data, coupled with TTNtv position, provide a robust strategy to discriminate pathogenic from benign TTNtv. We show that TTNtv is the most common genetic cause for DCM in ambulant patients in the community, identify clinically important manifestations of TTNtv-positive DCM, and define the penetrance and outcomes of TTNtv in the general population. By integrating genetic, transcriptome, and protein analyses we provide evidence for a length-dependent, dominant negative mechanism of disease. These data inform diagnostic criteria and management strategies for TTNtv-positive DCM patients and for TTNtv that are identified as incidental findings. PMID:25589632

NF1 truncating mutations associated to aggressive clinical phenotype with elephantiasis neuromatosa and solid malignancies.

PubMed

Ponti, Giovanni; Martorana, Davide; Pellacani, Giovanni; Ruini, Cristel; Loschi, Pietro; Baccarani, Alessio; De Santis, Giorgio; Pollio, Annamaria; Neri, Tauro Maria; Mandel, Victor Desmond; Maiorana, Antonio; Maccio, Livia; Maccaferri, Monia; Tomasi, Aldo

2014-06-01

Von Recklinghausen disease is a syndrome characterized by a wide phenotypic variability giving rise to both, cutaneous and visceral benign and malignant neoplasms. The first include cutaneous neurofibromas, subcutaneous and plexiform neurofibromas. The latter can undergo malignant transformation and/or determine elephantiasis neuromatosa. Visceral tumors may include malignant peripheral nerve sheet tumors, gastrointestinal stromal tumors, cerebral gliomas and abdominal neurofibromas. In the present study, the authors discuss the clinical and biomolecular characterization of a cohort of 20 families with a diagnosis of type 1 neurofibromatosis. Clinically, the cohort includes three probands with elephantiasis neuromatosa and a peculiarly high incidence of breast and gastrointestinal cancer. Among the 14 NF1 mutations documented, 10 encoding for a truncated protein have been associated to particularly aggressive clinical phenotypes including elephantiasis neuromatosa, malignant peripheral nerve sheet tumors, breast cancer, gastrointestinal stromal tumors. This effect on protein synthesis, rather than the type of NF1 mutation, is the key to the explanation of the genotype-phenotype correlations in the context of neurofibromatosis type 1. Copyright© 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Ambroxol improves lysosomal biochemistry in glucocerebrosidase mutation-linked Parkinson disease cells.

PubMed

McNeill, Alisdair; Magalhaes, Joana; Shen, Chengguo; Chau, Kai-Yin; Hughes, Derralyn; Mehta, Atul; Foltynie, Tom; Cooper, J Mark; Abramov, Andrey Y; Gegg, Matthew; Schapira, Anthony H V

2014-05-01

Gaucher disease is caused by mutations in the glucocerebrosidase gene, which encodes the lysosomal hydrolase glucosylceramidase. Patients with Gaucher disease and heterozygous glucocerebrosidase mutation carriers are at increased risk of developing Parkinson's disease. Indeed, glucocerebrosidase mutations are the most frequent risk factor for Parkinson's disease in the general population. Therefore there is an urgent need to understand the mechanisms by which glucocerebrosidase mutations predispose to neurodegeneration to facilitate development of novel treatments. To study this we generated fibroblast lines from skin biopsies of five patients with Gaucher disease and six heterozygous glucocerebrosidase mutation carriers with and without Parkinson's disease. Glucosylceramidase protein and enzyme activity levels were assayed. Oxidative stress was assayed by single cell imaging of dihydroethidium. Glucosylceramidase enzyme activity was significantly reduced in fibroblasts from patients with Gaucher disease (median 5% of controls, P = 0.0001) and heterozygous mutation carriers with (median 59% of controls, P = 0.001) and without (56% of controls, P = 0.001) Parkinson's disease compared with controls. Glucosylceramidase protein levels, assessed by western blot, were significantly reduced in fibroblasts from Gaucher disease (median glucosylceramidase levels 42% of control, P < 0.001) and heterozygous mutation carriers with (median 59% of control, P < 0.001) and without (median 68% of control, P < 0.001) Parkinson's disease. Single cell imaging of dihydroethidium demonstrated increased production of cytosolic reactive oxygen species in fibroblasts from patients with Gaucher disease (dihydroethidium oxidation rate increased by a median of 62% compared to controls, P < 0.001) and heterozygous mutation carriers with (dihydroethidium oxidation rate increased by a median of 68% compared with controls, P < 0.001) and without (dihydroethidium oxidation rate increased by a

Phenotypic diversity in patients with lipodystrophy associated with LMNA mutations.

PubMed

Mory, Patricia B; Crispim, Felipe; Freire, Maria Beatriz S; Salles, João Eduardo N; Valério, Cynthia M; Godoy-Matos, Amelio F; Dib, Sérgio A; Moisés, Regina S

2012-09-01

Mutations in LMNA have been linked to diverse disorders called laminopathies, which display heterogeneous phenotypes and include diseases affecting muscles, axonal neurons, progeroid syndromes, and lipodystrophies. Among the lipodystrophies, LMNA mutations have been reported most frequently in patients with familial partial lipodystrophy (FPLD) of the Dunnigan variety; however, phenotypic heterogeneity in the pattern of body fat loss has been observed. In this study, we searched for LMNA mutations in patients with various forms of lipodystrophy. We studied 21 unrelated individuals with lipodystrophy. Subjects underwent a complete clinical evaluation and were classified as typical FPLD (n=12), atypical partial lipodystrophy (n=7), or generalized lipodystrophy (n=2). Molecular analysis of LMNA gene, analysis of body fat by dual-energy X-ray absorptiometry, and biochemical measurements were performed. ALL PATIENTS WITH TYPICAL FPLD WERE FOUND TO CARRY LMNA MUTATIONS: seven patients harbored the heterozygous p.R482W (c.1444C>T), two patients harbored the p.R482Q (c.1445G>A), and two individuals harbored the novel heterozygous variant p.N466D (c.1396A>G), all in exon 8. Also, a homozygous p.R584H (c.1751 G>A) mutation in exon 11 was found. Among patients with atypical partial lipodystrophy, two of them were found to have LMNA mutations: a novel heterozygous p.R582C variation (c.1744 C>T) in exon 11 and a heterozygous substitution p.R349W (c.1045C>T) in exon 6. Among patients with generalized lipodystrophy, only one harbored LMNA mutation, a heterozygous p.T10I (c.29C>T) in exon 1. We have identified LMNA mutations in phenotypically diverse lipodystrophies. Also, our study broadens the spectrum of LMNA mutations in lipodystrophy.

Identification of a novel splicing mutation in the growth hormone (GH)-releasing hormone receptor gene in a Chinese family with pituitary dwarfism.

PubMed

Wang, Qi; Diao, Ying; Xu, Zhenping; Li, Xiaohui; Luo, Xiao Ping; Xu, Haibo; Ouyang, Ping; Liu, Mugen; Hu, Zhongli; Wang, Qing K; Liu, Jing Yu

2009-12-10

A Chinese family with autosomal recessive pituitary dwarfism was identified and the proband was evaluated by MRI and hormonal analysis, which revealed pituitary dwarfism with a complete growth hormone deficiency. MRI showed a pituitary gland with a small anterior pituitary of 2.2mm and evidence of hypoplastic pituitary. Linkage analysis with markers spanning 17 known genes for dwarfism revealed linkage of the family to the growth hormone-releasing hormone receptor (GHRHR) gene. Mutational analysis of all exons and exon-intron boundaries of GHRHR was carried out using direct DNA sequence analysis. A novel homozygosis mutation, a G to A transition located in the splice donor site at the beginning of intron 8 (IVS8+1G>A), was identified in the proband. The two other patients in the family are homozygous, whereas the living mother of the proband is heterozygous for the IVS8+1G>A mutation. The mutation was not found in 100 normal chromosomes from healthy Chinese individuals of Han nationality. An in vitro splicing assay using HeLa cells transfected with expression vectors containing the normal or the mutant GHRHR minigenes consisting of genomic fragments spanning exons 7-9 showed that the IVS8+1G>A mutation caused abnormal splicing, which is predicted to give rise to truncation or frameshift, leading to severely truncated GHRHR proteins. These results provide strong evidence that the splicing mutation IVS8+1G>A of GHRHR is a cause of pituitary dwarfism in the Chinese family.

Compound heterozygous mutations in electron transfer flavoprotein dehydrogenase identified in a young Chinese woman with late-onset glutaric aciduria type II.

PubMed

Xue, Ying; Zhou, Yun; Zhang, Keqin; Li, Ling; Kayoumu, Abudurexiti; Chen, Liye; Wang, Yuhui; Lu, Zhiqiang

2017-09-26

Glutaric aciduria type II (GA II) is an autosomal recessive disorder affecting fatty acid and amino acid metabolism. The late-onset form of GA II disorder is almost exclusively associated with mutations in the electron transfer flavoprotein dehydrogenase (ETFDH) gene. Till now, the clinical features of late-onset GA II vary widely and pose a great challenge for diagnosis. The aim of the current study is to characterize the clinical phenotypes and genetic basis of a late-onset GAII patient. In this study, we described the clinical and biochemical manifestations of a 23-year-old female Chinese patient with late-onset GA II, and performed genomic DNA-based PCR amplifications and sequence analysis of ETFDH gene of the whole pedigree. We also used in-silicon tools to analyze the mutation and evaluated the pathogenicity of the mutation according to the criteria proposed by American College of Medical Genetics and Genomics (ACMG). The muscle biopsy of this patient revealed lipid storage myopathy. Blood biochemical test and urine organic acid analyses were consistent with GA II. Direct sequence analysis of the ETFDH gene (NM_004453) revealed compound heterozygous mutations: c.250G > A (p.A84T) on exon 3 and c.920C > G (p.S307C) on exon 8. Both mutations were classified as "pathogenic" according to ACMG criteria. In conclusion, our study described the phenotype and genotype of a late-onset GA II patient, reiterating the importance of ETFDH gene screening in these patients.

A case report of heterozygous TINF2 gene mutation associated with pulmonary fibrosis in a patient with dyskeratosis congenita.

PubMed

Du, Hongchun; Guo, Yubiao; Ma, Di; Tang, Kejing; Cai, Decheng; Luo, Yifeng; Xie, Canmao

2018-05-01

Dyskeratosis congenita (DC) is a rare inherited disease characterized by the classical mucocutaneous triad. Pulmonary fibrosis, bone marrow failure, and solid tumors are the main causes of mortality in DC. Pathogenic variants in TERT, TERC, and DKC1 have been identified in individuals with familial pulmonary fibrosis. Mutations in TINF2 gene have been reported to be associated with bone marrow failure in most cases. However, the relationship between TINF2 mutation and pulmonary fibrosis is not yet clear. Here, we report the case of a 32-year-old woman presented with irritating cough for 2 years and progressive breathlessness for 6 months. The patient was diagnosed with DC based on the following clinical evidences. Along with some family members, she had the typical mucocutaneous triad and pulmonary fibrosis. A heterozygous mutation (c.844C>T), located in exon 6 of TINF2 gene, that changed arginine to cysteine (Arg282Cys) was identified in this proband by whole exome sequencing. The patient received corticosteroid therapy but refused to receive lung transplantation. The proband died of respiratory failure 4 months after the diagnosis. The missense mutation was located in the conserved region of TINF2 gene and predicted to be deleterious by altering the protein structure. Lung transplantation should be considered for improved survival of patients with DC, and pulmonary fibrosis. Whole exome and whole genome sequencing should be widely used in the identification of such rare genetic variants for clinical diagnosis. The study of DC with pulmonary fibrosis can provide a more appropriate means of clinical research and therapy to the unfortunate patients who suffer from this rare disorder.

Novel nonsense mutation of the endothelin-B receptor gene in a family with Waardenburg-Hirschsprung disease.

PubMed

Syrris, P; Carter, N D; Patton, M A

1999-11-05

Waardenburg syndrome (WS) comprises sensorineural hearing loss, hypopigmentation of skin and hair, and pigmentary disturbances of the irides. Four types of WS have been classified to date; in WS type IV (WS4), patients additionally have colonic aganglionosis (Hirschsprung disease, HSCR). Mutations in the endothelin-3 (EDN3), endothelin-B receptor (EDNRB), and Sox10 genes have been identified as causative for WS type IV. We screened a family with a combined WS-HSCR phenotype for mutations in the EDNRB locus using standard DNA mutation analysis and sequencing techniques. We have identified a novel nonsense mutation at codon 253 (CGA-->TGA, Arg-->STOP). This mutation leads to a premature end of the translation of EDNRB at exon 3, and it is predicted to produce a truncated and nonfunctional endothelin-B receptor. All affected relatives were heterozygous for the Arg(253)-->STOP mutation, whereas it was not observed in over 50 unrelated individuals used as controls. These data confirm the role of EDNRB in the cause of the Waardenburg-Hirschsprung syndrome and demonstrate that in WS-HSCR there is a lack of correlation between phenotype and genotype and a variable expression of disease even within the same family. Copyright 1999 Wiley-Liss, Inc.

A novel nonsense mutation in the EYA1 gene associated with branchio-oto-renal/branchiootic syndrome in an Afrikaner kindred.

PubMed

Clarke, J C; Honey, E M; Bekker, E; Snyman, L C; Raymond, R M; Lord, C; Brophy, P D

2006-07-01

Branchio-oto-renal (BOR) syndrome is an autosomal dominant disorder characterized by the associations of hearing loss, branchial arch defects and renal anomalies. Branchiootic (BO) syndrome is a related disorder that presents without the highly variable characteristic renal anomalies of BOR syndrome. Dominant mutations in the human homologue of the Drosophila eyes absent gene (EYA1) are frequently the cause of both BOR and BO syndromes. We report a South African family of Afrikaner descent with affected individuals presenting with pre-auricular abnormalities and either hearing loss or bilateral absence of the kidneys. Genetic analysis of the pedigree detected a novel EYA1 heterozygous nonsense mutation in affected family members but not in unaffected family members or a random DNA panel. Through mutational analysis, we conclude that this particular mutation is the cause of BOR/BO syndrome in this family as a result of a truncation of the EYA1 protein that ablates the critical EYA homologous region. To the best of our knowledge, this is the first case of BOR/BO syndrome reported in Africa or in those of the Afrikaner descent.

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.

Heterozygous Hb Hope [beta136(H14)Gly --> Asp] in association with heterozygous beta0-thalassemia with apparent homozygous expression, in a Spanish patient.

PubMed

Beneitez, David; Carrera, Alícia; Duran-Suárez, Joan Ramón; Paz, Victoria; León, Antonio; García Talavera, Juan

2006-01-01

Hb Hope [beta136(H14)Gly --> Asp (GGT --> GAT)] has been found alone or in combination with other globin gene mutations in several African-American families, as well as in Japanese, Thai, Laotian, Cuban and Mauritanian families. We report the hematological and molecular characteristics of a heterozygous association of Hb Hope with beta0-thalassemia (thal) in a Spanish patient, in whom the level of expression of abnormal hemoglobin (Hb) by cation exchange high performance liquid chromatography (HPLC) and electrophoresis suggested initially a homozygous expression of the abnormal Hb, although sequencing of the polymerase chain reaction (PCR)-amplified beta-globin gene demonstrated a heterozygous genotype for Hb Hope. To the best of our knowledge, this is the first description of a case of Hb Hope in a Spanish family.

POC1A Truncation Mutation Causes a Ciliopathy in Humans Characterized by Primordial Dwarfism

PubMed Central

Shaheen, Ranad; Faqeih, Eissa; Shamseldin, Hanan E.; Noche, Ramil R.; Sunker, Asma; Alshammari, Muneera J.; Al-Sheddi, Tarfa; Adly, Nouran; Al-Dosari, Mohammed S.; Megason, Sean G.; Al-Husain, Muneera; Al-Mohanna, Futwan; Alkuraya, Fowzan S.

2012-01-01

Primordial dwarfism (PD) is a phenotype characterized by profound growth retardation that is prenatal in onset. Significant strides have been made in the last few years toward improved understanding of the molecular underpinning of the limited growth that characterizes the embryonic and postnatal development of PD individuals. These include impaired mitotic mechanics, abnormal IGF2 expression, perturbed DNA-damage response, defective spliceosomal machinery, and abnormal replication licensing. In three families affected by a distinct form of PD, we identified a founder truncating mutation in POC1A. This gene is one of two vertebrate paralogs of POC1, which encodes one of the most abundant proteins in the Chlamydomonas centriole proteome. Cells derived from the index individual have abnormal mitotic mechanics with multipolar spindles, in addition to clearly impaired ciliogenesis. siRNA knockdown of POC1A in fibroblast cells recapitulates this ciliogenesis defect. Our findings highlight a human ciliopathy syndrome caused by deficiency of a major centriolar protein. PMID:22840364

Heterozygous deletion at the SOX10 gene locus in two patients from a Chinese family with Waardenburg syndrome type II.

PubMed

Wenzhi, He; Ruijin, Wen; Jieliang, Li; Xiaoyan, Ma; Haibo, Liu; Xiaoman, Wang; Jiajia, Xian; Shaoying, Li; Shuanglin, Li; Qing, Li

2015-10-01

Waardenburg syndrome (WS) is a rare disease characterized by sensorineural deafness and pigment disturbance. To date, almost 100 mutations have been reported, but few reports on cases with SOX10 gene deletion. The inheritance pattern of SOX10 gene deletion is still unclear. Our objective was to identify the genetic causes of Waardenburg syndrome type II in a two-generation Chinese family. Clinical evaluations were conducted in both of the patients. Microarray analysis and multiplex ligation-dependent probe amplification (MLPA) were performed to identify disease-related copy number variants (CNVs). DNA sequencing of the SOX10, MITF and SNAI2 genes was performed to identify the pathogenic mutation responsible for WS2. A 280kb heterozygous deletion at the 22q13.1 chromosome region (including SOX10) was detected in both of the patients. No mutation was found in the patients, unaffected family members and 30 unrelated healthy controls. This report is the first to describe SOX10 heterozygous deletions in Chinese WS2 patients. Our result conform the thesis that heterozygous deletions at SOX10 is an important pathogenicity for WS, and present as autosomal dominant inheritance. Nevertheless, heterozygous deletion of the SOX10 gene would be worth investigating to understand their functions and contributions to neurologic phenotypes. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Germline mutations in SUFU cause Gorlin syndrome-associated childhood medulloblastoma and redefine the risk associated with PTCH1 mutations.

PubMed

Smith, Miriam J; Beetz, Christian; Williams, Simon G; Bhaskar, Sanjeev S; O'Sullivan, James; Anderson, Beverley; Daly, Sarah B; Urquhart, Jill E; Bholah, Zaynab; Oudit, Deemesh; Cheesman, Edmund; Kelsey, Anna; McCabe, Martin G; Newman, William G; Evans, D Gareth R

2014-12-20

Heterozygous germline PTCH1 mutations are causative of Gorlin syndrome (naevoid basal cell carcinoma), but detection rates > 70% have rarely been reported. We aimed to define the causative mutations in individuals with Gorlin syndrome without PTCH1 mutations. We undertook exome sequencing on lymphocyte DNA from four unrelated individuals from families with Gorlin syndrome with no PTCH1 mutations found by Sanger sequencing, multiplex ligation-dependent probe amplification (MLPA), or RNA analysis. A germline heterozygous nonsense mutation in SUFU was identified in one of four exomes. Sanger sequencing of SUFU in 23 additional PTCH1-negative Gorlin syndrome families identified a SUFU mutation in a second family. Copy-number analysis of SUFU by MLPA revealed a large heterozygous deletion in a third family. All three SUFU-positive families fulfilled diagnostic criteria for Gorlin syndrome, although none had odontogenic jaw keratocysts. Each SUFU-positive family included a single case of medulloblastoma, whereas only two (1.7%) of 115 individuals with Gorlin syndrome and a PTCH1 mutation developed medulloblastoma. We demonstrate convincing evidence that SUFU mutations can cause classical Gorlin syndrome. Our study redefines the risk of medulloblastoma in Gorlin syndrome, dependent on the underlying causative gene. Previous reports have found a 5% risk of medulloblastoma in Gorlin syndrome. We found a < 2% risk in PTCH1 mutation-positive individuals, with a risk up to 20× higher in SUFU mutation-positive individuals. Our data suggest childhood brain magnetic resonance imaging surveillance is justified in SUFU-related, but not PTCH1-related, Gorlin syndrome. © 2014 by American Society of Clinical Oncology.

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

[Haplotype Analysis of Coagulation Factor VII Gene in a Patient with Congenital Coagulation Factor VII Deficiency with Heterozygous p.Arg337Cys Mutation and o.Aro413Gin Polymorphism..

PubMed

Suzuki, Keijiro; Yoshioka, Tomoko; Obara, Takehiro; Suwabe, Akira

2016-05-01

Congenital coagulation factor VII (FVII) deficiency is a rare hemorrhagic disease with an autosomal reces- sive inheritance pattern. We analyzed coagulation factor VII gene (F7) of a patient with FVII deficiency and used expression studies to investigate the effect of a missense mutation on FVII secretion. The proband, a 69-year-old Japanese woman, had a history of postpartum bleeding and excessive bleeding after dental extrac- tion. She was found to have mildly increased PT-INR (1.17) before an ophthalmic operation. FVII activity and antigen were reduced (29.0% and 32.8%). Suspecting that the proband was FVII deficient, we analyzed F7 of the patient. Sequence analysis revealed that the patient was heterozygous for a point mutation (p.Arg337Cys) in the catalytic domain and polymorphisms: the decanucleotide insertion at the promoter re- gion, dimorphism (c.525C >T) in exon 5, and p.Arg413Gln in exon 8. Haplotype analysis clarified that p.Arg337Cys was located on the p.Arg413 allele (Ml allele). The other allele had the p.Arg413Gln polymor- phism(M2 allele) which is known to produce less FVII. Expression studies revealed that p.Arg337Cys causes impairment of FVII secretion. Insufficient secretion of FVII arising from both the p.Arg337Cys/M1 allele and the p.Arg337/M2 allele might lower the FVII level of this patient(<50%). The FVII level in a heterozygous FVII deficient patient might be influenced by F7 polymorphisms on the normal allele. There- fore, genetic analyses are important for the diagnosis of heterozygous FVII deficiency.

A secreted WNT-ligand-binding domain of FZD5 generated by a frameshift mutation causes autosomal dominant coloboma

PubMed Central

Liu, Chunqiao; Widen, Sonya A.; Williamson, Kathleen A.; Ratnapriya, Rinki; Gerth-Kahlert, Christina; Rainger, Joe; Alur, Ramakrishna P.; Strachan, Erin; Manjunath, Souparnika H.; Balakrishnan, Archana; Floyd, James A.; Li, Tiansen; Waskiewicz, Andrew; Brooks, Brian P.; Lehmann, Ordan J.; FitzPatrick, David R.; Swaroop, Anand

2016-01-01

Ocular coloboma is a common eye malformation resulting from incomplete fusion of the optic fissure during development. Coloboma is often associated with microphthalmia and/or contralateral anophthalmia. Coloboma shows extensive locus heterogeneity associated with causative mutations identified in genes encoding developmental transcription factors or components of signaling pathways. We report an ultra-rare, heterozygous frameshift mutation in FZD5 (p.Ala219Glufs*49) that was identified independently in two branches of a large family with autosomal dominant non-syndromic coloboma. FZD5 has a single-coding exon and consequently a transcript with this frameshift variant is not a canonical substrate for nonsense-mediated decay. FZD5 encodes a transmembrane receptor with a conserved extracellular cysteine rich domain for ligand binding. The frameshift mutation results in the production of a truncated protein, which retains the Wingless-type MMTV integration site family member-ligand-binding domain, but lacks the transmembrane domain. The truncated protein was secreted from cells, and behaved as a dominant-negative FZD5 receptor, antagonizing both canonical and non-canonical WNT signaling. Expression of the resultant mutant protein caused coloboma and microphthalmia in zebrafish, and disruption of the apical junction of the retinal neural epithelium in mouse, mimicking the phenotype of Fz5/Fz8 compound conditional knockout mutants. Our studies have revealed a conserved role of Wnt–Frizzled (FZD) signaling in ocular development and directly implicate WNT–FZD signaling both in normal closure of the human optic fissure and pathogenesis of coloboma. PMID:26908622

Heterozygous SSBP1 start loss mutation co-segregates with hearing loss and the m.1555A>G mtDNA variant in a large multigenerational family.

PubMed

Kullar, Peter J; Gomez-Duran, Aurora; Gammage, Payam A; Garone, Caterina; Minczuk, Michal; Golder, Zoe; Wilson, Janet; Montoya, Julio; Häkli, Sanna; Kärppä, Mikko; Horvath, Rita; Majamaa, Kari; Chinnery, Patrick F

2018-01-01

The m.1555A>G mtDNA variant causes maternally inherited deafness, but the reasons for the highly variable clinical penetrance are not known. Exome sequencing identified a heterozygous start loss mutation in SSBP1, encoding the single stranded binding protein 1 (SSBP1), segregating with hearing loss in a multi-generational family transmitting m.1555A>G, associated with mtDNA depletion and multiple deletions in skeletal muscle. The SSBP1 mutation reduced steady state SSBP1 levels leading to a perturbation of mtDNA metabolism, likely compounding the intra-mitochondrial translation defect due to m.1555A>G in a tissue-specific manner. This family demonstrates the importance of rare trans-acting genetic nuclear modifiers in the clinical expression of mtDNA disease. © The Author (2017). Published by Oxford University Press on behalf of the Guarantors of Brain.

Four novel ELANE mutations in patients with congenital neutropenia.

PubMed

Kurnikova, Maria; Maschan, Michael; Dinova, Evgeniya; Shagina, Irina; Finogenova, Natalia; Mamedova, Elena; Polovtseva, Tatyana; Shagin, Dmitry; Shcherbina, Anna

2011-08-01

Congenital neutropenia is a heterogeneous bone marrow failure syndrome characterized by a maturation arrest of myelopoesis at the promyelocyte/myelocyte stage. Cyclic neutropenia (CyN) and severe congenital neutropenia (SCN) are two main forms of congenital neutropenia. Genetic analysis has shown that heterozygous mutations in the ELANE gene encoding the neutrophil elastase are the major cause of these disorders. We investigated the prevalence of ELANE mutations in a group of 16 patients from 14 families with congenital neutropenia. Five patients had typical manifestations of CyN, and 11 patients had SCN. Seven different heterozygous ELANE mutations were found, including four novel mutations. Copyright © 2011 Wiley-Liss, Inc.

Recurrent truncating mutations in alanine-glyoxylate aminotransferase gene in two South Indian families with primary hyperoxaluria type 1 causing later onset end-stage kidney disease

PubMed Central

Dutta, A. K.; Paulose, B. K.; Danda, S.; Alexander, S.; Tamilarasi, V.; Omprakash, S.

2016-01-01

Primary hyperoxaluria type 1 is an autosomal recessive inborn error of metabolism due to liver-specific peroxisomal enzyme alanine-glyoxylate transaminase deficiency. Here, we describe two unrelated patients who were diagnosed to have primary hyperoxaluria. Homozygous c.445_452delGTGCTGCT (p.L151Nfs*14) (Transcript ID: ENST00000307503; human genome assembly GRCh38.p2) (HGMD ID CD073567) mutation was detected in both the patients and the parents were found to be heterozygous carriers. Our patients developed end-stage renal disease at 23 years and 35 years of age. However, in the largest series published from OxalEurope cohort, the median age of end-stage renal disease for null mutations carriers was 9.9 years, which is much earlier than our cases. Our patients had slower progressions as compared to three unrelated patients from North India and Pakistan, who had homozygous c.302T>C (p.L101P) (HGMD ID CM093792) mutation in exon 2. Further, patients need to be studied to find out if c.445_452delGTGCTGCT mutation represents a founder mutation in Southern India. PMID:27512303

[NOTCH3 gene mutations in two Chinese families featuring cerebral autosomal dominant arteriopathy with subcortical infarct and leucoencephalopathy].

PubMed

Sun, Qiying; Li, Wenwen; Zhou, Yafang; Yi, Fang; Wang, Jianfeng; Hu, Yacen; Yao, Lingyan; Zhou, Lin; Xu, Hongwei

2017-12-10

To analyze potential mutations of the NOTCH3 gene in two Chinese families featuring cerebral autosomal dominant arteriopathy with subcortical infarct and leucoencephalopathy (CADASIL). The two probands and related family members and 100 healthy controls were recruited. Potential mutations of the NOTCH3 gene were screened by PCR and direct sequencing. PolyPhen-2 and SIFT software were used to predict the protein function. The conditions of both probands were adult-onset, with main clinical features including recurrent transient ischemic attacks and/or strokes, cognitive impairment. MRI findings suggested multiple cerebral infarcts and severe leukoencephalopathy. A heterozygous mutation c.328C>T (p.Arg110Cys), which was located in exon 3 of the NOTCH3 gene and known as a causative mutation, was identified in proband 1. A novel heterozygous mutation c.1013 G>C (p.Cys338Ser) located in exon 6 of the NOTCH3 gene was identified in the proband 2, which was not reported previously. The same mutations were not detected among the 100 unrelated healthy controls. Function analysis suggested that heterozygous mutation c.1013G>C can severely affect the functions of NOTCH3 protein. Two heterozygous missense mutations in the NOTCH3 gene have been identified in two families affected with CADASIL. The novel heterozygous Cys338Ser mutation in exon 6 of the NOTCH3 gene probably underlies the CADASIL.

New truncation mutation of the NR2E3 gene in a Japanese patient with enhanced S-cone syndrome.

PubMed

Kuniyoshi, Kazuki; Hayashi, Takaaki; Sakuramoto, Hiroyuki; Mishima, Hiroshi; Tsuneoka, Hiroshi; Tsunoda, Kazushige; Iwata, Takeshi; Shimomura, Yoshikazu

2016-11-01

The enhanced S-cone syndrome (ESCS) is a rare hereditary retinal degeneration that has enhanced short wavelength-sensitive cone (S-cone) functions. The longitudinal clinical course of this disease has been rarely reported, and the genetic aspects of ESCS have not been well investigated in the Japanese population. In this report, we present our clinical and genetic findings for 2 patients with ESCS. The patients were 2 unrelated Japanese men. Standard ophthalmic examinations and mutation screening for the NR2E3 gene were performed. Patient 1 was a 36-year-old man, and his clinical findings were typical of ESCS. His decimal best-corrected visual acuity (BCVA) was 1.0 OD and 0.5 OS after removal of cataracts. Genetic investigations revealed a homozygous truncation frameshift, the p.I307LfsX33 mutation. Patient 2 was an 11-year-old boy when he was first examined by us. His clinical findings were typical of ESCS except for uveitis in the left eye. His decimal BCVA at the age of 39 years was maintained at 1.5 in each eye, although the retinal degeneration and visual field impairments had progressed during the follow-up period. The genetic investigations revealed homozygous mutations of p.R104Q in the NR2E3 gene. The frameshift mutation, p.I307LfsX33, in the NR2E3 gene is a new causative mutation for ESCS. The clinical observations for patient 2 are the longest ever reported. The retinal degeneration caused by this mutation is slowly progressive, and these patients maintained good vision with maintenance of the foveal structure until their late thirties.

Allelic Mutations of KITLG, Encoding KIT Ligand, Cause Asymmetric and Unilateral Hearing Loss and Waardenburg Syndrome Type 2

PubMed Central

Zazo Seco, Celia; Serrão de Castro, Luciana; van Nierop, Josephine W.; Morín, Matías; Jhangiani, Shalini; Verver, Eva J.J.; Schraders, Margit; Maiwald, Nadine; Wesdorp, Mieke; Venselaar, Hanka; Spruijt, Liesbeth; Oostrik, Jaap; Schoots, Jeroen; van Reeuwijk, Jeroen; Lelieveld, Stefan H.; Huygen, Patrick L.M.; Insenser, María; Admiraal, Ronald J.C.; Pennings, Ronald J.E.; Hoefsloot, Lies H.; Arias-Vásquez, Alejandro; de Ligt, Joep; Yntema, Helger G.; Jansen, Joop H.; Muzny, Donna M.; Huls, Gerwin; van Rossum, Michelle M.; Lupski, James R.; Moreno-Pelayo, Miguel Angel; Kunst, Henricus P.M.; Kremer, Hannie

2015-01-01

Linkage analysis combined with whole-exome sequencing in a large family with congenital and stable non-syndromic unilateral and asymmetric hearing loss (NS-UHL/AHL) revealed a heterozygous truncating mutation, c.286_303delinsT (p.Ser96Ter), in KITLG. This mutation co-segregated with NS-UHL/AHL as a dominant trait with reduced penetrance. By screening a panel of probands with NS-UHL/AHL, we found an additional mutation, c.200_202del (p.His67_Cys68delinsArg). In vitro studies revealed that the p.His67_Cys68delinsArg transmembrane isoform of KITLG is not detectable at the cell membrane, supporting pathogenicity. KITLG encodes a ligand for the KIT receptor. Also, KITLG-KIT signaling and MITF are suggested to mutually interact in melanocyte development. Because mutations in MITF are causative of Waardenburg syndrome type 2 (WS2), we screened KITLG in suspected WS2-affected probands. A heterozygous missense mutation, c.310C>G (p.Leu104Val), that segregated with WS2 was identified in a small family. In vitro studies revealed that the p.Leu104Val transmembrane isoform of KITLG is located at the cell membrane, as is wild-type KITLG. However, in culture media of transfected cells, the p.Leu104Val soluble isoform of KITLG was reduced, and no soluble p.His67_Cys68delinsArg and p.Ser96Ter KITLG could be detected. These data suggest that mutations in KITLG associated with NS-UHL/AHL have a loss-of-function effect. We speculate that the mechanism of the mutation underlying WS2 and leading to membrane incorporation and reduced secretion of KITLG occurs via a dominant-negative or gain-of-function effect. Our study unveils different phenotypes associated with KITLG, previously associated with pigmentation abnormalities, and will thereby improve the genetic counseling given to individuals with KITLG variants. PMID:26522471

Allelic Mutations of KITLG, Encoding KIT Ligand, Cause Asymmetric and Unilateral Hearing Loss and Waardenburg Syndrome Type 2.

PubMed

Zazo Seco, Celia; Serrão de Castro, Luciana; van Nierop, Josephine W; Morín, Matías; Jhangiani, Shalini; Verver, Eva J J; Schraders, Margit; Maiwald, Nadine; Wesdorp, Mieke; Venselaar, Hanka; Spruijt, Liesbeth; Oostrik, Jaap; Schoots, Jeroen; van Reeuwijk, Jeroen; Lelieveld, Stefan H; Huygen, Patrick L M; Insenser, María; Admiraal, Ronald J C; Pennings, Ronald J E; Hoefsloot, Lies H; Arias-Vásquez, Alejandro; de Ligt, Joep; Yntema, Helger G; Jansen, Joop H; Muzny, Donna M; Huls, Gerwin; van Rossum, Michelle M; Lupski, James R; Moreno-Pelayo, Miguel Angel; Kunst, Henricus P M; Kremer, Hannie

2015-11-05

Linkage analysis combined with whole-exome sequencing in a large family with congenital and stable non-syndromic unilateral and asymmetric hearing loss (NS-UHL/AHL) revealed a heterozygous truncating mutation, c.286_303delinsT (p.Ser96Ter), in KITLG. This mutation co-segregated with NS-UHL/AHL as a dominant trait with reduced penetrance. By screening a panel of probands with NS-UHL/AHL, we found an additional mutation, c.200_202del (p.His67_Cys68delinsArg). In vitro studies revealed that the p.His67_Cys68delinsArg transmembrane isoform of KITLG is not detectable at the cell membrane, supporting pathogenicity. KITLG encodes a ligand for the KIT receptor. Also, KITLG-KIT signaling and MITF are suggested to mutually interact in melanocyte development. Because mutations in MITF are causative of Waardenburg syndrome type 2 (WS2), we screened KITLG in suspected WS2-affected probands. A heterozygous missense mutation, c.310C>G (p.Leu104Val), that segregated with WS2 was identified in a small family. In vitro studies revealed that the p.Leu104Val transmembrane isoform of KITLG is located at the cell membrane, as is wild-type KITLG. However, in culture media of transfected cells, the p.Leu104Val soluble isoform of KITLG was reduced, and no soluble p.His67_Cys68delinsArg and p.Ser96Ter KITLG could be detected. These data suggest that mutations in KITLG associated with NS-UHL/AHL have a loss-of-function effect. We speculate that the mechanism of the mutation underlying WS2 and leading to membrane incorporation and reduced secretion of KITLG occurs via a dominant-negative or gain-of-function effect. Our study unveils different phenotypes associated with KITLG, previously associated with pigmentation abnormalities, and will thereby improve the genetic counseling given to individuals with KITLG variants. Copyright © 2015 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

A novel nonsense mutation in the DMP1 gene in a Japanese family with autosomal recessive hypophosphatemic rickets.

PubMed

Koshida, Ryusuke; Yamaguchi, Hideki; Yamasaki, Koji; Tsuchimochi, Wakaba; Yonekawa, Tadato; Nakazato, Masamitsu

2010-09-01

Autosomal recessive hypophosphatemic rickets (ARHR) is an extremely rare disorder of autosomal recessive inheritance, characterized by hypophosphatemia resulting from renal phosphate wasting. Dentin matrix protein 1 (DMP1), a noncollagenous extracellular protein, plays critical roles in bone mineralization and phosphate homeostasis. Recently, loss-of-function mutations in DMP1 gene have been identified as the molecular cause of ARHR. Here, we describe a Japanese family that includes two ARHR-affected siblings carrying a novel mutation of the DMP1 gene. The patients were a 53-year-old woman and a 50-year-old man with short stature and skeletal deformities who were the offspring of a first-cousin marriage. Biochemical examination revealed hypophosphatemia with renal phosphate excretion and low levels of 1,25(OH)(2)D. Serum calcium, parathyroid hormone, and urinary calcium excretion were within the normal range, leading to clinical diagnosis of ARHR. Sequence analysis of peripheral leukocytes from the patients revealed that they carried a novel homozygous nonsense mutation in the DMP1 gene (98G>A, W33X), which leads to a truncated DMP protein with no putative biological function. Unaffected family members were heterozygous for the mutation. This is the first report of a Japanese family with ARHR carrying a novel mutation of the DMP1 gene.

Identification and functional analysis of SOX10 missense mutations in different subtypes of Waardenburg syndrome.

PubMed

Chaoui, Asma; Watanabe, Yuli; Touraine, Renaud; Baral, Viviane; Goossens, Michel; Pingault, Veronique; Bondurand, Nadege

2011-12-01

Waardenburg syndrome (WS) is a rare disorder characterized by pigmentation defects and sensorineural deafness, classified into four clinical subtypes, WS1-S4. Whereas the absence of additional features characterizes WS2, association with Hirschsprung disease defines WS4. WS is genetically heterogeneous, with six genes already identified, including SOX10. About 50 heterozygous SOX10 mutations have been described in patients presenting with WS2 or WS4, with or without myelination defects of the peripheral and central nervous system (PCWH, Peripheral demyelinating neuropathy-Central dysmyelinating leukodystrophy-Waardenburg syndrome-Hirschsprung disease, or PCW, PCWH without HD). The majority are truncating mutations that most often remove the main functional domains of the protein. Only three missense mutations have been thus far reported. In the present study, novel SOX10 missense mutations were found in 11 patients and were examined for effects on SOX10 characteristics and functions. The mutations were associated with various phenotypes, ranging from WS2 to PCWH. All tested mutations were found to be deleterious. Some mutants presented with partial cytoplasmic redistribution, some lost their DNA-binding and/or transactivation capabilities on various tissue-specific target genes. Intriguingly, several mutants were redistributed in nuclear foci. Whether this phenomenon is a cause or a consequence of mutation-associated pathogenicity remains to be determined, but this observation could help to identify new SOX10 modes of action. © 2011 Wiley-Liss, Inc.

Unusual cutaneous features associated with a heterozygous gain-of-function mutation in IFIH1: overlap between Aicardi–Goutières and Singleton–Merten syndromes

PubMed Central

Bursztejn, A.-C.; Briggs, T.A.; del Toro Duany, Y.; Anderson, B.H.; O’Sullivan, J.; Williams, S.G.; Bodemer, C.; Fraitag, S.; Gebhard, F.; Leheup, B.; Lemelle, I.; Oojageer, A.; Raffo, E.; Schmitt, E.; Rice, G.I.; Hur, S.; Crow, Y.J.

2016-01-01

Summary Cutaneous lesions described as chilblain lupus occur in the context of familial chilblain lupus or Aicardi–Goutières syndrome. To date, seven genes related to Aicardi–Goutières syndrome have been described. The most recently described encodes the cytosolic double-stranded RNA receptor IFIH1 (also known as MDA5), a key component of the antiviral type I interferon-mediated innate immune response. Enhanced type I interferon signalling secondary to gain-of-function mutations in IFIH1 can result in a range of neuroinflammatory phenotypes including classical Aicardi–Goutières syndrome. It is of note that none of the patients with a neurological phenotype so far described with mutations in this gene was reported to demonstrate cutaneous involvement. We present a family segregating a heterozygous pathogenic mutation in IFIH1 showing dermatological involvement as a prominent feature, variably associated with neurological disturbance and premature tooth loss. All three affected individuals exhibited increased expression of interferon-stimulated genes in whole blood, and the mutant protein resulted in enhanced interferon signalling in vitro, both in the basal state and following ligand stimulation. Our results further extend the phenotypic spectrum associated with mutations in IFIH1, indicating that the disease can be confined predominantly to the skin, while also highlighting phenotypic overlap with both Aicardi–Goutières syndrome and Singleton–Merten syndrome. PMID:26284909

POC1A truncation mutation causes a ciliopathy in humans characterized by primordial dwarfism.

PubMed

Shaheen, Ranad; Faqeih, Eissa; Shamseldin, Hanan E; Noche, Ramil R; Sunker, Asma; Alshammari, Muneera J; Al-Sheddi, Tarfa; Adly, Nouran; Al-Dosari, Mohammed S; Megason, Sean G; Al-Husain, Muneera; Al-Mohanna, Futwan; Alkuraya, Fowzan S

2012-08-10

Primordial dwarfism (PD) is a phenotype characterized by profound growth retardation that is prenatal in onset. Significant strides have been made in the last few years toward improved understanding of the molecular underpinning of the limited growth that characterizes the embryonic and postnatal development of PD individuals. These include impaired mitotic mechanics, abnormal IGF2 expression, perturbed DNA-damage response, defective spliceosomal machinery, and abnormal replication licensing. In three families affected by a distinct form of PD, we identified a founder truncating mutation in POC1A. This gene is one of two vertebrate paralogs of POC1, which encodes one of the most abundant proteins in the Chlamydomonas centriole proteome. Cells derived from the index individual have abnormal mitotic mechanics with multipolar spindles, in addition to clearly impaired ciliogenesis. siRNA knockdown of POC1A in fibroblast cells recapitulates this ciliogenesis defect. Our findings highlight a human ciliopathy syndrome caused by deficiency of a major centriolar protein. Copyright © 2012 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

Mutations in a Novel Isoform of TRIOBP That Encodes a Filamentous-Actin Binding Protein Are Responsible for DFNB28 Recessive Nonsyndromic Hearing Loss

PubMed Central

Shahin, Hashem; Walsh, Tom; Sobe, Tama; Abu Sa’ed, Judeh; Abu Rayan, Amal; Lynch, Eric D.; Lee, Ming K.; Avraham, Karen B.; King, Mary-Claire; Kanaan, Moein

2006-01-01

In a large consanguineous Palestinian kindred, we previously mapped DFNB28—a locus associated with recessively inherited, prelingual, profound sensorineural hearing impairment—to chromosome 22q13.1. We report here that mutations in a novel 218-kDa isoform of TRIOBP (TRIO and filamentous actin [F-actin] binding protein) are associated with DFNB28 hearing loss in a total of nine Palestinian families. Two nonsense mutations (R347X and Q581X) truncate the protein, and a potentially deleterious missense mutation (G1019R) occurs in a conserved motif in a putative SH3-binding domain. In seven families, 27 deaf individuals are homozygous for one of the nonsense mutations; in two other families, 3 deaf individuals are compound heterozygous for the two nonsense mutations or for Q581X and G1019R. The novel long isoform of TRIOBP has a restricted expression profile, including cochlea, retina, and fetal brain, whereas the original short isoform is widely expressed. Antibodies to TRIOBP reveal expression in sensory cells of the inner ear and colocalization with F-actin along the length of the stereocilia. PMID:16385458

Characterization of a Case of Pigmentary Retinopathy in Sanfilippo Syndrome Type IIIA Associated with Compound Heterozygous Mutations in the SGSH Gene.

PubMed

Wilkin, Justin; Kerr, Natalie C; Byrd, Kathryn W; Ward, Jewell C; Iannaccone, Alessandro

2016-06-01

To report longitudinal phenotypic findings in a patient with Sanfilippo syndrome type IIIA, harboring SGSH mutations, one of which is novel. Heparan-N-sulfatidase enzyme function testing in skin fibroblasts and white blood cells and SGSH gene sequencing were obtained. Clinical office examinations, examinations under anesthesia, electroretinogram, spectral domain optical coherence tomography (SD-OCT), and fundus photography were performed over a 5-year period. Fundus examination revealed a progressive breadcrumb-like pigmentary retinopathy with perifoveal pigmentary involvement. SD-OCT showed loss of normal neuroretinal lamination and cystic macular changes responsive to treatment with carbonic anhydrase inhibitors. Electroretinography exhibited complex characteristics indicative of a generalized retinal rod > cone dysfunction with significant ON > OFF postreceptoral response compromise. Sequencing revealed compound heterozygous mutations in the SGSH gene, the novel c.88G > C (p.A30P) change and a second, previously reported one (c.734G > A, p.R245H). We have identified ocular features of a patient with Sanfilippo syndrome type IIIA harboring a novel SGHS mutation that were not previously known to occur in this disease - namely, a progressive retinopathy with distinctive features, cystic macular changes responsive to carbonic anhydrase inhibitors, and complex electroretinographic abnormalities consistent with postreceptoral dysfunction. SD-OCT imaging revealed retinal lamination changes consistent with previously reported histologic studies. Both the SD-OCT and the electroretinogram changes appear attributable to intraretinal deposition of heparan sulfate.

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

Inactivating mutations in ESCO2 cause SC phocomelia and Roberts syndrome: no phenotype-genotype correlation.

PubMed

Schüle, Birgitt; Oviedo, Angelica; Johnston, Kathreen; Pai, Shashidhar; Francke, Uta

2005-12-01

The rare, autosomal recessive Roberts syndrome (RBS) is characterized by tetraphocomelia, profound growth deficiency of prenatal onset, craniofacial anomalies, microcephaly, and mental deficiency. SC phocomelia (SC) has a milder phenotype, with a lesser degree of limb reduction and with survival to adulthood. Since heterochromatin repulsion (HR) is characteristic for both disorders and is not complemented in somatic-cell hybrids, it has been hypothesized that the disorders are allelic. Recently, mutations in ESCO2 (establishment of cohesion 1 homolog 2) on 8p21.1 have been reported in RBS. To determine whether ESCO2 mutations are also responsible for SC, we studied three families with SC and two families in which variable degrees of limb and craniofacial abnormalities, detected by fetal ultrasound, led to pregnancy terminations. All cases were positive for HR. We identified seven novel mutations in exons 3-8 of ESCO2. In two families, affected individuals were homozygous--for a 5-nucleotide deletion in one family and a splice-site mutation in the other. In three nonconsanguineous families, probands were compound heterozygous for a single-nucleotide insertion or deletion, a nonsense mutation, or a splice-site mutation. Abnormal splice products were characterized at the RNA level. Since only protein-truncating mutations were identified, regardless of clinical severity, we conclude that genotype does not predict phenotype. Having established that RBS and SC are caused by mutations in the same gene, we delineated the clinical phenotype of the tetraphocomelia spectrum that is associated with HR and ESCO2 mutations and differentiated it from other types of phocomelia that are negative for HR.

Mutations in the Gardos channel (KCNN4) are associated with hereditary xerocytosis.

PubMed

Glogowska, Edyta; Lezon-Geyda, Kimberly; Maksimova, Yelena; Schulz, Vincent P; Gallagher, Patrick G

2015-09-10

Hereditary xerocytosis (HX; MIM 194380) is an autosomal-dominant hemolytic anemia characterized by primary erythrocyte dehydration. In many patients, heterozygous mutations associated with delayed channel inactivation have been identified in PIEZO1. This report describes patients from 2 well-phenotyped HX kindreds, including from one of the first HX kindreds described, who lack predicted heterozygous PIEZO1-linked variants. Whole-exome sequencing identified novel, heterozygous mutations affecting the Gardos channel, encoded by the KCNN4 gene, in both kindreds. Segregation analyses confirmed transmission of the Gardos channel mutations with disease phenotype in affected individuals. The KCNN4 variants were different mutations in the same residue, which is highly conserved across species and within members of the small-intermediate family of calcium-activated potassium channel proteins. Both mutations were predicted to be deleterious by mutation effect algorithms. In sickle erythrocytes, the Gardos channel is activated under deoxy conditions, leading to cellular dehydration due to salt and water loss. The identification of KCNN4 mutations in HX patients supports recent studies that indicate it plays a critical role in normal erythrocyte deformation in the microcirculation and participates in maintenance of erythrocyte volume homeostasis. © 2015 by The American Society of Hematology.

Mutations in the Gardos channel (KCNN4) are associated with hereditary xerocytosis

PubMed Central

Glogowska, Edyta; Lezon-Geyda, Kimberly; Maksimova, Yelena; Schulz, Vincent P.

2015-01-01

Hereditary xerocytosis (HX; MIM 194380) is an autosomal-dominant hemolytic anemia characterized by primary erythrocyte dehydration. In many patients, heterozygous mutations associated with delayed channel inactivation have been identified in PIEZO1. This report describes patients from 2 well-phenotyped HX kindreds, including from one of the first HX kindreds described, who lack predicted heterozygous PIEZO1-linked variants. Whole-exome sequencing identified novel, heterozygous mutations affecting the Gardos channel, encoded by the KCNN4 gene, in both kindreds. Segregation analyses confirmed transmission of the Gardos channel mutations with disease phenotype in affected individuals. The KCNN4 variants were different mutations in the same residue, which is highly conserved across species and within members of the small-intermediate family of calcium-activated potassium channel proteins. Both mutations were predicted to be deleterious by mutation effect algorithms. In sickle erythrocytes, the Gardos channel is activated under deoxy conditions, leading to cellular dehydration due to salt and water loss. The identification of KCNN4 mutations in HX patients supports recent studies that indicate it plays a critical role in normal erythrocyte deformation in the microcirculation and participates in maintenance of erythrocyte volume homeostasis. PMID:26198474

A case of early onset rectal cancer of Lynch syndrome with a novel deleterious PMS2 mutation.

PubMed

Nomura, Sachio; Fujimoto, Yoshiya; Yamamoto, Noriko; Sato, Yuri; Ashihara, Yuumi; Kita, Mizuho; Yamaguchi, Junya; Ishikawa, Yuichi; Ueno, Masashi; Arai, Masami

2015-10-01

Heterozygous deleterious mutation of the PMS2 gene is a cause of Lynch syndrome, an autosomal dominant cancer disease. However, the frequency of PMS2 mutation is rare compared with that of the other causative genes; MSH2, MLH1 and MSH6. PMS2 mutation has so far only been reported once from a Japanese facility. Detection of PMS2 mutation is relatively complicated due to the existence of 15 highly homologous pseudogenes, and its gene conversion event with the pseudogene PMS2CL. Therefore, for PMS2 mutation analysis, it is crucial to clearly distinguish PMS2 from its pseudogenes. We report here a novel deleterious 11 bp deletion mutation of exon 11 of PMS2 distinguished from PMS2CL in a 34-year-old Japanese female with rectal cancer. PMS2 mutated at c.1492del11 results in a truncated 500 amino acid protein rather than the wild-type protein of 862 amino acids. This is supported by the fact that, although there is usually concordance between MLH1 and PMS2 expression, cells were immunohistochemically positive for MLH1, whereas PMS2 could not be immunohistochemically stained using an anti-C-terminal PMS2 antibody, or effective PMS2 mRNA degradation with NMD caused by the frameshift mutation. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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

Expanding the Oro-Dental and Mutational Spectra of Kabuki Syndrome and Expression of KMT2D and KDM6A in Human Tooth Germs

PubMed Central

Porntaveetus, Thantrira; Abid, Mushriq F; Theerapanon, Thanakorn; Srichomthong, Chalurmpon; Ohazama, Atsushi; Kawasaki, Katsushige; Kawasaki, Maiko; Suphapeetiporn, Kanya; Sharpe, Paul T.; Shotelersuk, Vorasuk

2018-01-01

Kabuki syndrome is a rare genetic disorder characterized by distinct dysmorphic facial features, intellectual disability, and multiple developmental abnormalities. Despite more than 350 documented cases, the oro-dental spectrum associated with kabuki syndrome and expression of KMT2D (histone-lysine N-methyltransferase 2D) or KDM6A (lysine-specific demethylase 6A) genes in tooth development have not been well defined. Here, we report seven unrelated Thai patients with Kabuki syndrome having congenital absence of teeth, malocclusion, high-arched palate, micrognathia, and deviated tooth shape and size. Exome sequencing successfully identified that six patients were heterozygous for mutations in KMT2D, and one in KDM6A. Six were novel mutations, of which five were in KMT2D and one in KDM6A. They were truncating mutations including four frameshift deletions and two nonsense mutations. The predicted non-functional KMT2D and KDM6A proteins are expected to cause disease by haploinsufficiency. Our study expands oro-dental, medical, and mutational spectra associated with Kabuki syndrome. We also demonstrate for the first time that KMT2D and KDM6A are expressed in the dental epithelium of human tooth germs. PMID:29725259

The effect of novel mutations on the structure and enzymatic activity of unconventional myosins associated with autosomal dominant non-syndromic hearing loss.

PubMed

Kwon, Tae-Jun; Oh, Se-Kyung; Park, Hong-Joon; Sato, Osamu; Venselaar, Hanka; Choi, Soo Young; Kim, SungHee; Lee, Kyu-Yup; Bok, Jinwoong; Lee, Sang-Heun; Vriend, Gert; Ikebe, Mitsuo; Kim, Un-Kyung; Choi, Jae Young

2014-07-01

Mutations in five unconventional myosin genes have been associated with genetic hearing loss (HL). These genes encode the motor proteins myosin IA, IIIA, VI, VIIA and XVA. To date, most mutations in myosin genes have been found in the Caucasian population. In addition, only a few functional studies have been performed on the previously reported myosin mutations. We performed screening and functional studies for mutations in the MYO1A and MYO6 genes in Korean cases of autosomal dominant non-syndromic HL. We identified four novel heterozygous mutations in MYO6. Three mutations (p.R825X, p.R991X and Q918fsX941) produce a premature truncation of the myosin VI protein. Another mutation, p.R205Q, was associated with diminished actin-activated ATPase activity and actin gliding velocity of myosin VI in an in vitro analysis. This finding is consistent with the results of protein modelling studies and corroborates the pathogenicity of this mutation in the MYO6 gene. One missense variant, p.R544W, was found in the MYO1A gene, and in silico analysis suggested that this variant has deleterious effects on protein function. This finding is consistent with the results of protein modelling studies and corroborates the pathogenic effect of this mutation in the MYO6 gene.

The effect of novel mutations on the structure and enzymatic activity of unconventional myosins associated with autosomal dominant non-syndromic hearing loss

PubMed Central

Kwon, Tae-Jun; Oh, Se-Kyung; Park, Hong-Joon; Sato, Osamu; Venselaar, Hanka; Choi, Soo Young; Kim, SungHee; Lee, Kyu-Yup; Bok, Jinwoong; Lee, Sang-Heun; Vriend, Gert; Ikebe, Mitsuo; Kim, Un-Kyung; Choi, Jae Young

2014-01-01

Mutations in five unconventional myosin genes have been associated with genetic hearing loss (HL). These genes encode the motor proteins myosin IA, IIIA, VI, VIIA and XVA. To date, most mutations in myosin genes have been found in the Caucasian population. In addition, only a few functional studies have been performed on the previously reported myosin mutations. We performed screening and functional studies for mutations in the MYO1A and MYO6 genes in Korean cases of autosomal dominant non-syndromic HL. We identified four novel heterozygous mutations in MYO6. Three mutations (p.R825X, p.R991X and Q918fsX941) produce a premature truncation of the myosin VI protein. Another mutation, p.R205Q, was associated with diminished actin-activated ATPase activity and actin gliding velocity of myosin VI in an in vitro analysis. This finding is consistent with the results of protein modelling studies and corroborates the pathogenicity of this mutation in the MYO6 gene. One missense variant, p.R544W, was found in the MYO1A gene, and in silico analysis suggested that this variant has deleterious effects on protein function. This finding is consistent with the results of protein modelling studies and corroborates the pathogenic effect of this mutation in the MYO6 gene. PMID:25080041

Biallelic truncating mutations in FMN2, encoding the actin-regulatory protein Formin 2, cause nonsyndromic autosomal-recessive intellectual disability.

PubMed

Law, Rosalind; Dixon-Salazar, Tracy; Jerber, Julie; Cai, Na; Abbasi, Ansar A; Zaki, Maha S; Mittal, Kirti; Gabriel, Stacey B; Rafiq, Muhammad Arshad; Khan, Valeed; Nguyen, Maria; Ali, Ghazanfar; Copeland, Brett; Scott, Eric; Vasli, Nasim; Mikhailov, Anna; Khan, Muhammad Nasim; Andrade, Danielle M; Ayaz, Muhammad; Ansar, Muhammad; Ayub, Muhammad; Vincent, John B; Gleeson, Joseph G

2014-12-04

Dendritic spines represent the major site of neuronal activity in the brain; they serve as the receiving point for neurotransmitters and undergo rapid activity-dependent morphological changes that correlate with learning and memory. Using a combination of homozygosity mapping and next-generation sequencing in two consanguineous families affected by nonsyndromic autosomal-recessive intellectual disability, we identified truncating mutations in formin 2 (FMN2), encoding a protein that belongs to the formin family of actin cytoskeleton nucleation factors and is highly expressed in the maturing brain. We found that FMN2 localizes to punctae along dendrites and that germline inactivation of mouse Fmn2 resulted in animals with decreased spine density; such mice were previously demonstrated to have a conditioned fear-learning defect. Furthermore, patient neural cells derived from induced pluripotent stem cells showed correlated decreased synaptic density. Thus, FMN2 mutations link intellectual disability either directly or indirectly to the regulation of actin-mediated synaptic spine density. Copyright © 2014 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

The heterozygous A53T mutation in the alpha-synuclein gene in a Chinese Han patient with Parkinson disease: case report and literature review.

PubMed

Xiong, Wei-Xi; Sun, Yi-Min; Guan, Rong-Yuan; Luo, Su-Shan; Chen, Chen; An, Yu; Wang, Jian; Wu, Jian-Jun

2016-10-01

The missense mutation A53T of alpha-synuclein gene (SNCA) was reported to be a rare but definite cause of sporadic and familial Parkinson disease (PD). It seemed to be restricted geographically in Greece and Italy. We aimed to identify the SNCA mutations in a Chinese PD cohort. Ninety-one early onset PD patients or familial PD probands were collected consecutively for the screening of PD-related genes. The genetic analysis was carried out by target sequencing of the exons and the corresponding flanking regions of the PD-related genes using Illumina HiSeq 2000 sequencer and further confirmed by Sanger sequencing or restriction fragment length polymorphism. Dosage mutations of exons in these genes were carried out by multiple ligation-dependent probe amplification. Among the 91 patients, we found only one heterozygous mutation of SNCA A53T, in a 23-year-old male patient with negative family history. The [(11)C]-2β-carbomethoxy-3β-(4-fluorophenyl) tropan (CFT) PET and PD-related spatial covariance pattern (PDRP) via [(18)F]-fluorodeoxyglucos (FDG) PET confirmed a typical pattern of PD. After examining his parents, we found his mother was an asymptomatic carrier, with declined hand dexterity detected by quantitative motor tests. Reduced dopamine transporter uptake of his mother was identified by CFT PET, and abnormal PDRP pattern was found by FDG PET. Our investigation expanded the clinical and genetic spectrum of Chinese PD patients, and we suggested SNCA mutations to be screened in familial and early onset Chinese PD patients.

Deactivating germline mutations in LEMD3 cause osteopoikilosis and Buschke-Ollendorff syndrome, but not sporadic melorheostosis.

PubMed

Mumm, Steven; Wenkert, Deborah; Zhang, Xiafang; McAlister, William H; Mier, Richard J; Whyte, Michael P

2007-02-01

Autosomal dominant OPK and BOS feature widespread foci of osteosclerotic trabeculae without or with skin lesions, respectively. Occasionally, a larger area of dense bone in OPK or BOS resembles MEL, a sporadic sclerosing disorder primarily involving cortical bone. Others, finding deactivating germline LEMD3 mutations in OPK or BOS, concluded such defects explain all three conditions. We found germline LEMD3 mutations in OPK and BOS but not in sporadic MEL. In 2004, others discovered that heterozygous, loss-of-function, germline mutations in the LEMD3 gene (LEMD3 or MAN1) cause both osteopoikilosis (OPK) and Buschke-Ollendorff syndrome (BOS). OPK is an autosomal dominant, usually benign, skeletal dysplasia featuring multiple, small, especially metaphyseal, oval or round, dense trabecular foci distributed symmetrically throughout the skeleton. BOS combines OPK with connective tissue nevi comprised of collagen and elastin. In some OPK and BOS families, an individual may have relatively large, asymmetric areas of dense cortical bone interpreted as melorheostosis (MEL). MEL, however, classically refers to a sporadic, troublesome skeletal dysostosis featuring large, asymmetric, "flowing hyperostosis" of long bone cortices often with overlying, constricting soft tissue abnormalities. However, a heterozygous germline mutation in LEMD3 was offered to explain MEL. We studied 11 unrelated individuals with sclerosing bone disorders where LEMD3 mutation was a potential etiology: familial OPK (1), familial BOS (2), previously reported familial OPK with MEL (1), sporadic MEL (3), sporadic MEL with mixed-sclerosing-bone dystrophy (1), and patients with other unusual sclerosing bone disorders (3). All coding exons and adjacent mRNA splice sites for LEMD3 were amplified by PCR and sequenced using genomic DNA from leukocytes. We did not study lesional tissue from bone or skin. In the OPK family, a heterozygous nonsense mutation (c.1433T>A, p.L478X) was discovered in exon 1. In the

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.

Different inactivating mutations of the mineralocorticoid receptor in fourteen families affected by type I pseudohypoaldosteronism.

PubMed

Sartorato, Paola; Lapeyraque, Anne-Laure; Armanini, Decio; Kuhnle, Ursula; Khaldi, Yasmina; Salomon, Rémi; Abadie, Véronique; Di Battista, Eliana; Naselli, Arturo; Racine, Alain; Bosio, Maurizio; Caprio, Massimiliano; Poulet-Young, Véronique; Chabrolle, Jean-Pierre; Niaudet, Patrick; De Gennes, Christiane; Lecornec, Marie-Hélène; Poisson, Elodie; Fusco, Anna Maria; Loli, Paola; Lombès, Marc; Zennaro, Maria-Christina

2003-06-01

We have analyzed the human mineralocorticoid receptor (hMR) gene in 14 families with autosomal dominant or sporadic pseudohypoaldosteronism (PHA1), a rare form of mineralocorticoid resistance characterized by neonatal renal salt wasting and failure to thrive. Six heterozygous mutations were detected. Two frameshift mutations in exon 2 (insT1354, del8bp537) and one nonsense mutation in exon 4 (C2157A, Cys645stop) generate truncated proteins due to premature stop codons. Three missense mutations (G633R, Q776R, L979P) differently affect hMR function. The DNA binding domain mutant R633 exhibits reduced maximal transactivation, although its binding characteristics and ED(50) of transactivation are comparable with wild-type hMR. Ligand binding domain mutants R776 and P979 present reduced or absent aldosterone binding, respectively, which is associated with reduced or absent ligand-dependent transactivation capacity. Finally, P979 possesses a transdominant negative effect on wild-type hMR activity, whereas mutations G633R and Q776R probably result in haploinsufficiency in PHA1 patients. We conclude that hMR mutations are a common feature of autosomal dominant PHA1, being found in 70% of our familial cases. Their absence in some families underscores the importance of an extensive investigation of the hMR gene and the role of precise diagnostic procedures to allow for identification of other genes potentially involved in the disease.

Missense mutations in SURF1 associated with deficient cytochrome c oxidase assembly in Leigh syndrome patients.

PubMed

Poyau, A; Buchet, K; Bouzidi, M F; Zabot, M T; Echenne, B; Yao, J; Shoubridge, E A; Godinot, C

2000-02-01

We have studied the fibroblasts of three patients suffering from Leigh syndrome associated with cytochrome c oxidase deficiency (LS-COX-). Their mitochondrial DNA was functional and all nuclear COX subunits had a normal sequence. The expression of transcripts encoding mitochondrial and nuclear COX subunits was normal or slightly increased. Similarly, the OXA1 transcript coding for a protein involved in COX assembly was increased. However, several COX-protein subunits were severely depressed, indicating deficient COX assembly. Surf1, a factor involved in COX biogenesis, was recently reported as mutated in LS-COX- patients, all mutations predicting a truncated protein. Sequence analysis of SURF1 gene in our three patients revealed seven heterozygous mutations, six of which were new : an insertion, a nonsense mutation, a splicing mutation of intron 7 in addition to three missense mutations. The mutation G385 A (Gly124-->Glu) changes a Gly that is strictly conserved in Surfl homologs of 12 species. The substitution G618 C (Asp202-->His), changing an Asp that is conserved only in mammals, appears to be a polymorphism. The mutation T751 C changes Ile246 to Thr, a position at which a hydrophobic amino acid is conserved in all eukaryotic and some bacterial species. Replacing Ile246 by Thr disrupts a predicted beta sheet structure present in all higher eukaryotes. COX activity could be restored in fibroblasts of the three patients by complementation with a retroviral vector containing normal SURF1 cDNA. These mutations identify domains essential to Surf1 protein structure and/or function.

Three cases of congenital dysfibrinogenemia in unrelated Chinese families: heterozygous missense mutation in fibrinogen alpha chain Argl6His

PubMed Central

Luo, Meiling; Deng, Donghong; Xiang, Liqun; Cheng, Peng; Liao, Lin; Deng, Xuelian; Yan, Jie; Lin, Faquan

2016-01-01

Abstract Congenital dysfibrinogenemia (CD) is a qualitative fibrinogen disorder caused by an abnormal fibrinogen molecule structure, leading to dysfunctional blood coagulation. This study describes 3 cases of dysfibrinogenemia identified in the unrelated Chinese pedigrees. Routine coagulation screening tests were performed on the probands and their families. The antigens and functionality of fibrinogen was measured using an immunoturbidimetry assay and the Clauss method, respectively. To identify the genetic mutation responsible for these dysfibrinogens, genomic DNA extracted from the blood was analyzed using PCR amplification and direct sequencing. The presence of the mutant chains was determined using matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectroscopy. Purified plasma fibrinogen of 3 probands was analyzed using SDS–PAGE, fibrinogen clottability, fibrin polymerization, fibrinopeptide release, and scanning electron microscopy (SEM). The 3 probands had a long thrombin time. Levels of functional fibrinogen were found to be very low, while the fibrinogen antigen was within the normal range. DNA sequencing revealed a heterozygous Arg16His substitution in the fibrinogen Aα chain (FGA). The mutant chains were found to be expressed using MALDI-TOF mass spectroscopy. SDS–PAGE did not reveal any difference in the molecular weights of 3 polypeptide chains between normal and abnormal fibrinogens. Fibrinogen clottability showed a slower fibrin clot formation than the healthy control. Fibrin polymerization, after addition of thrombin, showed a prolonged lag phase and decreased final turbidity. The kinetics of fibrinopeptides release revealed a decreased amount of the released fibrinopeptide A. SEM of the patient's fibrin clot was found to be abnormal. Results indicate that the 3 probands with dysfibrinogenemia were caused by mutations of Aα chain Arg16His. Mutation of this fibrinogen induced dysfunction of plasma fibrinogen. PMID

Report of four new patients with protein-truncating mutations in C6orf221/KHDC3L and colocalization with NLRP7

PubMed Central

Reddy, Ramesh; Akoury, Elie; Phuong Nguyen, Ngoc Minh; Abdul-Rahman, Omar A; Dery, Christine; Gupta, Neerja; Daley, William P; Ao, Asangla; Landolsi, Hanene; Ann Fisher, Rosemary; Touitou, Isabelle; Slim, Rima

2013-01-01

To date, two maternal-effect genes have been shown to have causative roles in recurrent hydatidiform moles (RHMs); NLRP7 that is mutated in 48–60% of patients with RHMs and C6orf221 (HUGO-approved nomenclature is now KHDC3L), a recently identified gene, that is mutated in 14% of patients with RHMs who are negative for NLRP7 mutations. We sequenced KHDC3L in 97 patients with RHMs and reproductive loss who are mostly negative for NLRP7 mutations. We identified three unrelated patients, each homozygous for one of the two protein-truncating mutations, a novel 4-bp deletion resulting in a frameshift, c.299_302delTCAA, p.Ile100Argfs*2, and a previously described 4-bp deletion, c.322_325delGACT, p.Asp108Ilefs*30, transmitted on a shared haplotype to three patients from different populations. We show that five HM tissues from one of these patients are diploid and biparental similar to HMs from patients with two defective NLRP7 mutations. Using immunofluorescence, we show that KHDC3L protein displays a juxta perinuclear signal and colocalizes with NLRP7 in lymphoblastoid cell lines from normal subjects. Using cell lines from patients, we demonstrate that the KHDC3L mutations do not change the subcellular localization of the protein in hematopoietic cells. Our data highlight the similarities between the two causative genes for RHMs, KHDC3L and NLRP7, in their subcellular localization, the parental contribution to the HM tissues caused by them, and the presence of several founder mutations and variants in both of them indicating positive selection and adaptation. PMID:23232697

Molecular analysis of the PAX6 gene in Mexican patients with congenital aniridia: report of four novel mutations

PubMed Central

Villarroel, Camilo E.; Villanueva-Mendoza, Cristina; Orozco, Lorena; Alcántara-Ortigoza, Miguel Angel; Jiménez, Diana F.; Ordaz, Juan C.

2008-01-01

Purpose Paired box gene 6 (PAX6) heterozygous mutations are well known to cause congenital non-syndromic aniridia. These mutations produce primarily protein truncations and have been identified in approximately 40%–80% of all aniridia cases worldwide. In Mexico, there is only one previous report describing three intragenic deletions in five cases. In this study, we further analyze PAX6 variants in a group of Mexican aniridia patients and describe associated ocular findings. Methods We evaluated 30 nonrelated probands from two referral hospitals. Mutations were detected by single-strand conformation polymorphism (SSCP) and direct sequencing, and novel missense mutations and intronic changes were analyzed by in silico analysis. One intronic variation (IVS2+9G>A), which in silico analysis suggested had no pathological effects, was searched in 103 unaffected controls. Results Almost all cases exhibited phenotypes that were at the severe end of the aniridia spectrum with associated ocular alterations such as nystagmus, macular hypoplasia, and congenital cataracts. The mutation detection rate was 30%. Eight different mutations were identified: four (c.184_188dupGAGAC, c.361T>C, c.879dupC, and c.277G>A) were novel, and four (c.969C>T, IVS6+1G>C, c.853delC, and IVS7–2A>G) have been previously reported. The substitution at position 969 was observed in two patients. None of the intragenic deletions previously reported in Mexican patients were found. Most of the mutations detected predict either truncation of the PAX6 protein or conservative amino acid changes in the paired domain. We also detected two intronic non-pathogenic variations, IVS9–12C>T and IVS2+9G>A, that had been previously reported. Because the latter variation was considered potentially pathogenic, it was analyzed in 103 healthy Mexican newborns where we found an allelic frequency of 0.1116 for the A allele. Conclusions This study adds four novel mutations to the worldwide PAX6 mutational spectrum, and

Further delineation of COG8-CDG: A case with novel compound heterozygous mutations diagnosed by targeted exome sequencing.

PubMed

Yang, Aram; Cho, Sung Yoon; Jang, Ja-Hyun; Kim, Jinsup; Kim, Sook Za; Lee, Beom Hee; Yoo, Han-Wook; Jin, Dong-Kyu

2017-08-01

Congenital disorders of glycosylation (CDG) are a rapidly expanding group of inherited metabolic disorders with highly variable clinical presentations caused by deficient glycosylation of proteins and/or lipids. CDG-IIh is a very rare subgroup of CDG caused by mutations in the conserved oligomeric Golgi (COG) complex gene, COG8, and so far, only two cases have been reported in the medical literature. Here, we describe an 8-year-old Korean boy with psychomotor retardation, hypotonia, failure to thrive, elevated serum liver enzymes, microcephaly, and talipes equinovarus. A liver biopsy of the patient showed only interface hepatitis with mild lobular activity, and brain magnetic resonance imaging revealed cerebellar atrophy. Compared with the previous two reported cases, our patient showed relatively mild psychomotor retardation without a seizure history. The transferrin isoelectric focusing profiles in the patient showed a CDG type II pattern with increased disialo- and trisialo-transferrin. Targeted exome sequencing was performed to screen all CDG type II-related genes, and two novel frameshift mutations were found: c.171dupG (p.Leu58Alafs*29) and c.1656dupC (p.Ala553Argfs*15) in COG8. The parents were heterozygous carriers of each variant. CDG should be included in the initial differential diagnosis for children with a suspected unknown syndrome or unclassified inherited metabolic disorder or children with diverse clinical presentations, such as psychomotor retardation, hypotonia, skeletal deformity, microcephaly, cerebellar atrophy, and unexplained transient elevated liver enzyme. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of CHEK2 missense variant I157T on the risk of breast cancer in carriers of other CHEK2 or BRCA1 mutations.

PubMed

Cybulski, C; Górski, B; Huzarski, T; Byrski, T; Gronwald, J; Debniak, T; Wokolorczyk, D; Jakubowska, A; Serrano-Fernández, P; Dork, T; Narod, S A; Lubinski, J

2009-02-01

Carriers of heterozygous mutations in CHEK2 or BRCA1 are at increased risk of breast cancer. These mutations are rare and a very small number of women in a population will carry two mutations. However, it is of interest to estimate the breast cancer risks associated with carrying two mutations because this information may be informative for genetic counsellors and may provide clues to the carcinogenic process. We genotyped 7782 Polish breast cancer patients and 6233 controls for seven founder mutations in BRCA1 and CHEK2. Odds ratios (OR) and 95% confidence intervals (CI) were estimated for the mutations, singly and in combination. Of the 7782 women with breast cancer, 1091 had one mutation (14.0%) and 37 had two mutations (0.5%). Compared to controls, the odds ratio for a BRCA1 mutation in isolation was 13.1 (95% CI 8.2 to 21). The odds ratio was smaller for BRCA1 mutation carriers who also carried a CHEK2 mutation (OR 6.6, 95% CI 1.5 to 29), but the difference was not statistically significant. In contrast, the odds ratio for women who carried two CHEK2 mutations (OR 3.9, 95% CI 1.5 to 10) was greater than that for women who carried one CHEK2 mutation (OR 1.9, 95% CI 1.6 to 2.1). The odds ratio for women who carried both a truncating mutation and the missense mutation in CHEK2 was 7.0 (95% CI 0.9 to 56) and was greater than for women who carried the truncating mutation alone (OR 3.3, 95% CI 2.4 to 4.3) or the missense mutation alone (OR 1.6, 95% CI 1.4 to 1.9), but the difference was not statistically significant. Our study suggests that the risk of breast cancer in carriers of a deleterious CHEK2 mutation is increased if the second allele is the I157T missense variant. However, the presence of a CHEK2 mutation in women with a BRCA1 mutation may not increase their risk beyond that of the BRCA1 mutation alone. These suggestive findings need to be verified in other studies.

Mosaic synaptopathy and functional defects in Cav1.4 heterozygous mice and human carriers of CSNB2

PubMed Central

Michalakis, Stylianos; Shaltiel, Lior; Sothilingam, Vithiyanjali; Koch, Susanne; Schludi, Verena; Krause, Stefanie; Zeitz, Christina; Audo, Isabelle; Lancelot, Marie-Elise; Hamel, Christian; Meunier, Isabelle; Preising, Markus N.; Friedburg, Christoph; Lorenz, Birgit; Zabouri, Nawal; Haverkamp, Silke; Garrido, Marina Garcia; Tanimoto, Naoyuki; Seeliger, Mathias W.; Biel, Martin; Wahl-Schott, Christian A.

2014-01-01

Mutations in CACNA1F encoding the α1-subunit of the retinal Cav1.4 L-type calcium channel have been linked to Cav1.4 channelopathies including incomplete congenital stationary night blindness type 2A (CSNB2), Åland Island eye disease (AIED) and cone-rod dystrophy type 3 (CORDX3). Since CACNA1F is located on the X chromosome, Cav1.4 channelopathies are typically affecting male patients via X-chromosomal recessive inheritance. Occasionally, clinical symptoms have been observed in female carriers, too. It is currently unknown how these mutations lead to symptoms in carriers and how the retinal network in these females is affected. To investigate these clinically important issues, we compared retinal phenotypes in Cav1.4-deficient and Cav1.4 heterozygous mice and in human female carrier patients. Heterozygous Cacna1f carrier mice have a retinal mosaic consistent with differential X-chromosomal inactivation, characterized by adjacent vertical columns of affected and non-affected wild-type-like retinal network. Vertical columns in heterozygous mice are well comparable to either the wild-type retinal network of normal mice or to the retina of homozygous mice. Affected retinal columns display pronounced rod and cone photoreceptor synaptopathy and cone degeneration. These changes lead to vastly impaired vision-guided navigation under dark and normal light conditions and reduced retinal electroretinography (ERG) responses in Cacna1f carrier mice. Similar abnormal ERG responses were found in five human CACNA1F carriers, four of which had novel mutations. In conclusion, our data on Cav1.4 deficient mice and human female carriers of mutations in CACNA1F are consistent with a phenotype of mosaic CSNB2. PMID:24163243

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.

A novel Norrie disease pseudoglioma gene mutation, c.-1_2delAAT, responsible for Norrie disease in a Chinese family.

PubMed

Zhang, Xin-Yu; Jiang, Wei-Ying; Chen, Lu-Ming; Chen, Su-Qin

2013-01-01

To investigate the genetic findings and phenotypic characteristics of a Chinese family with Norrie disease (ND). Molecular genetic analysis and clinical examinations were performed on a Chinese family with ND. Mutations in the Norrie disease pseudoglioma (NDP) gene were detected by direct sequencing. Haplotypes were constructed and compared with the phenotypes in the family. Evolutionary comparisons and mutant open reading frame (ORF) prediction were also undertaken. Two family members with ocular manifestations were diagnosed with ND. No signs of sensorineural hearing loss were observed in either patient, while one of them showed signs of mild mental retardation. A novel heterozygous mutation in the NDP gene, c.-1_2delAAT, was detected in both patients. The mutation and the mutation bearing haplotype co-segregated with the ND phenotype in males and was transmitted from their mothers and/or grandmothers (II:2). The male without ND did not harbor the mutation. The mutation occurred at the highly conserved nucleotides. ORF finder predicted that the mutation would lead to the production of a truncated protein that lacks the first 11 N-terminal amino acids. A novel mutation, c.-1_2delAAT in the NDP gene, was identified in a Chinese family with ND. This mutation caused ND without obvious sensorineural hearing loss. Mental disorder was found in one but not the other patients. The clinical heterogeneity in the family indicated that other genetic variants and epigenetic factors may also play a role in the disease presentation.

Modest increased sensitivity to radiation oncogenesis in ATM heterozygous versus wild-type mammalian cells

NASA Technical Reports Server (NTRS)

Smilenov, L. B.; Brenner, D. J.; Hall, E. J.

2001-01-01

Subpopulations that are genetically predisposed to radiation-induced cancer could have significant public health consequences. Individuals homozygous for null mutations at the ataxia telangiectasia gene are indeed highly radiosensitive, but their numbers are very small. Ataxia Telangiectasia heterozygotes (1-2% of the population) have been associated with somewhat increased radiosensitivity for some end points, but none directly related to carcinogenesis. Here, intralitter comparisons between wild-type mouse embryo fibroblasts and mouse embryo fibroblasts carrying ataxia telangiectasia mutated (ATM) null mutation indicate that the heterozygous cells are more sensitive to radiation oncogenesis than their normal, litter-matched, counterparts. From these data we suggest that Ataxia Telangiectasia heterozygotes could indeed represent a societally-significant radiosensitive human subpopulation.

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.

Effects of endoplasmic reticulum stressors on maturation and signaling of hemizygous and heterozygous wild-type and mutant forms of KIT.

PubMed

Brahimi-Adouane, Sabrina; Bachet, Jean-Baptiste; Tabone-Eglinger, Séverine; Subra, Frédéric; Capron, Claude; Blay, Jean-Yves; Emile, Jean-François

2013-06-01

Gain of function mutations of KIT are frequent in some human tumors, and are sensible to tyrosine kinase inhibitors. In most tumors, oncogenic mutations are heterozygous, however most in vitro data of KIT activation have been obtained with hemizygous mutation. This study aimed to investigate the maturation and activation of wild-type (WT) and mutant (M) forms of KIT in hemizygous and heterozygous conditions. WT and two types of exon 11 deletions M forms of human KIT were expressed in NIH3T3 cell lines. Membrane expression of KIT was quantified by flow cytometry. Quantification of glycosylated forms of KIT and phosphorylated forms of AKT and ERK were performed by western blot. Simultaneous activation of WT KIT and treatment with endoplasmic reticulum (ER) inhibitors, tunicamycin or brefeldin A induced a complete inhibition of membrane expression of the 145 kDa form of KIT. By contrast activation or ER inhibitors alone, only partly inhibited this form. ER inhibitors also inhibited KIT activation-dependent phosphorylation of AKT and ERK1/2. Brefeldin A induced a complete down regulation of the 145 kDa form in hemizygous M, and induced an intra-cellular accumulation of the 125 kDa form in WT but not in hemizygous M. Heterozygous cells had glycosylation and response to ER inhibitors patterns more similar to WT than to hemizygous M. Phosphorylated AKT was reduced in hemizygous cells in comparison to WT KIT cells and heterozygous cells, and in the presence of brefeldin A in all cell lines. Effects of ER inhibitors are significantly different in hemizygous and heterozygous mutants. Differences in intra-cellular trafficking of KIT forms result in differences in downstream signaling pathways, and activation of PI3K/AKT pathway appears to be tied to the presence of the mature 145 kDa form of KIT at the membrane surface. Copyright © 2012 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

A Dominant Mutation in Nuclear Receptor Interacting Protein 1 Causes Urinary Tract Malformations via Dysregulation of Retinoic Acid Signaling.

PubMed

Vivante, Asaf; Mann, Nina; Yonath, Hagith; Weiss, Anna-Carina; Getwan, Maike; Kaminski, Michael M; Bohnenpoll, Tobias; Teyssier, Catherine; Chen, Jing; Shril, Shirlee; van der Ven, Amelie T; Ityel, Hadas; Schmidt, Johanna Magdalena; Widmeier, Eugen; Bauer, Stuart B; Sanna-Cherchi, Simone; Gharavi, Ali G; Lu, Weining; Magen, Daniella; Shukrun, Rachel; Lifton, Richard P; Tasic, Velibor; Stanescu, Horia C; Cavaillès, Vincent; Kleta, Robert; Anikster, Yair; Dekel, Benjamin; Kispert, Andreas; Lienkamp, Soeren S; Hildebrandt, Friedhelm

2017-08-01

Congenital anomalies of the kidney and urinary tract (CAKUT) are the most common cause of CKD in the first three decades of life. However, for most patients with CAKUT, the causative mutation remains unknown. We identified a kindred with an autosomal dominant form of CAKUT. By whole-exome sequencing, we identified a heterozygous truncating mutation (c.279delG, p.Trp93fs*) of the nuclear receptor interacting protein 1 gene ( NRIP1 ) in all seven affected members. NRIP1 encodes a nuclear receptor transcriptional cofactor that directly interacts with the retinoic acid receptors (RARs) to modulate retinoic acid transcriptional activity. Unlike wild-type NRIP1, the altered NRIP1 protein did not translocate to the nucleus, did not interact with RAR α , and failed to inhibit retinoic acid-dependent transcriptional activity upon expression in HEK293 cells. Notably, we also showed that treatment with retinoic acid enhanced NRIP1 binding to RAR α RNA in situ hybridization confirmed Nrip1 expression in the developing urogenital system of the mouse. In explant cultures of embryonic kidney rudiments, retinoic acid stimulated Nrip1 expression, whereas a pan-RAR antagonist strongly reduced it. Furthermore, mice heterozygous for a null allele of Nrip1 showed a CAKUT-spectrum phenotype. Finally, expression and knockdown experiments in Xenopus laevis confirmed an evolutionarily conserved role for NRIP1 in renal development. These data indicate that dominant NRIP1 mutations can cause CAKUT by interference with retinoic acid transcriptional signaling, shedding light on the well documented association between abnormal vitamin A levels and renal malformations in humans, and suggest a possible gene-environment pathomechanism in this disease. Copyright © 2017 by the American Society of Nephrology.

Inactivating Mutations in ESCO2 Cause SC Phocomelia and Roberts Syndrome: No Phenotype-Genotype Correlation

PubMed Central

Schüle, Birgitt; Oviedo, Angelica; Johnston, Kathreen; Pai, Shashidhar; Francke, Uta

2005-01-01

The rare, autosomal recessive Roberts syndrome (RBS) is characterized by tetraphocomelia, profound growth deficiency of prenatal onset, craniofacial anomalies, microcephaly, and mental deficiency. SC phocomelia (SC) has a milder phenotype, with a lesser degree of limb reduction and with survival to adulthood. Since heterochromatin repulsion (HR) is characteristic for both disorders and is not complemented in somatic-cell hybrids, it has been hypothesized that the disorders are allelic. Recently, mutations in ESCO2 (establishment of cohesion 1 homolog 2) on 8p21.1 have been reported in RBS. To determine whether ESCO2 mutations are also responsible for SC, we studied three families with SC and two families in which variable degrees of limb and craniofacial abnormalities, detected by fetal ultrasound, led to pregnancy terminations. All cases were positive for HR. We identified seven novel mutations in exons 3–8 of ESCO2. In two families, affected individuals were homozygous—for a 5-nucleotide deletion in one family and a splice-site mutation in the other. In three nonconsanguineous families, probands were compound heterozygous for a single-nucleotide insertion or deletion, a nonsense mutation, or a splice-site mutation. Abnormal splice products were characterized at the RNA level. Since only protein-truncating mutations were identified, regardless of clinical severity, we conclude that genotype does not predict phenotype. Having established that RBS and SC are caused by mutations in the same gene, we delineated the clinical phenotype of the tetraphocomelia spectrum that is associated with HR and ESCO2 mutations and differentiated it from other types of phocomelia that are negative for HR. PMID:16380922

Simultaneous Occurence of an Autosomal Dominant Inherited MSX1 Mutation and an X-linked Recessive Inherited EDA Mutation in One Chinese Family with Non-syndromic Oligodontia.

PubMed

Zhang, Xiao Xia; Wong, Sing Wai; Han, Dong; Feng, Hai Lan

2015-01-01

To describe the simultaneous occurence of an autosomal dominant inherited MSX1 mutation and an X-linked recessive inherited EDA mutation in one Chinese family with nonsyndromic oligodontia. Clinical data of characteristics of tooth agenesis were collected. MSX1 and EDA gene mutations were detected in a Chinese family of non-syndromic oligodontia. Mild hypodontia in the parents and severe oligodontia in the son was recorded. A novel missense heterozygous mutation c.517C>A (p.Arg173Ser) was detected in the MSX1 gene in the boy and the father. A homozygous missense mutation c.1001G>A (p.Arg334His) was detected in the EDA gene in the boy and the same mutant occurred heterozygously in the mother. Simultaneous occurence of two different gene mutations with different inheritence patterns, which both caused oligodontia, which occurred in one subject and in one family, was reported.

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

HMSN/ACC truncation mutations disrupt brain-type creatine kinase-dependant activation of K+/Cl- co-transporter 3.

PubMed

Salin-Cantegrel, Adèle; Shekarabi, Masoud; Holbert, Sébastien; Dion, Patrick; Rochefort, Daniel; Laganière, Janet; Dacal, Sandra; Hince, Pascale; Karemera, Liliane; Gaspar, Claudia; Lapointe, Jean-Yves; Rouleau, Guy A

2008-09-01

The potassium-chloride co-transporter 3 (KCC3) is mutated in hereditary motor and sensory neuropathy with agenesis of the corpus callosum (HMSN/ACC); however, the molecular mechanisms of HMSN/ACC pathogenesis and the exact role of KCC3 in the development of the nervous system remain poorly understood. The functional regulation of this transporter by protein partners is also largely unknown. Using a yeast two-hybrid approach, we discovered that the C-terminal domain (CTD) of KCC3, which is lost in most HMSN/ACC-causing mutations, directly interacts with brain-specific creatine kinase (CK-B), an ATP-generating enzyme that is also a partner of KCC2. The interaction of KCC3 with CK-B was further confirmed by in vitro glutathione S-transferase pull-down assay, followed by sequencing of the pulled-down complexes. In transfected cultured cells, immunofluorescence labeling showed that CK-B co-localizes with wild-type KCC3, whereas the kinase fails to interact with the inactive truncated KCC3. Finally, CK-B's inhibition by DNFB results in reduction of activity of KCC3 in functional assays using Xenopus laevis oocytes. This physical and functional association between the co-transporter and CK-B is, therefore, the first protein-protein interaction identified to be potentially involved in the pathophysiology of HMSN/ACC.

Analysis of HFE and non-HFE gene mutations in Brazilian patients with hemochromatosis.

PubMed

Bittencourt, Paulo Lisboa; Marin, Maria Lúcia Carnevale; Couto, Cláudia Alves; Cançado, Eduardo Luiz Rachid; Carrilho, Flair José; Goldberg, Anna Carla

2009-01-01

Approximately one-half of Brazilian patients with hereditary hemochromatosis (HH) are neither homozygous for the C282Y mutation nor compound heterozygous for the H63D and C282Y mutations that are associated with HH in Caucasians. Other mutations have been described in the HFE gene as well as in genes involved in iron metabolism, such as transferrin receptor 2 (TfR2) and ferroportin 1 (SCL40A1). To evaluate the role of HFE, TfR2 and SCL40A1 mutations in Brazilian subjects with HH. Nineteen male subjects (median age 42 [range: 20-72] years) with HH were evaluated using the Haemochromatosis StripAssay A. This assay is capable of detecting twelve HFE mutations, which are V53M, V59M, H63D, H63H, S65C, Q127H, P160delC, E168Q, E168X, W169X, C282Y and Q283, four TfR2 mutations, which are E60X, M172K, Y250X, AVAQ594-597del, and two SCL40A1 mutations, which are N144H and V162del. In our cohort, nine (47%) patients were homozygous for the C282Y mutation, two (11%) were heterozygous for the H63D mutation, and one each (5%) was either heterozygous for C282Y or compound heterozygous for C282Y and H63D. No other mutations in the HFE, TfR2 or SCL40A1 genes were observed in the studied patients. One-third of Brazilian subjects with the classical phenotype of HH do not carry HFE or other mutations that are currently associated with the disease in Caucasians. This observation suggests a role for other yet unknown mutations in the aforementioned genes or in other genes involved in iron homeostasis in the pathogenesis of HH in Brazil.

A novel AVP gene mutation in a Turkish family with neurohypophyseal diabetes insipidus.

PubMed

Ilhan, M; Tiryakioglu, N O; Karaman, O; Coskunpinar, E; Yildiz, R S; Turgut, S; Tiryakioglu, D; Toprak, H; Tasan, E

2016-03-01

Familial neurohypophyseal diabetes insipidus (FNDI) is a rare, autosomal dominant, inherited disorder which is characterized by severe polydipsia and polyuria generally presenting in early childhood. In the present study, we aimed to analyze the AVP gene in a Turkish family with FNDI. Four patients with neurohypophyseal diabetes insipidus and ten healthy members of the family were studied. Diabetes insipidus was diagnosed by the water deprivation test in affected family members. Mutation analysis was performed by sequencing the whole coding region of AVP-NPII gene using DNA isolated from peripheral blood samples. Urine osmolality was low (<300 mOsm/kg) during water deprivation test, and an increase more than 50 % in urine osmolality and recovery of the symptoms were observed by the administration of desmopressin in all patients. Plasma copeptin levels were lower than expected according to plasma osmolality. Pituitary MRI revealed partial empty sella with a bright spot in index patient and a normal neurohypophysis in the other affected subjects. Genetic screening revealed a novel, heterozygous mutation designated as c.-3A>C in all patients. c.-3A>C mutation in 5'UTR of AVP gene in this family might lead to the truncation of signal peptide, aggregation of AVP in the cytoplasm instead of targeting in the endoplasmic reticulum, thereby could disrupt AVP secretion without causing neuronal cytotoxicity, which might explain the presence of bright spot. The predicted effect of this mutation should be investigated by further in vitro molecular studies.

Effect of LDL cholesterol, statins and presence of mutations on the prevalence of type 2 diabetes in heterozygous familial hypercholesterolemia.

PubMed

Climent, Elisenda; Pérez-Calahorra, Sofía; Marco-Benedí, Victoria; Plana, Nuria; Sánchez, Rosa; Ros, Emilio; Ascaso, Juan F; Puzo, Jose; Almagro, Fátima; Lahoz, Carlos; Civeira, Fernando; Pedro-Botet, Juan

2017-07-17

Patients with heterozygous familial hypercholesterolemia (HeFH) have been reported to be less vulnerable to type 2 diabetes mellitus (T2DM), although the mechanism is unknown. The aims of the present study were to assess the effects of low density lipoprotein (LDL) cholesterol concentration and the presence of FH-causing mutations on T2DM prevalence in HeFH. Data were collected from the Dyslipidemia Registry of the Spanish Arteriosclerosis Society. Inclusion criteria were definite or probable HeFH in patients aged ≥18 years. T2DM prevalence in HeFH patients was compared with data of the general population. 1732 patients were included. The prevalence of T2DM was lower in patients with HeFH compared with the general population (5.94% vs 9.44%; OR: 0.606, 95% CI 0.486-0.755, p < 0.001). Risk factors for developing T2DM were male sex, age, body mass index, hypertension, baseline triglyceride levels and years on statin therapy. The prevalence of T2DM in HeFH patients was 40% lower than that observed in the general population. Gene mutations and LDL cholesterol concentrations were not risk factors associated with the prevalence of T2DM in patients with HeFH. The prevalence of T2DM in patients with HeFH was 40% lower than in the general population matched for age and sex.

An Upstream Truncation of the furA-katG Operon Confers High-Level Isoniazid Resistance in a Mycobacterium tuberculosis Clinical Isolate with No Known Resistance-Associated Mutations

PubMed Central

Yam, Wing Cheong; Zhang, Ying; Kao, Richard Y. T.

2014-01-01

Although the major causes of isoniazid (INH) resistance in Mycobacterium tuberculosis are confined to structural mutations in katG and promoter mutations in the mabA-inhA operon, a significant proportion of INH-resistant strains have unknown resistance mechanisms. Recently, we identified a high-level INH-resistant M. tuberculosis clinical isolate, GB005, with no known resistance-associated mutations. A comprehensive study was performed to investigate the molecular basis of drug resistance in this strain. Although no mutations were found throughout the katG and furA-katG intergenic region, the katG expression and the catalase activity were greatly diminished compared to those in H37Rv (P < 0.01). Northern blotting revealed that the katG transcript from the isolate was smaller than that of H37Rv. Sequencing analysis of furA and upstream genes discovered a 7.2-kb truncation extended from the 96th base preceding the initiation codon of katG. Complementation of the M. tuberculosis Δ(furA-katG) strain with katG and different portions of the truncated region identified a 134-bp upstream fragment of furA that was essential for full catalase activity and INH susceptibility in M. tuberculosis. The promoter activity of this fragment was also shown to be stronger than that of the furA-katG intergenic region (P < 0.01). Collectively, these findings demonstrate that deletion of the 134-bp furA upstream fragment is responsible for the reduction in katG expression, resulting in INH resistance in GB005. To our knowledge, this is the first report showing that deletion of the upstream region preceding the furA-katG operon causes high-level INH resistance in a clinical isolate of M. tuberculosis. PMID:25092698

De Novo GMNN Mutations Cause Autosomal-Dominant Primordial Dwarfism Associated with Meier-Gorlin Syndrome

PubMed Central

Burrage, Lindsay C.; Charng, Wu-Lin; Eldomery, Mohammad K.; Willer, Jason R.; Davis, Erica E.; Lugtenberg, Dorien; Zhu, Wenmiao; Leduc, Magalie S.; Akdemir, Zeynep C.; Azamian, Mahshid; Zapata, Gladys; Hernandez, Patricia P.; Schoots, Jeroen; de Munnik, Sonja A.; Roepman, Ronald; Pearring, Jillian N.; Jhangiani, Shalini; Katsanis, Nicholas; Vissers, Lisenka E.L.M.; Brunner, Han G.; Beaudet, Arthur L.; Rosenfeld, Jill A.; Muzny, Donna M.; Gibbs, Richard A.; Eng, Christine M.; Xia, Fan; Lalani, Seema R.; Lupski, James R.; Bongers, Ernie M.H.F.; Yang, Yaping

2015-01-01

Meier-Gorlin syndrome (MGS) is a genetically heterogeneous primordial dwarfism syndrome known to be caused by biallelic loss-of-function mutations in one of five genes encoding pre-replication complex proteins: ORC1, ORC4, ORC6, CDT1, and CDC6. Mutations in these genes cause disruption of the origin of DNA replication initiation. To date, only an autosomal-recessive inheritance pattern has been described in individuals with this disorder, with a molecular etiology established in about three-fourths of cases. Here, we report three subjects with MGS and de novo heterozygous mutations in the 5′ end of GMNN, encoding the DNA replication inhibitor geminin. We identified two truncating mutations in exon 2 (the 1st coding exon), c.16A>T (p.Lys6∗) and c.35_38delTCAA (p.Ile12Lysfs∗4), and one missense mutation, c.50A>G (p.Lys17Arg), affecting the second-to-last nucleotide of exon 2 and possibly RNA splicing. Geminin is present during the S, G2, and M phases of the cell cycle and is degraded during the metaphase-anaphase transition by the anaphase-promoting complex (APC), which recognizes the destruction box sequence near the 5′ end of the geminin protein. All three GMNN mutations identified alter sites 5′ to residue Met28 of the protein, which is located within the destruction box. We present data supporting a gain-of-function mechanism, in which the GMNN mutations result in proteins lacking the destruction box and hence increased protein stability and prolonged inhibition of replication leading to autosomal-dominant MGS. PMID:26637980

[Value of pre-gestational deafness-related mutation screening for the prevention and intervention of congenital deafness].

PubMed

Sun, Xuejing; Xing, Xinli; He, Qingqing; Zhou, Lin; Zhang, Jing; Zhao, Qing; Hou, Huili; Xi, Zuoming

2017-10-10

To assess the value of pre-gestational deafness-related mutation screening for the prevention and intervention of congenital deafness. In this study, 2168 couples with normal hearing were screened for common mutations associated with congenital deafness using real-time fluorescence quantitative PCR. The mutations have included GJB2 c.235delC and c.299_300delAT, SLC26A4 c.2168A>G and c.IVS7-2A>G, and mtDNA 12SrRNA c.1494C>T and c.1555A>G. For couples who have both carried heterozygous mutations of the same gene, genetic counseling and prenatal diagnosis were provided. Among of the 4 336 individuals, 178 (4.06%) were found to carry a mutation. Mutation rate for c.235delC and c.299_300delAT of GJB2 gene, c.IVS7-2 A>G and c.2168 A>G of SLC26A4 gene, c.1555 A>G and c.1494 C>T of DNA 12S rRNA gene were 0.91%, 0.20%, 0.68%, 0.11%, 0.1% and 0.01%, respectively. For six couples who have both carried mutations of the same gene, all fetuses showed a normal karyotype, while DNA sequencing indicated that two fetuses have carried homozygous c.235delC mutation of the GJB2 gene, one carried a heterozygous c.235delC mutation of the GJB2 gene, one carried heterozygous mutation of GJB2 gene (c.299_300delAT), and two have carried a heterozygous mutation of c.IVS7-2A>G of the SLC26A4 gene. Pre-gestational screening for deafness gene mutation can facilitate avoidance the birth of affected children and has a great clinical value for the prevention and intervention of birth defect.

Functional Consequences of Seven Novel Mutations in the CYP11B1 Gene: Four Mutations Associated with Nonclassic and Three Mutations Causing Classic 11β-Hydroxylase Deficiency

PubMed Central

Parajes, Silvia; Loidi, Lourdes; Reisch, Nicole; Dhir, Vivek; Rose, Ian T.; Hampel, Rainer; Quinkler, Marcus; Conway, Gerard S.; Castro-Feijóo, Lidia; Araujo-Vilar, David; Pombo, Manuel; Dominguez, Fernando; Williams, Emma L.; Cole, Trevor R.; Kirk, Jeremy M.; Kaminsky, Elke; Rumsby, Gill; Arlt, Wiebke; Krone, Nils

2010-01-01

Context: Steroid 11β-hydroxylase (CYP11B1) deficiency (11OHD) is the second most common form of congenital adrenal hyperplasia (CAH). Cases of nonclassic 11OHD are rare compared with the incidence of nonclassic 21-hydroxylase deficiency. Objective: The aim of the study was to analyze the functional consequences of seven novel CYP11B1 mutations (p.M88I, p.W116G, p.P159L, p.A165D, p.K254_A259del, p.R366C, p.T401A) found in three patients with classic 11OHD, two patients with nonclassic 11OHD, and three heterozygous carriers for CYP11B1 mutations. Methods: We conducted functional studies employing a COS7 cell in vitro expression system comparing wild-type (WT) and mutant CYP11B1 activity. Mutants were examined in a computational three-dimensional model of the CYP11B1 protein. Results: All mutations (p.W116G, p.A165D, p.K254_A259del) found in patients with classic 11OHD have absent or very little 11β-hydroxylase activity relative to WT. The mutations detected in patients with nonclassic 11OHD showed partial functional impairment, with one patient being homozygous (p.P159L; 25% of WT) and the other patient compound heterozygous for a novel mild p.M88I (40% of WT) and the known severe p.R383Q mutation. The two mutations detected in heterozygous carriers (p.R366C, p.T401A) also reduced CYP11B1 activity by 23 to 37%, respectively. Conclusion: Functional analysis results allow for the classification of novel CYP11B1 mutations as causative for classic and nonclassic 11OHD, respectively. Four partially inactivating mutations are predicted to result in nonclassic 11OHD. These findings double the number of mild CYP11B1 mutations previously described as associated with mild 11OHD. Our data are important to predict phenotypic expression and provide important information for clinical and genetic counseling in 11OHD. PMID:20089618

A new mutation within the porphobilinogen deaminase gene leading to a truncated protein as a cause of acute intermittent porphyria in an extended Indian family.

PubMed

Flachsová, E; Verma, I C; Ulbrichová, D; Saxena, R; Zeman, J; Saudek, V; Raman, C S; Martásek, P

2007-01-01

Based on Internet search, we were contacted by a 50-year-old man suffering from severe abdominal pain. Acute hepatic porphyria was considered from positive Watson-Schwartz test. He, not being a health professional, searched for centres with ability to do molecular diagnosis and for information about therapeutic possibilities. He asked his physician for haem-arginate (Normosang, Orphan Europe, Paris) treatment, arranged sending his blood to our laboratory and mediated genetic counselling for him and his family. Molecular analyses of the PBGD gene revealed a novel mutation in exon 15, the 973insG. Subsequently, genetic analysis was performed in 18 members of the proband's extensive family. In 12 members of the family, the same mutation was found. The mutation, which consisted of one nucleotide insertion, resulted in addition of four different amino acids leading to a protein that is prematurely truncated by the stop codon. The effect of this mutation was investigated by expression of the wildtype and mutated PBGD in a prokaryotic expression system. The mutation resulted in instability of the protein and loss of enzymatic function. The increasing access to a number of disease- and symptom-oriented web pages presents a new and unusual venue for gaining knowledge and enabling self-diagnosis and self-help. It is, therefore, important that diseaseoriented Internet pages for public use should be designed with clarity and accurate current knowledge based background.

Autosomal dominant mutation in the signal peptide of renin in a kindred with anemia, hyperuricemia, and CKD.

PubMed

Beck, Bodo B; Trachtman, Howard; Gitman, Michael; Miller, Ilene; Sayer, John A; Pannes, Andrea; Baasner, Anne; Hildebrandt, Friedhelm; Wolf, Matthias T F

2011-11-01

Homozygous or compound heterozygous mutations in renin (REN) cause renal tubular dysgenesis, which is characterized by death in utero due to kidney 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 kidney disease (CKD). To date, only 3 different heterozygous REN mutations have been published. We report mutation analysis of the REN gene in 39 kindreds with hyperuricemia and CKD who previously tested negative for mutations in the UMOD (uromodulin) and HNF1B (hepatocyte nuclear factor 1β) genes. We identified one kindred with a novel thymidine to cytosine mutation at position 28 in the REN complementary DNA, corresponding to a tryptophan to arginine substitution at amino acid 10, which is found within the signal sequence (c.28T>C; p.W10R). On this basis, we conclude that REN mutations are rare events in patients with CKD. Within the kindred, we found affected individuals over 4 generations who carried the novel REN mutation and were characterized by significant anemia, hyperuricemia, and CKD. Anemia was severe and disproportional to the degree of decreased kidney function. Because all heterozygous REN mutations that have been described are localized in the signal sequence, screening of the REN gene for patients with CKD with hyperuricemia and anemia may best be focused on sequencing of exon 1, which encodes the signal peptide. Published by Elsevier Inc.

Diseases associated with growth hormone-releasing hormone receptor (GHRHR) mutations.

PubMed

Martari, Marco; Salvatori, Roberto

2009-01-01

The growth hormone (GH)-releasing hormone (GHRH) receptor (GHRHR) belongs to the G protein-coupled receptors family. It is expressed almost exclusively in the anterior pituitary, where it is necessary for somatotroph cells proliferation and for GH synthesis and secretion. Mutations in the human GHRHR gene (GHRHR) can impair ligand binding and signal transduction, and have been estimated to cause about 10% of autosomal recessive familial isolated growth hormone deficiency (IGHD). Mutations reported to date include five splice donor site mutations, two microdeletions, two nonsense mutations, seven missense mutations, and one mutation in the promoter. These mutations have an autosomal recessive mode of inheritance, and heterozygous individuals do not show signs of IGHD, although the presence of an intermediate phenotype has been hypothesized. Conversely, patients with biallelic mutations have low serum insulin-like growth factor-1 and GH levels (with absent or reduced GH response to exogenous stimuli), resulting--if not treated--in proportionate dwarfism. This chapter reviews the biology of the GHRHR, the mutations that affect its gene and their effects in homozygous and heterozygous individuals. Copyright © 2009 Elsevier Inc. All rights reserved.

A novel Norrie disease pseudoglioma gene mutation, c.-1_2delAAT, responsible for Norrie disease in a Chinese family

PubMed Central

Zhang, Xin-Yu; Jiang, Wei-Ying; Chen, Lu-Ming; Chen, Su-Qin

2013-01-01

AIM To investigate the genetic findings and phenotypic characteristics of a Chinese family with Norrie disease (ND). METHODS Molecular genetic analysis and clinical examinations were performed on a Chinese family with ND. Mutations in the Norrie disease pseudoglioma (NDP) gene were detected by direct sequencing. Haplotypes were constructed and compared with the phenotypes in the family. Evolutionary comparisons and mutant open reading frame (ORF) prediction were also undertaken. RESULTS Two family members with ocular manifestations were diagnosed with ND. No signs of sensorineural hearing loss were observed in either patient, while one of them showed signs of mild mental retardation. A novel heterozygous mutation in the NDP gene, c.-1_2delAAT, was detected in both patients. The mutation and the mutation bearing haplotype co-segregated with the ND phenotype in males and was transmitted from their mothers and/or grandmothers (II:2). The male without ND did not harbor the mutation. The mutation occurred at the highly conserved nucleotides. ORF finder predicted that the mutation would lead to the production of a truncated protein that lacks the first 11 N-terminal amino acids. CONCLUSION A novel mutation, c.-1_2delAAT in the NDP gene, was identified in a Chinese family with ND. This mutation caused ND without obvious sensorineural hearing loss. Mental disorder was found in one but not the other patients. The clinical heterogeneity in the family indicated that other genetic variants and epigenetic factors may also play a role in the disease presentation. PMID:24392318

A new nonsense mutation in the NF1 gene with neurofibromatosis-Noonan syndrome phenotype.

PubMed

Yimenicioğlu, Sevgi; Yakut, Ayten; Karaer, Kadri; Zenker, Martin; Ekici, Arzu; Carman, Kürşat Bora

2012-12-01

Neurofibromatosis-Noonan syndrome is a rare autosomal dominant disorder which combines neurofibromatosis type 1 (NF1) features with Noonan syndrome. NF1 gene mutations are reported in the majority of these patients. Sequence analysis of the established genes for Noonan syndrome revealed no mutation; a heterozygous NF1 point mutation c.7549C>T in exon 51, creating a premature stop codon (p.R2517X), had been demonstrated. Neurofibromatosis-Noonan syndrome recently has been considered a subtype of NF1 and caused by different NF1 mutations. We report the case of a 14-year-old boy with neurofibromatosis type 1 with Noonan-like features, who complained of headache with triventricular hydrocephaly and a heterozygous NF1 point mutation c.7549C>T in exon 51.

A novel Werner Syndrome mutation: pharmacological treatment by read-through of nonsense mutations and epigenetic therapies

PubMed Central

Agrelo, Ruben; Sutz, Miguel Arocena; Setien, Fernando; Aldunate, Fabian; Esteller, Manel; Da Costa, Valeria; Achenbach, Ricardo

2015-01-01

Werner Syndrome (WS) is a rare inherited disease characterized by premature aging and increased propensity for cancer. Mutations in the WRN gene can be of several types, including nonsense mutations, leading to a truncated protein form. WRN is a RecQ family member with both helicase and exonuclease activities, and it participates in several cell metabolic pathways, including DNA replication, DNA repair, and telomere maintenance. Here, we reported a novel homozygous WS mutation (c.3767 C > G) in 2 Argentinian brothers, which resulted in a stop codon and a truncated protein (p.S1256X). We also observed increased WRN promoter methylation in the cells of patients and decreased messenger WRN RNA (WRN mRNA) expression. Finally, we showed that the read-through of nonsense mutation pharmacologic treatment with both aminoglycosides (AGs) and ataluren (PTC-124) in these cells restores full-length protein expression and WRN functionality. PMID:25830902

Neonatal High Bone Mass With First Mutation of the NF-κB Complex: Heterozygous De Novo Missense (p.Asp512Ser) RELA (Rela/p65).

PubMed

Frederiksen, Anja L; Larsen, Martin J; Brusgaard, Klaus; Novack, Deborah V; Knudsen, Peter Juel Thiis; Schrøder, Henrik Daa; Qiu, Weimin; Eckhardt, Christina; McAlister, William H; Kassem, Moustapha; Mumm, Steven; Frost, Morten; Whyte, Michael P

2016-01-01

Heritable disorders that feature high bone mass (HBM) are rare. The etiology is typically a mutation(s) within a gene that regulates the differentiation and function of osteoblasts (OBs) or osteoclasts (OCs). Nevertheless, the molecular basis is unknown for approximately one-fifth of such entities. NF-κB signaling is a key regulator of bone remodeling and acts by enhancing OC survival while impairing OB maturation and function. The NF-κB transcription complex comprises five subunits. In mice, deletion of the p50 and p52 subunits together causes osteopetrosis (OPT). In humans, however, mutations within the genes that encode the NF-κB complex, including the Rela/p65 subunit, have not been reported. We describe a neonate who died suddenly and unexpectedly and was found at postmortem to have HBM documented radiographically and by skeletal histopathology. Serum was not available for study. Radiographic changes resembled malignant OPT, but histopathological investigation showed morphologically normal OCs and evidence of intact bone resorption excluding OPT. Furthermore, mutation analysis was negative for eight genes associated with OPT or HBM. Instead, accelerated bone formation appeared to account for the HBM. Subsequently, trio-based whole exome sequencing revealed a heterozygous de novo missense mutation (c.1534_1535delinsAG, p.Asp512Ser) in exon 11 of RELA encoding Rela/p65. The mutation was then verified using bidirectional Sanger sequencing. Lipopolysaccharide stimulation of patient fibroblasts elicited impaired NF-κB responses compared with healthy control fibroblasts. Five unrelated patients with unexplained HBM did not show a RELA defect. Ours is apparently the first report of a mutation within the NF-κB complex in humans. The missense change is associated with neonatal osteosclerosis from in utero increased OB function rather than failed OC action. These findings demonstrate the importance of the Rela/p65 subunit within the NF-κB pathway for human

Sequencing the GRHL3 Coding Region Reveals Rare Truncating Mutations and a Common Susceptibility Variant for Nonsyndromic Cleft Palate

PubMed Central

Mangold, Elisabeth; Böhmer, Anne C.; Ishorst, Nina; Hoebel, Ann-Kathrin; Gültepe, Pinar; Schuenke, Hannah; Klamt, Johanna; Hofmann, Andrea; Gölz, Lina; Raff, Ruth; Tessmann, Peter; Nowak, Stefanie; Reutter, Heiko; Hemprich, Alexander; Kreusch, Thomas; Kramer, Franz-Josef; Braumann, Bert; Reich, Rudolf; Schmidt, Gül; Jäger, Andreas; Reiter, Rudolf; Brosch, Sibylle; Stavusis, Janis; Ishida, Miho; Seselgyte, Rimante; Moore, Gudrun E.; Nöthen, Markus M.; Borck, Guntram; Aldhorae, Khalid A.; Lace, Baiba; Stanier, Philip; Knapp, Michael; Ludwig, Kerstin U.

2016-01-01

Nonsyndromic cleft lip with/without cleft palate (nsCL/P) and nonsyndromic cleft palate only (nsCPO) are the most frequent subphenotypes of orofacial clefts. A common syndromic form of orofacial clefting is Van der Woude syndrome (VWS) where individuals have CL/P or CPO, often but not always associated with lower lip pits. Recently, ∼5% of VWS-affected individuals were identified with mutations in the grainy head-like 3 gene (GRHL3). To investigate GRHL3 in nonsyndromic clefting, we sequenced its coding region in 576 Europeans with nsCL/P and 96 with nsCPO. Most strikingly, nsCPO-affected individuals had a higher minor allele frequency for rs41268753 (0.099) than control subjects (0.049; p = 1.24 × 10−2). This association was replicated in nsCPO/control cohorts from Latvia, Yemen, and the UK (pcombined = 2.63 × 10−5; ORallelic = 2.46 [95% CI 1.6–3.7]) and reached genome-wide significance in combination with imputed data from a GWAS in nsCPO triads (p = 2.73 × 10−9). Notably, rs41268753 is not associated with nsCL/P (p = 0.45). rs41268753 encodes the highly conserved p.Thr454Met (c.1361C>T) (GERP = 5.3), which prediction programs denote as deleterious, has a CADD score of 29.6, and increases protein binding capacity in silico. Sequencing also revealed four novel truncating GRHL3 mutations including two that were de novo in four families, where all nine individuals harboring mutations had nsCPO. This is important for genetic counseling: given that VWS is rare compared to nsCPO, our data suggest that dominant GRHL3 mutations are more likely to cause nonsyndromic than syndromic CPO. Thus, with rare dominant mutations and a common risk variant in the coding region, we have identified an important contribution for GRHL3 in nsCPO. PMID:27018475

Hereditary Xerocytosis due to Mutations in PIEZO1 Gene Associated with Heterozygous Pyruvate Kinase Deficiency and Beta-Thalassemia Trait in Two Unrelated Families.

PubMed

Fermo, Elisa; Vercellati, Cristina; Marcello, Anna Paola; Zaninoni, Anna; van Wijk, Richard; Mirra, Nadia; Curcio, Cristina; Cortelezzi, Agostino; Zanella, Alberto; Barcellini, Wilma; Bianchi, Paola

2017-01-01

Hereditary xerocytosis (HX) is a rare disorder caused by defects of RBC permeability, associated with haemolytic anaemia of variable degree and iron overload. It is sometimes misdiagnosed as hereditary spherocytosis or other congenital haemolytic anaemia. Splenectomy is contraindicated due to increased risk of thromboembolic complications. We report the clinical, haematological, and molecular characteristics of four patients from two unrelated Italian families affected by HX, associated with beta-thalassemia trait and heterozygous pyruvate kinase deficiency, respectively. Two patients had been splenectomised and displayed thrombotic episodes. All patients had iron overload in the absence of transfusion, two of them requiring iron chelation. The diagnosis of HX was confirmed by LoRRca Osmoscan analysis showing a left-shifted curve. PIEZO1 gene sequencing revealed the presence of mutation p.E2496ELE, showing that this is one of the most frequent mutations in this disease. The concomitant defects did not aggravate the clinical phenotype; however, in one patient, the initial diagnosis of pyruvate kinase deficiency delayed the correct diagnosis of HX for many years and resulted in splenectomy followed by thrombotic complications. The study underlines the importance of a precise diagnosis in HX, particularly in view of splenectomy, and the need of a molecular confirmation of suspected RBC enzymopathy.

Hereditary Xerocytosis due to Mutations in PIEZO1 Gene Associated with Heterozygous Pyruvate Kinase Deficiency and Beta-Thalassemia Trait in Two Unrelated Families

PubMed Central

Vercellati, Cristina; Marcello, Anna Paola; Zaninoni, Anna; van Wijk, Richard; Mirra, Nadia; Curcio, Cristina; Cortelezzi, Agostino; Zanella, Alberto; Barcellini, Wilma; Bianchi, Paola

2017-01-01

Hereditary xerocytosis (HX) is a rare disorder caused by defects of RBC permeability, associated with haemolytic anaemia of variable degree and iron overload. It is sometimes misdiagnosed as hereditary spherocytosis or other congenital haemolytic anaemia. Splenectomy is contraindicated due to increased risk of thromboembolic complications. We report the clinical, haematological, and molecular characteristics of four patients from two unrelated Italian families affected by HX, associated with beta-thalassemia trait and heterozygous pyruvate kinase deficiency, respectively. Two patients had been splenectomised and displayed thrombotic episodes. All patients had iron overload in the absence of transfusion, two of them requiring iron chelation. The diagnosis of HX was confirmed by LoRRca Osmoscan analysis showing a left-shifted curve. PIEZO1 gene sequencing revealed the presence of mutation p.E2496ELE, showing that this is one of the most frequent mutations in this disease. The concomitant defects did not aggravate the clinical phenotype; however, in one patient, the initial diagnosis of pyruvate kinase deficiency delayed the correct diagnosis of HX for many years and resulted in splenectomy followed by thrombotic complications. The study underlines the importance of a precise diagnosis in HX, particularly in view of splenectomy, and the need of a molecular confirmation of suspected RBC enzymopathy. PMID:28367341

Cerebral infarction and femoral venous thrombosis detected in a patient with diabetic ketoacidosis and heterozygous factor V Leiden G1691A and PAI-1 4G/5G mutations.

PubMed

Yaroglu Kazanci, Selcen; Yesilbas, Osman; Ersoy, Melike; Kihtir, Hasan Serdar; Yildirim, Hamdi Murat; Sevketoglu, Esra

2015-09-01

Cerebral infarction is one of the serious neurological complications of diabetic ketoacidosis (DKA). Especially in patients who are genetically prone to thrombosis, cerebral infarction may develop due to inflammation, dehydration, and hyperviscocity secondary to DKA. A 6-year-old child with DKA is diagnosed with cerebral infarction after respiratory insufficiency, convulsion, and altered level of consciousness. Femoral and external iliac venous thrombosis also developed in a few hours after central femoral catheter had been inserted. Heterozygous type of factor V Leiden and PAI-14G/5G mutation were detected. In patients with DKA, cerebral infarction may be suspected other than cerebral edema when altered level of consciousness, convulsion, and respiratory insufficiency develop and once cerebral infarction occurs the patients should also be evaluated for factor V Leiden and PAI-14G/5G mutation analysis in addition to the other prothrombotic risk factors.

Expanded clinical spectrum of spondylocarpotarsal synostosis syndrome and possible manifestation in a heterozygous father.

PubMed

Mitter, Diana; Krakow, Deborah; Farrington-Rock, Claire; Meinecke, Peter

2008-03-15

We report on a 5-year-old boy with spondylocarpotarsal synostosis (SCT) syndrome who presents with disproportionate short stature, thoracic scoliosis, pes planus, dental enamel hypoplasia, unilateral conductive hearing loss and mild facial dysmorphisms. Radiographs showed abnormal segmentation of the spine with block vertebrae and carpal synostosis. In addition to the typical phenotype of SCT syndrome, he showed pronounced delay of carpal bone age and bilateral epiphyseal dysplasia of the proximal femora. The patient's father has mild short stature and unilateral hip dysplasia. Molecular studies of the filamin B gene (FLNB) revealed a homozygous mutation in the index patient while both parents were heterozygous for the mutation. In this report we expand the phenotype of SCT syndrome in a patient with a causal FLNB mutation. (c) 2008 Wiley-Liss, Inc.

Extreme muscle development in sheep heterozygous for both myostatin and callipyge mutations

USDA-ARS?s Scientific Manuscript database

Two mutations causing increased muscle size and decreased fat content in sheep have been described. The callipyge (CLPG) syndrome is only exhibited after 4 to 6 weeks of age in animals inheriting the mutation solely from their sire. In contrast, a mutation of the myostatin gene (MSTN) in the Texel...

Whole-exome sequencing revealed two novel mutations in Usher syndrome.

PubMed

Koparir, Asuman; Karatas, Omer Faruk; Atayoglu, Ali Timucin; Yuksel, Bayram; Sagiroglu, Mahmut Samil; Seven, Mehmet; Ulucan, Hakan; Yuksel, Adnan; Ozen, Mustafa

2015-06-01

Usher syndrome is a clinically and genetically heterogeneous autosomal recessive inherited disorder accompanied by hearing loss and retinitis pigmentosa (RP). Since the associated genes are various and quite large, we utilized whole-exome sequencing (WES) as a diagnostic tool to identify the molecular basis of Usher syndrome. DNA from a 12-year-old male diagnosed with Usher syndrome was analyzed by WES. Mutations detected were confirmed by Sanger sequencing. The pathogenicity of these mutations was determined by in silico analysis. A maternally inherited deleterious frameshift mutation, c.14439_14454del in exon 66 and a paternally inherited non-sense c.10830G>A stop-gain SNV in exon 55 of USH2A were found as two novel compound heterozygous mutations. Both of these mutations disrupt the C terminal of USH2A protein. As a result, WES revealed two novel compound heterozygous mutations in a Turkish USH2A patient. This approach gave us an opportunity to have an appropriate diagnosis and provide genetic counseling to the family within a reasonable time. Copyright © 2015 Elsevier B.V. All rights reserved.

Identification of novel mutations of the CHST6 gene in Vietnamese families affected with macular corneal dystrophy in two generations.

PubMed

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

2003-08-01

To report the clinical and genetic findings of Vietnamese families affected with macular corneal dystrophy (MCD) in 2 generations. Two families, including 7 patients and 3 unaffected members, were examined clinically. Blood samples were collected. Fifty normal Vietnamese individuals were used as controls. Genomic DNA was extracted from leukocytes. Analysis of the carbohydrate sulfotransferase (CHST6) gene was performed using polymerase chain reaction and direct sequencing. The typical form of MCD was recognized in family B, in which sequencing of CHST6 gene revealed an nt 1067-1068ins(GGCCGTG) mutation (frameshift after 125V) homozygously in MCD patients and heterozygously in the unaffected members. Family N also showed clinical features of MCD, moderate in the mother but severe in the affected son. Sequencing revealed a single heterozygous Arg211Gln in the mother, compound heterozygous Arg211Gln+ Gln82Stop in the affected son, and heterozygous Arg211Gln mutation in the unaffected members. The identified mutations in these pedigrees were excluded from normal controls. The novel frameshift and compound heterozygous mutations might be responsible for MCD in the families studied. The phenotypic variation between affected parents and offspring was unclear. In family N, severe MCD phenotype seen in the affected son may be due the fact that he had an early stop codon mutation (Gln82Stop).

Paternal Somatic Mosaicism of a Novel Frameshift Mutation in ELANE Causing Severe Congenital Neutropenia.

PubMed

Kim, Hee-Jung; Song, Min-Jung; Lee, Ki-O; Kim, Sun-Hee; Kim, Hee-Jin

2015-12-01

Severe congenital neutropenia (SCN) is a bone marrow failure disease with an autosomal dominant inheritance from mutations in ELANE. Here, we report a 7-week-old Korean male with SCN. His elder sister died from pneumonia at 2 years. Direct sequencing of ELANE in the proband identified a heterozygous novel frameshift mutation: c.658delC (p.Arg220Glyfs20*). Family study involving his asymptomatic parents with normal cell counts revealed that his father had the same mutation, but at a lower burden than expected in a typical heterozygous state. Further molecular investigation demonstrated somatic mosaicism with ~18% mutant alleles. We concluded the proband inherited the mutation from his somatic mosaic father. © 2015 Wiley Periodicals, Inc.

A Novel Deletion Mutation in the MEN1 Gene in a Patient with Prolactinoma and a Family History of Pancreatic Tumors.

PubMed

Kageyama, Kazunori; Usui, Takeshi; Yoshizawa, Kaori; Daimon, Makoto

2014-09-01

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant tumor syndrome caused by mutations in the MEN1 gene. Mutations in this tumor suppressor gene are often associated with neuroendocrine tumors. Here we describe a novel deletion mutation at codon 304 in the MEN1 gene of a patient with a prolactinoma and strong family history of pancreatic tumors. We describe the patient's clinical course and mutational analysis and review the relevant literature. A 30-year-old pregnant female was referred to our institution's psychological department for treatment of depression. She had developed a prolactinoma at age 17 and was being treated with 1 mg/week of cabergoline. A medical interview revealed a family history of pancreatic islet cell and other tumors; her mother died of pancreatic cancer, her brother is living with gastrinoma, and her sister died of leiomyosarcoma. Extensive examinations performed after delivery, including laboratory tests and computed tomography (CT) scans, did not reveal any other tumors. Mutational analysis of the MEN1 gene identified a heterozygous deletion mutation (c911_914delAGGT) at codon 304. This mutation produces a frameshift at p.304Lys and might disturb the splicing of intron 6 due to the lack of a donor site. The predicted menin protein from the mutated allele is truncated at amino acid 328. We report a novel deletion mutation (c911_914delAGGT) in the MEN1 gene that was likely associated with the patient's prolactinoma and her strong family history of pancreatic tumors.

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.

In-Frame Mutations in Exon 1 of SKI Cause Dominant Shprintzen-Goldberg Syndrome

PubMed Central

Carmignac, Virginie; Thevenon, Julien; Adès, Lesley; Callewaert, Bert; Julia, Sophie; Thauvin-Robinet, Christel; Gueneau, Lucie; Courcet, Jean-Benoit; Lopez, Estelle; Holman, Katherine; Renard, Marjolijn; Plauchu, Henri; Plessis, Ghislaine; De Backer, Julie; Child, Anne; Arno, Gavin; Duplomb, Laurence; Callier, Patrick; Aral, Bernard; Vabres, Pierre; Gigot, Nadège; Arbustini, Eloisa; Grasso, Maurizia; Robinson, Peter N.; Goizet, Cyril; Baumann, Clarisse; Di Rocco, Maja; Sanchez Del Pozo, Jaime; Huet, Frédéric; Jondeau, Guillaume; Collod-Beroud, Gwenaëlle; Beroud, Christophe; Amiel, Jeanne; Cormier-Daire, Valérie; Rivière, Jean-Baptiste; Boileau, Catherine; De Paepe, Anne; Faivre, Laurence

2012-01-01

Shprintzen-Goldberg syndrome (SGS) is characterized by severe marfanoid habitus, intellectual disability, camptodactyly, typical facial dysmorphism, and craniosynostosis. Using family-based exome sequencing, we identified a dominantly inherited heterozygous in-frame deletion in exon 1 of SKI. Direct sequencing of SKI further identified one overlapping heterozygous in-frame deletion and ten heterozygous missense mutations affecting recurrent residues in 18 of the 19 individuals screened for SGS; these individuals included one family affected by somatic mosaicism. All mutations were located in a restricted area of exon 1, within the R-SMAD binding domain of SKI. No mutation was found in a cohort of 11 individuals with other marfanoid-craniosynostosis phenotypes. The interaction between SKI and Smad2/3 and Smad 4 regulates TGF-β signaling, and the pattern of anomalies in Ski-deficient mice corresponds to the clinical manifestations of SGS. These findings define SGS as a member of the family of diseases associated with the TGF-β-signaling pathway. PMID:23103230

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

Waardenburg syndrome type 3 (Klein-Waardenburg syndrome) segregating with a heterozygous deletion in the paired box domain of PAX3: a simple variant or a true syndrome?

PubMed

Tekin, M; Bodurtha, J N; Nance, W E; Pandya, A

2001-10-01

Klein-Waardenburg syndrome or Waardenburg syndrome type 3 (WS-III; MIM 148820) is characterized by the presence of musculoskeletal abnormalities in association with clinical features of Waardenburg syndrome type 1 (WS-I). Since the description of the first patient in 1947 (D. Klein, Arch Klaus Stift Vererb Forsch 1947: 22: 336-342), a few cases have been reported. Only occasional families have demonstrated autosomal-dominant inheritance of WS-III. In a previous report, a missense mutation in the paired domain of the PAX3 gene has been described in a family with dominant segregation of WS-III. In this report, we present a second family (mother and son) with typical clinical findings of WS-III segregating with a heterozygous 13-bp deletion in the paired domain of the PAX3 gene. Although homozygosity or compound heterozygosity has also been documented in patients with severe limb involvement, a consistent genotype-phenotype correlation for limb abnormalities associated with heterozygous PAX3 mutations has not previously been apparent. Heterozygous mutations could either reflect a unique dominant-negative effect or possibly the contribution of other unlinked genetic modifiers in determining the phenotype.

Mineralocorticoid Receptor Mutations and a Severe Recessive Pseudohypoaldosteronism Type 1

PubMed Central

Hubert, Edwige-Ludiwyne; Teissier, Raphaël; Fernandes-Rosa, Fábio L.; Fay, Michel; Rafestin-Oblin, Marie-Edith; Jeunemaitre, Xavier; Metz, Chantal; Escoubet, Brigitte

2011-01-01

Pseudohypoaldosteronism type 1 (PHA1) is a rare genetic disease of mineralocorticoid resistance characterized by salt wasting and failure to thrive in infancy. Here we describe the first case of a newborn with severe recessive PHA1 caused by two heterozygous mutations in NR3C2, gene coding for the mineralocorticoid receptor (MR). Independent segregation of the mutations occurred in the family, with p.Ser166X being transmitted from the affected father and p.Trp806X from the asymptomatic mother Whereas the truncated MR166X protein was degraded, MR806X was expressed both at the mRNA and protein level. Functional studies demonstrated that despite its inability to bind aldosterone, MR806X had partial ligand-independent transcriptional activity. Partial nuclear localization of MR806X in the absence of hormone was identified as a prerequisite to initiate transcription. This exceptional case broadens the spectrum of clinical phenotypes of PHA1 and demonstrates that minimal residual activity of MR is compatible with life. It also suggests that rare hypomorphic NR3C2 alleles may be more common than expected from the prevalence of detected PHA1 cases. This might prove relevant for patient's care in neonatal salt losing disorders and may affect renal salt handling and blood pressure in the general population. PMID:21903996

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.

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

A deletion mutation in GJB6 cooperating with a GJB2 mutation in trans in non-syndromic deafness: A novel founder mutation in Ashkenazi Jews.

PubMed

Lerer, I; Sagi, M; Ben-Neriah, Z; Wang, T; Levi, H; Abeliovich, D

2001-11-01

A deletion of at least 140 kb starting approximately 35kb upstream (telomeric) to the GJB2 (CX26) gene was identified in 7 patients from 4 unrelated Jewish Ashkenazi families with non-syndromic hearing loss. These patients were heterozygous for one of the common mutations 167delT or 35delG in the GJB2 gene in trans to the deletion. The deletion started at 5' side of the GJB6 (CX30) gene including the first exon and it did not affect the integrity of the GJB2 gene. The deletion mutation segregated together with the hearing loss, and was not found in a control group of 100 Ashkenazi individuals. We suggest that the deletion is a recessive mutation causing hearing loss in individuals that are double heterozygous for the deletion and for a mutation in the GJB2 gene. The effect of the deletion mutation could be due to a digenic mode of inheritance of GJB2 and GJB6 genes that encode two different connexins; connexin 26 and connexin 30, or it may abolish control elements that are important in the expression of the GJB2 gene in the cochlea. Regardless which of the options is valid, it is apparent that the deletion mutation provides a new insight into connexin function in the auditory system. The deletion mutation was on the same haplotypic background in all the families, and therefore is a founder mutation that increases the impact of GJB2 in the etiology of prelingual recessive non-syndromic hearing loss in the Ashkenazi population. Copyright 2001 Wiley-Liss, Inc.

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.

Functional characterization of mutations in the myosin Vb gene associated with microvillus inclusion disease

PubMed Central

Szperl, Agata M.; Golachowska, Magdalena R.; Bruinenberg, Marcel; Prekeris, Rytis; Thunnissen, Andy-Mark W. H.; Karrenbeld, Arend; Dijkstra, Gerard; Hoekstra, Dick; Mercer, David; Ksiazyk, Janusz; Wijmenga, Cisca; Wapenaar, Martin C.; Rings, Edmond H. H. M.; van IJzendoorn, Sven C. D.

2010-01-01

Objectives Microvillus inclusion disease (MVID) is a rare autosomal recessive enteropathy characterized by intractable diarrhea and malabsorption. Recently, various MYO5B gene mutations have been identified in MVID patients. Interestingly, several MVID patients showed only a MYO5B mutation in one allele (heterozygous) or no mutations in the MYO5B gene, illustrating the need to further functionally characterize the cell biological effects of the MYO5B mutations. Methods The genomic DNA of nine patients diagnosed with microvillus inclusion disease was screened for MYO5B mutations, and qPCR and immunohistochemistry on the material of two patients was performed to investigate resultant cellular consequences. Results We demonstrate for the first time that MYO5B mutations can be correlated with altered myosin Vb mRNA expression and with an aberrant subcellular distribution of the myosin Vb protein. Moreover, we demonstrate that the typical and myosin Vb–controlled accumulation of rab11a-and FIP5-positive recycling endosomes in the apical cytoplasm of the cells is abolished in MVID enterocytes, which is indicative for altered myosin Vb function. Also, we report 8 novel MYO5B mutations in 9 MVID patients of various etnic backgrounds, including compound heterozygous mutations. Conclusions Our functional analysis indicate that MYO5B mutations can be correlated with an aberrant subcellular distribution of the myosin Vb protein and apical recycling endosomes which, together with the additional compound heterozygous mutations, significantly strengthen the link between MYO5B and MVID. PMID:21206382

A Telomerase Immortalized Human Proximal Tubule Cell Line with a Truncation Mutation (Q4004X) in Polycystin-1

PubMed Central

Herbert, Brittney-Shea; Grimes, Brenda R.; Xu, Wei Min; Werner, Michael; Ward, Christopher; Rossetti, Sandro; Harris, Peter; Bello-Reuss, Elsa; Ward, Heather H.; Miller, Caroline; Gattone, Vincent H.; Phillips, Carrie L.; Wandinger-Ness, Angela; Bacallao, Robert L.

2013-01-01

Autosomal dominant polycystic kidney disease (ADPKD) is associated with a variety of cellular phenotypes in renal epithelial cells. Cystic epithelia are secretory as opposed to absorptive, have higher proliferation rates in cell culture and have some characteristics of epithelial to mesenchymal transitions [1], [2]. In this communication we describe a telomerase immortalized cell line that expresses proximal tubule markers and is derived from renal cysts of an ADPKD kidney. These cells have a single detectable truncating mutation (Q4004X) in polycystin-1. These cells make normal appearing but shorter cilia and fail to assemble polycystin-1 in the cilia, and less uncleaved polycystin-1 in membrane fractions. This cell line has been maintained in continuous passage for over 35 passages without going into senescence. Nephron segment specific markers suggest a proximal tubule origin for these cells and the cell line will be useful to study mechanistic details of cyst formation in proximal tubule cells. PMID:23383103

De Novo GMNN Mutations Cause Autosomal-Dominant Primordial Dwarfism Associated with Meier-Gorlin Syndrome.

PubMed

Burrage, Lindsay C; Charng, Wu-Lin; Eldomery, Mohammad K; Willer, Jason R; Davis, Erica E; Lugtenberg, Dorien; Zhu, Wenmiao; Leduc, Magalie S; Akdemir, Zeynep C; Azamian, Mahshid; Zapata, Gladys; Hernandez, Patricia P; Schoots, Jeroen; de Munnik, Sonja A; Roepman, Ronald; Pearring, Jillian N; Jhangiani, Shalini; Katsanis, Nicholas; Vissers, Lisenka E L M; Brunner, Han G; Beaudet, Arthur L; Rosenfeld, Jill A; Muzny, Donna M; Gibbs, Richard A; Eng, Christine M; Xia, Fan; Lalani, Seema R; Lupski, James R; Bongers, Ernie M H F; Yang, Yaping

2015-12-03

Meier-Gorlin syndrome (MGS) is a genetically heterogeneous primordial dwarfism syndrome known to be caused by biallelic loss-of-function mutations in one of five genes encoding pre-replication complex proteins: ORC1, ORC4, ORC6, CDT1, and CDC6. Mutations in these genes cause disruption of the origin of DNA replication initiation. To date, only an autosomal-recessive inheritance pattern has been described in individuals with this disorder, with a molecular etiology established in about three-fourths of cases. Here, we report three subjects with MGS and de novo heterozygous mutations in the 5' end of GMNN, encoding the DNA replication inhibitor geminin. We identified two truncating mutations in exon 2 (the 1(st) coding exon), c.16A>T (p.Lys6(∗)) and c.35_38delTCAA (p.Ile12Lysfs(∗)4), and one missense mutation, c.50A>G (p.Lys17Arg), affecting the second-to-last nucleotide of exon 2 and possibly RNA splicing. Geminin is present during the S, G2, and M phases of the cell cycle and is degraded during the metaphase-anaphase transition by the anaphase-promoting complex (APC), which recognizes the destruction box sequence near the 5' end of the geminin protein. All three GMNN mutations identified alter sites 5' to residue Met28 of the protein, which is located within the destruction box. We present data supporting a gain-of-function mechanism, in which the GMNN mutations result in proteins lacking the destruction box and hence increased protein stability and prolonged inhibition of replication leading to autosomal-dominant MGS. Copyright © 2015 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

Compound Heterozygous Inheritance of Mutations in Coenzyme Q8A Results in Autosomal Recessive Cerebellar Ataxia and Coenzyme Q10 Deficiency in a Female Sib-Pair.

PubMed

Jacobsen, Jessie C; Whitford, Whitney; Swan, Brendan; Taylor, Juliet; Love, Donald R; Hill, Rosamund; Molyneux, Sarah; George, Peter M; Mackay, Richard; Robertson, Stephen P; Snell, Russell G; Lehnert, Klaus

2017-11-21

Autosomal recessive ataxias are characterised by a fundamental loss in coordination of gait with associated atrophy of the cerebellum. There is significant clinical and genetic heterogeneity amongst inherited ataxias; however, an early molecular diagnosis is essential with low-risk treatments available for some of these conditions. We describe two female siblings who presented early in life with unsteady gait and cerebellar atrophy. Whole exome sequencing revealed compound heterozygous inheritance of two pathogenic mutations (p.Leu277Pro, c.1506+1G>A) in the coenzyme Q8A gene (COQ8A), a gene central to biosynthesis of coenzyme Q (CoQ). The paternally derived p.Leu277Pro mutation is predicted to disrupt a conserved motif in the substrate-binding pocket of the protein, resulting in inhibition of CoQ 10 production. The maternal c.1506+1G>A mutation destroys a canonical splice donor site in exon 12 affecting transcript processing and subsequent protein translation. Mutations in this gene can result in primary coenzyme Q 10 deficiency type 4, which is characterized by childhood onset of cerebellar ataxia and exercise intolerance, both of which were observed in this sib-pair. Muscle biopsies revealed unequivocally low levels of CoQ 10, and the siblings were subsequently established on a therapeutic dose of CoQ 10 with distinct clinical evidence of improvement after 1 year of treatment. This case emphasises the importance of an early and accurate molecular diagnosis for suspected inherited ataxias, particularly given the availability of approved treatments for some subtypes.

AV59M KCNJ11 gene mutation leading to intermediate DEND syndrome in a Chinese child.

PubMed

Sang, Yanmei; Ni, Guichen; Gu, Yi; Liu, Min

2011-01-01

Heterozygous activating mutations in the KCNJ11 gene can cause permanent and transient neonatal diabetes. In the present study, we sequenced the KCNJ11 gene in a Chinese boy diagnosed with permanent neonatal diabetes mellitus (PNDM) and also in his parents. A heterozygous 175G > A (V59M) mutation was identified in the patient, while no KCNJ11 gene mutations were found in his parents, indicating that this mutation is de novo. The patient with the V59M mutation successfully switched from insulin injections to oral glibenclamide; 2 years of follow-up revealed that the patient had intermediate developmental delay, epilepsy and neonatal diabetes (DEND) syndrome. This is the first patient who is reported to have iDEND syndrome due to KCNJ11 V59M mutation in China.

Three patients with Schaaf-Yang syndrome exhibiting arthrogryposis and endocrinological abnormalities.

PubMed

Enya, Takuji; Okamoto, Nobuhiko; Iba, Yoshinori; Miyazawa, Tomoki; Okada, Mitsuru; Ida, Shinobu; Naruto, Takuya; Imoto, Issei; Fujita, Atsushi; Miyake, Noriko; Matsumoto, Naomichi; Sugimoto, Keisuke; Takemura, Tsukasa

2018-03-01

MAGEL2 is the paternally expressed gene within Prader-Willi syndrome critical region at 15q11.2. We encountered three individuals in whom truncating mutations of MAGEL2 were identified. Patients 1 and 2, siblings born to healthy, non-consanguineous Japanese parents, showed generalized hypotonia, lethargy, severe respiratory difficulty, poor feeding, and multiple anomalies including arthrogryposis soon after birth. We carried out whole-exome sequencing, which detected a MAGEL2 mutation (c.1912C>T, p.Gln638*, heterozygous). The patients' father was heterozygous for the mutation. Patient 3 was a female infant, showed respiratory difficulty reflecting pulmonary hypoplasia, generalized hypotonia, feeding difficulty and multiple anomalies soon after birth. Targeted next-generation sequencing detected a novel heterozygous mutation in MAGEL2 (c.3131C>A, p.Ser1044*). This mutation was not found in the parents. MAGEL2 mutations, first reported to be the cause of the Prader-Willi like syndrome with autism by Schaaf et al. (2013) Nature Genetics, 45: 1405-1408 show the wide range of phenotypic spectrum from lethal arthrogryposis multiplex congenital to autism spectrum disorder (ASD) and mild intellectual disability (ID). Our results indicate that MAGEL2 mutations cause multiple congenital anomalies and intellectual disability accompanied by arthrogryposis multiplex congenita and various endocrinologic abnormalities, supporting that the view that clinical phenotypes of MAGEL2 mutations are variable. © 2018 Wiley Periodicals, Inc.

A New COL3A1 Mutation in Ehlers-Danlos Syndrome Vascular Type With Different Phenotypes in the Same Family.

PubMed

Cortini, Francesca; Marinelli, Barbara; Romi, Silvia; Seresini, Agostino; Pesatori, Angela Cecilia; Seia, Manuela; Montano, Nicola; Bassotti, Alessandra

2017-04-01

Vascular Ehlers-Danlos syndrome (vEDS) is a rare and severe connective tissue disorder caused by mutations in the collagen type III alpha I chain ( COL3A1) gene. We describe a pathogenetic heterozygous COL3A1 mutation c.3140 G>A, p. Gly1047Asp, identified using next-generation sequencing, in a 40-year-old Italian female. The genetic test performed on her relatives, which present different clinical phenotypes, confirmed that they carry the same mutation in heterozygous state. This finding confirms that mutations causing vEDS have an incomplete penetrance.

Evidence for Mitotic Recombination in W(ei)/+ Heterozygous Mice

PubMed Central

Panthier, J. J.; Guenet, J. L.; Condamine, H.; Jacob, F.

1990-01-01

A number of alleles at coat color loci of the house mouse give rise to areas of wild-type pigmentation on the coats of otherwise mutant animals. Such unstable alleles include both recessive and dominant mutations. Among the latter are several alleles at the W locus. In this report, phenotypic reversions of the W(ei) allele at the W locus were studied Mice heterozygous in repulsion for both W(ei) and buff (bf) [i.e. W(ei)+/+bf] were examined for the occurrence of phenotypic reversion events. Buff (bf) is a recessive mutation, which lies 21 cM from W on the telomeric side of chromosome 5 and is responsible for the khaki colored coat of nonagouti buff homozygotes (a/a; bf/bf). Two kinds of fully pigmented reversion spots were recovered on the coats of a/a; W(ei)+/+bf mice: either solid black or khaki colored. Furthermore phenotypic reversions of W(ei)/+ were enhanced significantly following X-irradiation of 9.25-day-old W(ei)/+ embryos (P < 0.04). These observations are consistent with the suggestion of a role for mitotic recombination in the origin of these phenotypic reversions. In addition these results rise the intriguing possibility that some W mutations may enhance mitotic recombination in the house mouse. PMID:2341029

MEFV gene mutations and clinical course in pediatric patients with Henoch-Schönlein purpura.

PubMed

Can, Emrah; Kılınç Yaprak, Zubeyde; Hamilçıkan, Şahin; Erol, Meltem; Bostan Gayret Y Özgül Yiğit, Özlem

2018-06-01

To determine the frequency of the MEFV gene mutations in pediatric patients diagnosed with HSP and to assess the effect of the MEFV gene mutations on their prognosis. Material and Methods. Ccross-sectional study; pediatric patients between 2-11 years diagnosed with HSP were included. These cases were investigated for 6 MEFV gene mutations (M694V, M680I, A744S, R202Q, K695R, E148Q). Eighty cases were included in the study of which 55% were male (n= 44). The mean age was 6.44 ± 2.52 years. Disease recurrence occurred in 9 patients, invagination in 5 patients and convulsion in 1 patient during follow-up. Approximately half of the patients received steroids. The MEFV gene mutations was not detected in 44 (55%) of the patients. There was a heterozygous mutation in 19 (22%). E148Q was found in 8 patients, M694V in 5 patients, A744S in 4 patients, and the R202Q heterozygous mutation in 2 patients. The M608I homozygous mutation was detected in 1 patient and the M694V homozygous mutation in 1 patient. The compound heterozygous MEFV gene mutations was found in 15 patients. The presence of the MEFV gene mutations was not correlated with the frequency of renal and gastrointestinal involvement and prognosis, the development of complications and the use of steroids. The presence of the MEFV gene mutations does not correlate with the clinical course and complication in Turkish pediatric patients with HSP. Sociedad Argentina de Pediatría.

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.

A hot-spot mutation in CDC42 (p.Tyr64Cys) and novel phenotypes in the third patient with Takenouchi-Kosaki syndrome.

PubMed

Motokawa, Midori; Watanabe, Satoshi; Nakatomi, Akiko; Kondoh, Tatsuro; Matsumoto, Tadashi; Morifuji, Kanako; Sawada, Hirotake; Nishimura, Toyoki; Nunoi, Hiroyuki; Yoshiura, Koh-Ichiro; Moriuchi, Hiroyuki; Dateki, Sumito

2018-03-01

Takenouchi-Kosaki syndrome (TKS) is a congenital malformation syndrome characterized by severe developmental delay, macrothrombocytopenia, camptodactyly, sensorineural hearing loss, and dysmorphic facial features. Recently, a heterozygous de novo mutation (p.Tyr64Cys) in the CDC42 gene, which encodes a key small GTP-binding protein of the Rho-subfamily, was identified in two unrelated patients with TKS. We herein report a third patient with TKS who had the same heterozygous CDC42 mutation. The phenotype of the patient was very similar to those of the two previously reported patients with TKS; however, she also demonstrated novel clinical manifestations, such as congenital hypothyroidism and immunological disturbance. Thus, despite the heterozygous mutation of CDC42 (p.Tyr64Cys) likely being a hot-spot mutation for TKS, its phenotype may be variable. Further studies and the accumulation of patients with CDC42 mutations are needed to clarify the phenotype in patients with TKS and the pathophysiological roles of the CDC42 mutation.

Mutations at the PAX6 locus are found in heterogeneous anterior segment malformations including Peters' anomaly.

PubMed

Hanson, I M; Fletcher, J M; Jordan, T; Brown, A; Taylor, D; Adams, R J; Punnett, H H; van Heyningen, V

1994-02-01

Mutation or deletion of the PAX6 gene underlies many cases of aniridia. Three lines of evidence now converge to implicate PAX6 more widely in anterior segment malformations including Peters' anomaly. First, a child with Peters' anomaly is deleted for one copy of PAX6. Second, affected members of a family with dominantly inherited anterior segment malformations, including Peters' anomaly are heterozygous for an R26G mutation in the PAX6 paired box. Third, a proportion of Sey/+ Smalleye mice, heterozygous for a nonsense mutation in murine Pax-6, have an ocular phenotype resembling Peters' anomaly. We therefore propose that a variety of anterior segment anomalies may be associated with PAX6 mutations.

A novel mutation in PAX3 associated with Waardenburg syndrome type I in a Chinese family.

PubMed

Xiao, Yun; Luo, Jianfen; Zhang, Fengguo; Li, Jianfeng; Han, Yuechen; Zhang, Daogong; Wang, Mingming; Ma, Yalin; Xu, Lei; Bai, Xiaohui; Wang, Haibo

2016-01-01

The novel compound heterozygous mutation in PAX3 was the key genetic reason for WS1 in this family, which was useful to the molecular diagnosis of WS1. Screening the pathogenic mutations in a four generation Chinese family with Waardenburg syndrome type I (WS1). WS1 was diagnosed in a 4-year-old boy according to the Waardenburg syndrome Consortium criteria. The detailed family history revealed four affected members in the family. Routine clinical, audiological examination, and ophthalmologic evaluation were performed on four affected and 10 healthy members in this family. The genetic analysis was conducted, including the targeted next-generation sequencing of 127 known deafness genes combined with Sanger sequencing, TA clone and bioinformatic analysis. A novel compound heterozygous mutation c.[169_170insC;172_174delAAG] (p.His57ProfsX55) was identified in PAX3, which was co-segregated with WS1 in the Chinese family. This mutation was absent in the unaffected family members and 200 ethnicity-matched controls. The phylogenetic analysis and three-dimensional (3D) modeling of Pax3 protein further confirmed that the novel compound heterozygous mutation was pathogenic.

POLD1 Germline Mutations in Patients Initially Diagnosed with Werner Syndrome

PubMed Central

Lessel, Davor; Hisama, Fuki M.; Szakszon, Katalin; Saha, Bidisha; Sanjuanelo, Alexander Barrios; Salbert, Bonnie A.; Steele, Pamela D.; Baldwin, Jennifer; Brown, W. Ted; Piussan, Charles; Plauchu, Henri; Szilvássy, Judit; Horkay, Edit; Hoögel, Josef; Martin, George M.; Herr, Alan J.; Oshima, Junko; Kubisch, Christian

2015-01-01

Segmental progeroid syndromes are rare, heterogeneous disorders characterized by signs of premature aging affecting more than one tissue or organ. A prototypic example is the Werner syndrome (WS), caused by biallelic germline mutations in the Werner helicase gene (WRN). While heterozygous lamin A/C (LMNA) mutations are found in a few nonclassical cases of WS, another 10%–15% of patients initially diagnosed with WS do not have mutations in WRN or LMNA. Germline POLD1 mutations were recently reported in five patients with another segmental progeroid disorder: mandibular hypoplasia, deafness, progeroid features syndrome. Here, we describe eight additional patients with heterozygous POLD1 mutations, thereby substantially expanding the characterization of this new example of segmental progeroid disorders. First, we identified POLD1 mutations in patients initially diagnosed with WS. Second, we describe POLD1 mutation carriers without clinically relevant hearing impairment or mandibular underdevelopment, both previously thought to represent obligate diagnostic features. These patients also exhibit a lower incidence of metabolic abnormalities and joint contractures. Third, we document postnatal short stature and premature greying/loss of hair in POLD1 mutation carriers. We conclude that POLD1 germline mutations can result in a variably expressed and probably underdiagnosed segmental progeroid syndrome. PMID:26172944

A novel splicing site IRP1 somatic mutation in a patient with pheochromocytoma and JAK2V617F positive polycythemia vera: a case report.

PubMed

Pang, Ying; Gupta, Garima; Yang, Chunzhang; Wang, Herui; Huynh, Thanh-Truc; Abdullaev, Ziedulla; Pack, Svetlana D; Percy, Melanie J; Lappin, Terence R J; Zhuang, Zhengping; Pacak, Karel

2018-03-13

The role of the hypoxia signaling pathway in the pathogenesis of pheochromocytoma/paraganglioma (PPGL)-polycythemia syndrome has been elucidated. Novel somatic mutations in hypoxia-inducible factor type 2A (HIF2A) and germline mutations in prolyl hydroxylase type 1 and type 2 (PHD1 and PHD2) have been identified to cause upregulation of the hypoxia signaling pathway and its target genes including erythropoietin (EPO) and its receptor (EPOR). However, in a minority of patients presenting with this syndrome, the genetics and molecular pathogenesis remain unexplained. The aim of the present study was to uncover novel genetic causes of PPGL-polycythemia syndrome. A female presented with a history of JAK2 V617F positive PV, diagnosed in 2007, and right adrenal pheochromocytoma diagnosed and resected in 2011. Her polycythemia symptoms and hematocrit levels continued to worsen from 2007 to 2011, with an increased frequency of phlebotomies. Postoperatively, until early 2013, her hematocrit levels remained normalized. Following this, the hematocrit levels ranged between 46.4 and 48.9% [35-45%]. Tumor tissue from the patient was further tested for mutations in genes related to upregulation of the hypoxia signaling pathway including iron regulatory protein 1 (IRP1), which is a known regulator of HIF-2α mRNA translation. Functional studies were performed to investigate the consequences of these mutations, especially their effect on the HIF signaling pathway and EPO. Indel mutations (c.267-1_267delGGinsTA) were discovered at the exon 3 splicing site of IRP1. Minigene construct and splicing site analysis showed that the mutation led to a new splicing site and a frameshift mutation of IRP1, which caused a truncated protein. Fluorescence in situ hybridization analysis demonstrated heterozygous IRP1 deletions in tumor cells. Immunohistochemistry results confirmed the truncated IRP1 and overexpressed HIF-2α, EPO and EPOR in tumor cells. This is the first report which provides

Heterozygous Monocarboxylate Transporter 1 (MCT1, SLC16A1) Deficiency as a Cause of Recurrent Ketoacidosis.

PubMed

Balasubramaniam, Shanti; Lewis, Barry; Greed, Lawrence; Meili, David; Flier, Annegret; Yamamoto, Raina; Bilić, Karmen; Till, Claudia; Sass, Jörn Oliver

2016-01-01

We describe two half-siblings with monocarboxylate transporter 1 (MCT1, SLC16A1) deficiency, a defect on ketone body utilization, that has only recently been identified (van Hasselt et al., N Engl J Med, 371:1900-1907, 2014) as a cause for recurrent ketoacidoses. Our index patient is a boy with non-consanguineous parents who had presented acutely with impaired consciousness and severe metabolic ketoacidosis following a 3-day history of gastroenteritis at age 5 years. A 12.5-year-old half-brother who shared the proband's mother also had a previous history of recurrent ketoacidoses. Results of mutation and enzyme activity analyses in proband samples advocated against methylacetoacetyl-coenzyme A thiolase ("beta-ketothiolase") and succinyl-coenzyme A: 3-oxoacyl coenzyme A transferase (SCOT) deficiencies. A single heterozygous c.982C>T transition in the SLC16A1 gene resulting in a stop mutation (p.Arg328Ter) was detected in both boys. It was shared by their healthy mother and by the proband's half-sister, but was absent in the proband's father. MCT1 deficiency may be more prevalent than is apparent, as clinical manifestations can occur both in individuals with bi- and monoallelic mutations. It may be an important differential diagnosis in recurrent ketoacidosis with or without hypoglycemia, particularly in the absence of any specific metabolic profiles in blood and urine. Early diagnosis may enable improved disease management. Careful identification of potential triggers of metabolic decompensations in individuals even with single heterozygous mutations in the SLC16A1 gene is indicated.

AIP mutations in young patients with acromegaly and the Tampico Giant: the Mexican experience.

PubMed

Ramírez-Rentería, Claudia; Hernández-Ramírez, Laura C; Portocarrero-Ortiz, Lesly; Vargas, Guadalupe; Melgar, Virgilio; Espinosa, Etual; Espinosa-de-Los-Monteros, Ana Laura; Sosa, Ernesto; González, Baldomero; Zúñiga, Sergio; Unterländer, Martina; Burger, Joachim; Stals, Karen; Bussell, Anne-Marie; Ellard, Sian; Dang, Mary; Iacovazzo, Donato; Kapur, Sonal; Gabrovska, Plamena; Radian, Serban; Roncaroli, Federico; Korbonits, Márta; Mercado, Moisés

2016-08-01

Although aryl hydrocarbon receptor-interacting protein (AIP) mutations are rare in sporadic acromegaly, their prevalence among young patients is nonnegligible. The objectives of this study were to evaluate the frequency of AIP mutations in a cohort of Mexican patients with acromegaly with disease onset before the age of 30 and to search for molecular abnormalities in the AIP gene in teeth obtained from the "Tampico Giant". Peripheral blood DNA from 71 patients with acromegaly (51 females) with disease onset <30 years was analysed (median age of disease onset of 23 years) and correlated with clinical, biochemical and imaging characteristics. Sequencing was also carried out in DNA extracted from teeth of the Tampico Giant. Five patients (7 %) harboured heterozygous, germline mutations of the AIP gene. In two of them (a 9-year-old girl with gigantism and a young man with symptoms of GH excess since age 14) the c.910C>T (p.Arg304Ter), well-known truncating mutation was identified; in one of these two cases and her identical twin sister, the mutation proved to be a de novo event, since neither of their parents were found to be carriers. In the remaining three patients, new mutations were identified: a frameshift mutation (c.976_977insC, p.Gly326AfsTer), an in-frame deletion (c.872_877del, p.Val291_Leu292del) and a nonsense mutation (c.868A > T, p.Lys290Ter), which are predicted to be pathogenic based on in silico analysis. Patients with AIP mutations tended to have an earlier onset of acromegaly and harboured larger and more invasive tumours. A previously described genetic variant of unknown significance (c.869C > T, p.Ala299Val) was identified in DNA from the Tampico Giant. The prevalence of AIP mutations in young Mexican patients with acromegaly is similar to that of European cohorts. Our results support the need for genetic evaluation of patients with early onset acromegaly.

Incorporating Truncating Variants in PALB2, CHEK2 and ATM into the BOADICEA Breast Cancer Risk Model

PubMed Central

Lee, Andrew J.; Cunningham, Alex P.; Tischkowitz, Marc; Simard, Jacques; Pharoah, Paul D.; Easton, Douglas F.; Antoniou, Antonis C.

2016-01-01

Purpose The proliferation of gene-panel testing precipitates the need for a breast cancer (BC) risk model that incorporates the effects of mutations in several genes and family history (FH). We extended the BOADICEA model to incorporate the effects of truncating variants in PALB2, CHEK2 and ATM. Methods The BC incidence was modelled via the explicit effects of truncating variants in BRCA1/2, PALB2, CHEK2 and ATM and other unobserved genetic effects using segregation analysis methods. Results The predicted average BC risk by age 80 for an ATM mutation carrier is 28%, 30% for CHEK2, 50% for PALB2, 74% for BRCA1 and BRCA2. However, the BC risks are predicted to increase with FH-burden. In families with mutations, predicted risks for mutation-negative members depend on both FH and the specific mutation. The reduction in BC risk after negative predictive-testing is greatest when a BRCA1 mutation is identified in the family, but for women whose relatives carry a CHEK2 or ATM mutation, the risks decrease slightly. Conclusions The model may be a valuable tool for counselling women who have undergone gene-panel testing for providing consistent risks and harmonizing their clinical management. A web-application can be used to obtain BC- risks in clinical practice (http://ccge.medschl.cam.ac.uk/boadicea/). PMID:27464310

Incorporating truncating variants in PALB2, CHEK2, and ATM into the BOADICEA breast cancer risk model.

PubMed

Lee, Andrew J; Cunningham, Alex P; Tischkowitz, Marc; Simard, Jacques; Pharoah, Paul D; Easton, Douglas F; Antoniou, Antonis C

2016-12-01

The proliferation of gene panel testing precipitates the need for a breast cancer (BC) risk model that incorporates the effects of mutations in several genes and family history (FH). We extended the BOADICEA model to incorporate the effects of truncating variants in PALB2, CHEK2, and ATM. The BC incidence was modeled via the explicit effects of truncating variants in BRCA1/2, PALB2, CHEK2, and ATM and other unobserved genetic effects using segregation analysis methods. The predicted average BC risk by age 80 for an ATM mutation carrier is 28%, 30% for CHEK2, 50% for PALB2, and 74% for BRCA1 and BRCA2. However, the BC risks are predicted to increase with FH burden. In families with mutations, predicted risks for mutation-negative members depend on both FH and the specific mutation. The reduction in BC risk after negative predictive testing is greatest when a BRCA1 mutation is identified in the family, but for women whose relatives carry a CHEK2 or ATM mutation, the risks decrease slightly. The model may be a valuable tool for counseling women who have undergone gene panel testing for providing consistent risks and harmonizing their clinical management. A Web application can be used to obtain BC risks in clinical practice (http://ccge.medschl.cam.ac.uk/boadicea/).Genet Med 18 12, 1190-1198.

Insertion of an SVA element, a nonautonomous retrotransposon, in PMS2 intron 7 as a novel cause of Lynch syndrome.

PubMed

van der Klift, Heleen M; Tops, Carli M; Hes, Frederik J; Devilee, Peter; Wijnen, Juul T

2012-07-01

Heterozygous germline mutations in the mismatch repair gene PMS2 predispose carriers for Lynch syndrome, an autosomal dominant predisposition to cancer. Here, we present a LINE-1-mediated retrotranspositional insertion in PMS2 as a novel mutation type for Lynch syndrome. This insertion, detected with Southern blot analysis in the genomic DNA of the patient, is characterized as a 2.2 kb long 5' truncated SVA_F element. The insertion is not detectable by current diagnostic testing limited to MLPA and direct Sanger sequencing on genomic DNA. The molecular nature of this insertion could only be resolved in RNA from cultured lymphocytes in which nonsense-mediated RNA decay was inhibited. Our report illustrates the technical problems encountered in the detection of this mutation type. Especially large heterozygous insertions will remain unnoticed because of preferential amplification of the smaller wild-type allele in genomic DNA, and are probably underreported in the mutation spectra of autosomal dominant disorders. © 2012 Wiley Periodicals, Inc.

Melorheostosis: Exome sequencing of an associated dermatosis implicates postzygotic mosaicism of mutated KRAS.

PubMed

Whyte, Michael P; Griffith, Malachi; Trani, Lee; Mumm, Steven; Gottesman, Gary S; McAlister, William H; Krysiak, Kilannin; Lesurf, Robert; Skidmore, Zachary L; Campbell, Katie M; Rosman, Ilana S; Bayliss, Susan; Bijanki, Vinieth N; Nenninger, Angela; Van Tine, Brian A; Griffith, Obi L; Mardis, Elaine R

2017-08-01

Melorheostosis (MEL) is the rare sporadic dysostosis characterized by monostotic or polyostotic osteosclerosis and hyperostosis often distributed in a sclerotomal pattern. The prevailing hypothesis for MEL invokes postzygotic mosaicism. Sometimes scleroderma-like skin changes, considered a representation of the pathogenetic process of MEL, overlie the bony changes, and sometimes MEL becomes malignant. Osteopoikilosis (OPK) is the autosomal dominant skeletal dysplasia that features symmetrically distributed punctate osteosclerosis due to heterozygous loss-of-function mutation within LEMD3. Rarely, radiographic findings of MEL occur in OPK. However, germline mutation of LEMD3 does not explain sporadic MEL. To explore if mosaicism underlies MEL, we studied a boy with polyostotic MEL and characteristic overlying scleroderma-like skin, a few bony lesions consistent with OPK, and a large epidermal nevus known to usually harbor a HRAS, FGFR3, or PIK3CA gene mutation. Exome sequencing was performed to ~100× average read depth for his two dermatoses, two areas of normal skin, and peripheral blood leukocytes. As expected for non-malignant tissues, the patient's mutation burden in his normal skin and leukocytes was low. He, his mother, and his maternal grandfather carried a heterozygous, germline, in-frame, 24-base-pair deletion in LEMD3. Radiographs of the patient and his mother revealed bony foci consistent with OPK, but she showed no MEL. For the patient, somatic variant analysis, using four algorithms to compare all 20 possible pairwise combinations of his five DNA samples, identified only one high-confidence mutation, heterozygous KRAS Q61H (NM_033360.3:c.183A>C, NP_203524.1:p.Gln61His), in both his dermatoses but absent in his normal skin and blood. Thus, sparing our patient biopsy of his MEL bone, we identified a heterozygous somatic KRAS mutation in his scleroderma-like dermatosis considered a surrogate for MEL. This implicates postzygotic mosaicism of mutated KRAS

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.

In-frame mutations in exon 1 of SKI cause dominant Shprintzen-Goldberg syndrome.

PubMed

Carmignac, Virginie; Thevenon, Julien; Adès, Lesley; Callewaert, Bert; Julia, Sophie; Thauvin-Robinet, Christel; Gueneau, Lucie; Courcet, Jean-Benoit; Lopez, Estelle; Holman, Katherine; Renard, Marjolijn; Plauchu, Henri; Plessis, Ghislaine; De Backer, Julie; Child, Anne; Arno, Gavin; Duplomb, Laurence; Callier, Patrick; Aral, Bernard; Vabres, Pierre; Gigot, Nadège; Arbustini, Eloisa; Grasso, Maurizia; Robinson, Peter N; Goizet, Cyril; Baumann, Clarisse; Di Rocco, Maja; Sanchez Del Pozo, Jaime; Huet, Frédéric; Jondeau, Guillaume; Collod-Beroud, Gwenaëlle; Beroud, Christophe; Amiel, Jeanne; Cormier-Daire, Valérie; Rivière, Jean-Baptiste; Boileau, Catherine; De Paepe, Anne; Faivre, Laurence

2012-11-02

Shprintzen-Goldberg syndrome (SGS) is characterized by severe marfanoid habitus, intellectual disability, camptodactyly, typical facial dysmorphism, and craniosynostosis. Using family-based exome sequencing, we identified a dominantly inherited heterozygous in-frame deletion in exon 1 of SKI. Direct sequencing of SKI further identified one overlapping heterozygous in-frame deletion and ten heterozygous missense mutations affecting recurrent residues in 18 of the 19 individuals screened for SGS; these individuals included one family affected by somatic mosaicism. All mutations were located in a restricted area of exon 1, within the R-SMAD binding domain of SKI. No mutation was found in a cohort of 11 individuals with other marfanoid-craniosynostosis phenotypes. The interaction between SKI and Smad2/3 and Smad 4 regulates TGF-β signaling, and the pattern of anomalies in Ski-deficient mice corresponds to the clinical manifestations of SGS. These findings define SGS as a member of the family of diseases associated with the TGF-β-signaling pathway. Copyright © 2012 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

Juvenile Paget’s Disease With Heterozygous Duplication In TNFRSF11A Encoding RANK

PubMed Central

Whyte, Michael P.; Tau, Cristina; McAlister, William H.; Zhang, Xiafang; Novack, Deborah V.; Preliasco, Virginia; Santini-Araujo, Eduardo; Mumm, Steven

2014-01-01

Mendelian disorders of RANKL/OPG/RANK signaling feature the extremes of aberrant osteoclastogenesis and cause either osteopetrosis or rapid turnover skeletal disease. The patients with autosomal dominant accelerated bone remodeling have familial expansile osteolysis, early-onset Paget’s disease of bone, expansile skeletal hyperphosphatasia, or panostotic expansile bone disease due to heterozygous 18-, 27-, 15-, and 12-bp insertional duplications, respectively, within exon 1 of TNFRSF11A that encodes the signal peptide of RANK. Juvenile Paget’s disease (JPD), an autosomal recessive disorder, manifests extremely fast skeletal remodeling, and is usually caused by loss-of-function mutations within TNFRSF11B that encodes OPG. These disorders are ultra-rare. A 13-year-old Bolivian girl was referred at age 3 years. One femur was congenitally short and curved. Then, both bowed. Deafness at age 2 years involved missing ossicles and eroded cochleas. Teeth often had absorbed roots, broke, and were lost. Radiographs had revealed acquired tubular bone widening, cortical thickening, and coarse trabeculation. Biochemical markers indicated rapid skeletal turnover. Histopathology showed accelerated remodeling with abundant osteoclasts. JPD was diagnosed. Immobilization from a femur fracture caused severe hypercalcemia that responded rapidly to pamidronate treatment followed by bone turnover marker and radiographic improvement. No TNFRSF11B mutation was found. Instead, a unique heterozygous 15-bp insertional tandem duplication (87dup15) within exon 1 of TNFRSF11A predicted the same pentapeptide extension of RANK that causes expansile skeletal hyperphosphatasia (84dup15). Single nucleotide polymorphisms in TNFRSF11A and TNFRSF11B possibly impacted her phenotype. Our findings: i) reveal that JPD can be associated with an activating mutation within TNFRSF11A, ii) expand the range and overlap of phenotypes among the mendelian disorders of RANK activation, and iii) call for mutation

The historical Coffin-Lowry syndrome family revisited: identification of two novel mutations of RPS6KA3 in three male patients.

PubMed

Nishimoto, Hiromi Koso; Ha, Kyungsoo; Jones, Julie R; Dwivedi, Alka; Cho, Hyun-Min; Layman, Lawrence C; Kim, Hyung-Goo

2014-09-01

Coffin-Lowry syndrome (CLS) is a rare X-linked dominant disorder characterized by intellectual disability, craniofacial abnormalities, short stature, tapering fingers, hypotonia, and skeletal malformations. CLS is caused by mutations in the Ribosomal Protein S6 Kinase, 90 kDa, Polypeptide 3 (RPS6KA3) gene located at Xp22.12, which encodes Ribosomal S6 Kinase 2 (RSK2). Here we analyzed RPS6KA3 in three unrelated CLS patients including one from the historical Coffin-Lowry syndrome family and found two novel mutations. To date, over 140 mutations in RPS6KA3 have been reported. However, the etiology of the very first familial case, which was described in 1971 by Lowry with detailed phenotype and coined the term CLS, has remained unknown. More than 40 years after the report, we succeeded in identifying deposited fibroblast cells from one patient of this historic family and found a novel heterozygous 216 bp in-frame deletion, encompassing exons 15 and 16 of RPS6KA3. Drop episodes in CLS patients were reported to be associated with truncating mutations deleting the C-terminal kinase domain (KD), and only one missense mutation and one single basepair duplication involving the C-terminal KD of RSK2 in the patients with drop episode have been reported thus far. Here we report the first in-frame deletion in C-terminal KD of RPS6KA3 in a CLS patient with drop episodes. © 2014 Wiley Periodicals, Inc.

WNT10A mutation results in severe tooth agenesis in a family of three sisters.

PubMed

Abid, M F; Simpson, M A; Barbosa, I A; Seppala, M; Irving, M; Sharpe, P T; Cobourne, M T

2018-06-21

To identify the genetic basis of severe tooth agenesis in a family of three affected sisters. A family of three sisters with severe tooth agenesis was recruited for whole-exome sequencing to identify potential genetic variation responsible for this penetrant phenotype. The unaffected father was tested for specific mutations using Sanger sequencing. Gene discovery was supplemented with in situ hybridization to localize gene expression during human tooth development. We report a nonsense heterozygous mutation in exon 2 of WNT10A c.321C>A[p.Cys107*] likely to be responsible for the severe tooth agenesis identified in this family through the creation of a premature stop codon, resulting in truncation of the amino acid sequence and therefore loss of protein function. In situ hybridization showed expression of WNT10A in odontogenic epithelium during the early and late stages of human primary tooth development. WNT10A has previously been associated with both syndromic and non-syndromic forms of tooth agenesis, and this report further expands our knowledge of genetic variation underlying non-syndromic forms of this condition. We also demonstrate expression of WNT10A in the epithelial compartment of human tooth germs during development. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

[Mutation analysis of FGFR3 gene in a family featuring hereditary dwarfism].

PubMed

Zhang, Qiong; Jiang, Hai-ou; Quan, Qing-li; Li, Jun; He, Ting; Huang, Xue-shuang

2011-12-01

To investigate the clinical symptoms and potential mutation in FGFR3 gene for a family featuring hereditary dwarfism in order to attain diagnosis and provide prenatal diagnosis. Five patients and two unaffected relatives from the family, in addition with 100 healthy controls, were recruited. Genome DNA was extracted. Exons 10 and 13 of the FGFR3 gene were amplified using polymerase chain reaction (PCR). PCR products were sequenced in both directions. All patients had similar features including short stature, short limbs, lumbar hyperlordosis but normal craniofacial features. A heterozygous mutation G1620T (N540K) was identified in the cDNA from all patients but not in the unaffected relatives and 100 control subjects. A heterozygous G380R mutation was excluded. The hereditary dwarfism featured by this family has been caused by hypochondroplasia (HCH) due to a N540K mutation in the FGFR3 gene.

The roles played by highly truncated splice variants of G protein-coupled receptors

PubMed Central

2012-01-01

Alternative splicing of G protein-coupled receptor (GPCR) genes greatly increases the total number of receptor isoforms which may be expressed in a cell-dependent and time-dependent manner. This increased diversity of cell signaling options caused by the generation of splice variants is further enhanced by receptor dimerization. When alternative splicing generates highly truncated GPCRs with less than seven transmembrane (TM) domains, the predominant effect in vitro is that of a dominant-negative mutation associated with the retention of the wild-type receptor in the endoplasmic reticulum (ER). For constitutively active (agonist-independent) GPCRs, their attenuated expression on the cell surface, and consequent decreased basal activity due to the dominant-negative effect of truncated splice variants, has pathological consequences. Truncated splice variants may conversely offer protection from disease when expression of co-receptors for binding of infectious agents to cells is attenuated due to ER retention of the wild-type co-receptor. In this review, we will see that GPCRs retained in the ER can still be functionally active but also that highly truncated GPCRs may also be functionally active. Although rare, some truncated splice variants still bind ligand and activate cell signaling responses. More importantly, by forming heterodimers with full-length GPCRs, some truncated splice variants also provide opportunities to generate receptor complexes with unique pharmacological properties. So, instead of assuming that highly truncated GPCRs are associated with faulty transcription processes, it is time to reassess their potential benefit to the host organism. PMID:22938630

Equivalence of truncated count mixture distributions and mixtures of truncated count distributions.

PubMed

Böhning, Dankmar; Kuhnert, Ronny

2006-12-01

This article is about modeling count data with zero truncation. A parametric count density family is considered. The truncated mixture of densities from this family is different from the mixture of truncated densities from the same family. Whereas the former model is more natural to formulate and to interpret, the latter model is theoretically easier to treat. It is shown that for any mixing distribution leading to a truncated mixture, a (usually different) mixing distribution can be found so that the associated mixture of truncated densities equals the truncated mixture, and vice versa. This implies that the likelihood surfaces for both situations agree, and in this sense both models are equivalent. Zero-truncated count data models are used frequently in the capture-recapture setting to estimate population size, and it can be shown that the two Horvitz-Thompson estimators, associated with the two models, agree. In particular, it is possible to achieve strong results for mixtures of truncated Poisson densities, including reliable, global construction of the unique NPMLE (nonparametric maximum likelihood estimator) of the mixing distribution, implying a unique estimator for the population size. The benefit of these results lies in the fact that it is valid to work with the mixture of truncated count densities, which is less appealing for the practitioner but theoretically easier. Mixtures of truncated count densities form a convex linear model, for which a developed theory exists, including global maximum likelihood theory as well as algorithmic approaches. Once the problem has been solved in this class, it might readily be transformed back to the original problem by means of an explicitly given mapping. Applications of these ideas are given, particularly in the case of the truncated Poisson family.

Extended mutation spectrum of Usher syndrome in Finland.

PubMed

Västinsalo, Hanna; Jalkanen, Reetta; Bergmann, Carsten; Neuhaus, Christine; Kleemola, Leenamaija; Jauhola, Liisa; Bolz, Hanno Jörn; Sankila, Eeva-Marja

2013-06-01

The Finnish distribution of clinical Usher syndrome (USH) types is 40% USH3, 34% USH1 and 12% USH2. All patients with USH3 carry the founder mutation in clarin 1 (CLRN1), whereas we recently reported three novel myosin VIIA (MYO7A) mutations in two unrelated patients with USH1. This study was carried out to further investigate the USH mutation spectrum in Finnish patients. We analysed samples from nine unrelated USH patients/families without known mutations and two USH3 families with atypically severe phenotype. The Asper Ophthalmics USH mutation chip was used to screen for known mutations and to evaluate the chip in molecular diagnostics of Finnish patients. The chip revealed a heterozygous usherin (USH2A) mutation, p.N346H, in one patient. Sequencing of MYO7A and/or USH2A in three index patients revealed two novel heterozygous mutations, p.R873W in MYO7A and c.14343+2T>C in USH2A. We did not identify definite pathogenic second mutations in the patients, but identified several probably nonpathogenic variations that may modify the disease phenotype. Possible digenism could not be excluded in two families segregating genomic variations in both MYO7A and USH2A, and two families with CLRN1 and USH2A. We conclude that there is considerable genetic heterogeneity of USH1 and USH2 in Finland, making molecular diagnostics and genetic counselling of patients and families challenging. © 2012 The Authors. Acta Ophthalmologica © 2012 Acta Ophthalmologica Scandinavica Foundation.

Null missense ABCR (ABCA4) mutations in a family with stargardt disease and retinitis pigmentosa.

PubMed

Shroyer, N F; Lewis, R A; Yatsenko, A N; Lupski, J R

2001-11-01

To determine the type of ABCR mutations that segregate in a family that manifests both Stargardt disease (STGD) and retinitis pigmentosa (RP), and the functional consequences of the underlying mutations. Direct sequencing of all 50 exons and flanking intronic regions of ABCR was performed for the STGD- and RP-affected relatives. RNA hybridization, Western blot analysis, and azido-adenosine triphosphate (ATP) labeling was used to determine the effect of disease-associated ABCR mutations in an in vitro assay system. Compound heterozygous missense mutations were identified in patients with STGD and RP. STGD-affected individual AR682-03 was compound heterozygous for the mutation 2588G-->C and a complex allele, [W1408R; R1640W]. RP-affected individuals AR682-04 and-05 were compound heterozygous for the complex allele [W1408R; R1640W] and the missense mutation V767D. Functional analysis of the mutation V767D by Western blot and ATP binding revealed a severe reduction in protein expression. In vitro analysis of ABCR protein with the mutations W1408R and R1640W showed a moderate effect of these individual mutations on expression and ATP-binding; the complex allele [W1408R; R1640W] caused a severe reduction in protein expression. These data reveal that missense ABCR mutations may be associated with RP. Functional analysis reveals that the RP-associated missense ABCR mutations are likely to be functionally null. These studies of the complex allele W1408R; R1640W suggest a synergistic effect of the individual mutations. These data are congruent with a model in which RP is associated with homozygous null mutations and with the notion that severity of retinal disease is inversely related to residual ABCR activity.

FANCA Gene Mutations with 8 Novel Molecular Changes in Indian Fanconi Anemia Patients.

PubMed

Solanki, Avani; Mohanty, Purvi; Shukla, Pallavi; Rao, Anita; Ghosh, Kanjaksha; Vundinti, Babu Rao

2016-01-01

Fanconi anemia (FA), a rare heterogeneous genetic disorder, is known to be associated with 19 genes and a spectrum of clinical features. We studied FANCA molecular changes in 34 unrelated and 2 siblings of Indian patients with FA and have identified 26 different molecular changes of FANCA gene, of which 8 were novel mutations (a small deletion c.2500delC, 4 non-sense mutations c.2182C>T, c.2630C>G, c.3677C>G, c.3189G>A; and 3 missense mutations; c.1273G>C, c.3679 G>C, and c.3992 T>C). Among these only 16 patients could be assigned FA-A complementation group, because we could not confirm single exon deletions detected by MLPA or cDNA amplification by secondary confirmation method and due to presence of heterozygous non-pathogenic variations or heterozygous pathogenic mutations. An effective molecular screening strategy should be developed for confirmation of these mutations and determining the breakpoints for single exon deletions.

FANCA Gene Mutations with 8 Novel Molecular Changes in Indian Fanconi Anemia Patients

PubMed Central

Solanki, Avani; Mohanty, Purvi; Shukla, Pallavi; Rao, Anita; Ghosh, Kanjaksha; Vundinti, Babu Rao

2016-01-01

Fanconi anemia (FA), a rare heterogeneous genetic disorder, is known to be associated with 19 genes and a spectrum of clinical features. We studied FANCA molecular changes in 34 unrelated and 2 siblings of Indian patients with FA and have identified 26 different molecular changes of FANCA gene, of which 8 were novel mutations (a small deletion c.2500delC, 4 non-sense mutations c.2182C>T, c.2630C>G, c.3677C>G, c.3189G>A; and 3 missense mutations; c.1273G>C, c.3679 G>C, and c.3992 T>C). Among these only 16 patients could be assigned FA-A complementation group, because we could not confirm single exon deletions detected by MLPA or cDNA amplification by secondary confirmation method and due to presence of heterozygous non-pathogenic variations or heterozygous pathogenic mutations. An effective molecular screening strategy should be developed for confirmation of these mutations and determining the breakpoints for single exon deletions. PMID:26799702

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

Genotypic and phenotypic analysis of 396 individuals with mutations in Sonic Hedgehog.

PubMed

Solomon, Benjamin D; Bear, Kelly A; Wyllie, Adrian; Keaton, Amelia A; Dubourg, Christele; David, Veronique; Mercier, Sandra; Odent, Sylvie; Hehr, Ute; Paulussen, Aimee; Clegg, Nancy J; Delgado, Mauricio R; Bale, Sherri J; Lacbawan, Felicitas; Ardinger, Holly H; Aylsworth, Arthur S; Bhengu, Ntombenhle Louisa; Braddock, Stephen; Brookhyser, Karen; Burton, Barbara; Gaspar, Harald; Grix, Art; Horovitz, Dafne; Kanetzke, Erin; Kayserili, Hulya; Lev, Dorit; Nikkel, Sarah M; Norton, Mary; Roberts, Richard; Saal, Howard; Schaefer, G B; Schneider, Adele; Smith, Erika K; Sowry, Ellen; Spence, M Anne; Shalev, Stavit A; Steiner, Carlos E; Thompson, Elizabeth M; Winder, Thomas L; Balog, Joan Z; Hadley, Donald W; Zhou, Nan; Pineda-Alvarez, Daniel E; Roessler, Erich; Muenke, Maximilian

2012-07-01

Holoprosencephaly (HPE), the most common malformation of the human forebrain, may result from mutations in over 12 genes. Sonic Hedgehog (SHH) was the first such gene discovered; mutations in SHH remain the most common cause of non-chromosomal HPE. The severity spectrum is wide, ranging from incompatibility with extrauterine life to isolated midline facial differences. To characterise genetic and clinical findings in individuals with SHH mutations. Through the National Institutes of Health and collaborating centres, DNA from approximately 2000 individuals with HPE spectrum disorders were analysed for SHH variations. Clinical details were examined and combined with published cases. This study describes 396 individuals, representing 157 unrelated kindreds, with SHH mutations; 141 (36%) have not been previously reported. SHH mutations more commonly resulted in non-HPE (64%) than frank HPE (36%), and non-HPE was significantly more common in patients with SHH than in those with mutations in the other common HPE related genes (p<0.0001 compared to ZIC2 or SIX3). Individuals with truncating mutations were significantly more likely to have frank HPE than those with non-truncating mutations (49% vs 35%, respectively; p=0.012). While mutations were significantly more common in the N-terminus than in the C-terminus (including accounting for the relative size of the coding regions, p=0.00010), no specific genotype-phenotype correlations could be established regarding mutation location. SHH mutations overall result in milder disease than mutations in other common HPE related genes. HPE is more frequent in individuals with truncating mutations, but clinical predictions at the individual level remain elusive.

A novel OPA1 mutation in a Chinese family with autosomal dominant optic atrophy

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

Zhang, Juanjuan; Yuan, Yimin; Lin, Bing

2012-03-23

Highlights: Black-Right-Pointing-Pointer We report the characterization of a four-generation large Chinese family with ADOA. Black-Right-Pointing-Pointer We find a new heterozygous mutation c.C1198G in OPA1 gene which may be a novel pathogenic mutation in this pedigree. Black-Right-Pointing-Pointer We do not find any mitochondrial DNA mutations associated with optic atrophy. Black-Right-Pointing-Pointer Other factors may also contribute to the phenotypic variability of ADOA in this pedigree. -- Abstract: A large four-generation Chinese family with autosomal dominant optic atrophy (ADOA) was investigated in the present study. Eight of the family members were affected in this pedigree. The affected family members exhibited early-onset and progressivemore » visual impairment, resulting in mild to profound loss of visual acuity. The average age-at-onset was 15.9 years. A new heterozygous mutation c.C1198G was identified by sequence analysis of the 12th exon of the OPA1 gene. This mutation resulted in a proline to alanine substitution at codon 400, which was located in an evolutionarily conserved region. This missense mutation in the GTPase domain was supposed to result in a loss of function for the encoded protein and act through a dominant negative effect. No other mutations associated with optic atrophy were found in our present study. The c.C1198G heterozygous mutation in the OPA1 gene may be a novel key pathogenic mutation in this pedigree with ADOA. Furthermore, additional nuclear modifier genes, environmental factors, and psychological factors may also contribute to the phenotypic variability of ADOA in this pedigree.« less

Comparative analyses of lung transcriptomes in patients with alveolar capillary dysplasia with misalignment of pulmonary veins and in foxf1 heterozygous knockout mice

USDA-ARS?s Scientific Manuscript database

Alveolar Capillary Dysplasia with Misalignment of Pulmonary Veins (ACDMPV) is a developmental disorder of the lungs, primarily affecting their vasculature. FOXF1 haploinsufficiency due to heterozygous genomic deletions and point mutations have been reported in most patients with ACDMPV. The majority...

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.

Novel compound heterozygous SPTA1 mutations in a patient with hereditary elliptocytosis

PubMed Central

Ma, Shiyue; Qin, Jinqiu; Wei, Aiqiu; Li, Xiaohong; Qin, Yuanyuan; Liao, Lin; Lin, Faquan

2018-01-01

Hereditaryelliptocytosis (HE) is a hereditary hemolytic disease, characterized by the presence of many elliptical erythrocytes in the peripheral blood that is caused by abnormal cytoskeletal proteins in the erythrocyte membrane. In the present study, a novel, causal HE mutation was reported. Routine blood examinations were performed on the proband and their family, and the fluorescence intensity of eosin-5-maleimide (EMA)-labeled erythrocytes was determined via flow cytometry. Subsequently, DNA was extracted from the peripheral blood of the proband and their family members, and amplified by quantitative polymerase chain reaction. The Sanger sequencing approach was used to determine and identify gene mutations, which were verified by matrix-assisted laser desorption-ionization time of flight (MALDI-TOF) mass spectrometry. To exclude genetic polymorphisms, newly identified mutations were subjected to large-scale gene screening using high-resolution melt analysis. Protein expression levels in the erythrocyte membrane of the proband were determined via SDS-PAGE, which demonstrated that, compared with healthy controls, the proband exhibited a reduction in EMA-labeled erythrocytes. In addition, DNA analysis demonstrated that the proband carried three mutations in the spectrin α chain erythrocytic 1 (SPTA1) gene: c.161A>C, c.5572C>G and 6531-12C>T. The corresponding mutant polypeptides were also analyzed by MALDI-TOF mass spectroscopy. SDS-PAGE analysis indicated that the proband exhibited normal levels of erythrocyte membrane proteins. In the present study, a novel HE case with a His54Pro mutation in the SPTA1 gene was reported. The results suggested that the His54Pro mutation influenced the role of erythrocyte membrane proteins without reducing its level of expression. PMID:29484404

FAK-heterozygous mice display enhanced tumour angiogenesis.

PubMed

Kostourou, Vassiliki; Lechertier, Tanguy; Reynolds, Louise E; Lees, Delphine M; Baker, Marianne; Jones, Dylan T; Tavora, Bernardo; Ramjaun, Antoine R; Birdsey, Graeme M; Robinson, Stephen D; Parsons, Maddy; Randi, Anna M; Hart, Ian R; Hodivala-Dilke, Kairbaan

2013-01-01

Genetic ablation of endothelial focal adhesion kinase (FAK) can inhibit pathological angiogenesis, suggesting that loss of endothelial FAK is sufficient to reduce neovascularization. Here we show that reduced stromal FAK expression in FAK-heterozygous mice unexpectedly enhances both B16F0 and CMT19T tumour growth and angiogenesis. We further demonstrate that cell proliferation and microvessel sprouting, but not migration, are increased in serum-stimulated FAK-heterozygous endothelial cells. FAK-heterozygous endothelial cells display an imbalance in FAK phosphorylation at pY397 and pY861 without changes in Pyk2 or Erk1/2 activity. By contrast, serum-stimulated phosphorylation of Akt is enhanced in FAK-heterozygous endothelial cells and these cells are more sensitive to Akt inhibition. Additionally, low doses of a pharmacological FAK inhibitor, although too low to affect FAK autophosphorylation in vitro, can enhance angiogenesis ex vivo and tumour growth in vivo. Our results highlight a potential novel role for FAK as a nonlinear, dose-dependent regulator of angiogenesis where heterozygous levels of FAK enhance angiogenesis.

FAK-heterozygous mice display enhanced tumour angiogenesis

PubMed Central

Kostourou, Vassiliki; Lechertier, Tanguy; Reynolds, Louise E.; Lees, Delphine M.; Baker, Marianne; Jones, Dylan T.; Tavora, Bernardo; Ramjaun, Antoine R.; Birdsey, Graeme M.; Robinson, Stephen D.; Parsons, Maddy; Randi, Anna M.; Hart, Ian R; Hodivala-Dilke, Kairbaan

2013-01-01

Genetic ablation of endothelial Focal Adhesion Kinase (FAK) can inhibit pathological angiogenesis, suggesting that loss of endothelial FAK is sufficient to reduce neovascularisation. Here we show that reduced stromal-FAK expression in FAK-heterozygous mice unexpectedly enhances both B16F0 and CMT19T tumour growth and angiogenesis. We further demonstrate that cell proliferation and microvessel sprouting, but not migration, are increased in serum-stimulated FAK-heterozygous endothelial cells. FAK-heterozygous endothelial cells display an imbalance in FAK phosphorylation at pY397 and pY861 without changes in Pyk2 or Erk1/2 activity. By contrast, serum-stimulated phosphorylation of Akt is enhanced in FAK-heterozygous endothelial cells and these cells are more sensitive to Akt inhibition. Additionally, low doses of a pharmacological FAK inhibitor, although too low to affect FAK autophosphorylation in vitro, can enhance angiogenesis ex vivo and tumor growth in vivo. Our results highlight a potential novel role for FAK as a non-linear, dose-dependent regulator of angiogenesis where heterozygous levels of FAK enhance angiogenesis. PMID:23799510

[Analysis of clinical phenotype and genetic mutations of a pedigree of familial hemophagocytic lymphohistiocytosis].

PubMed

Sun, Shuwen; Guo, Xia; Zhu, Yiping; Yang, Xue; Li, Qiang; Gao, Ju

2014-10-01

To analyze mutations in a pedigree of familial hemophagocytic lymphohistiocytosis (FHLH) from Sichuan and provide genetic counseling for the family. Clinical data of a case with FHLH diagnosed at West China Second Hospital was retrospectively analyzed. Genomic DNA was extracted from peripheral blood samples of the proband and his family members. Eight candidate genes for primary HLH were amplified with PCR and analyzed by direct sequencing. The proband was diagnosed as HLH based on clinical manifestations of recurrent fever for 2 months, hepatosplenomegaly, lymphadenopathy, pancytopenia, hyperferritinemia, and decreased fibrinogen and hemophagocytosis in bone marrow. Genetic testing for primary HLH was carried out considering the relapse of illness after hormone therapy for 8 weeks and the family history. The results of gene sequencing showed that the proband has carried compound heterozygous mutations in PRF1 gene (c.1349C> T in exon 3 and c.445G> A in exon 2). His father has carried a heterozygous mutation (c.445G> A in exon 2) and nonsense mutation (c.900C> T in exon 3), and his mother carried a heterozygous mutation (c.1349C> T in exon 3). Both c.1349C> T and c.445G> A have been previously reported as pathogenic mutations. The family has been diagnosed as familial HLH type 2 based on clinical and laboratory examinations and molecular genetic testing. Gene sequencing has indicated that is was a recessive type familial HLH.

The identification of HESX1 mutations in Kallmann syndrome

PubMed Central

Newbern, Kayce; Natrajan, Nithya; Kim, Hyung-Goo; Chorich, Lynn .P.; Halvorson, Lisa; Cameron, Richard S.; Layman, Lawrence C.

2013-01-01

Objective To determine if HESX1 mutations are present in patients with idiopathic hypogonadotropic hypogonadism (IHH)/Kallmann syndrome (KS). HESX1 mutations have previously been characterized in patients with septo-optic dysplasia (SOD), isolated growth hormone deficiency (IGHD), and combined pituitary hormone deficiency (CPHD). We hypothesized that IHH/KS represents a milder phenotypic variant of SOD. Design PCR-based DNA sequencing was performed on 217 well-characterized IHH/KS patients. Putative missense mutations were analyzed by sorting intolerant from tolerant (SIFT) and Clustal Ω. Setting An academic medical center Patients 217 IHH/KS and 192 controls Interventions DNA was extracted from patients and controls; genotype/phenotype comparisons were made Main Outcome Measures DNA sequence of HESX1, SIFT analysis, and ortholog alignment Results Two novel heterozygous missense mutations (p.H42Y and p.V75L) and previously reported heterozygous missense mutation p.Q6H in HESX1 were identified in 3/217 (1.4%) patients. All were males with KS. Both p.Q6H and p.H42Y were predicted to be deleterious by SIFT, while p.V75L was conserved in 8/9 species. No other IHH/KS gene mutations were present. Conclusions HESX1 mutations may cause KS in addition to more severe phenotypes. Our findings expand the phenotypic spectrum of HESX1 mutations in humans, thereby broadening its role in development. PMID:23465708

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.

[Genetic mutation and clinical features of osteogenesis imperfecta type V].

PubMed

Guan, Shizhen; Bai, Xue; Wang, Yi; Liu, Zhigang; Ren, Xiuzhi; Zhang, Tianke; Ju, Mingyan; Li, Keqiu; Li, Guang

2017-12-10

To explore genetic mutations and clinical features of osteogenesis imperfecta type V. Clinical record of five patients (including one familial case) with osteogenesis imperfecta type V were retrospectively analyzed. Peripheral blood samples of the patients, one family member, as well as healthy controls were collected. Mutation of IFITM5 gene was identified by PCR amplification and Sanger sequencing. A heterozygous mutation (c.-14C>T) in the 5-UTR of the IFITM5 gene was identified in all of the patients and one mother. The clinical findings included frequent fractures and spine and/or extremities deformities, absence of dentinogenesis imperfecta, absence of hearing impairment, and blue sclera in 1 case. Radiographic findings revealed calcification of the interosseous membrane between the radius-ulna in all cases. Hyperplastic callus formation was found in 3 cases. Four had radial-head dislocation. A single heterozygous mutation c.-14C>T was found in the 5-UTR of the IFITM5 gene in 5 patients with osteogensis imperfecta type V. The patients showed specific radiological features including calcification of interosseous membrane, hyperplastic callus formation, and radial-head dislocation.

A novel DARS2 mutation in a Japanese patient with leukoencephalopathy with brainstem and spinal cord involvement but no lactate elevation

PubMed Central

Shimojima, Keiko; Higashiguchi, Takafumi; Kishimoto, Kanako; Miyatake, Satoko; Miyake, Noriko; Takanashi, Jun-ichi; Matsumoto, Naomichi; Yamamoto, Toshiyuki

2017-01-01

The mitochondrial aspartyl-tRNA synthetase 2 gene (DARS2) is responsible for leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL). A Japanese patient with LBSL showed compound heterozygous DARS2 mutations c.358_359delinsTC (p.Gly120Ser) and c.228-15C>G (splicing error). This provides further evidence that most patients with LBSL show compound heterozygous mutations in DARS2 in association with a common splicing mutation in the splicing acceptor site of intron 2. PMID:29138691

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.

Foxp2 mutations impair auditory-motor association learning.

PubMed

Kurt, Simone; Fisher, Simon E; Ehret, Günter

2012-01-01

Heterozygous mutations of the human FOXP2 transcription factor gene cause the best-described examples of monogenic speech and language disorders. Acquisition of proficient spoken language involves auditory-guided vocal learning, a specialized form of sensory-motor association learning. The impact of etiological Foxp2 mutations on learning of auditory-motor associations in mammals has not been determined yet. Here, we directly assess this type of learning using a newly developed conditioned avoidance paradigm in a shuttle-box for mice. We show striking deficits in mice heterozygous for either of two different Foxp2 mutations previously implicated in human speech disorders. Both mutations cause delays in acquiring new motor skills. The magnitude of impairments in association learning, however, depends on the nature of the mutation. Mice with a missense mutation in the DNA-binding domain are able to learn, but at a much slower rate than wild type animals, while mice carrying an early nonsense mutation learn very little. These results are consistent with expression of Foxp2 in distributed circuits of the cortex, striatum and cerebellum that are known to play key roles in acquisition of motor skills and sensory-motor association learning, and suggest differing in vivo effects for distinct variants of the Foxp2 protein. Given the importance of such networks for the acquisition of human spoken language, and the fact that similar mutations in human FOXP2 cause problems with speech development, this work opens up a new perspective on the use of mouse models for understanding pathways underlying speech and language disorders.

Infantile Alexander Disease: Spectrum of GFAP Mutations and Genotype-Phenotype Correlation

PubMed Central

Rodriguez, Diana; Gauthier, Fernande; Bertini, Enrico; Bugiani, Marianna; Brenner, Michael; N'guyen, Sylvie; Goizet, Cyril; Gelot, Antoinette; Surtees, Robert; Pedespan, Jean-Michel; Hernandorena, Xavier; Troncoso, Monica; Uziel, Graziela; Messing, Albee; Ponsot, Gérard; Pham-Dinh, Danielle; Dautigny, André; Boespflug-Tanguy, Odile

2001-01-01

Heterozygous, de novo mutations in the glial fibrillary acidic protein (GFAP) gene have recently been reported in 12 patients affected by neuropathologically proved Alexander disease. We searched for GFAP mutations in a series of patients who had heterogeneous clinical symptoms but were candidates for Alexander disease on the basis of suggestive neuroimaging abnormalities. Missense, heterozygous, de novo GFAP mutations were found in exons 1 or 4 for 14 of the 15 patients analyzed, including patients without macrocephaly. Nine patients carried arginine mutations (four had R79H; four had R239C; and one had R239H) that have been described elsewhere, whereas the other five had one of four novel mutations, of which two affect arginine (2R88C and 1R88S) and two affect nonarginine residues (1L76F and 1N77Y). All mutations were located in the rod domain of GFAP, and there is a correlation between clinical severity and the affected amino acid. These results confirm that GFAP mutations are a reliable molecular marker for the diagnosis of infantile Alexander disease, and they also form a basis for the recommendation of GFAP analysis for prenatal diagnosis to detect potential cases of germinal mosaicism. PMID:11567214

A novel homozygous Fas ligand mutation leads to early protein truncation, abrogation of death receptor and reverse signaling and a severe form of the autoimmune lymphoproliferative syndrome.

PubMed

Nabhani, Schafiq; Hönscheid, Andrea; Oommen, Prasad T; Fleckenstein, Bernhard; Schaper, Jörg; Kuhlen, Michaela; Laws, Hans-Jürgen; Borkhardt, Arndt; Fischer, Ute

2014-12-01

We report a novel type of mutation in the death ligand FasL that was associated with a severe phenotype of the autoimmune lymphoproliferative syndrome in two patients. A frameshift mutation in the intracellular domain led to complete loss of FasL expression. Cell death signaling via its receptor and reverse signaling via its intracellular domain were completely abrogated. In vitro lymphocyte proliferation induced by weak T cell receptor stimulation could be blocked and cell death was induced by engagement of FasL in T cells derived from healthy individuals and a heterozygous carrier, but not in FasL-deficient patient derived cells. Expression of genes implicated in lymphocyte proliferation and activation (CCND1, NFATc1, NF-κB1) was increased in FasL-deficient T cells and could not be downregulated by FasL engagement as in healthy cells. Our data thus suggest, that deficiency in FasL reverse signaling may contribute to the clinical lymphoproliferative phenotype of ALPS. Copyright © 2014 Elsevier Inc. All rights reserved.

A novel WFS1 mutation in a family with dominant low frequency sensorineural hearing loss with normal VEMP and EcochG findings

PubMed Central

Bramhall, Naomi F; Kallman, Jeremy C; Verrall, Aimee M; Street, Valerie A

2008-01-01

Background Low frequency sensorineural hearing loss (LFSNHL) is an uncommon clinical finding. Mutations within three different identified genes (DIAPH1, MYO7A, and WFS1) are known to cause LFSNHL. The majority of hereditary LFSNHL is associated with heterozygous mutations in the WFS1 gene (wolframin protein). The goal of this study was to use genetic analysis to determine if a small American family's hereditary LFSNHL is linked to a mutation in the WFS1 gene and to use VEMP and EcochG testing to further characterize the family's audiovestibular phenotype. Methods The clinical phenotype of the American family was characterized by audiologic testing, vestibular evoked myogenic potentials (VEMP), and electrocochleography (EcochG) evaluation. Genetic characterization was performed by microsatellite analysis and direct sequencing of WFS1 for mutation detection. Results Sequence analysis of the WFS1 gene revealed a novel heterozygous mutation at c.2054G>C predicting a p.R685P amino acid substitution in wolframin. The c.2054G>C mutation segregates faithfully with hearing loss in the family and is absent in 230 control chromosomes. The p.R685 residue is located within the hydrophilic C-terminus of wolframin and is conserved across species. The VEMP and EcochG findings were normal in individuals segregating the WFS1 c.2054G>C mutation. Conclusion We discovered a novel heterozygous missense mutation in exon 8 of WFS1 predicting a p.R685P amino acid substitution that is likely to underlie the LFSNHL phenotype in the American family. For the first time, we describe VEMP and EcochG findings for individuals segregating a heterozygous WFS1 mutation. PMID:18518985

A novel WFS1 mutation in a family with dominant low frequency sensorineural hearing loss with normal VEMP and EcochG findings.

PubMed

Bramhall, Naomi F; Kallman, Jeremy C; Verrall, Aimee M; Street, Valerie A

2008-06-02

Low frequency sensorineural hearing loss (LFSNHL) is an uncommon clinical finding. Mutations within three different identified genes (DIAPH1, MYO7A, and WFS1) are known to cause LFSNHL. The majority of hereditary LFSNHL is associated with heterozygous mutations in the WFS1 gene (wolframin protein). The goal of this study was to use genetic analysis to determine if a small American family's hereditary LFSNHL is linked to a mutation in the WFS1 gene and to use VEMP and EcochG testing to further characterize the family's audiovestibular phenotype. The clinical phenotype of the American family was characterized by audiologic testing, vestibular evoked myogenic potentials (VEMP), and electrocochleography (EcochG) evaluation. Genetic characterization was performed by microsatellite analysis and direct sequencing of WFS1 for mutation detection. Sequence analysis of the WFS1 gene revealed a novel heterozygous mutation at c.2054G>C predicting a p.R685P amino acid substitution in wolframin. The c.2054G>C mutation segregates faithfully with hearing loss in the family and is absent in 230 control chromosomes. The p.R685 residue is located within the hydrophilic C-terminus of wolframin and is conserved across species. The VEMP and EcochG findings were normal in individuals segregating the WFS1 c.2054G>C mutation. We discovered a novel heterozygous missense mutation in exon 8 of WFS1 predicting a p.R685P amino acid substitution that is likely to underlie the LFSNHL phenotype in the American family. For the first time, we describe VEMP and EcochG findings for individuals segregating a heterozygous WFS1 mutation.

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.

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

An initiator codon mutation in SDE2 causes recessive embryonic lethality in Holstein cattle.

PubMed

Fritz, Sébastien; Hoze, Chris; Rebours, Emmanuelle; Barbat, Anne; Bizard, Méline; Chamberlain, Amanda; Escouflaire, Clémentine; Vander Jagt, Christy; Boussaha, Mekki; Grohs, Cécile; Allais-Bonnet, Aurélie; Philippe, Maëlle; Vallée, Amélie; Amigues, Yves; Hayes, Benjamin J; Boichard, Didier; Capitan, Aurélien

2018-04-18

Researching depletions in homozygous genotypes for specific haplotypes among the large cohorts of animals genotyped for genomic selection is a very efficient strategy to map recessive lethal mutations. In this study, by analyzing real or imputed Illumina BovineSNP50 (Illumina Inc., San Diego, CA) genotypes from more than 250,000 Holstein animals, we identified a new locus called HH6 showing significant negative effects on conception rate and nonreturn rate at 56 d in at-risk versus control mating. We fine-mapped this locus in a 1.1-Mb interval and analyzed genome sequence data from 12 carrier and 284 noncarrier Holstein bulls. We report the identification of a strong candidate mutation in the gene encoding SDE2 telomere maintenance homolog (SDE2), a protein essential for genomic stability in eukaryotes. This A-to-G transition changes the initiator ATG (methionine) codon to ACG because the gene is transcribed on the reverse strand. Using RNA sequencing and quantitative reverse-transcription PCR, we demonstrated that this mutation does not significantly affect SDE2 splicing and expression level in heterozygous carriers compared with control animals. Initiation of translation at the closest in-frame methionine codon would truncate the SDE2 precursor by 83 amino acids, including the cleavage site necessary for its activation. Finally, no homozygote for the G allele was observed in a large population of nearly 29,000 individuals genotyped for the mutation. The low frequency (1.3%) of the derived allele in the French population and the availability of a diagnostic test on the Illumina EuroG10K SNP chip routinely used for genomic evaluation will enable rapid and efficient selection against this deleterious mutation. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Additive loss-of-function proteasome subunit mutations in CANDLE/PRAAS patients promote type I IFN production

PubMed Central

Brehm, Anja; Liu, Yin; Sheikh, Afzal; Marrero, Bernadette; Omoyinmi, Ebun; Zhou, Qing; Montealegre, Gina; Biancotto, Angelique; Reinhardt, Adam; Almeida de Jesus, Adriana; Pelletier, Martin; Tsai, Wanxia L.; Remmers, Elaine F.; Kardava, Lela; Hill, Suvimol; Kim, Hanna; Lachmann, Helen J.; Megarbane, Andre; Chae, Jae Jin; Brady, Jilian; Castillo, Rhina D.; Brown, Diane; Casano, Angel Vera; Gao, Ling; Chapelle, Dawn; Huang, Yan; Stone, Deborah; Chen, Yongqing; Sotzny, Franziska; Lee, Chyi-Chia Richard; Kastner, Daniel L.; Torrelo, Antonio; Zlotogorski, Abraham; Moir, Susan; Gadina, Massimo; McCoy, Phil; Wesley, Robert; Rother, Kristina; Hildebrand, Peter W.; Brogan, Paul; Krüger, Elke; Aksentijevich, Ivona; Goldbach-Mansky, Raphaela

2015-01-01

Autosomal recessive mutations in proteasome subunit β 8 (PSMB8), which encodes the inducible proteasome subunit β5i, cause the immune-dysregulatory disease chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperature (CANDLE), which is classified as a proteasome-associated autoinflammatory syndrome (PRAAS). Here, we identified 8 mutations in 4 proteasome genes, PSMA3 (encodes α7), PSMB4 (encodes β7), PSMB9 (encodes β1i), and proteasome maturation protein (POMP), that have not been previously associated with disease and 1 mutation in PSMB8 that has not been previously reported. One patient was compound heterozygous for PSMB4 mutations, 6 patients from 4 families were heterozygous for a missense mutation in 1 inducible proteasome subunit and a mutation in a constitutive proteasome subunit, and 1 patient was heterozygous for a POMP mutation, thus establishing a digenic and autosomal dominant inheritance pattern of PRAAS. Function evaluation revealed that these mutations variably affect transcription, protein expression, protein folding, proteasome assembly, and, ultimately, proteasome activity. Moreover, defects in proteasome formation and function were recapitulated by siRNA-mediated knockdown of the respective subunits in primary fibroblasts from healthy individuals. Patient-isolated hematopoietic and nonhematopoietic cells exhibited a strong IFN gene-expression signature, irrespective of genotype. Additionally, chemical proteasome inhibition or progressive depletion of proteasome subunit gene transcription with siRNA induced transcription of type I IFN genes in healthy control cells. Our results provide further insight into CANDLE genetics and link global proteasome dysfunction to increased type I IFN production. PMID:26524591

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.

Heterozygous inactivation of tsc2 enhances tumorigenesis in p53 mutant zebrafish

PubMed Central

Kim, Seok-Hyung; Kowalski, Marie L.; Carson, Robert P.; Bridges, L. Richard; Ess, Kevin C.

2013-01-01

SUMMARY Tuberous sclerosis complex (TSC) is a multi-organ disorder caused by mutations of the TSC1 or TSC2 genes. A key function of these genes is to inhibit mTORC1 (mechanistic target of rapamycin complex 1) kinase signaling. Cells deficient for TSC1 or TSC2 have increased mTORC1 signaling and give rise to benign tumors, although, as a rule, true malignancies are rarely seen. In contrast, other disorders with increased mTOR signaling typically have overt malignancies. A better understanding of genetic mechanisms that govern the transformation of benign cells to malignant ones is crucial to understand cancer pathogenesis. We generated a zebrafish model of TSC and cancer progression by placing a heterozygous mutation of the tsc2 gene in a p53 mutant background. Unlike tsc2 heterozygous mutant zebrafish, which never exhibited cancers, compound tsc2;p53 mutants had malignant tumors in multiple organs. Tumorigenesis was enhanced compared with p53 mutant zebrafish. p53 mutants also had increased mTORC1 signaling that was further enhanced in tsc2;p53 compound mutants. We found increased expression of Hif1-α, Hif2-α and Vegf-c in tsc2;p53 compound mutant zebrafish compared with p53 mutant zebrafish. Expression of these proteins probably underlies the increased angiogenesis seen in compound mutant zebrafish compared with p53 mutants and might further drive cancer progression. Treatment of p53 and compound mutant zebrafish with the mTORC1 inhibitor rapamycin caused rapid shrinkage of tumor size and decreased caliber of tumor-associated blood vessels. This is the first report using an animal model to show interactions between tsc2, mTORC1 and p53 during tumorigenesis. These results might explain why individuals with TSC rarely have malignant tumors, but also suggest that cancer arising in individuals without TSC might be influenced by the status of TSC1 and/or TSC2 mutations and be potentially treatable with mTORC1 inhibitors. PMID:23580196

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.

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

Multigeneration family with dominant SPG30 hereditary spastic paraplegia.

PubMed

Roda, Ricardo H; Schindler, Alice B; Blackstone, Craig

2017-11-01

Autosomal recessive KIF1A missense mutations cause hereditary spastic paraplegia (HSP) type SPG30, while recessive truncations lead to sensory and autonomic neuropathy (HSN2C) and many de novo missense mutations are associated with cognitive impairment. Here, we describe family members across three generations with pure HSP. A heterozygous p.Ser69Leu KIF1A mutation segregates with those afflicted. The same variant was previously reported in a Finnish father and son with pure HSP as well as four members of a Sicilian kindred with more intrafamilial phenotypic variability. This further validates the pathogenicity of the p.Ser69Leu mutation and suggests that it may represent a mutation hot spot.

[Clinical classification and genetic mutation study of two pedigrees with type II Waardenburg syndrome].

PubMed

Chen, Yong; Yang, Fuwei; Zheng, Hexin; Zhu, Ganghua; Hu, Peng; Wu, Weijing

2015-12-01

To explore the molecular etiology of two pedigrees affected with type II Waardenburg syndrome (WS2) and to provide genetic diagnosis and counseling. Blood samples were collected from the proband and his family members. Following extraction of genomic DNA, the coding sequences of PAX3, MITF, SOX10 and SNAI2 genes were amplified with PCR and subjected to DNA sequencing to detect potential mutations. A heterozygous deletional mutation c.649_651delAGA in exon 7 of the MITF gene has been identified in all patients from the first family, while no mutation was found in the other WS2 related genes including PAX3, MITF, SOX10 and SNAI2. The heterozygous deletion mutation c.649_651delAGA in exon 7 of the MITF gene probably underlies the disease in the first family. It is expected that other genes may also underlie WS2.

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.

New insights into thyroglobulin gene: molecular analysis of seven novel mutations associated with goiter and hypothyroidism.

PubMed

Citterio, Cintia E; Machiavelli, Gloria A; Miras, Mirta B; Gruñeiro-Papendieck, Laura; Lachlan, Katherine; Sobrero, Gabriela; Chiesa, Ana; Walker, Joanna; Muñoz, Liliana; Testa, Graciela; Belforte, Fiorella S; González-Sarmiento, Rogelio; Rivolta, Carina M; Targovnik, Héctor M

2013-01-30

The thyroglobulin (TG) gene is organized in 48 exons, spanning over 270 kb on human chromosome 8q24. Up to now, 62 inactivating mutations in the TG gene have been identified in patients with congenital goiter and endemic or non-endemic simple goiter. The purpose of the present study was to identify and characterize new mutations in the TG gene. We report 13 patients from seven unrelated families with goiter, hypothyroidism and low levels of serum TG. All patients underwent clinical, biochemical and imaging evaluation. Single-strand conformation polymorphism (SSCP) analysis, endonuclease restriction analysis, sequencing of DNA, genotyping, population screening, and bioinformatics studies were performed. Molecular analyses revealed seven novel inactivating TG mutations: c.378C>A [p.Y107X], c.2359C>T [p.R768X], c.2736delG [p.R893fsX946], c.3842G>A [p.C1262Y], c.5466delA [p.K1803fsX1833], c.6000C>G [p.C1981W] and c.6605C>G [p.P2183R] and three previously reported mutations: c.886C>T [p.R277X], c.6701C>A [p.A2215D] and c.7006C>T [p.R2317X]. Six patients from two families were homozygous for p.R277X mutation, four were compound heterozygous mutations (p.Y107X/p.C1262Y, p.R893fsX946/p.A2215D, p.K1803fsX1832/p.R2317X), one carried three identified mutations (p.R277X/p.C1981W-p.P2183R) together with a hypothetical micro deletion and the remaining two siblings from another family with typical phenotype had a single p.R768X mutated allele. In conclusion, our results confirm the genetic heterogeneity of TG defects and the pathophysiological importance of altered TG folding as a consequency of truncated TG proteins and missense mutations located in ACHE-like domain or that replace cysteine. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Remarkable stabilization of a psychrotrophic RNase HI by a combination of thermostabilizing mutations identified by the suppressor mutation method.

PubMed

Tadokoro, Takashi; Matsushita, Kyoko; Abe, Yumi; Rohman, Muhammad Saifur; Koga, Yuichi; Takano, Kazufumi; Kanaya, Shigenori

2008-08-05

Ribonuclease HI from the psychrotrophic bacterium Shewanella oneidensis MR-1 (So-RNase HI) is much less stable than Escherichia coli RNase HI (Ec-RNase HI) by 22.4 degrees C in T m and 12.5 kJ mol (-1) in Delta G(H 2O), despite their high degrees of structural and functional similarity. To examine whether the stability of So-RNase HI increases to a level similar to that of Ec-RNase HI via introduction of several mutations, the mutations that stabilize So-RNase HI were identified by the suppressor mutation method and combined. So-RNase HI and its variant with a C-terminal four-residue truncation (154-RNase HI) complemented the RNase H-dependent temperature-sensitive (ts) growth phenotype of E. coli strain MIC3001, while 153-RNase HI with a five-residue truncation could not. Analyses of the activity and stability of these truncated proteins suggest that 153-RNase HI is nonfunctional in vivo because of a great decrease in stability. Random mutagenesis of 153-RNase HI using error-prone PCR, followed by screening for the revertants, allowed us to identify six single suppressor mutations that make 153-RNase HI functional in vivo. Four of them markedly increased the stability of the wild-type protein by 3.6-6.7 degrees C in T m and 1.7-5.2 kJ mol (-1) in Delta G(H 2O). The effects of these mutations were nearly additive, and combination of these mutations increased protein stability by 18.7 degrees C in T m and 12.2 kJ mol (-1) in Delta G(H 2O). These results suggest that several residues are not optimal for the stability of So-RNase HI, and their replacement with other residues strikingly increases it to a level similar to that of the mesophilic counterpart.

A Foxp2 Mutation Implicated in Human Speech Deficits Alters Sequencing of Ultrasonic Vocalizations in Adult Male Mice.

PubMed

Chabout, Jonathan; Sarkar, Abhra; Patel, Sheel R; Radden, Taylor; Dunson, David B; Fisher, Simon E; Jarvis, Erich D

2016-01-01

Development of proficient spoken language skills is disrupted by mutations of the FOXP2 transcription factor. A heterozygous missense mutation in the KE family causes speech apraxia, involving difficulty producing words with complex learned sequences of syllables. Manipulations in songbirds have helped to elucidate the role of this gene in vocal learning, but findings in non-human mammals have been limited or inconclusive. Here, we performed a systematic study of ultrasonic vocalizations (USVs) of adult male mice carrying the KE family mutation. Using novel statistical tools, we found that Foxp2 heterozygous mice did not have detectable changes in USV syllable acoustic structure, but produced shorter sequences and did not shift to more complex syntax in social contexts where wildtype animals did. Heterozygous mice also displayed a shift in the position of their rudimentary laryngeal motor cortex (LMC) layer-5 neurons. Our findings indicate that although mouse USVs are mostly innate, the underlying contributions of FoxP2 to sequencing of vocalizations are conserved with humans.

Newborn screening of glucose-6-phosphate dehydrogenase deficiency in Guangxi, China: determination of optimal cutoff value to identify heterozygous female neonates.

PubMed

Fu, Chunyun; Luo, Shiyu; Li, Qifei; Xie, Bobo; Yang, Qi; Geng, Guoxing; Lin, Caijuan; Su, Jiasun; Zhang, Yue; Wang, Jin; Qin, Zailong; Luo, Jingsi; Chen, Shaoke; Fan, Xin

2018-01-16

The aim of this study is to assess the disease incidence and mutation spectrum of glucose-6-phosphate dehydrogenase (G6PD) deficiency in Guangxi, China, and to determine an optimal cutoff value to identify heterozygous female neonates. A total of 130, 635 neonates were screened from the year of 2013 to 2017. Neonates suspected for G6PD deficiency were further analyzed by quantitatively enzymatic assay and G6PD mutation analysis. The overall incidence of G6PD deficiency was 7.28%. A total of 14 G6PD mutations were identified, and different mutations lead to varying levels of G6PD enzymatic activities. The best cut-off value of G6PD activity in male subjects is 2.2 U/g Hb, same as conventional setting. In female population, however, the cut-off value is found to be 2.8 U/g Hb (sensitivity: 97.5%, specificity: 87.7%, AUC: 0.964) to best discriminate between normal and heterozygotes, and 1.6 U/g Hb (sensitivity: 82.2%, specificity: 85.9%, AUC: 0.871) between heterozygotes and deficient subjects. In conclusion, we have conducted a comprehensive newborn screening of G6PD deficiency in a large cohort of population from Guangxi, China, and first established a reliable cut-off value of G6PD activity to distinguish heterozygous females from either normal or deficient subjects.

A de novo deletion mutation in SOX10 in a Chinese family with Waardenburg syndrome type 4.

PubMed

Wang, Xiong; Zhu, Yaowu; Shen, Na; Peng, Jing; Wang, Chunyu; Liu, Haiyi; Lu, Yanjun

2017-01-27

Waardenburg syndrome type 4 (WS4) or Waardenburg-Shah syndrome is a rare genetic disorder with a prevalence of <1/1,000,000 and characterized by the association of congenital sensorineural hearing loss, pigmentary abnormalities, and intestinal aganglionosis. There are three types of WS4 (WS4A-C) caused by mutations in endothelin receptor type B, endothelin 3, and SRY-box 10 (SOX10), respectively. This study investigated a genetic mutation in a Chinese family with one WS4 patient in order to improve genetic counselling. Genomic DNA was extracted, and mutation analysis of the three WS4 related genes was performed using Sanger sequencing. We detected a de novo heterozygous deletion mutation [c.1333delT (p.Ser445Glnfs*57)] in SOX10 in the patient; however, this mutation was absent in the unaffected parents and 40 ethnicity matched healthy controls. Subsequent phylogenetic analysis and three-dimensional modelling of the SOX10 protein confirmed that the c.1333delT heterozygous mutation was pathogenic, indicating that this mutation might constitute a candidate disease-causing mutation.

A de novo deletion mutation in SOX10 in a Chinese family with Waardenburg syndrome type 4

PubMed Central

Wang, Xiong; Zhu, Yaowu; Shen, Na; Peng, Jing; Wang, Chunyu; Liu, Haiyi; Lu, Yanjun

2017-01-01

Waardenburg syndrome type 4 (WS4) or Waardenburg-Shah syndrome is a rare genetic disorder with a prevalence of <1/1,000,000 and characterized by the association of congenital sensorineural hearing loss, pigmentary abnormalities, and intestinal aganglionosis. There are three types of WS4 (WS4A–C) caused by mutations in endothelin receptor type B, endothelin 3, and SRY-box 10 (SOX10), respectively. This study investigated a genetic mutation in a Chinese family with one WS4 patient in order to improve genetic counselling. Genomic DNA was extracted, and mutation analysis of the three WS4 related genes was performed using Sanger sequencing. We detected a de novo heterozygous deletion mutation [c.1333delT (p.Ser445Glnfs*57)] in SOX10 in the patient; however, this mutation was absent in the unaffected parents and 40 ethnicity matched healthy controls. Subsequent phylogenetic analysis and three-dimensional modelling of the SOX10 protein confirmed that the c.1333delT heterozygous mutation was pathogenic, indicating that this mutation might constitute a candidate disease-causing mutation. PMID:28128317

Truncated ORF1 proteins can suppress LINE-1 retrotransposition in trans

PubMed Central

Sokolowski, Mark; Chynces, May; deHaro, Dawn; Christian, Claiborne M.

2017-01-01

Abstract Long interspersed element 1 (L1) is an autonomous non-LTR retroelement that is active in mammalian genomes. Although retrotranspositionally incompetent and functional L1 loci are present in the same genomes, it remains unknown whether non-functional L1s have any trans effect on mobilization of active elements. Using bioinformatic analysis, we identified over a thousand of human L1 loci containing at least one stop codon in their ORF1 sequence. RNAseq analysis confirmed that many of these loci are expressed. We demonstrate that introduction of equivalent stop codons in the full-length human L1 sequence leads to the expression of truncated ORF1 proteins. When supplied in trans some truncated human ORF1 proteins suppress human L1 retrotransposition. This effect requires the N-terminus and coiled-coil domain (C-C) as mutations within the ORF1p C-C domain abolish the suppressive effect of truncated proteins on L1 retrotransposition. We demonstrate that the expression levels and length of truncated ORF1 proteins influence their ability to suppress L1 retrotransposition. Taken together these findings suggest that L1 retrotransposition may be influenced by coexpression of defective L1 loci and that these L1 loci may reduce accumulation of de novo L1 integration events. PMID:28431148

Mutation screening of the USH2A gene in retinitis pigmentosa and USHER patients in a Han Chinese population.

PubMed

Huang, Lulin; Mao, Yao; Yang, Jiyun; Li, Yuanfeng; Li, Yang; Yang, Zhenglin

2018-06-13

USH2A encodes for usherin, a basement membrane protein in the inner ear and retina. USH2A can cause retinitis pigmentosa (RP) with or without hearing loss. The aim of this study was to detect USH2A mutations in a Chinese cohort of 75 small RP families and 10 Usher syndrome families. We performed a direct Sanger sequencing analysis of the USH2A gene to identify mutations for this cohort. We identified a total of eight mutations in four of the 75 small RP families (5.3%) and two mutations in one of the 10 Usher families (10%); all families were detected to have compound heterozygous mutations. In families with nonsyndromic RP, we identified the compound heterozygous mutations p.Pro4818Leuand p.Leu2395Hisfs*19 in family No. 19114, p.Arg4493His and p.His1677Glnfs*15 in family No.19162, c.8559-2A > G and p.Arg1549* in family No.19123 and p.Ser5060Pro and p.Arg34Leufs*41 in family No.19178. We also identified the heterozygous mutations p.Arg3719His and p.Cys934Trp in family No.19124, which was the Usher syndrome family. These mutations were predicted to be harmful by SIFT, PROVEAN, Mutation Taster or PolyPhen-2. Our results revealed six novel mutations in the USH2A gene in a Chinese population, which is beneficial for the clinical use of genetic testing of USH2A in patients with autosomal-recessive or sporadic RP and Usher syndrome.

A COL7A1 Mutation Causes Dystrophic Epidermolysis Bullosa in Rotes Höhenvieh Cattle