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  1. Novel mutations in CYP51B from Penicillium digitatum involved in prochloraz resistance.

    PubMed

    Wang, Jinlong; Yu, Jinhui; Liu, Jing; Yuan, Yongze; Li, Na; He, Muqing; Qi, Ting; Hui, Geng; Xiong, Li; Liu, Deli

    2014-09-01

    Green mold caused by Penicillium digitatum is one of the most serious postharvest diseases of citrus fruit, and it is ubiquitous in all citrus growing regions in the world. Sterol 14α-demethylase (CYP51) is one of the key enzymes of sterol biosynthesis in the biological kingdom and a prime target of antifungal drugs. Mutations in CYP51s have been found to be correlated with resistance to azole fungicides in many fungal species. To investigate the mechanism of resistance to prochloraz (PRC) in P. digitatum, the PRC sensitivity was determined in vitro in this study to assess the sensitivity of 78 P. digitatum isolates collected in Hubei province. The results showed that 25 isolates were prochloraz-resistant (PRC-R), including six high-resistant (HR) strains, twelve medium-resistant (MR) and seven low-resistant (LR) strains. A sequence analysis showed no consistent point mutations of PdCYP51A in the PRC-R strains, but four substitutions of CYP51B were found, Q309H in LR strains, Y136H and Q309H in HR strains, and G459S and F506I in MR strains, which corresponded to the four sensitivity levels. Based on the sequence alignment analysis and homology modeling followed by the molecular docking of the PdCYP51B protein, the potential correlation between the mutations and PRC resistance is proposed. PMID:25085733

  2. Identification of novel mutations in the VPS33B gene involved in arthrogryposis, renal dysfunction, and cholestasis syndrome.

    PubMed

    Seo, S H; Hwang, S M; Ko, J M; Ko, J S; Hyun, Y J; Cho, S I; Park, H; Kim, S Y; Seong, M-W; Park, S S

    2015-07-01

    Arthrogryposis, renal dysfunction, and cholestasis (ARC) syndrome is an autosomal recessive disorder caused by mutations in the VPS33B and VIPAS39. Here, we report novel mutations identified in four patients with ARC syndrome. We analyzed the entire coding regions of the VPS33B and VIPAS39 genes by direct sequencing. To detect novel splice site mutations, mRNA transcripts were analyzed by reverse transcription-polymerase chain reaction (RT-PCR) and sequencing. All four patients had compound heterozygous variants in the VPS33B gene. One patient had a previously reported splice site variant with unknown significance, c.239+5G>A, and a novel nonsense mutation, c.621G>A. The other three patients had the c.403+2T>A mutation, and each of them carried one of the splice site variants, c.239+5G>A or c.499-11G>A. c.239+5G>A and c.499-11G>A created novel splice sites which resulted in abnormal transcripts. No significant VIPAS39 mutation was detected in all patients. In patients suspected with ARC syndrome, mutation analysis of the VPS33B gene should be employed as a primary diagnostic test before performing invasive testing procedures such as organ biopsies. Performing mRNA analysis can be useful in predicting the pathogenic phenotype when the mutation seems to affect a normal splicing mechanism. PMID:24917129

  3. Suppression of a deletion mutation in the gene encoding essential PBP2b reveals a new lytic transglycosylase involved in peripheral peptidoglycan synthesis in Streptococcus pneumoniae D39.

    PubMed

    Tsui, Ho-Ching Tiffany; Zheng, Jiaqi J; Magallon, Ariel N; Ryan, John D; Yunck, Rachel; Rued, Britta E; Bernhardt, Thomas G; Winkler, Malcolm E

    2016-06-01

    In ellipsoid-shaped ovococcus bacteria, such as the pathogen Streptococcus pneumoniae (pneumococcus), side-wall (peripheral) peptidoglycan (PG) synthesis emanates from midcells and is catalyzed by the essential class B penicillin-binding protein PBP2b transpeptidase (TP). We report that mutations that inactivate the pneumococcal YceG-domain protein, Spd_1346 (renamed MltG), remove the requirement for PBP2b. ΔmltG mutants in unencapsulated strains accumulate inactivation mutations of class A PBP1a, which possesses TP and transglycosylase (TG) activities. The 'synthetic viable' genetic relationship between Δpbp1a and ΔmltG mutations extends to essential ΔmreCD and ΔrodZ mutations that misregulate peripheral PG synthesis. Remarkably, the single MltG(Y488D) change suppresses the requirement for PBP2b, MreCD, RodZ and RodA. Structural modeling and comparisons, catalytic-site changes and an interspecies chimera indicate that pneumococcal MltG is the functional homologue of the recently reported MltG endo-lytic transglycosylase of Escherichia coli. Depletion of pneumococcal MltG or mltG(Y488D) increases sphericity of cells, and MltG localizes with peripheral PG synthesis proteins during division. Finally, growth of Δpbp1a ΔmltG or mltG(Y488D) mutants depends on induction of expression of the WalRK TCS regulon of PG hydrolases. These results fit a model in which MltG releases anchored PG glycan strands synthesized by PBP1a for crosslinking by a PBP2b:RodA complex in peripheral PG synthesis. PMID:26933838

  4. Mutational analysis of signal transduction by ArcB, a membrane sensor protein responsible for anaerobic repression of operons involved in the central aerobic pathways in Escherichia coli.

    PubMed Central

    Iuchi, S; Lin, E C

    1992-01-01

    In Escherichia coli, the expression of a group of operons involved in aerobic metabolism is regulated by a two-component signal transduction system in which the arcB gene specifies the membrane sensor protein and the arcA gene specifies the cytoplasmic regulator protein. ArcB is a large protein belonging to a subclass of sensors that have both a transmitter domain (on the N-terminal side) and a receiver domain (on the C-terminal side). In this study, we explored the essential structural features of ArcB by using mutant analysis. The conserved His-292 in the transmitter domain is indispensable, indicating that this residue is the autophosphorylation site, as shown for other homologous sensor proteins. Compression of the range of respiratory control resulting from deletion of the receiver domain and the importance of the conserved Asp-533 and Asp-576 therein suggest that the domain has a kinetic regulatory role in ArcB. There is no evidence that the receiver domain enhances the specificity of signal transduction by ArcB. The defective phenotype of all arcB mutants was corrected by the presence of the wild-type gene. We also showed that the expression of the gene itself is not under respiratory regulation. Images PMID:1597416

  5. Hemophilia B: Molecular Pathogenesis and Mutation Analysis

    PubMed Central

    Goodeve, Anne C.

    2015-01-01

    Summary Hemophilia B is an X-chromosome-linked inherited bleeding disorder primarily affecting males, while those carrier females having reduced factor IX:C levels may also experience some bleeding issues. Genetic analysis has been undertaken for hemophilia B since the mid-1980s, both through linkage analysis to track inheritance of an affected allele and to enable determination of the familial mutation. Mutation analysis using PCR and Sanger sequencing along with dosage analysis for detection of large deletions/duplications enables mutation detection in more than 97% of hemophila B patients. Risk of inhibitory antibodies, reported in ~2% of hemophilia B patients can be predicted, especially in patients with large deletions and these individuals are also at risk of anaphylaxis, and nephrotic syndrome if they receive immune tolerance induction. Inhibitors also occur in patients with nonsense mutations, occasionally with small insertions/deletions, splice mutations and rarely with missense mutations (p.Gln237Lys and p.Gln241His). Hemophilia B results from several different mechanisms and those associated with hemophilia B Leyden, ribosome readthrough of nonsense mutations and apparently "silent" changes that do not alter amino acid coding are explored. Large databases of genetic variants in healthy individuals and patients with a range of disorders including hemophilia B are yielding useful information on sequence variant frequency to help establish possible variant pathogenicity whilst a growing range of algorithms is available to help predict pathogenicity for previously unreported variants. PMID:25851415

  6. Mutation analysis of the gene involved in adrenoleukodystrophy

    SciTech Connect

    Oost, B.A. van; Ligtenberg, M.J.L.; Kemp, S.; Bolhuis, P.A.

    1994-09-01

    A gene responsible for the X-linked genetic disorder adrenoleukodystrophy (ALD) that is characterized by demyelination of the nervous system and adrenocortical insufficiency has been identified by positional cloning. The gene encodes an ATP-binding transporter which is located in the peroxisomal membrane. Deficiency of the gene leads to accumulation of unsaturated very long chain fatty acids due to impaired peroxisomal {beta}-oxidation. A systematic analysis of the open reading frame of the ALD gene unraveled the mutations in 28 different families using reverse transcriptase-PCR followed by direct sequencing. No entire gene deletions or drastic promoter mutations have been detected. Only in one family did the mutation involved multiple exons. The remaining mutations were subtle alterations leading to missense (about 50%) or nonsense mutations, frameshifts or splice acceptor site defects. In one patient a single codon was missing. Mutations affecting a single amino acid were concentrated in the region between the third and fourth putative membrane spanning fragments and in the ATP-binding domain. This overview of mutations aids in the determination of structural and functional important regions and facilitates the screening for mutations in other ALD patients. The detection of mutations in virtually all ALD families tested indicates that the isolated gene is the only gene responsible for ALD located in Xq28.

  7. Analysis of mutational signatures in exomes from B-cell lymphoma cell lines suggest APOBEC3 family members to be involved in the pathogenesis of primary effusion lymphoma

    DOE PAGESBeta

    Wagener, R.; Alexandrov, L. B.; Montesinos-Rongen, M.; Schlesner, M.; Haake, A.; Drexler, H. G.; Richter, J.; Bignell, G. R.; McDermott, U.; Siebert, R.

    2015-02-04

    Here, primary effusion lymphoma (PEL) is a rare large B-cell neoplasm particularly affecting immunodeficient hosts with an increased incidence in young or middle-aged males infected with the HIV.1 The clinical outcome of patients with PEL is unfavorable with a median survival of <6 months.1 PEL has been closely associated with human herpes virus 8 (HHV8, previously called Kaposi sarcoma herpesvirus) infection.1 In some cases a coinfection of HHV8 with the Epstein–Barr Virus (EBV) has been described.1 HHV8 encodes various genes homologous to cellular genes that have proliferative and anti-apoptotic functions.2 Although HHV8 is supposed to be a major driver ofmore » PEL, it alone is not sufficient for a full-blown lymphomagenesis.2 PEL usually shows complex karyotypes with many chromosomal aberrations.3 This chromosomal complexity might be driven by the viral infection and lead to genetic alterations cooperating with HHV8 in PEL lymphomagenesis.4« less

  8. Analysis of mutational signatures in exomes from B-cell lymphoma cell lines suggest APOBEC3 family members to be involved in the pathogenesis of primary effusion lymphoma

    SciTech Connect

    Wagener, R.; Alexandrov, L. B.; Montesinos-Rongen, M.; Schlesner, M.; Haake, A.; Drexler, H. G.; Richter, J.; Bignell, G. R.; McDermott, U.; Siebert, R.

    2015-02-04

    Here, primary effusion lymphoma (PEL) is a rare large B-cell neoplasm particularly affecting immunodeficient hosts with an increased incidence in young or middle-aged males infected with the HIV.1 The clinical outcome of patients with PEL is unfavorable with a median survival of <6 months.1 PEL has been closely associated with human herpes virus 8 (HHV8, previously called Kaposi sarcoma herpesvirus) infection.1 In some cases a coinfection of HHV8 with the Epstein–Barr Virus (EBV) has been described.1 HHV8 encodes various genes homologous to cellular genes that have proliferative and anti-apoptotic functions.2 Although HHV8 is supposed to be a major driver of PEL, it alone is not sufficient for a full-blown lymphomagenesis.2 PEL usually shows complex karyotypes with many chromosomal aberrations.3 This chromosomal complexity might be driven by the viral infection and lead to genetic alterations cooperating with HHV8 in PEL lymphomagenesis.4

  9. B Decays Involving Light Mesons

    SciTech Connect

    Eschrich, Ivo Gough; /UC, Irvine

    2007-01-09

    Recent BABAR results for decays of B-mesons to combinations of non-charm mesons are presented. This includes B decays to two vector mesons, B {yields} {eta}{prime}({pi}, K, {rho}) modes, and a comprehensive Dalitz Plot analysis of B {yields} KKK decays.

  10. Do mutations in SCN1B cause Dravet syndrome?

    PubMed

    Kim, Young Ok; Dibbens, Leanne; Marini, Carla; Suls, Arvid; Chemaly, Nicole; Mei, Davide; McMahon, Jacinta M; Iona, Xenia; Berkovic, Samuel F; De Jonghe, Peter; Guerrini, Renzo; Nabbout, Rima; Scheffer, Ingrid E

    2013-01-01

    A homozygous SCN1B mutation was previously identified in a patient with early onset epileptic encephalopathy (EOEE) described as Dravet syndrome (DS) despite a more severe phenotype than DS. We investigated whether SCN1B mutations are a common cause of DS. Patients with DS who did not have a SCN1A sequencing mutation or copy number variation were studied. Genomic DNA was Sanger sequenced for mutations in the 6 exons of SCN1B. In 54 patients with DS recruited from four centres, no SCN1B mutations were identified. SCN1B mutation is not a common cause of DS. PMID:23182416

  11. Base substitution mutations induced by metabolically activated aflatoxin B1.

    PubMed

    Foster, P L; Eisenstadt, E; Miller, J H

    1983-05-01

    We have determined the base substitutions generated by metabolically activated aflatoxin B1 in the lacI gene of a uvrB- strain of Escherichia coli. By monitoring over 70 different nonsense mutation sites, we show that activated aflatoxin B1 specifically induced GxC leads to TxA transversions. One possible pathway leading to this base change involves depurination at guanine residues. We consider this mechanism of mutagenesis in the light of our other findings that the carcinogens benzo[a]pyrene diol epoxide and N-acetoxyacetylaminofluorene also specifically induce GxC leads to TxA transversions. PMID:6405385

  12. Novel mutations in PDE6B causing human retinitis pigmentosa

    PubMed Central

    Cheng, Lu-Lu; Han, Ru-Yi; Yang, Fa-Yu; Yu, Xin-Ping; Xu, Jin-Ling; Min, Qing-Jie; Tian, Jie; Ge, Xiang-Lian; Zheng, Si-Si; Lin, Ye-Wen; Zheng, Yi-Han; Qu, Jia; Gu, Feng

    2016-01-01

    AIM To identify the genetic defects of a Chinese patient with sporadic retinitis pigmentosa (RP). METHODS Ophthalmologic examinations were performed on the sporadic RP patient, 144 genes associated with retinal diseases were scanned with capture next generation sequencing (CNGS) approach. Two heterozygous mutations in PDE6B were confirmed in the pedigree by Sanger sequencing subsequently. The carrier frequency of PDE6B mutations of reported PDE6B mutations based on the available two public exome databases (1000 Genomes Project and ESP6500 Genomes Project) and one in-house exome database was investigated. RESULTS We identified compound heterozygosity of two novel nonsense mutations c.1133G>A (p.W378X) and c.2395C>T (p.R799X) in PDE6B, one reported causative gene for RP. Neither of the two mutations in our study was presented in three exome databases. Two mutations (p.R74C and p.T604I) in PDE6B have relatively high frequencies in the ESP6500 and in-house databases, respectively, while no common dominant mutation in each of the database or across all databases. CONCLUSION We demonstrates that compound heterozygosity of two novel nonsense mutations in PDE6B could lead to RP. These results collectively point to enormous potential of next-generation sequencing in determining the genetic etiology of RP and how various mutations in PDE6B contribute to the genetic heterogeneity of RP. PMID:27588261

  13. The Italian haemophilia B mutation database: a tool for genetic counselling, carrier detection and prenatal diagnosis

    PubMed Central

    Tagariello, Giuseppe; Belvini, Donata; Salviato, Roberta; Di Gaetano, Rosanna; Zanotto, Daniela; Radossi, Paolo; Risato, Renzo; Sartori, Roberto; Tassinari, Cristina

    2007-01-01

    Introduction The Italian database of factor IX gene (F9) mutations has been built since 2001 and is, so far, the most practical instrument for comprehensive genetic counselling, carrier detection and prenatal diagnosis. Over time the haemophilia B database has been enriched by entries on a larger number of patients and molecular genetic data identifying heterogeneous mutations spanning the entire F9. Methods Conformation sensitive gel electrophoresis is a variant of heteroduplex analysis, which has been applied for screening F9 for mutations, which are further fully characterised by direct sequencing of the amplified mutated regions. This project has involved 29 Italian haemophilia centres and provides data concerning the analysis of a cohort of 306 unrelated patients with haemophilia B (191 with severe, 67 with moderate and 48 with mild disease, including 8 patients with severe haemophilia B with inhibitors). The recorded data include levels of factor IX clotting activity, inhibitor status and clinical severity. Results Detailed analysis of the mutations revealed 164 different mutations, that are considered as unique molecular events (8 large deletions, 11 small deletions, 1 combined deletion/ insertion, 2 insertions, 104 missense, 20 nonsense, 14 mutations in a splicing site, 3 in the promoter and 1 silent). The data recorded in the Italian F9 mutation database provided the basis to study 85 families with haemophilia B, involving 180 females (20 obligate carriers, 106 carriers and 54 non-carriers) and enabled 14 prenatal diagnoses to be made in 12 females. Conclusions Genetic analysis is required to determine female carrier status reliably. Female relatives may request carrier analysis, when a male relative is first diagnosed as having haemophilia or when they are pregnant. At present, the data collected in the Italian national register of mutations in haemophilia B provide the opportunity to perform prompt and precise determination of carrier status and prenatal

  14. Two novel mutations involved in hereditary tyrosinemia type I

    SciTech Connect

    St-Louis, M.; Poudrier, J.; Phaneuf, D.

    1994-09-01

    The deficiency of fumarylacetoacetate hydrolase, the last enzyme in the tyrosine catabolic pathway is the cause of hereditary tyrosinemia type I (HT1), an autosomal recessive disease. The disease has been reported worldwide. The incidence is much higher in two clusters: the Saguenay- Lac St-Jean region (Quebec, Canada) and in Scandinavia. Seven mutations have been reported in the last two years. Here we describe two new missense mutations identified by direct sequencing of PCR products in two HT1 patients, a Norwegian (patient No. 1) and a French-Canadian (patient No. 2). The first mutation consists of a G to A transition at position 337 of the FAH gene which predicts a change from glycine to serine (G337S). The second mutation is an A to G transition at position 381 which predicts a change from arginine to glycine (R381G). Patient No. 1 seems heterozygous for the G337S mutation and for a splice mutation (IVS12+5G{r_arrow}A) which was previously described. Patient No. 2 was also found heterozygous for the R381G mutation and for a rare nonsense mutation (E357X) already reported. In vitro transcription and translation were performed on mutant cDNA to demonstrate the responsibility of these two mutations in causing the decreased amount of FAH detected by Western blot analysis.

  15. Congenital B cell lymphocytosis explained by novel germline CARD11 mutations.

    PubMed

    Snow, Andrew L; Xiao, Wenming; Stinson, Jeffrey R; Lu, Wei; Chaigne-Delalande, Benjamin; Zheng, Lixin; Pittaluga, Stefania; Matthews, Helen F; Schmitz, Roland; Jhavar, Sameer; Kuchen, Stefan; Kardava, Lela; Wang, Wei; Lamborn, Ian T; Jing, Huie; Raffeld, Mark; Moir, Susan; Fleisher, Thomas A; Staudt, Louis M; Su, Helen C; Lenardo, Michael J

    2012-11-19

    Nuclear factor-κB (NF-κB) controls genes involved in normal lymphocyte functions, but constitutive NF-κB activation is often associated with B cell malignancy. Using high-throughput whole transcriptome sequencing, we investigated a unique family with hereditary polyclonal B cell lymphocytosis. We found a novel germline heterozygous missense mutation (E127G) in affected patients in the gene encoding CARD11, a scaffolding protein required for antigen receptor (AgR)-induced NF-κB activation in both B and T lymphocytes. We subsequently identified a second germline mutation (G116S) in an unrelated, phenotypically similar patient, confirming mutations in CARD11 drive disease. Like somatic, gain-of-function CARD11 mutations described in B cell lymphoma, these germline CARD11 mutants spontaneously aggregate and drive constitutive NF-κB activation. However, these CARD11 mutants rendered patient T cells less responsive to AgR-induced activation. By reexamining this rare genetic disorder first reported four decades ago, our findings provide new insight into why activating CARD11 mutations may induce B cell expansion and preferentially predispose to B cell malignancy without dramatically perturbing T cell homeostasis. PMID:23129749

  16. Congenital B cell lymphocytosis explained by novel germline CARD11 mutations

    PubMed Central

    Xiao, Wenming; Stinson, Jeffrey R.; Lu, Wei; Chaigne-Delalande, Benjamin; Zheng, Lixin; Pittaluga, Stefania; Matthews, Helen F.; Schmitz, Roland; Jhavar, Sameer; Kuchen, Stefan; Kardava, Lela; Wang, Wei; Lamborn, Ian T.; Jing, Huie; Raffeld, Mark; Moir, Susan; Fleisher, Thomas A.; Staudt, Louis M.; Su, Helen C.

    2012-01-01

    Nuclear factor-κB (NF-κB) controls genes involved in normal lymphocyte functions, but constitutive NF-κB activation is often associated with B cell malignancy. Using high-throughput whole transcriptome sequencing, we investigated a unique family with hereditary polyclonal B cell lymphocytosis. We found a novel germline heterozygous missense mutation (E127G) in affected patients in the gene encoding CARD11, a scaffolding protein required for antigen receptor (AgR)–induced NF-κB activation in both B and T lymphocytes. We subsequently identified a second germline mutation (G116S) in an unrelated, phenotypically similar patient, confirming mutations in CARD11 drive disease. Like somatic, gain-of-function CARD11 mutations described in B cell lymphoma, these germline CARD11 mutants spontaneously aggregate and drive constitutive NF-κB activation. However, these CARD11 mutants rendered patient T cells less responsive to AgR-induced activation. By reexamining this rare genetic disorder first reported four decades ago, our findings provide new insight into why activating CARD11 mutations may induce B cell expansion and preferentially predispose to B cell malignancy without dramatically perturbing T cell homeostasis. PMID:23129749

  17. Phenotypic Involvement in Females with the FMR1 Gene Mutation.

    ERIC Educational Resources Information Center

    Riddle, J. E.; Cheema, A.; Sobesky, W. E.; Gardner, S. C.; Taylor, A. K.; Pennington, B. F.; Hagerman, R. J.

    1998-01-01

    A study investigated phenotypic effects seen in 114 females with premutation and 41 females (ages 18-58) with full Fragile X mental retardation gene mutation. Those with the full mutation had a greater incidence of hand-flapping, eye contact problems, special education help for reading and math, and grade retention. (Author/CR)

  18. Functional diversity and mutational analysis of Agrobacterium 6B oncoproteins.

    PubMed

    Helfer, A; Pien, S; Otten, L

    2002-07-01

    Many Agrobacterium T-DNA genes belong to a diverse family of T-DNA genes, the rolB family. These genes cause various growth abnormalities but their modes of action remain largely unknown. So far, none of the RolB-like proteins has been subjected to mutational analysis. The RolB-like oncoprotein 6B, which induces tumours on species such as Nicotiana glauca and Kalanchoe tubiflora, was chosen to investigate the role of the most conserved amino acid residues within the RolB family. We first determined which of the natural 6B variants had the strongest oncogenic activity; to this end, six 6b coding sequences (A- 6b, AB- 6b, C- 6b, CG- 6b, S- 6b and T- 6b) were placed under the control of the strong constitutive 2x35S promoter and compared for tumour induction on N. glauca, N. tabacum and K. daigremontiana. Oncogenicity increased in the order C- 6b/CG- 6b, A- 6b/AB- 6b, and S- 6b/T- 6b. The most conserved amino acid residues in the strongly oncogenic T-6B protein were mutated and shown to be required for oncogenicity and accumulation of the T-6B protein in planta but not in bacteria. Hybrids between T-6B and the weakly oncogenic A-6B protein revealed an additional oncogenic determinant required for the formation of large tumours. PMID:12172796

  19. DNA repair genes are selectively mutated in diffuse large B cell lymphomas

    PubMed Central

    de Miranda, Noel FCC; Peng, Roujun; Georgiou, Konstantinos; Wu, Chenglin; Sörqvist, Elin Falk; Berglund, Mattias; Chen, Longyun; Gao, Zhibo; Lagerstedt, Kristina; Lisboa, Susana; Roos, Fredrik; van Wezel, Tom; Teixeira, Manuel R.; Rosenquist, Richard; Sundström, Christer; Enblad, Gunilla; Nilsson, Mats; Zeng, Yixin; Kipling, David

    2013-01-01

    DNA repair mechanisms are fundamental for B cell development, which relies on the somatic diversification of the immunoglobulin genes by V(D)J recombination, somatic hypermutation, and class switch recombination. Their failure is postulated to promote genomic instability and malignant transformation in B cells. By performing targeted sequencing of 73 key DNA repair genes in 29 B cell lymphoma samples, somatic and germline mutations were identified in various DNA repair pathways, mainly in diffuse large B cell lymphomas (DLBCLs). Mutations in mismatch repair genes (EXO1, MSH2, and MSH6) were associated with microsatellite instability, increased number of somatic insertions/deletions, and altered mutation signatures in tumors. Somatic mutations in nonhomologous end-joining (NHEJ) genes (DCLRE1C/ARTEMIS, PRKDC/DNA-PKcs, XRCC5/KU80, and XRCC6/KU70) were identified in four DLBCL tumors and cytogenetic analyses revealed that translocations involving the immunoglobulin-heavy chain locus occurred exclusively in NHEJ-mutated samples. The novel mutation targets, CHEK2 and PARP1, were further screened in expanded DLBCL cohorts, and somatic as well as novel and rare germline mutations were identified in 8 and 5% of analyzed tumors, respectively. By correlating defects in a subset of DNA damage response and repair genes with genomic instability events in tumors, we propose that these genes play a role in DLBCL lymphomagenesis. PMID:23960188

  20. Mutation analysis of mycobacterial rpoB genes and rifampin resistance using recombinant Mycobacterium smegmatis.

    PubMed

    Nakata, Noboru; Kai, Masanori; Makino, Masahiko

    2012-04-01

    Rifampin is a major drug used to treat leprosy and tuberculosis. The rifampin resistance of Mycobacterium leprae and Mycobacterium tuberculosis results from a mutation in the rpoB gene, encoding the β subunit of RNA polymerase. A method for the molecular determination of rifampin resistance in these two mycobacteria would be clinically valuable, but the relationship between the mutations and susceptibility to rifampin must be clarified before its use. Analyses of mutations responsible for rifampin resistance using clinical isolates present some limitations. Each clinical isolate has its own genetic variations in some loci other than rpoB, which might affect rifampin susceptibility. For this study, we constructed recombinant strains of Mycobacterium smegmatis carrying the M. leprae or M. tuberculosis rpoB gene with or without mutation and disrupted their own rpoB genes on the chromosome. The rifampin and rifabutin susceptibilities of the recombinant bacteria were measured to examine the influence of the mutations. The results confirmed that several mutations detected in clinical isolates of these two pathogenic mycobacteria can confer rifampin resistance, but they also suggested that some mutations detected in M. leprae isolates or rifampin-resistant M. tuberculosis isolates are not involved in rifampin resistance. PMID:22252831

  1. Mutation assays involving blood cells that metabolize toxic substances

    DOEpatents

    Crespi, Charles L.; Thilly, William G.

    1985-01-01

    A line of human blood cells which have high levels of oxidative activity (such as oxygenase, oxidase, peroxidase, and hydroxylase activity) is disclosed. Such cells grow in suspension culture, and are useful to determine the mutagenicity of xenobiotic substances that are metabolized into toxic or mutagenic substances. Mutation assays using these cells, and other cells with similar characteristics, are also disclosed.

  2. Involvement of and Interaction between WNT10A and EDA Mutations in Tooth Agenesis Cases in the Chinese Population

    PubMed Central

    Feng, Hailan; Qu, Hong; Song, Shujuan; Bai, Baojing; Zhang, Zhenting

    2013-01-01

    Background Dental agenesis is the most common, often heritable, developmental anomaly in humans. Although WNT10A gene mutations are known to cause rare syndromes associated with tooth agenesis, including onycho-odontodermal dysplasia (OODD), Schöpf-Schulz-Passarge syndrome (SSPS), hypohidrotic ectodermal dysplasia (HED), and more than half of the cases of isolated oligodontia recently, the genotype-phenotype correlations and the mode of inheritance of WNT10A mutations remain unclear. The phenotypic expression with WNT10A mutations shows a high degree of variability, suggesting that other genes might function with WNT10A in regulating ectodermal organ development. Moreover, the involvement of mutations in other genes, such as EDA, which is also associated with HED and isolated tooth agenesis, is not clear. Therefore, we hypothesized that EDA mutations interact with WNT10A mutations to play a role in tooth agenesis. Additionally, EDA, EDAR, and EDARADD encode signaling molecules in the Eda/Edar/NF-κB signaling pathways, we also checked EDAR and EDARADD in this study. Methods WNT10A, EDA, EDAR and EDARADD were sequenced in 88 patients with isolated oligodontia and 26 patients with syndromic tooth agenesis. The structure of two mutated WNT10A and two mutated EDA proteins was analyzed. Results Digenic mutations of both WNT10A and EDA were identified in 2 of 88 (2.27%) isolated oligodontia cases and 4 of 26 (15.38%) syndromic tooth agenesis cases. No mutation in EDAR or EDARADD gene was found. Conclusions WNT10A and EDA digenic mutations could result in oligodontia and syndromic tooth agenesis in the Chinese population. Moreover, our results will greatly expand the genotypic spectrum of tooth agenesis. PMID:24312213

  3. Structural and functional consequences of succinate dehydrogenase subunit B mutations.

    PubMed

    Kim, E; Rath, E M; Tsang, V H M; Duff, A P; Robinson, B G; Church, W B; Benn, D E; Dwight, T; Clifton-Bligh, R J

    2015-06-01

    Mitochondrial dysfunction, due to mutations of the gene encoding succinate dehydrogenase (SDH), has been implicated in the development of adrenal phaeochromocytomas, sympathetic and parasympathetic paragangliomas, renal cell carcinomas, gastrointestinal stromal tumours and more recently pituitary tumours. Underlying mechanisms behind germline SDH subunit B (SDHB) mutations and their associated risk of disease are not clear. To investigate genotype-phenotype correlation of SDH subunit B (SDHB) variants, a homology model for human SDH was developed from a crystallographic structure. SDHB mutations were mapped, and biochemical effects of these mutations were predicted in silico. Results of structural modelling indicated that many mutations within SDHB are predicted to cause either failure of functional SDHB expression (p.Arg27*, p.Arg90*, c.88delC and c.311delAinsGG), or disruption of the electron path (p.Cys101Tyr, p.Pro197Arg and p.Arg242His). GFP-tagged WT SDHB and mutant SDHB constructs were transfected (HEK293) to determine biological outcomes of these mutants in vitro. According to in silico predictions, specific SDHB mutations resulted in impaired mitochondrial localisation and/or SDH enzymatic activity. These results indicated strong genotype-functional correlation for SDHB variants. This study reveals new insights into the effects of SDHB mutations and the power of structural modelling in predicting biological consequences. We predict that our functional assessment of SDHB mutations will serve to better define specific consequences for SDH activity as well as to provide a much needed assay to distinguish pathogenic mutations from benign variants. PMID:25972245

  4. Mutations in FAM111B Cause Hereditary Fibrosing Poikiloderma with Tendon Contracture, Myopathy, and Pulmonary Fibrosis

    PubMed Central

    Mercier, Sandra; Küry, Sébastien; Shaboodien, Gasnat; Houniet, Darren T.; Khumalo, Nonhlanhla P.; Bou-Hanna, Chantal; Bodak, Nathalie; Cormier-Daire, Valérie; David, Albert; Faivre, Laurence; Figarella-Branger, Dominique; Gherardi, Romain K.; Glen, Elise; Hamel, Antoine; Laboisse, Christian; Le Caignec, Cédric; Lindenbaum, Pierre; Magot, Armelle; Munnich, Arnold; Mussini, Jean-Marie; Pillay, Komala; Rahman, Thahira; Redon, Richard; Salort-Campana, Emmanuelle; Santibanez-Koref, Mauro; Thauvin, Christel; Barbarot, Sébastien; Keavney, Bernard; Bézieau, Stéphane; Mayosi, Bongani M.

    2013-01-01

    Congenital poikiloderma is characterized by a combination of mottled pigmentation, telangiectasia, and epidermal atrophy in the first few months of life. We have previously described a South African European-descent family affected by a rare autosomal-dominant form of hereditary fibrosing poikiloderma accompanied by tendon contracture, myopathy, and pulmonary fibrosis. Here, we report the identification of causative mutations in FAM111B by whole-exome sequencing. In total, three FAM111B missense mutations were identified in five kindreds of different ethnic backgrounds. The mutation segregated with the disease in one large pedigree, and mutations were de novo in two other pedigrees. All three mutations were absent from public databases and were not observed on Sanger sequencing of 388 ethnically matched control subjects. The three single-nucleotide mutations code for amino acid changes that are clustered within a putative trypsin-like cysteine/serine peptidase domain of FAM111B. These findings provide evidence of the involvement of FAM111B in congenital poikiloderma and multisystem fibrosis. PMID:24268661

  5. Mutation assays involving blood cells that metabolize toxic substances

    SciTech Connect

    Crespi, Charles L.; Thilly, William G.

    1999-01-01

    The present invention pertains to a line of human blood cells which have high levels of oxidative activity (such as oxygenase, oxidase, peroxidase, and hydroxylase activity). Such cells grow in suspension culture, and are useful to determine the mutagenicity of xenobiotic substances that are metabolized into toxic or mutagenic substances. The invention also includes mutation assays using these cells, and other cells with similar characteristics.

  6. Mutation assays involving blood cells that metabolize toxic substances

    DOEpatents

    Crespi, C.L.; Thilly, W.G.

    1999-08-10

    The present invention pertains to a line of human blood cells which have high levels of oxidative activity (such as oxygenase, oxidase, peroxidase, and hydroxylase activity). Such cells grow in suspension culture, and are useful to determine the mutagenicity of xenobiotic substances that are metabolized into toxic or mutagenic substances. The invention also includes mutation assays using these cells, and other cells with similar characteristics. 3 figs.

  7. Loss-of-function mutations in RAB39B are associated with typical early-onset Parkinson disease.

    PubMed

    Lesage, Suzanne; Bras, Jose; Cormier-Dequaire, Florence; Condroyer, Christel; Nicolas, Aude; Darwent, Lee; Guerreiro, Rita; Majounie, Elisa; Federoff, Monica; Heutink, Peter; Wood, Nicholas W; Gasser, Thomas; Hardy, John; Tison, François; Singleton, Andrew; Brice, Alexis

    2015-06-01

    Rab proteins are small molecular weight guanosine triphosphatases involved in the regulation of vesicular trafficking.(1) Three of 4 X-linked RAB genes are specific to the brain, including RAB39B. Recently, Wilson et al.(2) reported that mutations in RAB39B cause X-linked intellectual disability (ID) and pathologically confirmed Parkinson disease (PD). They identified a ∼45-kb deletion resulting in the complete loss of RAB39B in an Australian kindred and a missense mutation in a large Wisconsin kindred. Here, we report an additional affected man with typical PD and mild mental retardation harboring a new truncating mutation in RAB39B. PMID:27066548

  8. Cancer-associated SF3B1 mutations affect alternative splicing by promoting alternative branchpoint usage

    PubMed Central

    Alsafadi, Samar; Houy, Alexandre; Battistella, Aude; Popova, Tatiana; Wassef, Michel; Henry, Emilie; Tirode, Franck; Constantinou, Angelos; Piperno-Neumann, Sophie; Roman-Roman, Sergio; Dutertre, Martin; Stern, Marc-Henri

    2016-01-01

    Hotspot mutations in the spliceosome gene SF3B1 are reported in ∼20% of uveal melanomas. SF3B1 is involved in 3′-splice site (3′ss) recognition during RNA splicing; however, the molecular mechanisms of its mutation have remained unclear. Here we show, using RNA-Seq analyses of uveal melanoma, that the SF3B1R625/K666 mutation results in deregulated splicing at a subset of junctions, mostly by the use of alternative 3′ss. Modelling the differential junctions in SF3B1WT and SF3B1R625/K666 cell lines demonstrates that the deregulated splice pattern strictly depends on SF3B1 status and on the 3'ss-sequence context. SF3B1WT knockdown or overexpression do not reproduce the SF3B1R625/K666 splice pattern, qualifying SF3B1R625/K666 as change-of-function mutants. Mutagenesis of predicted branchpoints reveals that the SF3B1R625/K666-promoted splice pattern is a direct result of alternative branchpoint usage. Altogether, this study provides a better understanding of the mechanisms underlying splicing alterations induced by mutant SF3B1 in cancer, and reveals a role for alternative branchpoints in disease. PMID:26842708

  9. Mutations in B3GALNT2 Cause Congenital Muscular Dystrophy and Hypoglycosylation of α-Dystroglycan

    PubMed Central

    Stevens, Elizabeth; Carss, Keren J.; Cirak, Sebahattin; Foley, A. Reghan; Torelli, Silvia; Willer, Tobias; Tambunan, Dimira E.; Yau, Shu; Brodd, Lina; Sewry, Caroline A.; Feng, Lucy; Haliloglu, Goknur; Orhan, Diclehan; Dobyns, William B.; Enns, Gregory M.; Manning, Melanie; Krause, Amanda; Salih, Mustafa A.; Walsh, Christopher A.; Hurles, Matthew; Campbell, Kevin P.; Manzini, M. Chiara; Stemple, Derek; Lin, Yung-Yao; Muntoni, Francesco

    2013-01-01

    Mutations in several known or putative glycosyltransferases cause glycosylation defects in α-dystroglycan (α-DG), an integral component of the dystrophin glycoprotein complex. The hypoglycosylation reduces the ability of α-DG to bind laminin and other extracellular matrix ligands and is responsible for the pathogenesis of an inherited subset of muscular dystrophies known as the dystroglycanopathies. By exome and Sanger sequencing we identified two individuals affected by a dystroglycanopathy with mutations in β-1,3-N-acetylgalactosaminyltransferase 2 (B3GALNT2). B3GALNT2 transfers N-acetyl galactosamine (GalNAc) in a β-1,3 linkage to N-acetyl glucosamine (GlcNAc). A subsequent study of a separate cohort of individuals identified recessive mutations in four additional cases that were all affected by dystroglycanopathy with structural brain involvement. We show that functional dystroglycan glycosylation was reduced in the fibroblasts and muscle (when available) of these individuals via flow cytometry, immunoblotting, and immunocytochemistry. B3GALNT2 localized to the endoplasmic reticulum, and this localization was perturbed by some of the missense mutations identified. Moreover, knockdown of b3galnt2 in zebrafish recapitulated the human congenital muscular dystrophy phenotype with reduced motility, brain abnormalities, and disordered muscle fibers with evidence of damage to both the myosepta and the sarcolemma. Functional dystroglycan glycosylation was also reduced in the b3galnt2 knockdown zebrafish embryos. Together these results demonstrate a role for B3GALNT2 in the glycosylation of α-DG and show that B3GALNT2 mutations can cause dystroglycanopathy with muscle and brain involvement. PMID:23453667

  10. Homozygous familial hypobetalipoproteinemia: A Turkish case carrying a missense mutation in apolipoprotein B.

    PubMed

    Yilmaz, Berna Seker; Mungan, Neslihan Onenli; Di Leo, Enza; Magnolo, Lucia; Artuso, Lucia; Bernardis, Isabella; Tumgor, Gokhan; Kor, Deniz; Tarugi, Patrizia

    2016-01-15

    The autosomal co-dominant disorder familial hypobetalipoproteinemia (FHBL) may be due to mutations in the APOB gene encoding apolipoprotein B (apoB), the main constituent peptide of chylomicrons, very low and low density lipoproteins. We describe an 11month-old child with failure to thrive, intestinal lipid malabsorption, hepatic steatosis and severe hypobetalipoproteinemia, suggesting the diagnosis of homozygous FHBL, abetalipoproteinemia (ABL) or chylomicron retention disease (CMRD). The analysis of candidate genes showed that patient was homozygous for a variant (c.1594 C>T) in the APOB gene causing arginine to tryptophan conversion at position 505 of mature apoB (Arg505Trp). No mutations were found in a panel of other potential candidate genes for hypobetalipoproteinemia. In vitro studies showed a reduced secretion of mutant apoB-48 with respect to the wild-type apoB-48 in transfected McA-RH7777 cells. The Arg505Trp substitution is located in the βα1 domain of apoB involved in the lipidation of apoB mediated by microsomal triglyceride transfer protein (MTP), the first step in VLDL and chylomicron formation. The patient's condition improved in response to a low fat diet supplemented with fat-soluble vitamins. Homozygosity for a rare missense mutation in the βα1 domain of apoB may be the cause of both severe hypobetalipoproteinemia and intestinal lipid malabsorption. PMID:26612772

  11. Clinical implications of hepatitis B virus mutations: recent advances.

    PubMed

    Lazarevic, Ivana

    2014-06-28

    Hepatitis B virus (HBV) infection is a major cause of acute and chronic hepatitis, and of its long-term complications. It is the most variable among DNA viruses, mostly because of its unique life cycle which includes the activity of error-prone enzyme, reverse transcriptase, and the very high virion production per day. In last two decades, numerous research studies have shown that the speed of disease progression, reliability of diagnostic methods and the success of antiviral therapy and immunization are all influenced by genetic variability of this virus. It was shown that mutations in specific regions of HBV genome could be responsible for unwanted clinical outcomes or evasion of detection by diagnostic tools, thus making the monitoring for these mutations a necessity in proper evaluation of patients. The success of the vaccination programs has now been challenged by the discovery of mutant viruses showing amino acid substitutions in hepatitis B surface antigen (HBsAg), which may lead to evasion of vaccine-induced immunity. However, the emergence of these mutations has not yet raised concern since it was shown that they develop slowly. Investigations of HBV genetic variability and clinical implications of specific mutations have resulted in significant advances over the past decade, particularly in regard to management of resistance to antiviral drugs. In the era of drugs with high genetic barrier for resistance, on-going monitoring for possible resistance is still essential since prolonged therapy is often necessary. Understanding the frequencies and clinical implications of viral mutations may contribute to improvement of diagnostic procedures, more proper planning of immunization programs and creating the most efficient therapeutic protocols. PMID:24976703

  12. Clinical implications of hepatitis B virus mutations: Recent advances

    PubMed Central

    Lazarevic, Ivana

    2014-01-01

    Hepatitis B virus (HBV) infection is a major cause of acute and chronic hepatitis, and of its long-term complications. It is the most variable among DNA viruses, mostly because of its unique life cycle which includes the activity of error-prone enzyme, reverse transcriptase, and the very high virion production per day. In last two decades, numerous research studies have shown that the speed of disease progression, reliability of diagnostic methods and the success of antiviral therapy and immunization are all influenced by genetic variability of this virus. It was shown that mutations in specific regions of HBV genome could be responsible for unwanted clinical outcomes or evasion of detection by diagnostic tools, thus making the monitoring for these mutations a necessity in proper evaluation of patients. The success of the vaccination programs has now been challenged by the discovery of mutant viruses showing amino acid substitutions in hepatitis B surface antigen (HBsAg), which may lead to evasion of vaccine-induced immunity. However, the emergence of these mutations has not yet raised concern since it was shown that they develop slowly. Investigations of HBV genetic variability and clinical implications of specific mutations have resulted in significant advances over the past decade, particularly in regard to management of resistance to antiviral drugs. In the era of drugs with high genetic barrier for resistance, on-going monitoring for possible resistance is still essential since prolonged therapy is often necessary. Understanding the frequencies and clinical implications of viral mutations may contribute to improvement of diagnostic procedures, more proper planning of immunization programs and creating the most efficient therapeutic protocols. PMID:24976703

  13. Severe Prenatal Renal Anomalies Associated with Mutations in HNF1B or PAX2 Genes

    PubMed Central

    Madariaga, Leire; Morinière, Vincent; Jeanpierre, Cécile; Bouvier, Raymonde; Loget, Philippe; Martinovic, Jelena; Dechelotte, Pierre; Leporrier, Nathalie; Thauvin-Robinet, Christel; Jensen, Uffe Birk; Gaillard, Dominique; Mathieu, Michele; Turlin, Bruno; Attie-Bitach, Tania; Salomon, Rémi; Gübler, Marie-Claire; Antignac, Corinne

    2013-01-01

    Summary Background and objectives Congenital anomalies of the kidney and urinary tract (CAKUT) are a frequent cause of renal failure in children, and their detection in utero is now common with fetal screening ultrasonography. The clinical course of CAKUT detected before birth is very heterogeneous and depends on the level of nephron reduction. The most severe forms cause life-threatening renal failure, leading to perinatal death or the need for very early renal replacement therapy. Design, setting, participants, & measurements This study reports the screening of two genes (HNF1B and PAX2) involved in monogenic syndromic CAKUT in a cohort of 103 fetuses from 91 families with very severe CAKUT that appeared isolated by fetal ultrasound examination and led to termination of pregnancy. Results This study identified a disease-causing mutation in HNF1B in 12 cases from 11 families and a mutation in PAX2 in 4 unrelated cases. Various renal phenotypes were observed, but no case of bilateral agenesis was associated with HNF1B or PAX2 mutations. Autopsy identified extrarenal abnormalities not detected by ultrasonography in eight cases but confirmed the absence of extrarenal defects in eight other cases. A positive family history of renal disease was not significantly more frequent in cases with an identified mutation. Moreover, in cases with an inherited mutation, there was a great phenotypic variability regarding the severity of the renal disease within a single family. Conclusions Our results suggest that mutations in genes involved in syndromic CAKUT with Mendelian inheritance are not rare in fetal cases with severe CAKUT appearing isolated at prenatal ultrasound, a finding of clinical importance because of genetic counseling. PMID:23539225

  14. Mutational Analysis of Cvab, an ABC Transporter Involved in the Secretion of Active Colicin V

    PubMed Central

    Tai, Phang C.

    2012-01-01

    CvaB is the central membrane transporter of the colicin V secretion system that belongs to an ATP-binding cassette superfamily. Previous data showed that the N-terminal and C-terminal domains of CvaB are essential for the function of CvaB. N-terminal domain of CvaB possesses Ca2+-dependent cysteine proteolytic activity, and two critical residues, Cys32 and His105, have been identified. In this study, we also identify Asp121 as being the third residue of the putative catalytic triad within the active site of the enzyme. The Asp121 mutants lose both their colicin V secretion activity and N-terminal proteolytic activity. The adjacent residue Pro122 also appears to play a critical role in the colicin V secretion. However, the reversal of the two residues D121P - P122D results in loss of activity. Based on molecular modeling and protein sequence alignment, several residues adjacent to the critical residues, Cys32 and His105, were also examined and characterized. Site-directed mutagenesis of Trp101, Asp102, Val108, Leu76, Gly77, and Gln26 indicate that the neighboring residues around the catalytic triad affect colicin V secretion. Several mutated CvaB proteins with defective secretion were also tested, including Asp121 and Pro122, and were found to be structurally stable. These results indicate that the residues surrounding the identified catalytic triad are functionally involved in the secretion of biologically active colicin V. PMID:22539970

  15. Recurrent CDKN1B (p27) mutations in hairy cell leukemia.

    PubMed

    Dietrich, Sascha; Hüllein, Jennifer; Lee, Stanley Chun-Wei; Hutter, Barbara; Gonzalez, David; Jayne, Sandrine; Dyer, Martin J S; Oleś, Małgorzata; Else, Monica; Liu, Xiyang; Słabicki, Mikołaj; Wu, Bian; Troussard, Xavier; Dürig, Jan; Andrulis, Mindaugas; Dearden, Claire; von Kalle, Christof; Granzow, Martin; Jauch, Anna; Fröhling, Stefan; Huber, Wolfgang; Meggendorfer, Manja; Haferlach, Torsten; Ho, Anthony D; Richter, Daniela; Brors, Benedikt; Glimm, Hanno; Matutes, Estella; Abdel Wahab, Omar; Zenz, Thorsten

    2015-08-20

    Hairy cell leukemia (HCL) is marked by near 100% mutational frequency of BRAFV600E mutations. Recurrent cooperating genetic events that may contribute to HCL pathogenesis or affect the clinical course of HCL are currently not described. Therefore, we performed whole exome sequencing to explore the mutational landscape of purine analog refractory HCL. In addition to the disease-defining BRAFV600E mutations, we identified mutations in EZH2, ARID1A, and recurrent inactivating mutations of the cell cycle inhibitor CDKN1B (p27). Targeted deep sequencing of CDKN1B in a larger cohort of HCL patients identify deleterious CDKN1B mutations in 16% of patients with HCL (n = 13 of 81). In 11 of 13 patients the CDKN1B mutation was clonal, implying an early role of CDKN1B mutations in the pathogenesis of HCL. CDKN1B mutations were not found to impact clinical characteristics or outcome in this cohort. These data identify HCL as having the highest frequency of CDKN1B mutations among cancers and identify CDNK1B as the second most common mutated gene in HCL. Moreover, given the known function of CDNK1B, these data suggest a novel role for alterations in regulation of cell cycle and senescence in HCL with CDKN1B mutations. PMID:26065650

  16. B-cell lymphoma mutations: improving diagnostics and enabling targeted therapies

    PubMed Central

    Vaqué, José P.; Martínez, Nerea; Batlle-López, Ana; Pérez, Cristina; Montes-Moreno, Santiago; Sánchez-Beato, Margarita; Piris, Miguel A.

    2014-01-01

    B-cell lymphomas comprise an increasing number of clinicopathological entities whose characterization has historically been based mainly on histopathological features. In recent decades, the analysis of chromosomal aberrations as well as gene and miRNA expression profile studies have helped distinguish particular tumor types and also enabled the detection of a number of targets with therapeutic implications, such as those activated downstream of the B-cell receptor. Our ability to identify the mechanisms involved in B-cell lymphoma pathogenesis has been boosted recently through the use of Next Generation Sequencing techniques in the analysis of human cancer. This work summarizes the recent findings in the molecular pathogenesis of B-cell neoplasms with special focus on those clinically relevant somatic mutations with the potential to be explored as candidates for the development of new targeted therapies. Our work includes a comparison between the mutational indexes and ranges observed in B-cell lymphomas and also with other solid tumors and describes the most striking mutational data for the major B-cell neoplasms. This review describes a highly dynamic field that currently offers many opportunities for personalized therapy, although there is still much to be gained from the further molecular characterization of these clinicopathological entities. PMID:24497559

  17. Mutations in RIT1 cause Noonan syndrome with possible juvenile myelomonocytic leukemia but are not involved in acute lymphoblastic leukemia.

    PubMed

    Cavé, Hélène; Caye, Aurélie; Ghedira, Nehla; Capri, Yline; Pouvreau, Nathalie; Fillot, Natacha; Trimouille, Aurélien; Vignal, Cédric; Fenneteau, Odile; Alembik, Yves; Alessandri, Jean-Luc; Blanchet, Patricia; Boute, Odile; Bouvagnet, Patrice; David, Albert; Dieux Coeslier, Anne; Doray, Bérénice; Dulac, Olivier; Drouin-Garraud, Valérie; Gérard, Marion; Héron, Delphine; Isidor, Bertrand; Lacombe, Didier; Lyonnet, Stanislas; Perrin, Laurence; Rio, Marlène; Roume, Joëlle; Sauvion, Sylvie; Toutain, Annick; Vincent-Delorme, Catherine; Willems, Marjorie; Baumann, Clarisse; Verloes, Alain

    2016-08-01

    Noonan syndrome is a heterogeneous autosomal dominant disorder caused by mutations in at least eight genes involved in the RAS/MAPK signaling pathway. Recently, RIT1 (Ras-like without CAAX 1) has been shown to be involved in the pathogenesis of some patients. We report a series of 44 patients from 30 pedigrees (including nine multiplex families) with mutations in RIT1. These patients display a typical Noonan gestalt and facial phenotype. Among the probands, 8.7% showed postnatal growth retardation, 90% had congenital heart defects, 36% had hypertrophic cardiomyopathy (a lower incidence compared with previous report), 50% displayed speech delay and 52% had learning difficulties, but only 22% required special education. None had major skin anomalies. One child died perinatally of juvenile myelomonocytic leukemia. Compared with the canonical Noonan phenotype linked to PTPN11 mutations, patients with RIT1 mutations appear to be less severely growth retarded and more frequently affected by cardiomyopathy. Based on our experience, we estimate that RIT1 could be the cause of 5% of Noonan syndrome patients. Because mutations found constitutionally in Noonan syndrome are also found in several tumors in adulthood, we evaluated the potential contribution of RIT1 to leukemogenesis in Noonan syndrome. We screened 192 pediatric cases of acute lymphoblastic leukemias (96 B-ALL and 96 T-ALL) and 110 cases of juvenile myelomonocytic leukemias (JMML), but detected no variation in these tumoral samples, suggesting that Noonan patients with germline RIT1 mutations are not at high risk to developing JMML or ALL, and that RIT1 has at most a marginal role in these sporadic malignancies. PMID:26757980

  18. BCL-6 mutations in normal germinal center B cells: Evidence of somatic hypermutation acting outside Ig loci

    PubMed Central

    Pasqualucci, Laura; Migliazza, Anna; Fracchiolla, Nicola; William, Christopher; Neri, Antonino; Baldini, Luca; Chaganti, R. S. K.; Klein, Ulf; Küppers, Ralf; Rajewsky, Klaus; Dalla-Favera, Riccardo

    1998-01-01

    The molecular mechanism involved in the process of antigen-driven somatic hypermutation of Ig genes is unknown, but it is commonly believed that this mechanism is restricted to the Ig loci. B cell lymphomas commonly display multiple somatic mutations clustering in the 5′-regulatory region of BCL-6, a proto-oncogene encoding for a POZ/Zinc finger transcriptional repressor expressed in germinal center (GC) B cells and required for GC formation. To determine whether BCL-6 mutations represent a tumor-associated phenomenon or reflect a physiologic mechanism, we screened single human tonsillar GC B cells for mutations occurring in the BCL-6 5′-noncoding region and in the Ig variable heavy chain sequences. Thirty percent of GC B cells, but not naive B cells, displayed mutations in the 742 bp region analyzed within the first intron of BCL-6 (overall frequency: 5 × 10−4/bp). Accordingly, an expanded survey in lymphoid malignancies showed that BCL-6 mutations are restricted to B cell tumors displaying GC or post-GC phenotype and carrying mutated Ig variable heavy chain sequences. These results indicate that the somatic hypermutation mechanism active in GC B cells physiologically targets non-Ig sequences. PMID:9751748

  19. Mutations in the Cilia Gene ARL13B Lead to the Classical Form of Joubert Syndrome

    PubMed Central

    Cantagrel, Vincent; Silhavy, Jennifer L.; Bielas, Stephanie L.; Swistun, Dominika; Marsh, Sarah E.; Bertrand, Julien Y.; Audollent, Sophie; Attié-Bitach, Tania; Holden, Kenton R.; Dobyns, William B.; Traver, David; Al-Gazali, Lihadh; Ali, Bassam R.; Lindner, Tom H.; Caspary, Tamara; Otto, Edgar A.; Hildebrandt, Friedhelm; Glass, Ian A.; Logan, Clare V.; Johnson, Colin A.; Bennett, Christopher; Brancati, Francesco; Valente, Enza Maria; Woods, C. Geoffrey; Gleeson, Joseph G.

    2008-01-01

    Joubert syndrome (JS) and related disorders are a group of autosomal-recessive conditions sharing the “molar tooth sign” on axial brain MRI, together with cerebellar vermis hypoplasia, ataxia, and psychomotor delay. JS is suggested to be a disorder of cilia function and is part of a spectrum of disorders involving retinal, renal, digital, oral, hepatic, and cerebral organs. We identified mutations in ARL13B in two families with the classical form of JS. ARL13B belongs to the Ras GTPase family, and in other species is required for ciliogenesis, body axis formation, and renal function. The encoded Arl13b protein was expressed in developing murine cerebellum and localized to the cilia in primary neurons. Overexpression of human wild-type but not patient mutant ARL13B rescued the Arl13b scorpion zebrafish mutant. Thus, ARL13B has an evolutionarily conserved role mediating cilia function in multiple organs. PMID:18674751

  20. malB Region in Escherichia coli K-12: Characterization of New Mutations

    PubMed Central

    Hofnung, Maurice; Hatfield, Dolph; Schwartz, Maxime

    1974-01-01

    Phenotypic characterization and mapping of more than 50 Mal− mutations located in the malB region lead one to divide the site for Mal−λs mutations (formerly called gene malB) in that region, into two adjacent genetic segments malJ and malK. malJ and malK are both involved in maltose permeation. It is suggested that (i) malK and lamB, the only known gene specifically involved in phage λ adsorption (20), constitute an operon of polarity malK lamB. (ii) malJ and malK correspond to two different genes, and (iii) a promoter for the malK lamB operon is located between malJ and malK. Since λ receptors and maltose permease are inducible by maltose and absent in malT mutants, it is likely that the expression of the malK lamB operon is controlled by the product of gene malT, the positive regulatory gene of the maltose system. PMID:4587612

  1. Signature mutations from B. subtilis spores exposed to radiations and simulated space environments

    NASA Astrophysics Data System (ADS)

    Munakata, , Nobuo; Natsume, Toshiyuki; Konishi, Teruaki; Hieda, Kotaro; Panitz, Corinna; Horneck, Gerda

    Rifampicin-resistant mutants were collected from the spores of three B. subtilis strains, HA101 (HA, repair proficient), TKJ6312 (US, UV-repair defective) and TKJ6412 (RF, recombination deficient) grown after exposure to various radiations and simulated space environments. All of 563 mutations analyzed carried sequence changes in the N-terminal region of the rpoB gene cod-ing for the subunit β of RNA polymerase II and belonged to 56 alleles. (1) Most of spontaneous mutants from the three strains belonged to 13 single-base substitution (SBS) alleles, exceptions (<2%) being one 3 bp insertion and one tandem double substitution (TDS). (2) About 6 % and 16 % of the mutations from the HA and RF spores, respectively, exposed to ionizing radiations were complex mutations including multiple-base substitutions, insertions and deletions. Several TDS and non-tandem double substitutions (NTDS), and 3, 6, 9 and one 30 bp deletions seem to provide signatures of the exposure to ionizing radiations. (3) Except one TDS from US and one NTDS from HA spores, UV or solar exposure seemed not to leave unique footprints. (4) In space simulation experiments, the only conditions involving high vacuum consistently increased the mutation frequency, and exhibited high occurrences (>50%) of TDS. In HA spores, the al-lele r201 (CA to TT at 1460) was the most frequent, while in US spores, another allele r210 (TC to AA at 1404) was the most frequent. In conclusion, some of the conditions encountered in space environments, such as space vacuum and ionizing radiations, could produce unique mutational signatures in the rpoB gene of B. subtilis spores.

  2. Spontaneous mutation 7B-1 in tomato impairs blue light-induced stomatal opening.

    PubMed

    Hlavinka, Jan; Nauš, Jan; Fellner, Martin

    2013-08-01

    It was reported earlier that 7B-1 mutant in tomato (Solanum lycopersicum L.), an ABA overproducer, is defective in blue light (BL) signaling leading to BL-specific resistance to abiotic and biotic stresses. In this work, we examine responses of stomata to blue, red and white lights, fusicoccin, anion channel blockers (anthracene-9-carboxylic acid; 9-AC and niflumic acid; NIF) and ABA. Our results showed that the aperture of 7B-1 stomata does not increase in BL, suggesting that 7B-1 mutation impairs an element of BL signaling pathway involved in stomatal opening. Similar stomatal responses of 7B-1 and wild type (WT) to fusicoccin or 9-AC points out that activity of H(+)-ATPase and 9-AC-sensitive anion channels per se is not likely affected by the mutation. Since 9-AC restored stomatal opening of 7B-1 in BL, it seems that 9-AC and BL could block similar type of anion channels. The stomata of both genotypes did not respond to NIF neither in darkness nor in any light conditions tested. In light, 9-AC but not NIF restored stomatal opening inhibited by ABA in WT and 7B-1. We suggest that in comparison to WT, the activity of S-type anion channels in 7B-1 is more promoted by increased ABA content, and less reduced by BL, because of the mutant resistance to BL. PMID:23759105

  3. Two Japanese CADASIL families exhibiting Notch3 mutation R75P not involving cysteine residue.

    PubMed

    Mizuno, Toshiki; Muranishi, Manabu; Torugun, Torusunjian; Tango, Hiromi; Nagakane, Yoshinari; Kudeken, Tukasa; Kawase, Yuji; Kawabe, Kiyokazu; Oshima, Fumiko; Yaoi, Takeshi; Itoh, Kyoko; Fushiki, Shinji; Nakagawa, Masanori

    2008-01-01

    Most previously reported mutations in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) result in an odd number of cysteine residues within the epidermal growth factor (EGF)-like repeats in Notch3. We report here R75P mutation in two Japanese CADASIL families not directly involving cysteine residues located within the first EGF-like repeats. Probands in both families had repeated episodes of stroke, depression, dementia as well as T2 high-intensity lesions in the basal ganglia and periventricular white matter, but fewer white matter lesions in the temporal pole on MRI. These families provide new insights into the diagnosis and pathomechanisms of CADASIL. PMID:19043263

  4. The NOTCH pathway is recurrently mutated in diffuse large B-cell lymphoma associated with hepatitis C virus infection

    PubMed Central

    Arcaini, Luca; Rossi, Davide; Lucioni, Marco; Nicola, Marta; Bruscaggin, Alessio; Fiaccadori, Valeria; Riboni, Roberta; Ramponi, Antonio; Ferretti, Virginia V.; Cresta, Stefania; Casaluci, Gloria Margiotta; Bonfichi, Maurizio; Gotti, Manuel; Merli, Michele; Maffi, Aldo; Arra, Mariarosa; Varettoni, Marzia; Rattotti, Sara; Morello, Lucia; Guerrera, Maria Luisa; Sciarra, Roberta; Gaidano, Gianluca; Cazzola, Mario; Paulli, Marco

    2015-01-01

    Hepatitis C virus has been found to be associated with B-cell non-Hodgkin lymphomas, mostly marginal zone lymphomas and diffuse large B-cell lymphoma. Deregulation of signaling pathways involved in normal marginal zone development (NOTCH pathway, NF-κB, and BCR signaling) has been demonstrated in splenic marginal zone lymphoma. We studied mutations of NOTCH pathway signaling in 46 patients with hepatitis C virus-positive diffuse large B-cell lymphoma and in 64 patients with diffuse large B-cell lymphoma unrelated to HCV. NOTCH2 mutations were detected in 9 of 46 (20%) hepatitis C virus-positive patients, and NOTCH1 mutations in 2 of 46 (4%). By contrast, only one of 64 HCV-negative patients had a NOTCH1 or NOTCH2 mutation. The frequency of the NOTCH pathway lesions was significantly higher in hepatitis C virus-positive patients (P=0.002). The 5-year overall survival was 27% (95%CI: 5%–56%) for hepatitis C virus-positive diffuse large B-cell lymphoma patients carrying a NOTCH pathway mutation versus 62% (95%CI: 42%–77%) for those without these genetic lesions. By univariate analysis, age over 60 years, NOTCH2 mutation, and any mutation of the NOTCH pathway (NOTCH2, NOTCH1, SPEN) were associated with shorter overall survival. Mutation of the NOTCH pathway retained an independent significance (P=0.029). In conclusion, a subset of patients with hepatitis C virus-positive diffuse large B-cell lymphoma displays a molecular signature of splenic marginal zone and has a worse clinical outcome. PMID:25381127

  5. A single point mutation in the embB gene is responsible for resistance to ethambutol in Mycobacterium smegmatis.

    PubMed Central

    Lety, M A; Nair, S; Berche, P; Escuyer, V

    1997-01-01

    Ethambutol [EMB; dextro-2,2'-(ethylenediimino)-di-1-butanol] is an effective drug when used in combination with isoniazid for the treatment of tuberculosis. It inhibits the polymerization of arabinan in the arabinogalactan and lipoarabinomannan of the mycobacterial cell wall. Recent studies have shown that arabinosyltransferases could be targets of EMB. These enzymes are encoded by the emb locus that was identified in Mycobacterium smegmatis, Mycobacterium leprae, Mycobacterium avium, and Mycobacterium tuberculosis. We demonstrate that a missense mutation in the M. smegmatis embB gene, one of the genes of the emb locus, confers resistance to EMB. The level of resistance is not dependent on the number of copies of the mutated embB gene, indicating that this is a true mechanism of resistance. The mutation is located in a region of the EmbB protein that is highly conserved among the different mycobacterial species. We also identified in this region two other independent mutations that confer EMB resistance. Furthermore, mutations have recently been described in the same region of the EmbB protein from clinical EMB-resistant M. tuberculosis isolates. Together, these data strongly suggest that one of the mechanisms of resistance to EMB consists of missense mutations in a particular region of the EmbB protein that could be directly involved in the interaction with the EMB molecule. PMID:9420031

  6. ARC syndrome with high GGT cholestasis caused by VPS33B mutations

    PubMed Central

    Wang, Jian-She; Zhao, Jing; Li, Li-Ting

    2014-01-01

    Arthrogryposis, renal dysfunction and cholestasis (ARC) syndrome (OMIM 208085) is an autosomal recessive disorder that is caused by mutations in 2 interacting genes VPS33B and VIPAS39. Mutations in VPS33B gene account for most cases of ARC. As low or normal gamma-glutamyl transpeptidase (GGT) activity has been described in all patients with ARC syndrome identified so far, ARC syndrome is a possible diagnosis for low GGT cholestasis. Here we describe a Chinese patient with neonatal cholestasis and a high GGT level in three consecutive tests. She had other typical manifestations of ARC syndrome, including arthrogryposis multiplex congenita, renal involvement and ichthyosis. Genetic study of the VPS33B gene further confirmed the diagnosis by identification of compound heterozygosity of two known disease-causing mutations, c.403+2T > A and c.1509-1510insG. The mechanism of high GGT in this patient is unclear. Nevertheless, this case indicates that ARC syndrome cannot be excluded from the differential diagnosis of neonatal cholestasis even if high GGT activity is found. PMID:24782640

  7. ARC syndrome with high GGT cholestasis caused by VPS33B mutations.

    PubMed

    Wang, Jian-She; Zhao, Jing; Li, Li-Ting

    2014-04-28

    Arthrogryposis, renal dysfunction and cholestasis (ARC) syndrome (OMIM 208085) is an autosomal recessive disorder that is caused by mutations in 2 interacting genes VPS33B and VIPAS39. Mutations in VPS33B gene account for most cases of ARC. As low or normal gamma-glutamyl transpeptidase (GGT) activity has been described in all patients with ARC syndrome identified so far, ARC syndrome is a possible diagnosis for low GGT cholestasis. Here we describe a Chinese patient with neonatal cholestasis and a high GGT level in three consecutive tests. She had other typical manifestations of ARC syndrome, including arthrogryposis multiplex congenita, renal involvement and ichthyosis. Genetic study of the VPS33B gene further confirmed the diagnosis by identification of compound heterozygosity of two known disease-causing mutations, c.403+2T > A and c.1509-1510insG. The mechanism of high GGT in this patient is unclear. Nevertheless, this case indicates that ARC syndrome cannot be excluded from the differential diagnosis of neonatal cholestasis even if high GGT activity is found. PMID:24782640

  8. SF3B1 mutation identifies a distinct subset of myelodysplastic syndrome with ring sideroblasts

    PubMed Central

    Karimi, Mohsen; Papaemmanuil, Elli; Ambaglio, Ilaria; Jädersten, Martin; Jansson, Monika; Elena, Chiara; Gallì, Anna; Walldin, Gunilla; Della Porta, Matteo G.; Raaschou-Jensen, Klas; Travaglino, Erica; Kallenbach, Klaus; Pietra, Daniela; Ljungström, Viktor; Conte, Simona; Boveri, Emanuela; Invernizzi, Rosangela; Rosenquist, Richard; Campbell, Peter J.; Cazzola, Mario; Hellström Lindberg, Eva

    2015-01-01

    Refractory anemia with ring sideroblasts (RARS) is a myelodysplastic syndrome (MDS) characterized by isolated erythroid dysplasia and 15% or more bone marrow ring sideroblasts. Ring sideroblasts are found also in other MDS subtypes, such as refractory cytopenia with multilineage dysplasia and ring sideroblasts (RCMD-RS). A high prevalence of somatic mutations of SF3B1 was reported in these conditions. To identify mutation patterns that affect disease phenotype and clinical outcome, we performed a comprehensive mutation analysis in 293 patients with myeloid neoplasm and 1% or more ring sideroblasts. SF3B1 mutations were detected in 129 of 159 cases (81%) of RARS or RCMD-RS. Among other patients with ring sideroblasts, lower prevalence of SF3B1 mutations and higher prevalence of mutations in other splicing factor genes were observed (P < .001). In multivariable analyses, patients with SF3B1 mutations showed significantly better overall survival (hazard ratio [HR], .37; P = .003) and lower cumulative incidence of disease progression (HR = 0.31; P = .018) compared with SF3B1-unmutated cases. The independent prognostic value of SF3B1 mutation was retained in MDS without excess blasts, as well as in sideroblastic categories (RARS and RCMD-RS). Among SF3B1-mutated patients, coexisting mutations in DNA methylation genes were associated with multilineage dysplasia (P = .015) but had no effect on clinical outcome. TP53 mutations were frequently detected in patients without SF3B1 mutation, and were associated with poor outcome. Thus, SF3B1 mutation identifies a distinct MDS subtype that is unlikely to develop detrimental subclonal mutations and is characterized by indolent clinical course and favorable outcome. PMID:25957392

  9. Mutations in DARS Cause Hypomyelination with Brain Stem and Spinal Cord Involvement and Leg Spasticity

    PubMed Central

    Taft, Ryan J.; Vanderver, Adeline; Leventer, Richard J.; Damiani, Stephen A.; Simons, Cas; Grimmond, Sean M.; Miller, David; Schmidt, Johanna; Lockhart, Paul J.; Pope, Kate; Ru, Kelin; Crawford, Joanna; Rosser, Tena; de Coo, Irenaeus F.M.; Juneja, Monica; Verma, Ishwar C.; Prabhakar, Prab; Blaser, Susan; Raiman, Julian; Pouwels, Petra J.W.; Bevova, Marianna R.; Abbink, Truus E.M.; van der Knaap, Marjo S.; Wolf, Nicole I.

    2013-01-01

    Inherited white-matter disorders are a broad class of diseases for which treatment and classification are both challenging. Indeed, nearly half of the children presenting with a leukoencephalopathy remain without a specific diagnosis. Here, we report on the application of high-throughput genome and exome sequencing to a cohort of ten individuals with a leukoencephalopathy of unknown etiology and clinically characterized by hypomyelination with brain stem and spinal cord involvement and leg spasticity (HBSL), as well as the identification of compound-heterozygous and homozygous mutations in cytoplasmic aspartyl-tRNA synthetase (DARS). These mutations cause nonsynonymous changes to seven highly conserved amino acids, five of which are unchanged between yeast and man, in the DARS C-terminal lobe adjacent to, or within, the active-site pocket. Intriguingly, HBSL bears a striking resemblance to leukoencephalopathy with brain stem and spinal cord involvement and elevated lactate (LBSL), which is caused by mutations in the mitochondria-specific DARS2, suggesting that these two diseases might share a common underlying molecular pathology. These findings add to the growing body of evidence that mutations in tRNA synthetases can cause a broad range of neurologic disorders. PMID:23643384

  10. Mutation prediction by PolyPhen or functional assay, a detailed comparison of CYP27B1 missense mutations.

    PubMed

    Zou, Minjing; Baitei, Essa Y; Alzahrani, Ali S; Parhar, Ranjit S; Al-Mohanna, Futwan A; Meyer, Brian F; Shi, Yufei

    2011-08-01

    Vitamin D-dependent rickets type 1 (VDDR-I) is caused by mutation in CYP27B1. The glycine residue at codon 102 is not conserved between human (G(102)) and rodent (S(102)). G102E mutation results in 80% reduction in its enzymatic activity but PolyPhen predicts benign change. It is not known whether G102S has any damaging effect on 1α-hydroxylase activity. We investigated the effect of CYP27B1 (G102S) on its enzymatic activity and compared mutation prediction accuracy for all known CYP27B1 mutations among three free online protein prediction programs: PolyPhen, PolyPhen-2, and PSIPRED. G102S has no damaging effect on 1α-hydroxylase activity. G102D retained 30% enzymatic activity. All three programs correctly predicted damaging change for G102D. PolyPhen predicted benign change for G102S, whereas PolyPhen-2 and PSIPRED indicated possible damaging effect. Among 24 reported damaging mutations, PSIPRED, PolyPhen-2, and PolyPhen achieved 100%, 91.7% (22/24), and 75% (18/24) accuracy rate, respectively. The residues of incorrectly predicted mutations were not conserved. We conclude that G102D resulted in a significant reduction in 1α-hydroxylase activity, whereas G102S did not. PSIPRED and PolyPhen-2 are superior to PolyPhen in predicting damaging mutations. PMID:21604088

  11. Recurrent mutations at codon 625 of the splicing factor SF3B1 in uveal melanoma

    PubMed Central

    Harbour, J. William; Roberson, Elisha D. O.; Anbunathan, Hima; Onken, Michael D.; Worley, Lori A.; Bowcock, Anne M.

    2013-01-01

    Uveal melanoma is the most common primary cancer of the eye and often results in fatal metastasis. Here, we describe mutations occurring exclusively at arginine-625 in splicing factor 3B subunit 1 (SF3B1) in low-grade uveal melanomas with good prognosis. Thus, uveal melanoma is among a small group of cancers associated with SF3B1 mutation, and these mutations denote a distinct molecular subset of uveal melanomas. PMID:23313955

  12. Recurrent mutations at codon 625 of the splicing factor SF3B1 in uveal melanoma.

    PubMed

    Harbour, J William; Roberson, Elisha D O; Anbunathan, Hima; Onken, Michael D; Worley, Lori A; Bowcock, Anne M

    2013-02-01

    Uveal melanoma is the most common primary cancer of the eye and often results in fatal metastasis. Here, we describe mutations occurring exclusively at codon 625 of the SF3B1 gene, encoding splicing factor 3B subunit 1, in low-grade uveal melanomas with good prognosis. Thus, uveal melanoma is among a small group of cancers associated with SF3B1 mutations, and these mutations denote a distinct molecular subset of uveal melanomas. PMID:23313955

  13. Germ-line origins of mutation in families with hemophilia B: The sex ratio varies with the type of mutation

    SciTech Connect

    Ketterling, R.P.; Vielhaber, E.; Bottema, C.D.K.; Schaid, D.J.; Sommer, S.S. ); Cohen, M.P. ); Sexauer, C.L. )

    1993-01-01

    Previous epidemiological and biochemical studies have generated conflicting estimates of the sex ratio of mutation. Direct genomic sequencing in combination with haplotype analysis extends previous analyses by allowing the precise mutation to be determined in a given family. From analysis of the factor IX gene of 260 consecutive families with hemophilia B, the authors report the germ-line origin of mutation in 25 families. When combined with 14 origins of mutation reported by others and with 4 origins previously reported by them, a total of 25 occur in the female germ line, and 18 occur in the male germ line. The excess of germ-line origins in females does not imply an overall excess mutation rate per base pair in the female germ line. Bayesian analysis of the data indicates that the sex ratio varies with the type of mutation. The aggregate of single-base substitutions shows a male predominance of germ-line mutations (P < .002). The maximum-likelihood estimate of the male predominance is 3.5-fold. Of the single-base substitutions, deletions display a sex ratio of unity. Analysis of the parental age at transmission of a new mutation suggests that germ-line mutations are associated with a small increase in parental age in females but little, if any, increase in males. Although direct genomic sequencing offers a general method for defining the origin of mutation in specific families, accurate estimates of the sex ratios of different mutational classes require large sample sizes and careful correction for multiple biases of ascertainment. The biases in the present data result in an underestimate of the enhancement of mutation in males. 62 refs., 1 fig., 5 tabs.

  14. The site-directed mutation I(L177)H in Rhodobacter sphaeroides reaction center affects coordination of P(A) and B(B) bacteriochlorophylls.

    PubMed

    Vasilieva, L G; Fufina, T Y; Gabdulkhakov, A G; Leonova, M M; Khatypov, R A; Shuvalov, V A

    2012-08-01

    To explore the influence of the I(L177)H single mutation on the properties of the nearest bacteriochlorophylls (BChls), three reaction centers (RCs) bearing double mutations were constructed in the photosynthetic purple bacterium Rhodobacter sphaeroides, and their properties and pigment content were compared with those of the correspondent single mutant RCs. Each pair of the mutations comprised the amino acid substitution I(L177)H and another mutation altering histidine ligand of BChl P(A) or BChl B(B). Contrary to expectations, the double mutation I(L177)H+H(L173)L does not bring about a heterodimer RC but causes a 46nm blue shift of the long-wavelength P absorbance band. The histidine L177 or a water molecule were suggested as putative ligands for P(A) in the RC I(L177)H+H(L173)L although this would imply a reorientation of the His backbone and additional rearrangements in the primary donor environment or even a repositioning of the BChl dimer. The crystal structure of the mutant I(L177)H reaction center determined to a resolution of 2.9Å shows changes at the interface region between the BChl P(A) and the monomeric BChl B(B). Spectral and pigment analysis provided evidence for β-coordination of the BChl B(B) in the double mutant RC I(L177)H+H(M182)L and for its hexacoordination in the mutant reaction center I(L177)H. Computer modeling suggests involvement of two water molecules in the β-coordination of the BChl B(B). Possible structural consequences of the L177 mutation affecting the coordination of the two BChls P(A) and B(B) are discussed. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial. PMID:22365928

  15. Involvement of B cells in non-infectious uveitis

    PubMed Central

    Smith, Justine R; Stempel, Andrew J; Bharadwaj, Arpita; Appukuttan, Binoy

    2016-01-01

    Non-infectious uveitis—or intraocular inflammatory disease—causes substantial visual morbidity and reduced quality of life amongst affected individuals. To date, research of pathogenic mechanisms has largely been focused on processes involving T lymphocyte and/or myeloid leukocyte populations. Involvement of B lymphocytes has received relatively little attention. In contrast, B-cell pathobiology is a major field within general immunological research, and large clinical trials have showed that treatments targeting B cells are highly effective for multiple systemic inflammatory diseases. B cells, including the terminally differentiated plasma cell that produces antibody, are found in the human eye in different forms of non-infectious uveitis; in some cases, these cells outnumber other leukocyte subsets. Recent case reports and small case series suggest that B-cell blockade may be therapeutic for patients with non-infectious uveitis. As well as secretion of antibody, B cells may promote intraocular inflammation by presentation of antigen to T cells, production of multiple inflammatory cytokines and support of T-cell survival. B cells may also perform various immunomodulatory activities within the eye. This translational review summarizes the evidence for B-cell involvement in non-infectious uveitis, and considers the potential contributions of B cells to the development and control of the disease. Manipulations of B cells and/or their products are promising new approaches to the treatment of non-infectious uveitis. PMID:26962453

  16. Identification of Novel FAM134B (JK1) Mutations in Oesophageal Squamous Cell Carcinoma

    PubMed Central

    Haque, Md. Hakimul; Gopalan, Vinod; Chan, Kwok-wah; Shiddiky, Muhammad J. A.; Smith, Robert Anthony; Lam, Alfred King-yin

    2016-01-01

    Mutation of FAM134B (Family with Sequence Similarity 134, Member B) leading to loss of function of its encoded Golgi protein and has been reported induce apoptosis in neurological disorders. FAM134B mutation is still unexplored in cancer. Herein, we studied the DNA copy number variation and novel mutation sites of FAM134B in a large cohort of freshly collected oesophageal squamous cell carcinoma (ESCC) tissue samples. In ESCC tissues, 37% (38/102) showed increased FAM134B DNA copies whereas 35% (36/102) showed loss of FAM134B copies relative to matched non-cancer tissues. Novel mutations were detected in exons 4, 5, 7, 9 as well as introns 2, 4-8 of FAM134B via HRM (High-Resolution Melt) and Sanger sequencing analysis. Overall, thirty-seven FAM134B mutations were noted in which most (31/37) mutations were homozygous. FAM134B mutations were detected in all the cases with metastatic ESCC in the lymph node tested and in 14% (8/57) of the primary ESCC. Genetic alteration of FAM134B is a frequent event in the progression of ESCCs. These findings imply that mutation might be the major driving source of FAM134B genetic modulation in ESCCs. PMID:27373372

  17. Identification of Novel FAM134B (JK1) Mutations in Oesophageal Squamous Cell Carcinoma.

    PubMed

    Haque, Md Hakimul; Gopalan, Vinod; Chan, Kwok-Wah; Shiddiky, Muhammad J A; Smith, Robert Anthony; Lam, Alfred King-Yin

    2016-01-01

    Mutation of FAM134B (Family with Sequence Similarity 134, Member B) leading to loss of function of its encoded Golgi protein and has been reported induce apoptosis in neurological disorders. FAM134B mutation is still unexplored in cancer. Herein, we studied the DNA copy number variation and novel mutation sites of FAM134B in a large cohort of freshly collected oesophageal squamous cell carcinoma (ESCC) tissue samples. In ESCC tissues, 37% (38/102) showed increased FAM134B DNA copies whereas 35% (36/102) showed loss of FAM134B copies relative to matched non-cancer tissues. Novel mutations were detected in exons 4, 5, 7, 9 as well as introns 2, 4-8 of FAM134B via HRM (High-Resolution Melt) and Sanger sequencing analysis. Overall, thirty-seven FAM134B mutations were noted in which most (31/37) mutations were homozygous. FAM134B mutations were detected in all the cases with metastatic ESCC in the lymph node tested and in 14% (8/57) of the primary ESCC. Genetic alteration of FAM134B is a frequent event in the progression of ESCCs. These findings imply that mutation might be the major driving source of FAM134B genetic modulation in ESCCs. PMID:27373372

  18. Mutational and transcriptomic changes involved in the development of macrolide resistance in Campylobacter jejuni.

    PubMed

    Hao, Haihong; Yuan, Zonghui; Shen, Zhangqi; Han, Jing; Sahin, Orhan; Liu, Peng; Zhang, Qijing

    2013-03-01

    Macrolide antibiotics are important for clinical treatment of infections caused by Campylobacter jejuni. Development of resistance to this class of antibiotics in Campylobacter is a complex process, and the dynamic molecular changes involved in this process remain poorly defined. Multiple lineages of macrolide-resistant mutants were selected by stepwise exposure of C. jejuni to escalating doses of erythromycin or tylosin. Mutations in target genes were determined by DNA sequencing, and the dynamic changes in the expression of antibiotic efflux transporters and the transcriptome of C. jejuni were examined by real-time reverse transcription-PCR, immunoblotting, and DNA microarray analysis. Multiple types of mutations in ribosomal proteins L4 and L22 occurred early during stepwise selection. On the contrary, the mutations in the 23S rRNA gene, mediating high resistance to macrolides, were observed only in the late-stage mutants. Upregulation of antibiotic efflux genes was observed in the intermediately resistant mutants, and the magnitude of upregulation declined with the occurrence of mutations in the 23S rRNA gene. DNA microarray analysis revealed the differential expression of 265 genes, most of which occurred in the intermediate mutant, including the upregulation of genes encoding ribosomal proteins and the downregulation of genes involved in energy metabolism and motility. These results indicate (i) that mutations in L4 and L22 along with temporal overexpression of antibiotic efflux genes precede and may facilitate the development of high-level macrolide resistance and (ii) that the development of macrolide resistance affects the pathways important for physiology and metabolism in C. jejuni, providing an explanation for the reduced fitness of macrolide-resistant Campylobacter. PMID:23274667

  19. Gene Mutation Profiles in Primary Diffuse Large B Cell Lymphoma of Central Nervous System: Next Generation Sequencing Analyses

    PubMed Central

    Todorovic Balint, Milena; Jelicic, Jelena; Mihaljevic, Biljana; Kostic, Jelena; Stanic, Bojana; Balint, Bela; Pejanovic, Nadja; Lucic, Bojana; Tosic, Natasa; Marjanovic, Irena; Stojiljkovic, Maja; Karan-Djurasevic, Teodora; Perisic, Ognjen; Rakocevic, Goran; Popovic, Milos; Raicevic, Sava; Bila, Jelena; Antic, Darko; Andjelic, Bosko; Pavlovic, Sonja

    2016-01-01

    The existence of a potential primary central nervous system lymphoma-specific genomic signature that differs from the systemic form of diffuse large B cell lymphoma (DLBCL) has been suggested, but is still controversial. We investigated 19 patients with primary DLBCL of central nervous system (DLBCL CNS) using the TruSeq Amplicon Cancer Panel (TSACP) for 48 cancer-related genes. Next generation sequencing (NGS) analyses have revealed that over 80% of potentially protein-changing mutations were located in eight genes (CTNNB1, PIK3CA, PTEN, ATM, KRAS, PTPN11, TP53 and JAK3), pointing to the potential role of these genes in lymphomagenesis. TP53 was the only gene harboring mutations in all 19 patients. In addition, the presence of mutated TP53 and ATM genes correlated with a higher total number of mutations in other analyzed genes. Furthermore, the presence of mutated ATM correlated with poorer event-free survival (EFS) (p = 0.036). The presence of the mutated SMO gene correlated with earlier disease relapse (p = 0.023), inferior event-free survival (p = 0.011) and overall survival (OS) (p = 0.017), while mutations in the PTEN gene were associated with inferior OS (p = 0.048). Our findings suggest that the TP53 and ATM genes could be involved in the molecular pathophysiology of primary DLBCL CNS, whereas mutations in the PTEN and SMO genes could affect survival regardless of the initial treatment approach. PMID:27164089

  20. Gene Mutation Profiles in Primary Diffuse Large B Cell Lymphoma of Central Nervous System: Next Generation Sequencing Analyses.

    PubMed

    Todorovic Balint, Milena; Jelicic, Jelena; Mihaljevic, Biljana; Kostic, Jelena; Stanic, Bojana; Balint, Bela; Pejanovic, Nadja; Lucic, Bojana; Tosic, Natasa; Marjanovic, Irena; Stojiljkovic, Maja; Karan-Djurasevic, Teodora; Perisic, Ognjen; Rakocevic, Goran; Popovic, Milos; Raicevic, Sava; Bila, Jelena; Antic, Darko; Andjelic, Bosko; Pavlovic, Sonja

    2016-01-01

    The existence of a potential primary central nervous system lymphoma-specific genomic signature that differs from the systemic form of diffuse large B cell lymphoma (DLBCL) has been suggested, but is still controversial. We investigated 19 patients with primary DLBCL of central nervous system (DLBCL CNS) using the TruSeq Amplicon Cancer Panel (TSACP) for 48 cancer-related genes. Next generation sequencing (NGS) analyses have revealed that over 80% of potentially protein-changing mutations were located in eight genes (CTNNB1, PIK3CA, PTEN, ATM, KRAS, PTPN11, TP53 and JAK3), pointing to the potential role of these genes in lymphomagenesis. TP53 was the only gene harboring mutations in all 19 patients. In addition, the presence of mutated TP53 and ATM genes correlated with a higher total number of mutations in other analyzed genes. Furthermore, the presence of mutated ATM correlated with poorer event-free survival (EFS) (p = 0.036). The presence of the mutated SMO gene correlated with earlier disease relapse (p = 0.023), inferior event-free survival (p = 0.011) and overall survival (OS) (p = 0.017), while mutations in the PTEN gene were associated with inferior OS (p = 0.048). Our findings suggest that the TP53 and ATM genes could be involved in the molecular pathophysiology of primary DLBCL CNS, whereas mutations in the PTEN and SMO genes could affect survival regardless of the initial treatment approach. PMID:27164089

  1. Partial T and B lymphocyte immunodeficiency and predisposition to lymphoma in patients with hypomorphic mutations in Artemis

    PubMed Central

    Moshous, Despina; Pannetier, Christophe; Chasseval, Régina de; Deist, Françoise le; Cavazzana-Calvo, Marina; Romana, Serge; Macintyre, Elizabeth; Canioni, Danielle; Brousse, Nicole; Fischer, Alain; Casanova, Jean-Laurent; Villartay, Jean-Pierre de

    2003-01-01

    We have previously described the identification of Artemis, a factor involved in the nonhomologous end joining (NHEJ) phase of V(D)J recombination of T and B cell receptor genes. Null mutations of the Artemis gene result in a complete absence of T and B lymphocytes that is associated with increased cell radiosensitivity, causing the radiosensitive T–B– SCID (RS-SCID) condition. We presently report the occurrence of hypomorphic mutations of the Artemis gene in four patients from two kindreds. Partially preserved in vivo activity of Artemis is associated with the presence of polyclonal T and B lymphocyte populations, albeit in reduced numbers, along with chromosomal instability and development of EBV-associated lymphoma in two of four patients. This syndrome emphasizes the role of Artemis in the NHEJ pathway of DNA repair and suggests that other, yet ill-defined, conditions associating immunodeficiency and lymphoma could be caused by mutations in genes encoding NHEJ factors. PMID:12569164

  2. Identification of a Mutation in FGF23 Involved in Mandibular Prognathism

    PubMed Central

    Chen, Fengshan; Li, Qin; Gu, Mingliang; Li, Xin; Yu, Jun; Zhang, Yong-Biao

    2015-01-01

    Mandibular prognathism (MP) is a severe maxillofacial disorder with undetermined genetic background. We collected a Chinese pedigree with MP which involved in 23 living members of 4 generations. Genome-wide linkage analysis were carried out to obtain the information in this family and a new MP-susceptibility locus, 12pter-p12.3 was identified. Whole-exome sequencing identified a novel heterozygous mutation in fibroblast growth factor (FGF) 23 (; p.A12D) which well segregated with MP in this pedigree within the locus. The mutation was also detected in 3 cases out of 65 sporadic MP patients, but not in any of the 342 control subjects. The p.A12D mutation may disrupt signal peptide function and inhibit secretory in FGF23. Furthermore, mutant FGF23 was overexpressed in 293T cells, increased cytoplasmic accumulation was observed compared with the wild type. We have discovered that c.35C>A mutation in FGF23 strongly associated with MP, which expand our understanding of the genetic contribution to MP pathogenesis. PMID:26059428

  3. Renal, Ocular, and Neuromuscular Involvements in Patients with CLDN19 Mutations

    PubMed Central

    Chauveau, Dominique; Cintas, Pascal; Tack, Ivan; Cointault, Olivier; Rostaing, Lionel; Vargas-Poussou, Rosa; Ribes, David

    2011-01-01

    Summary Background and objectives The objective of this study was to describe the renal and extrarenal findings in patients with recessively inherited familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC) associated with CLDN19 mutations. Design, setting, participants, & measurements Medical records of three patients from two French unrelated families with CLDN19 mutations were retrospectively examined. Results Direct sequencing of CLDN19 identified a known variant (p.Gly20Asp) in all patients and a new missense mutation (p.Val44Met) in one (compound heterozygous). The patients' renal phenotype closely mimicked CLDN16-related nephropathy: low serum Mg2+ (<0.65 mmol/L) despite oral supplementation, hypercalciuria partly thiazide-sensitive, and progressive renal decline with ESRD reached at age 16 and 22 years in two individuals. Primary characteristics (failure to thrive, recurrent urinary tract infections, or abdominal pain), age at onset (0.8 to 16 years), and rate of renal decline were highly heterogeneous. Ocular involvement was identified in all patients, although two patients did not have visual loss. Additionally, exercise intolerance with pain, weakness, and electromyographical alterations mimicking a Ca2+/K+ channelopathy (pattern V) were observed in two of three individuals. These features persisted despite the normalization of serum K+ and Mg2+ after renal transplantation. Conclusions Ocular manifestations, even subtle, and exercise intolerance mimicking mild to moderate periodic paralysis are two symptoms that need to be searched for in patients with FHHNC and may indicate CLDN19 mutations. PMID:21030577

  4. Mutations in MYH7 cause Multi-minicore Disease (MmD) with variable cardiac involvement.

    PubMed

    Cullup, T; Lamont, P J; Cirak, S; Damian, M S; Wallefeld, W; Gooding, R; Tan, S V; Sheehan, J; Muntoni, F; Abbs, S; Sewry, C A; Dubowitz, V; Laing, N G; Jungbluth, H

    2012-12-01

    Central Core Disease (CCD) and Multi-minicore Disease (MmD) (the "core myopathies") have been mainly associated with mutations in the skeletal muscle ryanodine receptor (RYR1) and the selenoprotein N (SEPN1) gene. A proportion of cases remain unresolved. Mutations in MYH7 encoding the beta myosin heavy chain protein have been implicated in cardiac and, less frequently, skeletal muscle disorders. Here we report four patients from two families with a histopathological diagnosis of MmD, presenting in childhood with slowly progressive muscle weakness, more proximal in Family 1 and more distal in Family 2, and variable degrees of cardiorespiratory impairment evolving later in life. There was also a strong family history of sudden death in the first family. Muscle biopsies obtained in early childhood showed multiple minicores as the most prominent feature. Sequencing of the MYH7 gene revealed heterozygous missense mutations, c.4399C>G; p.Leu1467Val (exon 32) in Family 1 and c.4763G>C; p.Arg1588Pro (exon 34) in Family 2. These findings suggest MYH7 mutations as another cause of a myopathy with multiple cores, in particular if associated with dominant inheritance and cardiac involvement. However, clinical features previously associated with this genetic background, namely a more distal distribution of weakness and an associated cardiomyopathy, may only evolve over time. PMID:22784669

  5. Multi-systemic involvement in NGLY1-related disorder caused by two novel mutations.

    PubMed

    Heeley, Jennifer; Shinawi, Marwan

    2015-04-01

    NGLY1-related disorder is a newly described autosomal recessive condition characterized by neurological, hepatic, ophthalmological findings and associated with dysmorphic features, constipation and scoliosis. It is caused by mutations in NGLY1, which encodes an enzyme, N-glycanase 1, involved in deglycosylation of glycoproteins, an essential step in the endoplasmic reticulum-associated degradation (ERAD) pathway. The disorder has been described in eight patients. We investigated the molecular basis and phenotype of NGLY1-related disorder in an additional patient. The proband is a 14-year-old who presented in early infancy with profound hypotonia and elevated transaminases. Liver biopsy showed lipid accumulation with dilated endoplasmic reticulum. He exhibited global developmental delay, acquired microcephaly, seizures, involuntary body movements, muscle atrophy, absent reflexes, and poor growth. He had multiple procedures for lacrimal duct stenosis and strabismus and had intractable blepharitis. He had severe osteopenia and persistent hypocholesterolemia. Whole exome sequencing revealed two novel variants in NGLY1: a truncating mutation, c.347C > G (p.S116X), and a splicing mutation, c.881 + 5G (p.IVS5 + 5G>T), predicted to abolish the splice donor site of exon 5. This study, along with previously reported cases, suggests that mutations in NGLY1 cause a recognizable phenotype and targeted sequencing should be considered in patients with typical presentation. This study expands the molecular spectrum of NGLY1-related condition and suggests that osteopenia and hypocholesterolemia may be part of the phenotype. PMID:25707956

  6. Conditional Mutations in γ-Tubulin Reveal Its Involvement in Chromosome Segregation and Cytokinesis

    PubMed Central

    Hendrickson, Triscia W.; Yao, Joyce; Bhadury, Saswata; Corbett, Anita H.; Joshi, Harish C.

    2001-01-01

    γ-Tubulin is a conserved essential protein required for assembly and function of the mitotic spindle in humans and yeast. For example, human γ-tubulin can replace the γ-tubulin gene in Schizosaccharomyces pombe. To understand the structural/functional domains of γ-tubulin, we performed a systematic alanine-scanning mutagenesis of human γ-tubulin (TUBG1) and studied phenotypes of each mutant allele in S. pombe. Our screen, both in the presence and absence of the endogenous S. pombe γ-tubulin, resulted in 11 lethal mutations and 12 cold-sensitive mutations. Based on structural mapping onto a homology model of human γ-tubulin generated by free energy minimization, all deleterious mutations are found in residues predicted to be located on the surface, some in positions to interact with α- and/or β-tubulins in the microtubule lattice. As expected, one class of tubg1 mutations has either an abnormal assembly or loss of the mitotic spindle. Surprisingly, a subset of mutants with abnormal spindles does not arrest in M phase but proceeds through anaphase followed by abnormal cytokinesis. These studies reveal that in addition to its previously appreciated role in spindle microtubule nucleation, γ-tubulin is involved in the coordination of postmetaphase events, anaphase, and cytokinesis. PMID:11514629

  7. Nonsense mutation in the regulatory gene ETH2 involved in methionine biosynthesis in Saccharomyces cervisiae.

    PubMed

    Masselot, M; Robichon-Szulmajster, H

    1972-08-01

    Ethionine-resistant mutants, mapping at the locus eth2-the product of which is involved in pleiotropic regulation of methionine biosynthesis-have been isolated in a strain carrying five ochre nonsense mutations. Selection for nonsense suppressors in such a strain led to characterization of several allele-specific but gene non-specific suppressors which are active on the recessive heteroallele eth2-2 (resulting in partial recovery of sensitivity toward ethionine) as well as on the five other suppressible alleles. Two of these suppressors are unlinked to the eth2 gene and either dominant or semi-dominant. It is concluded that the mutation eth2-2 resulted in a nonsense codon. Enzyme studies indicate that this mutation results in a complete absence of an active product of gene eth2, in contrast with the effect of a former mutation eth2-1 which was interpreted as leading to a modified product of this gene (Cherest, Surdin-Kerjan and de Robichon-Szulmajster 1971). This conclusion is based on the absence of repressibility of methionine group I enzymes and the observation that in a heteroallelic diploid, eth2-1 expression is not masked by eth2-2. The nonsense suppressors studied lead to at least partial recovery of repressibility of methionine group I enzymes. All these results support the idea that the product of gene ETH2 is an aporepressor protein. PMID:4560067

  8. The myosin chaperone UNC45B is involved in lens development and autosomal dominant juvenile cataract

    PubMed Central

    Hansen, Lars; Comyn, Sophie; Mang, Yuan; Lind-Thomsen, Allan; Myhre, Layne; Jean, Francesca; Eiberg, Hans; Tommerup, Niels; Rosenberg, Thomas; Pilgrim, David

    2014-01-01

    Genome-wide linkage analysis, followed by targeted deep sequencing, in a Danish multigeneration family with juvenile cataract revealed a region of chromosome 17 co-segregating with the disease trait. Affected individuals were heterozygous for two potentially protein-disrupting alleles in this region, in ACACA and UNC45B. As alterations of the UNC45B protein have been shown to affect eye development in model organisms, effort was focused on the heterozygous UNC45B missense mutation. UNC45B encodes a myosin-specific chaperone that, together with the general heat shock protein HSP90, is involved in myosin assembly. The mutation changes p.Arg805 to Trp in the UCS domain, an amino acid that is highly conserved from yeast to human. UNC45B is strongly expressed in the heart and skeletal muscle tissue, but here we show expression in human embryo eye and zebrafish lens. The zebrafish mutant steif, carrying an unc45b nonsense mutation, has smaller eyes than wild-type embryos and shows accumulation of nuclei in the lens. Injection of RNA encoding the human wild-type UNC45B protein into the steif homozygous embryo reduced the nuclei accumulation and injection of human mutant UNC45B cDNA in wild-type embryos resulted in development of a phenotype similar to the steif mutant. The p.Arg805Trp alteration in the mammalian UNC45B gene suggests that developmental cataract may be caused by a defect in non-muscle myosin assembly during maturation of the lens fiber cells. PMID:24549050

  9. A ΔdinB mutation that sensitizes Escherichia coli to the lethal effects of UV and X-radiation

    PubMed Central

    Lee, Mei-Chong W.; Franco, Magdalena; Vargas, Doris M.; Hudman, Deborah A.; White, Steven J.; Fowler, Robert G.; Sargentini, Neil J.

    2014-01-01

    The DinB (PolIV) protein of Escherichia coli participates in several cellular functions. We investigated a dinB mutation, Δ(dinB-yafN)883(::kan) [referred to as ΔdinB883], which strongly sensitized E. coli cells to both UV- and X-radiation killing. Earlier reports indicated dinB mutations had no obvious effect on UV radiation sensitivity which we confirmed by showing that normal UV radiation sensitivity is conferred by the ΔdinB749 allele. Compared to a wild-type strain, the ΔdinB883 mutant was most sensitive (160-fold) in early to mid-logarithmic growth phase and much less sensitive (twofold) in late log or stationary phases, thus showing a growth phase-dependence for UV radiation sensitivity. This sensitizing effect of ΔdinB883 is assumed to be completely dependent upon the presence of UmuDC protein; since the ΔdinB883 mutation did not sensitize the ΔumuDC strain to UV radiation killing throughout log phase and early stationary phase growth. The DNA damage checkpoint activity of UmuDC was clearly affected by ΔdinB883 as shown by testing a umuC104 ΔdinB883 double-mutant. The sensitivities of the ΔumuDC strain and the ΔdinB883 ΔumuDC double-mutant strain were significantly greater than for the ΔdinB883 strain, suggesting that the ΔdinB883 allele only partially suppresses UmuDC activity. The ΔdinB883 mutation partially sensitized (fivefold) uvrA and uvrB strains to UV radiation, but did not sensitize a ΔrecA strain. A comparison of the DNA sequences of the ΔdinB883 allele with the sequences of the Δ(dinB-yafN)882(::kan) and ΔdinB749 alleles, which do not sensitize cells to UV radiation, revealed ΔdinB883 is likely a “gain-of-function” mutation. The ΔdinB883 allele encodes the first 54 amino acids of wild-type DinB followed by 29 predicted residues resulting from the continuation of the dinB reading frame into an adjacent insertion fragment. The resulting polypeptide is proposed to interfere directly or indirectly with UmuDC function

  10. Distinct phenotype of a Wilson disease mutation reveals a novel trafficking determinant in the copper transporter ATP7B

    PubMed Central

    Braiterman, Lelita T.; Murthy, Amrutha; Jayakanthan, Samuel; Nyasae, Lydia; Tzeng, Eric; Gromadzka, Grazyna; Woolf, Thomas B.; Lutsenko, Svetlana; Hubbard, Ann L.

    2014-01-01

    Wilson disease (WD) is a monogenic autosomal-recessive disorder of copper accumulation that leads to liver failure and/or neurological deficits. WD is caused by mutations in ATP7B, a transporter that loads Cu(I) onto newly synthesized cupro-enzymes in the trans-Golgi network (TGN) and exports excess copper out of cells by trafficking from the TGN to the plasma membrane. To date, most WD mutations have been shown to disrupt ATP7B activity and/or stability. Using a multidisciplinary approach, including clinical analysis of patients, cell-based assays, and computational studies, we characterized a patient mutation, ATP7BS653Y, which is stable, does not disrupt Cu(I) transport, yet renders the protein unable to exit the TGN. Bulky or charged substitutions at position 653 mimic the phenotype of the patient mutation. Molecular modeling and dynamic simulation suggest that the S653Y mutation induces local distortions within the transmembrane (TM) domain 1 and alter TM1 interaction with TM2. S653Y abolishes the trafficking-stimulating effects of a secondary mutation in the N-terminal apical targeting domain. This result indicates a role for TM1/TM2 in regulating conformations of cytosolic domains involved in ATP7B trafficking. Taken together, our experiments revealed an unexpected role for TM1/TM2 in copper-regulated trafficking of ATP7B and defined a unique class of WD mutants that are transport-competent but trafficking-defective. Understanding the precise consequences of WD-causing mutations will facilitate the development of advanced mutation-specific therapies. PMID:24706876

  11. Mutations in JMJD1C are involved in Rett syndrome and intellectual disability

    PubMed Central

    Sáez, Mauricio A.; Fernández-Rodríguez, Juana; Moutinho, Catia; Sanchez-Mut, Jose V.; Gomez, Antonio; Vidal, Enrique; Petazzi, Paolo; Szczesna, Karolina; Lopez-Serra, Paula; Lucariello, Mario; Lorden, Patricia; Delgado-Morales, Raul; de la Caridad, Olga J.; Huertas, Dori; Gelpí, Josep L.; Orozco, Modesto; López-Doriga, Adriana; Milà, Montserrat; Perez-Jurado, Luís A.; Pineda, Mercedes; Armstrong, Judith; Lázaro, Conxi; Esteller, Manel

    2016-01-01

    Purpose: Autism spectrum disorders are associated with defects in social response and communication that often occur in the context of intellectual disability. Rett syndrome is one example in which epilepsy, motor impairment, and motor disturbance may co-occur. Mutations in histone demethylases are known to occur in several of these syndromes. Herein, we aimed to identify whether mutations in the candidate histone demethylase JMJD1C (jumonji domain containing 1C) are implicated in these disorders. Genet Med 18 1, 378–385. Methods: We performed the mutational and functional analysis of JMJD1C in 215 cases of autism spectrum disorders, intellectual disability, and Rett syndrome without a known genetic defect. Genet Med 18 1, 378–385. Results: We found seven JMJD1C variants that were not present in any control sample (~ 6,000) and caused an amino acid change involving a different functional group. From these, two de novo JMJD1C germline mutations were identified in a case of Rett syndrome and in a patient with intellectual disability. The functional study of the JMJD1C mutant Rett syndrome patient demonstrated that the altered protein had abnormal subcellular localization, diminished activity to demethylate the DNA damage-response protein MDC1, and reduced binding to MECP2. We confirmed that JMJD1C protein is widely expressed in brain regions and that its depletion compromises dendritic activity. Genet Med 18 1, 378–385. Conclusions: Our findings indicate that mutations in JMJD1C contribute to the development of Rett syndrome and intellectual disability. Genet Med 18 1, 378–385. PMID:26181491

  12. Generalized epilepsy with febrile seizures plus: mutation of the sodium channel subunit SCN1B.

    PubMed

    Wallace, R H; Scheffer, I E; Parasivam, G; Barnett, S; Wallace, G B; Sutherland, G R; Berkovic, S F; Mulley, J C

    2002-05-14

    Generalized epilepsy with febrile seizures plus (GEFS(+)) is an important childhood genetic epilepsy syndrome with heterogeneous phenotypes, including febrile seizures (FS) and generalized epilepsies of variable severity. Forty unrelated GEFS(+) and FS patients were screened for mutations in the sodium channel beta-subunits SCN1B and SCN2B, and the second GEFS(+) family with an SCN1B mutation is described here. The family had 19 affected individuals: 16 with typical GEFS(+) phenotypes and three with other epilepsy phenotypes. Site-specific mutation within SCN1B remains a rare cause of GEFS(+), and the authors found no evidence to implicate SCN2B in this syndrome. PMID:12011299

  13. Mutational analysis of the myelin protein zero (MPZ) gene associated with Charcot-Marie-Tooth neuropathy type 1B

    SciTech Connect

    Roa, B.B.; Warner, L.E.; Lupski, J.R.

    1994-09-01

    The MPZ gene that maps to chromosome 1q22q23 encodes myelin protein zero, which is the most abundant peripheral nerve myelin protein that functions as a homophilic adhesion molecule in myelin compaction. Association of the MPZ gene with the dysmyelinating peripheral neuropathies Charcot-Marie-Tooth disease type 1B (CMT1B) and the more severe Dejerine-Sottas syndrome (DSS) was previously demonstrated by MPZ mutations identified in CMT1B and in rare DSS patients. In this study, the coding region of the MPZ gene was screened for mutations in a cohort of 74 unrelated patients with either CMT type 1 or DSS who do not carry the most common CMT1-associated molecular lesion of a 1.5 Mb DNA duplication on 17p11.2-p12. Heteroduplex analysis detected base mismatches in ten patients that were distributed over three exons of MPZ. Direct sequencing of PCR-amplified genomic DNA identified a de novo MPZ mutation associated with CMT1B that predicts an Ile(135)Thr substitution. This finding further confirms the role of MPZ in the CMT1B disease process. In addition, two polymorphisms were identified within the Gly(200) and Ser(228) codons that do not alter the respective amino acid residues. A fourth base mismatch in MPZ exon 3 detected by heteroduplex analysis is currently being characterized by direct sequence determination. Previously, four unrelated patients in this same cohort were found to have unique point mutations in the coding region of the PMP22 gene. The collective findings on CMT1 point mutations could suggest that regulatory region mutations, and possibly mutations in CMT gene(s) apart from the MPZ, PMP22 and Cx32 genes identified thus far, may prove to be significant for a number of CMT1 cases that do not involve DNA duplication.

  14. Temporal lobe epilepsy and GEFS+ phenotypes associated with SCN1B mutations.

    PubMed

    Scheffer, Ingrid E; Harkin, Louise A; Grinton, Bronwyn E; Dibbens, Leanne M; Turner, Samantha J; Zielinski, Marta A; Xu, Ruwei; Jackson, Graeme; Adams, Judith; Connellan, Mary; Petrou, Steven; Wellard, R Mark; Briellmann, Regula S; Wallace, Robyn H; Mulley, John C; Berkovic, Samuel F

    2007-01-01

    SCN1B, the gene encoding the sodium channel beta 1 subunit, was the first gene identified for generalized epilepsy with febrile seizures plus (GEFS+). Only three families have been published with SCN1B mutations. Here, we present four new families with SCN1B mutations and characterize the associated phenotypes. Analysis of SCN1B was performed on 402 individuals with various epilepsy syndromes. Four probands with missense mutations were identified. Detailed electroclinical phenotyping was performed on all available affected family members including quantitative MR imaging in those with temporal lobe epilepsy (TLE). Two new families with the original C121W SCN1B mutation were identified; novel mutations R85C and R85H were each found in one family. The following phenotypes occurred in the six families with SCN1B missense mutations: 22 febrile seizures, 20 febrile seizures plus, five TLE, three other GEFS+ phenotypes, two unclassified and ten unaffected individuals. All individuals with confirmed TLE had the C121W mutation; two underwent temporal lobectomy (one with hippocampal sclerosis and one without) and both are seizure free. We confirm the role of SCN1B in GEFS+ and show that the GEFS+ spectrum may include TLE alone. TLE with an SCN1B mutation is not a contraindication to epilepsy surgery. PMID:17020904

  15. [Mutational Analysis of Hemophilia B in Russia: Molecular-Genetic Study].

    PubMed

    Surin, V L; Demidova, E Yu; Selivanova, D S; Luchinina, Yu A; Salomashkina, V V; Pshenichnikova, O S; Likhacheva, E A

    2016-04-01

    Hemophilia B is a hereditary X-linked coagulation disorder. This pathology is caused by various defects in the factor IX gene, which is, being about 34 kb long and consisting of eight exons, localized in the Xq27 locus of the. X-chromosome long arm. Mutations were revealed in 56 unrelated patients with hemophilia B in this study by using direct sequencing of factor IX gene functionally important fragments. Forty-six mutations were found with prevailing missense mutations (n = 30). The rest of the mutations were nonsense (n = 4) and splicing (n = 4) mutations, large deletions (n = 3), microdeletions (n = 2), microinsertions (n = 2), and promoter mutations (n = 1). Eleven of 46 mutations were previously unknown for human populations. PMID:27529981

  16. nfxB as a Novel Target for Analysis of Mutation Spectra in Pseudomonas aeruginosa

    PubMed Central

    Miguel, Virginia; Argaraña, Carlos E.

    2013-01-01

    nfxB encodes a negative regulator of the mexCD-oprJ genes for drug efflux in the opportunistic pathogen Pseudomonas aeruginosa. Inactivating mutations in this transcriptional regulator constitute one of the main mechanisms of resistance to ciprofloxacin (Cipr). In this work, we evaluated the use of nfxB/Cipr as a new test system to study mutation spectra in P. aeruginosa. The analysis of 240 mutations in nfxB occurring spontaneously in the wild-type and mutator backgrounds or induced by mutagens showed that nfxB/Cipr offers several advantages compared with other mutation detection systems. Identification of nfxB mutations was easy since the entire open reading frame and its promoter region were sequenced from the chromosome using a single primer. Mutations detected in nfxB included all transitions and transversions, 1-bp deletions and insertions, >1-bp deletions and duplications. The broad mutation spectrum observed in nfxB relies on the selection of loss-of-function changes, as we confirmed by generating a structural model of the NfxB repressor and evaluating the significance of each detected mutation. The mutation spectra characterized in the mutS, mutT, mutY and mutM mutator backgrounds or induced by the mutagenic agents 2-aminopurine, cisplatin and hydrogen peroxide were in agreement with their predicted mutational specificities. Additionally, this system allowed the analysis of sequence context effects since point mutations occurred at 85 different sites distributed over the entire nfxB. Significant hotspots and preferred sequence contexts were observed for spontaneous and mutagen-induced mutation spectra. Finally, we demonstrated the utility of a luminescence-based reporter for identification of nfxB mutants previous to sequencing analysis. Thus, the nfxB/Cipr system in combination with the luminescent reporter may be a valuable tool for studying mutational processes in Pseudomonas spp. wherein the genes encoding the NfxB repressor and the associated efflux

  17. Chromosome 17q12 microdeletions but not intragenic HNF1B mutations link developmental kidney disease and psychiatric disorder.

    PubMed

    Clissold, Rhian L; Shaw-Smith, Charles; Turnpenny, Peter; Bunce, Benjamin; Bockenhauer, Detlef; Kerecuk, Larissa; Waller, Simon; Bowman, Pamela; Ford, Tamsin; Ellard, Sian; Hattersley, Andrew T; Bingham, Coralie

    2016-07-01

    Heterozygous mutations of the HNF1B gene are the commonest known monogenic cause of developmental kidney disease. Half of patients have a deletion (approximately 1.3 Mb) of chromosome 17q12, encompassing HNF1B plus 14 additional genes. This 17q12 deletion has been linked with an increased risk of neurodevelopmental disorders, such as autism. Here we compared the neurodevelopmental phenotype of 38 patients with HNF1B-associated renal disease due to an intragenic mutation in 18 patients or due to 17q12 deletion in 20 patients to determine whether haploinsufficiency of HNF1B is responsible for the neurodevelopmental phenotype. Significantly, brief behavioral screening in children with the deletion showed high levels of psychopathology and its impact. Eight individuals (40%) with a deletion had a clinical diagnosis of a neurodevelopmental disorder compared to none with an intragenic mutation. The 17q12 deletions were also associated with more autistic traits. Two independent clinical geneticists were able to predict the presence of a deletion with a sensitivity of 83% and specificity of 79% when assessing facial dysmorphic features as a whole. Thus, the 17q12 deletions but not HNF1B intragenic mutations are associated with neurodevelopmental disorders. Hence, the HNF1B gene is not involved in the neurodevelopmental phenotype of these patients. Nephrologists need to be aware of this association to ensure appropriate referral to psychiatric services. PMID:27234567

  18. Mutations in WNT9B are associated with Mayer-Rokitansky-Küster-Hauser syndrome.

    PubMed

    Waschk, D E J; Tewes, A-C; Römer, T; Hucke, J; Kapczuk, K; Schippert, C; Hillemanns, P; Wieacker, P; Ledig, S

    2016-05-01

    Mayer-Rokitansky-Küster-Hauser syndrome (MRKHS) is a well-known malformation pattern of the Müllerian ducts (MDs) characterized by congenital absence of the uterus and vagina. To date, most cases remain unexplained at molecular level. As female Wnt9b-/- mice show a MRKHS-like phenotype, WNT9B has emerged as a promising candidate gene for this disease. We performed retrospective sequence analyses of WNT9B in 226 female patients with disorders of the MDs, including 109 patients with MRKHS, as well as in 135 controls. One nonsense mutation and five likely pathogenic missense mutations were detected in WNT9B. Five of these mutations were found in cases with MRKHS accounting for 4.6% of the patients with this phenotype. No pathogenic mutations were detected in the control group (p = 0.017). Interestingly, all of the MRKHS patients with a WNT9B mutation were classified as MRKHS type 1, representing 8.5% of the cases from this subgroup. In previous studies, two of the patients with a WNT9B mutation were found to carry either an additional deletion of LHX1 or a missense mutation in TBX6. We conclude that mutations in WNT9B were frequently associated with MRKHS in our cohort and some cases may be explained by a digenic disease model. PMID:26610373

  19. Intracardiac Thrombosis Involving All Four Cardiac Chambers after Extracardiac Membranous Oxygenation Associated with MTHFR Mutations.

    PubMed

    Kim, Bong Jun; Song, Seung Hwan; Shin, Yu Rim; Park, Han Ki; Park, Young Hwan; Shin, Hong Ju

    2016-06-01

    A 4-month-old boy diagnosed with acute myocarditis was treated with extracorporeal membrane oxygenation (ECMO). Follow-up echocardiography eight hours after ECMO revealed intracardiac thrombosis involving all four heart chambers. Because of the high risk of systemic embolization due to a pedunculated thrombus of the aortic valve, we performed an emergency thrombectomy. After the operation, the patient had a minor neurologic sequela of left upper arm hypertonia, which had almost disappeared at the last outpatient clinic two months later. He was diagnosed with a major mutation in MTHFR (methylenetetrahydrofolate reductase), which is related to thrombosis. PMID:27298801

  20. Intracardiac Thrombosis Involving All Four Cardiac Chambers after Extracardiac Membranous Oxygenation Associated with MTHFR Mutations

    PubMed Central

    Kim, Bong Jun; Song, Seung Hwan; Shin, Yu Rim; Park, Han Ki; Park, Young Hwan; Shin, Hong Ju

    2016-01-01

    A 4-month-old boy diagnosed with acute myocarditis was treated with extracorporeal membrane oxygenation (ECMO). Follow-up echocardiography eight hours after ECMO revealed intracardiac thrombosis involving all four heart chambers. Because of the high risk of systemic embolization due to a pedunculated thrombus of the aortic valve, we performed an emergency thrombectomy. After the operation, the patient had a minor neurologic sequela of left upper arm hypertonia, which had almost disappeared at the last outpatient clinic two months later. He was diagnosed with a major mutation in MTHFR (methylenetetrahydrofolate reductase), which is related to thrombosis. PMID:27298801

  1. Telomerase reverse transcriptase promoter mutations in hepatitis B virus-associated hepatocellular carcinoma.

    PubMed

    Yang, Xunjun; Guo, Xiuchan; Chen, Yao; Chen, Guorong; Ma, Yin; Huang, Kate; Zhang, Yuning; Zhao, Qiongya; Winkler, Cheryl A; An, Ping; Lyu, Jianxin

    2016-05-10

    Telomerase reverse transcriptase (TERT) promoter mutations are among the most frequent noncoding somatic mutations in multiple cancers, including hepatocellular carcinoma (HCC). The clinical and pathological implications of TERT promoter mutations in hepatitis B virus (HBV)-associated HCC have not been resolved. To investigate TERT promoter mutations, protein expression, and their clinical-pathological implications, we sequenced the TERT promoter region for hotspot mutations in HCC tissues and performed immunostaining for TERT protein expression from HBV-associated HCC in Chinese patients. Of 276 HCC tumor DNA samples sequenced, 85 (31%) carried TERT promoter mutations. TERT promoter mutations were more frequent in those with low α-fetoprotein (AFP) serum levels (p = 0.03), advanced age (p = 0.04), and in those lacking HCC family history (p = 0.02), but were not correlated with HCC stages and grades. TERT protein levels were higher in HCC (n = 28) compared to normal liver tissues (n = 8) (p =0.001), but did not differ between mutated and non-mutated tumor tissues. In conclusion, TERT promoter mutations are common somatic mutations in HCC of Han Chinese with HBV infection. Detection of TERT promoter mutations in those with low levels of AFP may aid diagnosis of HCC with atypical presentation. PMID:27056898

  2. Modeling SF3B1 Mutations in Cancer: Advances, Challenges, and Opportunities.

    PubMed

    Inoue, Daichi; Abdel-Wahab, Omar

    2016-09-12

    In this issue of Cancer Cell, Obeng et al. identify the consequences of expressing the most common mutation in the spliceosomal gene SF3B1 on hematopoiesis. The knockin mouse model described represents a valuable tool to dissect the effects of SF3B1 mutations on transformation, splicing, and less well-characterized functions of SF3B1. PMID:27622329

  3. Spectrum and Consequences of SMC1A Mutations: The Unexpected Involvement of a Core Component of Cohesin in Human Disease

    PubMed Central

    Mannini, Linda; Liu, Jinglan; Krantz, Ian D.; Musio, Antonio

    2009-01-01

    SMC1A encodes a structural component of the cohesin complex, which isnecessary for sister chromatid cohesion. In addition to its canonical role, cohesin has been shown to be involved in gene expression regulation and maintenance of genome stability. Recently, it has been demonstrated that mutations in the SMC1A gene are responsible for Cornelia de Lange syndrome (CdLS). CdLS is a genetically heterogeneous multisystem developmental disorder with variable expressivity, typically characterized by consistent facial dysmorphia, upper extremity malformations, hirsutism, cardiac defects, growth and cognitive retardation, gastrointestinal abnormalities and other systemic involvement. SMC1A mutations have also been identified in colorectal cancers. So far a total of 26 different mutations of the SMC1A gene have been reported. All mutations reported to date are either missense or small in frame deletions that maintain the open reading frame and presumably result in a protein with residual function. The mutations involve all domains of the protein but appear to cluster in key functional loci. At the functional level, elucidation of the effects that specific SMC1A mutations have on cohesin activity will be necessary to understand the etiopathology of CdLS and its possible involvement in tumorigenesis. In this review, we summarize the current knowledge of SMC1A mutations. PMID:19842212

  4. Evidence of a wide spectrum of cardiac involvement due to ACAD9 mutations: Report on nine patients.

    PubMed

    Dewulf, Joseph P; Barrea, Catherine; Vincent, Marie-Françoise; De Laet, Corinne; Van Coster, Rudy; Seneca, Sara; Marie, Sandrine; Nassogne, Marie-Cécile

    2016-07-01

    Acyl-CoA dehydrogenase 9 (ACAD9) is a mitochondrial protein involved in oxidative phosphorylation complex I biogenesis. This protein also exhibits acyl-CoA dehydrogenase (ACAD) activity. ACAD9-mutated patients have been reported to suffer from primarily heart, muscle, liver, and nervous system disorders. ACAD9 mutation is suspected in cases of elevated lactic acid levels combined with complex I deficiency, and confirmed by ACAD9 gene analysis. At least 18 ACAD9-mutated patients have previously been reported, usually displaying severe cardiac involvement. We retrospectively studied nine additional patients from three unrelated families with a wide spectrum of cardiac involvement between the families as well as the patients from the same families. All patients exhibited elevated lactate levels. Deleterious ACAD9 mutations were identified in all patients except one for whom it was not possible to recover DNA. To our knowledge, this is one of the first reports on isolated mild ventricular hypertrophy due to ACAD9 mutation in a family with moderate symptoms during adolescence. This report also confirms that dilated cardiomyopathy may occur in conjunction with ACAD9 mutation and that some patients may respond clinically to riboflavin treatment. Of note, several patients suffered from patent ductus arteriosus (PDA), with one exhibiting a complex congenital heart defect. It is yet unknown whether these cardiac manifestations were related to ACAD9 mutation. In conclusion, this disorder should be suspected in the presence of lactic acidosis, complex I deficiency, and any cardiac involvement, even mild. PMID:27233227

  5. Evolution and mutations of hepatitis B virus quasispecies in genotype B and C during vertical transmission.

    PubMed

    Wu, Quanxin; Xu, Cheng; Li, Junnan; Li, Li; Yan, Guohua; Yue, Liangliang; Zeng, Yi; Huang, Hongfei; Deng, Guohong; Wang, Yuming

    2016-06-01

    Evolution patterns of HBV QS between genotype B and C during vertical transmission are not well understood. In this study, we enrolled 10 HBV infected mother-infant pairs (four pairs with genotype B, four pairs with genotype C, and two with co-infection) without anti-viral therapy. Serum HBV DNA of mothers and infants were sequenced, HBV QS complexity and diversity were analyzed, polymorphisms and mutation sites were recorded, and phylogenetic trees were performed. Our result showed that the QS complexities in P (amino acid), C/PreC (amino acid), and PreS1 (nucleotide) gene were significantly higher in mothers than in infants in pairs with genotype C (P < 0.05), however, full-length and other genes showed non-significant differences (P > 0.05). Unlike genotype C, QS complexity of P gene (nucleotide) was significantly higher in infants than in mothers (P < 0.05) in pairs with genotype B, similarly, QS complexities of full-length and other genes (except Pre S2) were also higher in infants than in mothers but without significant differences (P > 0.05). QS diversities of full-length and most genes in genotype B were comparable between mothers and their infants (P > 0.05), in pairs with genotype C, dS of P, X, RT genes, genetic distance of Pre S1 gene (amino acid) and dN of Pre S1 gene were significant higher in mothers than in infants (P < 0.05). Several HBV mutations correlated with immune escape, e antigen loss and drug resistance were observed in infants. The results indicated that differences of HBV QS evolution patterns between genotype B and C during vertical transmission might contribute to distinct prognosis. J. Med. Virol. 88:1018-1026, 2016. © 2015 Wiley Periodicals, Inc. PMID:26531675

  6. Delineation of Molecular Pathways Involved in Cardiomyopathies Caused by Troponin T Mutations.

    PubMed

    Gilda, Jennifer E; Lai, Xianyin; Witzmann, Frank A; Gomes, Aldrin V

    2016-06-01

    Familial hypertrophic cardiomyopathy (FHC) is associated with mild to severe cardiac problems and is the leading cause of sudden death in young people and athletes. Although the genetic basis for FHC is well-established, the molecular mechanisms that ultimately lead to cardiac dysfunction are not well understood. To obtain important insights into the molecular mechanism(s) involved in FHC, hearts from two FHC troponin T models (Ile79Asn [I79N] and Arg278Cys [R278C]) were investigated using label-free proteomics and metabolomics. Mutations in troponin T are the third most common cause of FHC, and the I79N mutation is associated with a high risk of sudden cardiac death. Most FHC-causing mutations, including I79N, increase the Ca(2+) sensitivity of the myofilament; however, the R278C mutation does not alter Ca(2+) sensitivity and is associated with a better prognosis than most FHC mutations. Out of more than 1200 identified proteins, 53 and 76 proteins were differentially expressed in I79N and R278C hearts, respectively, when compared with wild-type hearts. Interestingly, more than 400 proteins were differentially expressed when the I79N and R278C hearts were directly compared. The three major pathways affected in I79N hearts relative to R278C and wild-type hearts were the ubiquitin-proteasome system, antioxidant systems, and energy production pathways. Further investigation of the proteasome system using Western blotting and activity assays showed that proteasome dysfunction occurs in I79N hearts. Metabolomic results corroborate the proteomic data and suggest the glycolytic, citric acid, and electron transport chain pathways are important pathways that are altered in I79N hearts relative to R278C or wild-type hearts. Our findings suggest that impaired energy production and protein degradation dysfunction are important mechanisms in FHCs associated with poor prognosis and that cardiac hypertrophy is not likely needed for a switch from fatty acid to glucose metabolism

  7. Germline CARD11 mutation in a patient with severe congenital B cell lymphocytosis

    PubMed Central

    Brohl, Andrew S.; Stinson, Jeffrey; Su, Helen C.; Badgett, Thomas; Jennings, Chester D.; Sukumar, Gauthaman; Sindiri, Sivasish; Wang, Wei; Kardava, Lela; Moir, Susan; Dalgard, Clifton L.; Moscow, Jeffrey A.; Snow, Andrew L.; Khan, Javed

    2015-01-01

    Purpose Activating germline mutations in CARD11 have recently been linked to a rare genetic disorder associated with congenital B cell lymphocytosis. We describe a patient with a similar clinical phenotype who had a de novo germline G123D CARD11 mutation. Methods Whole exome sequencing was performed on DNA from the patient and his biological parents. Laboratory studies examined characteristics of the patient’s B and T lymphocytes. A CARD11 cDNA containing the mutation was transfected into a lymphocyte cell line to gain an understanding of its function. RNA sequencing was performed on samples from the patient and from patients with alternate germline CARD11 mutations and differential gene expression analysis was performed. Results The patient had a decade-long history of severe polyclonal B lymphocytosis in the 20,000–90,000 lymphocytes/mm3 range, which was markedly exacerbated by EBV infection and splenectomy at different times. He had a heterozygous germline CARD11 mutation causing a G123D amino acid substitution, which was demonstrated to induce NF-κB activation in unstimulated lymphocytes. In contrast to previous patients with CARD11 mutations, this patient’s B cells exhibited higher expression of several cell cycle progression genes, as well as enhanced proliferation and improved survival following B cell receptor stimulation. Conclusions This is the third reported germline and first de novo CARD11 mutation shown to cause congenital B cell lymphocytosis. The mutation was associated with a dramatically greater lymphocytosis than in previously described cases, disproportionate to the level of constitutive NF-κB activation. However, comparative review of the patient’s clinical history, combined with additional genomic and functional analyses, underscore other important variables that may affect pathophysiology or regulate mutant CARD11 function in B cell proliferation and disease. We now refer to these patients as having BENTA disease (B cell Expansion

  8. Mutation Processes in 293-Based Clones Overexpressing the DNA Cytosine Deaminase APOBEC3B

    PubMed Central

    Quist, Jelmar S.; Temiz, Nuri A.; Tutt, Andrew N. J.; Grigoriadis, Anita; Harris, Reuben S.

    2016-01-01

    Molecular, cellular, and clinical studies have combined to demonstrate a contribution from the DNA cytosine deaminase APOBEC3B (A3B) to the overall mutation load in breast, head/neck, lung, bladder, cervical, ovarian, and other cancer types. However, the complete landscape of mutations attributable to this enzyme has yet to be determined in a controlled human cell system. We report a conditional and isogenic system for A3B induction, genomic DNA deamination, and mutagenesis. Human 293-derived cells were engineered to express doxycycline-inducible A3B-eGFP or eGFP constructs. Cells were subjected to 10 rounds of A3B-eGFP exposure that each caused 80–90% cell death. Control pools were subjected to parallel rounds of non-toxic eGFP exposure, and dilutions were done each round to mimic A3B-eGFP induced population fluctuations. Targeted sequencing of portions of TP53 and MYC demonstrated greater mutation accumulation in the A3B-eGFP exposed pools. Clones were generated and microarray analyses were used to identify those with the greatest number of SNP alterations for whole genome sequencing. A3B-eGFP exposed clones showed global increases in C-to-T transition mutations, enrichments for cytosine mutations within A3B-preferred trinucleotide motifs, and more copy number aberrations. Surprisingly, both control and A3B-eGFP clones also elicited strong mutator phenotypes characteristic of defective mismatch repair. Despite this additional mutational process, the 293-based system characterized here still yielded a genome-wide view of A3B-catalyzed mutagenesis in human cells and a system for additional studies on the compounded effects of simultaneous mutation mechanisms in cancer cells. PMID:27163364

  9. Analysis of FOXO1 mutations in diffuse large B-cell lymphoma | Office of Cancer Genomics

    Cancer.gov

    Abstract: Diffuse large B-cell lymphoma (DLBCL) accounts for 30% to 40% of newly diagnosed lymphomas and has an overall cure rate of approximately 60%. Previously, we observed FOXO1 mutations in non-Hodgkin lymphoma patient samples. To explore the effects of FOXO1 mutations, we assessed FOXO1 status in 279 DLBCL patient samples and 22 DLBCL-derived cell lines.

  10. Novel mutations of APOB cause ApoB truncations undetectable in plasma and familial hypobetalipoproteinemia.

    PubMed

    Yue, Pin; Yuan, Bo; Gerhard, Daniela S; Neuman, Rosalind J; Isley, William L; Harris, William S; Schonfeld, Gustav

    2002-08-01

    Familial hypobetalipoproteinemia (FHBL) is a genetic disorder characterized by low levels of apoB-100 and LDL cholesterol. Truncation-producing mutations of apoB (chromosome 2) are among several potential causes of FHBL in patients. Ten new families with FHBL linked to chromosome 2 were identified. In Family 8, a 4432delT in exon 26 produces a frame-shift and a premature stop codon predicted to produce a truncated apoB-30.9. Even though this truncation is just 10 amino acid shorter than the well-documented apoB-31, which is readily detectable in plasma, apoB-30.9 is undetectable. Most truncations shorter than apoB-30 are not detectable in plasma. In Family 34, an acceptor splicing mutation at position -1 of exon 14 changes the acceptor splice site AG to AA. Two families (Family 50 and 52) had mutations (apoB-9 and apoB-29) reported previously. In Family 98, a novel point mutation in exon 26 (11163T>G) causes a premature stop codon, and produces a truncated apoB-80.5 readily detectable in plasma. Sequencing of the ApoB gene in families 1, 5, 18, 58, and 59 did not reveal mutations. PMID:12124991

  11. Mutations in pre-core and basic core promoter regions of hepatitis B virus in chronic hepatitis B patients

    PubMed Central

    Wang, Xiao-Ling; Ren, Jian-Ping; Wang, Xue-Qing; Wang, Xiao-Hong; Yang, Shao-Fang; Xiong, Yi

    2016-01-01

    AIM: To investigate the frequency of mutations in pre-core (pre-C) and basic core promoter (BCP) regions of hepatitis B virus (HBV) from Shanxi Province, and the association between mutations and disease related indexes. METHODS: One hundred chronic hepatitis B patients treated at Shanxi Province Hospital of Traditional Chinese Medicine were included in this study. PCR-reverse dot blot hybridization and mismatch amplification mutation assay (MAMA)-PCR were used to detect the mutations in the HBV pre-C and BCP regions. HBV DNA content and liver function were compared between patients with mutant HBV pre-C and BCP loci and those with wild-type loci. The consistency between PCR-reverse dot blot hybridization and MAMA-PCR for detecting mutations in the HBV pre-C and BCP regions was assessed. RESULTS: Of the 100 serum samples detected, 9.38% had single mutations in the pre-C region, 29.17% had single mutations in the BCP region, 41.67% had mutations in both BCP and pre-C regions, and 19.79% had wild-type loci. The rates of BCP and pre-C mutations were 65.7% and 34.3%, respectively, in hepatitis B e antigen (HBeAg) positive patients, and 84.6% and 96.2%, respectively, in HBeAg negative patients. The rate of pre-C mutations was significantly higher in HBeAg negative patients than in HBeAg positive patients (χ2 = 26.62, P = 0.00), but there was no significant difference in the distribution of mutations in the BCP region between HBeAg positive and negative patients (χ2 = 2.43, P = 0.12). The presence of mutations in the pre-C (Wilcoxon W = 1802.5, P = 0.00) and BCP regions (Wilcoxon W = 2906.5, P = 0.00) was more common in patients with low HBV DNA content. Both AST and GGT were significantly higher in patients with mutant pre-C and BCP loci than in those with wild-type loci (P < 0.05). PCR-reverse dot blot hybridization and MAMA-PCR for detection of mutations in the BCP and pre-C regions had good consistency, and the Kappa values obtained were 0.91 and 0.58, respectively

  12. Spectrum of HNF1B Mutations in a Large Cohort of Patients Who Harbor Renal Diseases

    PubMed Central

    Decramer, Stéphane; Pawtowski, Audrey; Morinière, Vincent; Bandin, Flavio; Knebelmann, Bertrand; Lebre, Anne-Sophie; Faguer, Stanislas; Guigonis, Vincent; Antignac, Corinne; Salomon, Rémi

    2010-01-01

    Background and objectives: Hepatocyte nuclear factor 1β (HNF1β) is a transcription factor that is critical for the development of kidney and pancreas. In humans, mutations in HNF1B lead to congenital anomalies of the kidney and urinary tract, pancreas atrophy, and maturity-onset diabetes of the young type 5 and genital malformations. Design, setting, participants, & measurements: We report HNF1B screening in a cohort of 377 unrelated cases with various kidney phenotypes (hyperechogenic kidneys with size not more than +3 SD, multicystic kidney disease, renal agenesis, renal hypoplasia, cystic dysplasia, or hyperuricemic tubulointerstitial nephropathy not associated with UMOD mutation). Results: We found a heterozygous mutation in 75 (19.9%) index cases, consisting of a deletion of the whole gene in 42, deletion of one exon in one, and small mutations in 32. Eighteen mutations were novel. De novo mutations accounted for 66% of deletions and 40% of small mutations. In patients who carried HNF1B mutation and for whom we were able to study prenatal ultrasonography (56 probands), isolated hyperechogenic kidneys with normal or slightly enhanced size were the more frequent (34 of 56) phenotype before birth. Various other prenatal renal phenotypes were associated with HNF1B mutations, at a lesser frequency. Diabetes developed in four probands. Hyperuricemia and hypomagnesemia, although not systematically investigated, were frequently associated. Conclusions: This large series showed that the severity of the renal disease associated with HNF1B mutations was extremely variable (from prenatal renal failure to normal renal function in adulthood) and was not correlated with the genotype. PMID:20378641

  13. Mutational analysis of ATP7B in Chinese Wilson disease patients.

    PubMed

    Hua, Rui; Hua, Fang; Jiao, Yonggeng; Pan, Yu; Yang, Xu; Peng, Shanshan; Niu, Junqi

    2016-01-01

    Wilson Disease (WD) is an inborn error of copper metabolism inherited in an autosomal recessive manner caused by the mutations in the P-type ATPase gene (ATP7B). In this study, we screen and detect the mutations of the ATP7B gene in unrelated Chinese WD patients. A total of 68 individuals from ten provinces of China with WD were recruited. Of them, 43 were males and 25 were females, and their onset ages were from 1 to 48 years with a median onset age of 22.2 years. All the exons and exon/intron boundaries of ATP7B gene of the patients were sequenced and aligned to the referred ATP7B gene sequence. The results suggested that 66 of the 68 patents carried with at least one mutation and 48 different mutations were identified including 34 missense, one synonymous, two nonsense, two splicing, and nine frameshift mutations (five insertion and four deletion). Among these mutations, c.2333G>T, c.2310C>G, c.2975C>T, and c.3443T>C were the most prevalent mutants and c.2310C>G always linked with c.2333G>T. The eighth, 11(th), and 18(th) exons carried more mutations (6/48, 5/48, and 5/48, respectively) than others. After comparing with the mutations reported previously, 22 out of the 48 mutations were identified as novel mutations. A popular algorithm, Polyphen-2, was used to predict the effects of the amino-acid substitution due to the mutations on the structure and function of ATP7B function and the predicted results indicated that all the missense mutations were unfavorable except c.121A>G and c.748G>A. Phenotype/genotype correlation analysis suggested that the patients with c.2975C>T or c.3809A>G often presented WD features before 12 years old while the patients with c.3443T>C almost presented WD after 12 years old. This is the first time to identify the common mutations contributing to early onset age in Chinese WD patients. Our study will broaden our knowledge about ATP7B mutations in WD patients. PMID:27398169

  14. Mutational analysis of ATP7B in Chinese Wilson disease patients

    PubMed Central

    Hua, Rui; Hua, Fang; Jiao, Yonggeng; Pan, Yu; Yang, Xu; Peng, Shanshan; Niu, Junqi

    2016-01-01

    Wilson Disease (WD) is an inborn error of copper metabolism inherited in an autosomal recessive manner caused by the mutations in the P-type ATPase gene (ATP7B). In this study, we screen and detect the mutations of the ATP7B gene in unrelated Chinese WD patients. A total of 68 individuals from ten provinces of China with WD were recruited. Of them, 43 were males and 25 were females, and their onset ages were from 1 to 48 years with a median onset age of 22.2 years. All the exons and exon/intron boundaries of ATP7B gene of the patients were sequenced and aligned to the referred ATP7B gene sequence. The results suggested that 66 of the 68 patents carried with at least one mutation and 48 different mutations were identified including 34 missense, one synonymous, two nonsense, two splicing, and nine frameshift mutations (five insertion and four deletion). Among these mutations, c.2333G>T, c.2310C>G, c.2975C>T, and c.3443T>C were the most prevalent mutants and c.2310C>G always linked with c.2333G>T. The eighth, 11th, and 18th exons carried more mutations (6/48, 5/48, and 5/48, respectively) than others. After comparing with the mutations reported previously, 22 out of the 48 mutations were identified as novel mutations. A popular algorithm, Polyphen-2, was used to predict the effects of the amino-acid substitution due to the mutations on the structure and function of ATP7B function and the predicted results indicated that all the missense mutations were unfavorable except c.121A>G and c.748G>A. Phenotype/genotype correlation analysis suggested that the patients with c.2975C>T or c.3809A>G often presented WD features before 12 years old while the patients with c.3443T>C almost presented WD after 12 years old. This is the first time to identify the common mutations contributing to early onset age in Chinese WD patients. Our study will broaden our knowledge about ATP7B mutations in WD patients. PMID:27398169

  15. Early white matter involvement in an infant carrying a novel mutation in ACOX1.

    PubMed

    Masson, R; Guerra, S; Cerini, R; Pensato, V; Gellera, C; Taroni, F; Simonati, A

    2016-05-01

    We describe the clinical findings and MRI features observed in a child who presented a two-step disease course: he was hypotonic at birth and soon afterwards developed seizures, which were partially responsive to treatment; he subsequently showed developmental delay and a progressive neurological deterioration with the onset of severe seizures at around three years of age. Head MRI at age 20 days was unremarkable, whereas at 25 months it showed bilateral hyperintensity of the deep cerebellar nuclei; five months later, the signal hyperintensity was also present in the cerebellar white matter and ventral pontine fibre tracts. Molecular analysis revealed a novel ACOX1 mutation, predicting a largely truncated protein. The white matter involvement, which followed an ascending trajectory from cerebellar and brainstem structures to the cerebral hemispheres, seemed to originate from the perinuclear white matter of the deep cerebellar nuclei. PMID:26965209

  16. MNGIE with lack of skeletal muscle involvement and a novel TP splice site mutation.

    PubMed

    Szigeti, K; Wong, L-J C; Perng, C-L; Saifi, G M; Eldin, K; Adesina, A M; Cass, D L; Hirano, M; Lupski, J R; Scaglia, F

    2004-02-01

    Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is an autosomal recessive multisystem disorder caused by thymidine phosphorylase (TP) deficiency, resulting in severe gastrointestinal dysmotility and skeletal muscle abnormalities. A patient is reported with a classical MNGIE clinical presentation but without skeletal muscle involvement at morphological, enzymatic, or mitochondrial DNA level, though gastrointestinal myopathy was present. MNGIE was diagnosed by markedly raised plasma thymidine and reduced thymidine phosphorylase activity. Molecular genetic analysis showed a homozygous novel splice site mutation in TP. On immunohistochemical studies there was marked TP expression in the CNS, in contrast to what has been observed in rodents. It is important to examine the most significantly affected tissue and to measure TP activity and plasma thymidine in order to arrive at an accurate diagnosis in this condition. PMID:14757860

  17. Mutations in STX1B, encoding a presynaptic protein, cause fever-associated epilepsy syndromes.

    PubMed

    Schubert, Julian; Siekierska, Aleksandra; Langlois, Mélanie; May, Patrick; Huneau, Clément; Becker, Felicitas; Muhle, Hiltrud; Suls, Arvid; Lemke, Johannes R; de Kovel, Carolien G F; Thiele, Holger; Konrad, Kathryn; Kawalia, Amit; Toliat, Mohammad R; Sander, Thomas; Rüschendorf, Franz; Caliebe, Almuth; Nagel, Inga; Kohl, Bernard; Kecskés, Angela; Jacmin, Maxime; Hardies, Katia; Weckhuysen, Sarah; Riesch, Erik; Dorn, Thomas; Brilstra, Eva H; Baulac, Stephanie; Møller, Rikke S; Hjalgrim, Helle; Koeleman, Bobby P C; Jurkat-Rott, Karin; Lehman-Horn, Frank; Roach, Jared C; Glusman, Gustavo; Hood, Leroy; Galas, David J; Martin, Benoit; de Witte, Peter A M; Biskup, Saskia; De Jonghe, Peter; Helbig, Ingo; Balling, Rudi; Nürnberg, Peter; Crawford, Alexander D; Esguerra, Camila V; Weber, Yvonne G; Lerche, Holger

    2014-12-01

    Febrile seizures affect 2-4% of all children and have a strong genetic component. Recurrent mutations in three main genes (SCN1A, SCN1B and GABRG2) have been identified that cause febrile seizures with or without epilepsy. Here we report the identification of mutations in STX1B, encoding syntaxin-1B, that are associated with both febrile seizures and epilepsy. Whole-exome sequencing in independent large pedigrees identified cosegregating STX1B mutations predicted to cause an early truncation or an in-frame insertion or deletion. Three additional nonsense or missense mutations and a de novo microdeletion encompassing STX1B were then identified in 449 familial or sporadic cases. Video and local field potential analyses of zebrafish larvae with antisense knockdown of stx1b showed seizure-like behavior and epileptiform discharges that were highly sensitive to increased temperature. Wild-type human syntaxin-1B but not a mutated protein rescued the effects of stx1b knockdown in zebrafish. Our results thus implicate STX1B and the presynaptic release machinery in fever-associated epilepsy syndromes. PMID:25362483

  18. A homozygous mutation of voltage-gated sodium channel β(I) gene SCN1B in a patient with Dravet syndrome.

    PubMed

    Ogiwara, Ikuo; Nakayama, Tojo; Yamagata, Tetsushi; Ohtani, Hideyuki; Mazaki, Emi; Tsuchiya, Shigeru; Inoue, Yushi; Yamakawa, Kazuhiro

    2012-12-01

    Dravet syndrome is a severe form of epileptic encephalopathy characterized by early onset epileptic seizures followed by ataxia and cognitive decline. Approximately 80% of patients with Dravet syndrome have been associated with heterozygous mutations in SCN1A gene encoding voltage-gated sodium channel (VGSC) α(I) subunit, whereas a homozygous mutation (p.Arg125Cys) of SCN1B gene encoding VGSC β(I) subunit was recently described in a patient with Dravet syndrome. To further examine the involvement of homozygous SCN1B mutations in the etiology of Dravet syndrome, we performed mutational analyses on SCN1B in 286 patients with epileptic disorders, including 67 patients with Dravet syndrome who have been negative for SCN1A and SCN2A mutations. In the cohort, we found one additional homozygous mutation (p.Ile106Phe) in a patient with Dravet syndrome. The identified homozygous SCN1B mutations indicate that SCN1B is an etiologic candidate underlying Dravet syndrome. PMID:23148524

  19. Catalysis of Methyl Group Transfers Involving Tetrahydrofolate and B12

    PubMed Central

    Ragsdale, Stephen W.

    2011-01-01

    This review focuses on the reaction mechanism of enzymes that use B12 and tetrahydrofolate (THF) to catalyze methyl group transfers. It also covers the related reactions that use B12 and tetrahydromethanopterin (THMPT), which is a THF analog used by archaea. In the past decade, our understanding of the mechanisms of these enzymes has increased greatly because the crystal structures for three classes of B12-dependent methyltransferases have become available and because biophysical and kinetic studies have elucidated the intermediates involved in catalysis. These steps include binding of the cofactors and substrates, activation of the methyl donors and acceptors, the methyl transfer reaction itself, and product dissociation. Activation of the methyl donor in one class of methyltransferases is achieved by an unexpected proton transfer mechanism. The cobalt (Co) ion within the B12 macrocycle must be in the Co(I) oxidation state to serve as a nucleophile in the methyl transfer reaction. Recent studies have uncovered important principles that control how this highly reducing active state of B12 is generated and maintained. PMID:18804699

  20. Multisystem disorder associated with a missense mutation in the mitochondrial cytochrome b gene.

    PubMed

    Wibrand, F; Ravn, K; Schwartz, M; Rosenberg, T; Horn, N; Vissing, J

    2001-10-01

    Mitochondrial cytochrome b mutations have been reported to have a homogenous phenotype of pure exercise intolerance. We describe a novel mutation in the cytochrome b gene of mitochondrial DNA (A15579G) associated with a selective decrease of muscle complex III activity in a patient who, besides severe exercise intolerance, also has multisystem manifestations (deafness, mental retardation, retinitis pigmentosa, cataract, growth retardation, epilepsy). The point mutation is heteroplasmic in muscle (88%) and leukocytes (15%), and changes a highly conserved tyrosine to cysteine at amino acid position 278. PMID:11601507

  1. Familial ligand-defective apolipoprotein B. Identification of a new mutation that decreases LDL receptor binding affinity.

    PubMed

    Pullinger, C R; Hennessy, L K; Chatterton, J E; Liu, W; Love, J A; Mendel, C M; Frost, P H; Malloy, M J; Schumaker, V N; Kane, J P

    1995-03-01

    Detection of new ligand-defective mutations of apolipoprotein B (apoB) will enable identification of sequences involved in binding to the LDL receptor. Genomic DNA from patients attending a lipid clinic was screened by single-strand conformation polymorphism analysis for novel mutations in the putative LDL receptor-binding domain of apoB-100. A 46-yr-old woman of Celtic and Native American ancestry with primary hypercholesterolemia (total cholesterol [TC] 343 mg/dl; LDL cholesterol [LDL-C] 241 mg/dl) and pronounced peripheral vascular disease was found to be heterozygous for a novel Arg3531-->Cys mutation, caused by a C-->T transition at nucleotide 10800. One unrelated 59-yr-old man of Italian ancestry was found with the same mutation after screening 1,560 individuals. He had coronary heart disease, a TC of 310 mg/dl, and an LDL-C of 212 mg/dl. A total of eight individuals were found with the defect in the families of the two patients. They had an age- and sex-adjusted TC of 240 +/- 14 mg/dl and LDL-C of 169 +/- 10 mg/dl. This compares with eight unaffected family members with age- and sex-adjusted TC of 185 +/- 12 mg/dl and LDL-C of 124 +/- 12 mg/dl. In a dual-label fibroblast binding assay, LDL from the eight subjects with the mutation had an affinity for the LDL receptor that was 63% that of control LDL. LDL from eight unaffected family members had an affinity of 91%. By way of comparison, LDL from six patients heterozygous for the Arg3500-->Gln mutation had an affinity of 36%. The percentage mass ratio of the defective Cys3531 LDL to normal LDL was 59:41, as determined using the mAb MB19 and dynamic laser light scattering. Thus, the defective LDL had accumulated in the plasma of these patients. Using this mass ratio, it was calculated that the defective Cys3531 LDL particles bound with 27% of normal affinity. Deduced haplotypes using 10 apoB gene markers showed the Arg3531-->Cys alleles to be different in the two kindreds and indicates that the mutations arose

  2. 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

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

    PubMed

    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

    2016-05-01

    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

  4. Myelin protein zero gene mutated in Charcot-Marie-Tooth type 1B patients

    SciTech Connect

    Su, Ying; Li, Lanying; Lepercq, J.; Lebo, R.V. ); Brooks, D.G.; Ravetch, J.V. ); Trofatter, J.A. )

    1993-11-15

    The autosomal dominant of Charcot-Marie-Tooth disease (CMT), whose gene is type 1B (CMT1B), has slow nerve conduction with demyelinated Schwann cells. In this study the abundant peripheral myelin protein zero (MPZ) gene, MPZ, was mapped 130 kb centromeric to the Fc receptor immunoglobulin gene cluster in band 1q22, and a major MPZ point mutation was found to cosegregate with CMT1B in one large CMT1B family. The MPZ point mutation in 18 of 18 related CMT1B pedigree 1 patients converts a positively charged lysine in codon 96 to a negatively charged glutamate. The same MPZ locus cosegregates with the CMT1B disease gene in a second CMT1B family [total multipoint logarithm of odds (lod) = 11.4 at [theta] = 0.00] with a splice junction mutation. Both mutations occur in MPZ protein regions otherwise conserved identically in human, rat, and cow since these species diverged 100 million years ago. MPZ protein, expressed exclusively in myelinated peripheral nerve Schwann cells, constitutes >50% of myelin protein. These mutations are anticipated to disrupt homophilic MPZ binding and result in CMT1B peripheral nerve demyelination.

  5. Occurrence and new mutations involved in rifampicin-resistant Propionibacterium acnes strains isolated from biofilm or device-related infections.

    PubMed

    Furustrand Tafin, Ulrika; Aubin, Guillaume Ghislain; Eich, Gerhard; Trampuz, Andrej; Corvec, Stéphane

    2015-08-01

    We described for the first time the amino acid substitutions conferring rifampicin resistance in eight Propionibacterium acnes strains isolated from patients with biofilm or device-related infections. We identified different mutations in cluster I and one mutation, never reported, in cluster II of the rpoB gene (I480V) associated with the most frequent one in cluster I (S442L). Half of the patients previously received treatment with rifampicin. PMID:25999299

  6. MEF2B mutations in non-Hodgkin lymphoma dysregulate cell migration by decreasing MEF2B target gene activation

    PubMed Central

    Pon, Julia R.; Wong, Jackson; Saberi, Saeed; Alder, Olivia; Moksa, Michelle; Grace Cheng, S. -W.; Morin, Gregg B.; Hoodless, Pamela A.; Hirst, Martin; Marra, Marco A.

    2015-01-01

    Myocyte enhancer factor 2B (MEF2B) is a transcription factor with mutation hotspots at K4, Y69 and D83 in diffuse large B-cell lymphoma (DLBCL). To provide insight into the regulatory network of MEF2B, in this study, we analyse global gene expression and DNA-binding patterns. We find that candidate MEF2B direct target genes include RHOB, RHOD, CDH13, ITGA5 and CAV1, and that indirect target genes of MEF2B include MYC, TGFB1, CARD11, MEF2C, NDRG1 and FN1. MEF2B overexpression increases HEK293A cell migration and epithelial–mesenchymal transition, and decreases DLBCL cell chemotaxis. K4E, Y69H and D83V MEF2B mutations decrease the capacity of MEF2B to activate transcription and decrease its' effects on cell migration. The K4E and D83V mutations decrease MEF2B DNA binding. In conclusion, our map of the MEF2B regulome connects MEF2B to drivers of oncogenesis. PMID:26245647

  7. MEF2B mutations in non-Hodgkin lymphoma dysregulate cell migration by decreasing MEF2B target gene activation.

    PubMed

    Pon, Julia R; Wong, Jackson; Saberi, Saeed; Alder, Olivia; Moksa, Michelle; Grace Cheng, S-W; Morin, Gregg B; Hoodless, Pamela A; Hirst, Martin; Marra, Marco A

    2015-01-01

    Myocyte enhancer factor 2B (MEF2B) is a transcription factor with mutation hotspots at K4, Y69 and D83 in diffuse large B-cell lymphoma (DLBCL). To provide insight into the regulatory network of MEF2B, in this study, we analyse global gene expression and DNA-binding patterns. We find that candidate MEF2B direct target genes include RHOB, RHOD, CDH13, ITGA5 and CAV1, and that indirect target genes of MEF2B include MYC, TGFB1, CARD11, MEF2C, NDRG1 and FN1. MEF2B overexpression increases HEK293A cell migration and epithelial-mesenchymal transition, and decreases DLBCL cell chemotaxis. K4E, Y69H and D83V MEF2B mutations decrease the capacity of MEF2B to activate transcription and decrease its' effects on cell migration. The K4E and D83V mutations decrease MEF2B DNA binding. In conclusion, our map of the MEF2B regulome connects MEF2B to drivers of oncogenesis. PMID:26245647

  8. Mitochondrial 12S rRNA A827G mutation is involved in the genetic susceptibility to aminoglycoside ototoxicity

    SciTech Connect

    Xing Guangqian; Chen Zhibin; Wei Qinjun; Tian Huiqin; Li Xiaolu; Zhou Aidong; Bu Xingkuan; Cao Xin . E-mail: caoxin@njmu.edu.cn

    2006-08-11

    We have analyzed the clinical and molecular characterization of a Chinese family with aminoglycoside-induced and non-syndromic hearing impairment. Clinical evaluations revealed that only those family members who had a history of exposure to aminoglycoside antibiotics subsequently developed hearing loss, suggesting mitochondrial genome involvement. Sequence analysis of the mitochondrial 12S rRNA and tRNA{sup Ser(UCN)} genes led to the identification of a homoplasmic A827G mutation in all maternal relatives, a mutation that was identified previously in a few sporadic patients and in another Chinese family with non-syndromic deafness. The pathogenicity of the A827G mutation is strongly supported by the occurrence of the same mutation in two independent families and several genetically unrelated subjects. The A827G mutation is located at the A-site of the mitochondrial 12S rRNA gene which is highly conserved in mammals. It is possible that the alteration of the tertiary or quaternary structure of this rRNA by the A827G mutation may lead to mitochondrial dysfunction, thereby playing a role in the pathogenesis of hearing loss and aminoglycoside hypersensitivity. However, incomplete penetrance of hearing impairment indicates that the A827G mutation itself is not sufficient to produce clinical phenotype but requires the involvement of modifier factors for the phenotypic expression. Indeed, aminoglycosides may contribute to the phenotypic manifestation of the A827G mutation in this family. In contrast with the congenital or early-onset hearing impairment in another Chinese family carrying the A827G mutation, three patients in this pedigree developed hearing loss only after use of aminoglycosides. This discrepancy likely reflects the difference of genetic backgrounds, either mitochondrial haplotypes or nuclear modifier genes, between two families.

  9. CD45RO enriches for activated, highly mutated human germinal center B cells

    PubMed Central

    Jackson, Stephen M.; Harp, Natessa; Patel, Darshna; Zhang, Jeffrey; Willson, Savannah; Kim, Yoon J.; Clanton, Christian

    2007-01-01

    To date, there is no consensus regarding the influence of different CD45 isoforms during peripheral B-cell development. Examining correlations between surface CD45RO expression and various physiologic processes ongoing during the germinal center (GC) reaction, we hypothesized that GC B cells, like T cells, that up-regulate surface RO should progressively acquire phenotypes commonly associated with activated, differentiating lymphocytes. GC B cells (IgD−CD38+) were subdivided into 3 surface CD45RO fractions: RO−, RO+/−, and RO+. We show here that the average number of mutations per IgVH transcript increased in direct correlation with surface RO levels. Conjunctional use of RO and CD69 further delineated low/moderately and highly mutated fractions. Activation-induced cytidine deaminase (AID) mRNA was slightly reduced among RO+ GC B cells, suggesting that higher mutation averages are unlikely due to elevated somatic mutation activity. Instead, RO+ GC B cells were negative for Annexin V, comprised mostly (93%) of CD77− centrocytes, and were enriched for CD69+ cells. Collectively, RO+ GC B cells occupy what seems to be a specialized niche comprised mostly of centrocytes that may be in transition between activation states. These findings are among the first to sort GC B cells into populations enriched for live mutated cells solely using a single extracellular marker. PMID:17644737

  10. SOCS1 Mutation Subtypes Predict Divergent Outcomes in Diffuse Large B-Cell Lymphoma (DLBCL) Patients

    PubMed Central

    Kohler, Christian W.; Bentink, Stefan; Kreuz, Markus; Melzner, Ingo; Ritz, Olga; Trümper, Lorenz; Loeffler, Markus; Spang, Rainer; Möller, Peter

    2013-01-01

    Suppressor of cytokine signaling 1 (SOCS1) is frequently mutated in primary mediastinal and diffuse large B-cell lymphomas (DLBCL). Currently, the prognostic relevance of these mutations in DLBCL is unknown. To evaluate the value of the SOCS1 mutation status as a prognostic biomarker in DLBCL patients, we performed full-length SOCS1 sequencing in tumors of 154 comprehensively characterized DLBCL patients. We identified 90 SOCS1 mutations in 16% of lymphomas. With respect to molecular consequences of mutations, we defined two distinct subtypes: those with truncating (major) and those with non-truncating mutations (minor), respectively. The SOCS1 mutated subgroup or the minor/major subtypes cannot be predicted on clinical grounds; however, assignment of four established gene-expression profile-based classifiers revealed significant associations of SOCS1 major cases with germinal center and specific pathway activation pattern signatures. Above all, SOCS1 major cases have an excellent overall survival, even better than the GCB-like subgroup. SOCS1 minor cases had a dismal survival, even worse than the ABC gene signature group. The SOCS1 mutation subsets retained prognostic significance in uni- and multivariate analyses. Together our data indicate that assessment of the SOCS1 mutation status is a single gene prognostic biomarker in DLBCL. PMID:23296022

  11. Discovery of somatic STAT5b mutations in large granular lymphocytic leukemia

    PubMed Central

    Rajala, Hanna L. M.; Eldfors, Samuli; Kuusanmäki, Heikki; van Adrichem, Arjan J.; Olson, Thomas; Lagström, Sonja; Andersson, Emma I.; Jerez, Andres; Clemente, Michael J.; Yan, Yiyi; Zhang, Dan; Awwad, Andy; Ellonen, Pekka; Kallioniemi, Olli; Wennerberg, Krister; Porkka, Kimmo; Maciejewski, Jaroslaw P.; Loughran, Thomas P.; Heckman, Caroline

    2013-01-01

    Large granular lymphocytic (LGL) leukemia is characterized by clonal expansion of cytotoxic T cells or natural killer cells. Recently, somatic mutations in the signal transducer and activator of transcription 3 (STAT3) gene were discovered in 28% to 40% of LGL leukemia patients. By exome and transcriptome sequencing of 2 STAT3 mutation-negative LGL leukemia patients, we identified a recurrent, somatic missense mutation (Y665F) in the Src-like homology 2 domain of the STAT5b gene. Targeted amplicon sequencing of 211 LGL leukemia patients revealed 2 additional patients with STAT5b mutations (N642H), resulting in a total frequency of 2% (4 of 211) of STAT5b mutations across all patients. The Y665F and N642H mutant constructs increased the transcriptional activity of STAT5 and tyrosine (Y694) phosphorylation, which was also observed in patient samples. The clinical course of the disease in patients with the N642H mutation was aggressive and fatal, clearly different from typical LGL leukemia with a relatively favorable outcome. This is the first time somatic STAT5 mutations are discovered in human cancer and further emphasizes the role of STAT family genes in the pathogenesis of LGL leukemia. PMID:23596048

  12. Genome-wide profiling identifies a DNA methylation signature that associates with TET2 mutations in diffuse large B-cell lymphoma.

    PubMed

    Asmar, Fazila; Punj, Vasu; Christensen, Jesper; Pedersen, Marianne T; Pedersen, Anja; Nielsen, Anders B; Hother, Christoffer; Ralfkiaer, Ulrik; Brown, Peter; Ralfkiaer, Elisabeth; Helin, Kristian; Grønbæk, Kirsten

    2013-12-01

    The discovery that the Ten-Eleven Translocation (TET) hydroxylases cause DNA demethylation has fundamentally changed the notion of how DNA methylation is regulated. Clonal analysis of the hematopoetic stem cell compartment suggests that TET2 mutations can be early events in hematologic cancers and recent investigations have shown TET2 mutations in diffuse large B-cell lymphoma. However, the detection rates and the types of TET2 mutations vary, and the relation to global methylation patterns has not been investigated. Here, we show TET2 mutations in 12 of 100 diffuse large B-cell lymphomas with 7% carrying loss-of-function and 5% carrying missense mutations. Genome-wide methylation profiling using 450K Illumina arrays identified 315 differentially methylated genes between TET2 mutated and TET2 wild-type cases. TET2 mutations are primarily associated with hypermethylation within CpG islands (70%; P<0.0001), and at CpG-rich promoters (60%; P<0.0001) of genes involved in hematopoietic differentiation and cellular development. Hypermethylated loci in TET2 mutated samples overlap with the bivalent (H3K27me3/H3K4me3) silencing mark in human embryonic stem cells (P=1.5×10(-30)). Surprisingly, gene expression profiling showed that only 11% of the hypermethylated genes were down-regulated, among which there were several genes previously suggested to be tumor suppressors. A meta-analysis suggested that the 35 hypermethylated and down-regulated genes are associated with the activated B-cell-like type of diffuse large B-cell lymphoma in other studies. In conclusion, our data suggest that TET2 mutations may cause aberrant methylation mainly of genes involved in hematopoietic development, which are silenced but poised for activation in human embryonic stem cells. PMID:23831920

  13. GRIN2B Mutations in West Syndrome and Intellectual Disability with Focal Epilepsy

    PubMed Central

    Lemke, Johannes R; Hendrickx, Rik; Geider, Kirsten; Laube, Bodo; Schwake, Michael; Harvey, Robert J; James, Victoria M; Pepler, Alex; Steiner, Isabelle; Hörtnagel, Konstanze; Neidhardt, John; Ruf, Susanne; Wolff, Markus; Bartholdi, Deborah; Caraballo, Roberto; Platzer, Konrad; Suls, Arvid; De Jonghe, Peter; Biskup, Saskia; Weckhuysen, Sarah

    2014-01-01

    Objective To identify novel epilepsy genes using a panel approach and describe the functional consequences of mutations. Methods Using a panel approach, we screened 357 patients comprising a vast spectrum of epileptic disorders for defects in genes known to contribute to epilepsy and/or intellectual disability (ID). After detection of mutations in a novel epilepsy gene, we investigated functional effects in Xenopus laevis oocytes and screened a follow-up cohort. Results We revealed de novo mutations in GRIN2B encoding the NR2B subunit of the N-methyl-D-aspartate (NMDA) receptor in 2 individuals with West syndrome and severe developmental delay as well as 1 individual with ID and focal epilepsy. The patient with ID and focal epilepsy had a missense mutation in the extracellular glutamate-binding domain (p.Arg540His), whereas both West syndrome patients carried missense mutations within the NR2B ion channel-forming re-entrant loop (p.Asn615Ile, p.Val618Gly). Subsequent screening of 47 patients with unexplained infantile spasms did not reveal additional de novo mutations, but detected a carrier of a novel inherited GRIN2B splice site variant in close proximity (c.2011-5_2011-4delTC). Mutations p.Asn615Ile and p.Val618Gly cause a significantly reduced Mg2+ block and higher Ca2+ permeability, leading to a dramatically increased Ca2+ influx, whereas p.Arg540His caused less severe disturbance of channel function, corresponding to the milder patient phenotype. Interpretation We identified GRIN2B gain-of-function mutations as a cause of West syndrome with severe developmental delay as well as of ID with childhood onset focal epilepsy. Severely disturbed channel function corresponded to severe clinical phenotypes, underlining the important role of facilitated NMDA receptor signaling in epileptogenesis. PMID:24272827

  14. Mutation screening of GRIN2B in schizophrenia and autism spectrum disorder in a Japanese population.

    PubMed

    Takasaki, Yuto; Koide, Takayoshi; Wang, Chenyao; Kimura, Hiroki; Xing, Jingrui; Kushima, Itaru; Ishizuka, Kanako; Mori, Daisuke; Sekiguchi, Mariko; Ikeda, Masashi; Aizawa, Miki; Tsurumaru, Naoko; Iwayama, Yoshimi; Yoshimi, Akira; Arioka, Yuko; Yoshida, Mami; Noma, Hiromi; Oya-Ito, Tomoko; Nakamura, Yukako; Kunimoto, Shohko; Aleksic, Branko; Uno, Yota; Okada, Takashi; Ujike, Hiroshi; Egawa, Jun; Kuwabara, Hitoshi; Someya, Toshiyuki; Yoshikawa, Takeo; Iwata, Nakao; Ozaki, Norio

    2016-01-01

    N-methyl-d-aspartate receptors (NMDARs) play a critical role in excitatory synaptic transmission and plasticity in the central nervous systems. Recent genetics studies in schizophrenia (SCZ) show that SCZ is susceptible to NMDARs and the NMDAR signaling complex. In autism spectrum disorder (ASD), several studies report dysregulation of NMDARs as a risk factor for ASD. To further examine the association between NMDARs and SCZ/ASD development, we conducted a mutation screening study of GRIN2B which encodes NR2B subunit of NMDARs, to identify rare mutations that potentially cause diseases, in SCZ and ASD patients (n = 574 and 152, respectively). This was followed by an association study in a large sample set of SCZ, ASD, and normal healthy controls (n = 4145, 381, and 4432, respectively). We identified five rare missense mutations through the mutation screening of GRIN2B. Although no statistically significant association between any single mutation and SCZ or ASD was found, one of its variant, K1292R, is found only in the patient group. To further examine the association between mutations in GRIN2B and SCZ/ASD development, a larger sample size and functional experiments are needed. PMID:27616045

  15. Prevalence of BTK mutations in male Algerian patterns with agammaglobulinemia and severe B cell lymphopenia.

    PubMed

    Boushaki, Soraya; Tahiat, Azzedine; Meddour, Yanis; Chan, Koon Wing; Chaib, Samia; Benhalla, Nafissa; Smati, Leila; Bensenouci, Abdellatif; Lau, Yu-Lung; Magdinier, Frédérique; Djidjik, Réda

    2015-12-01

    X linked agammaglobulinemia (XLA) is the first described primary immunodeficiency and the most common form of agammaglobulinemia. It is characterized by susceptibility to recurrent infections, profound decrease of all immunoglobulin isotypes and very low level of B lymphocytes in peripheral blood. The disorder is caused by mutations in the Bruton's Tyrosine Kinase (BTK). Nine male patients suspected to have XLA from nine unrelated families were enrolled in this study. We performed sequencing of the BTK gene in all nine patients, and in the patients' relatives when possible. The XLA diagnosis was confirmed for six patients with six different mutations; we identified a novel mutation (c.1522G>A) and five known mutations. One third of nine unrelated patients do not have mutations in BTK and thus likely suffer from autosomal recessive agammaglobulinemia in the setting of consanguinity. Our results support that the autosomal recessive agammaglobulinemia can be more common in Algeria. PMID:26387629

  16. Unusual multisystemic involvement and a novel BAG3 mutation revealed by NGS screening in a large cohort of myofibrillar myopathies

    PubMed Central

    2014-01-01

    Background Myofibrillar myopathies (MFM) are a group of phenotypically and genetically heterogeneous neuromuscular disorders, which are characterized by protein aggregations in muscle fibres and can be associated with multisystemic involvement. Methods We screened a large cohort of 38 index patients with MFM for mutations in the nine thus far known causative genes using Sanger and next generation sequencing (NGS). We studied the clinical and histopathological characteristics in 38 index patients and five additional relatives (n = 43) and particularly focused on the associated multisystemic symptoms. Results We identified 14 heterozygous mutations (diagnostic yield of 37%), among them the novel p.Pro209Gln mutation in the BAG3 gene, which was associated with onset in adulthood, a mild phenotype and an axonal sensorimotor polyneuropathy, in the absence of giant axons at the nerve biopsy. We revealed several novel clinical phenotypes and unusual multisystemic presentations with previously described mutations: hearing impairment with a FLNC mutation, dysphonia with a mutation in DES and the first patient with a FLNC mutation presenting respiratory insufficiency as the initial symptom. Moreover, we described for the first time respiratory insufficiency occurring in a patient with the p.Gly154Ser mutation in CRYAB. Interestingly, we detected a polyneuropathy in 28% of the MFM patients, including a BAG3 and a MYOT case, and hearing impairment in 13%, including one patient with a FLNC mutation and two with mutations in the DES gene. In four index patients with a mutation in one of the MFM genes, typical histological findings were only identified at the ultrastructural level (29%). Conclusions We conclude that extraskeletal symptoms frequently occur in MFM, particularly cardiac and respiratory involvement, polyneuropathy and/or deafness. BAG3 mutations should be considered even in cases with a mild phenotype or an adult onset. We identified a genetic defect in one of

  17. Consequences of the recurrent MYD88(L265P) somatic mutation for B cell tolerance.

    PubMed

    Wang, James Q; Jeelall, Yogesh S; Beutler, Bruce; Horikawa, Keisuke; Goodnow, Christopher C

    2014-03-10

    MYD88(L265P) has recently been discovered as an extraordinarily frequent somatic mutation in benign monoclonal IgM gammopathy, Waldenström's macroglobulinemia, and diffuse large B cell lymphoma. In this study, we analyze the consequences for antigen-activated primary B cells of acquiring MYD88(L265P). The mutation induced rapid B cell division in the absence of exogenous TLR ligands and was inhibited by Unc93b1(3d) mutation and chloroquine or TLR9 deficiency, indicating continued dependence on upstream TLR9 activation. Proliferation and NF-κB activation induced by MYD88(L265P) were nevertheless rapidly countered by the induction of TNFAIP3, an NF-κB inhibitor frequently inactivated in MYD88(L265P)-bearing lymphomas, and extinguished by Bim-dependent apoptosis. MYD88(L265P) caused self-reactive B cells to accumulate in vivo only when apoptosis was opposed by Bcl2 overexpression. These results reveal checkpoints that fortify TLR responses against aberrant B cell proliferation in response to ubiquitous TLR and BCR self-ligands and suggest that tolerance failure requires the accumulation of multiple somatic mutations. PMID:24534189

  18. A missense mutation in the neutrophil cytochrome b heavy chain in cytochrome-positive X-linked chronic granulomatous disease.

    PubMed Central

    Dinauer, M C; Curnutte, J T; Rosen, H; Orkin, S H

    1989-01-01

    A membrane-bound cytochrome b, a heterodimer formed by a 91-kD glycoprotein and a 22-kD polypeptide, is a critical component of the phagocyte NADPH-oxidase responsible for the generation of superoxide anion. Mutations in the gene for the 91-kD chain of this cytochrome result in the X-linked form of chronic granulomatous disease (CGD), in which phagocytes are unable to produce superoxide. Typically, there is a marked deficiency of the 91-kD subunit and the cytochrome spectrum is absent (X- CGD). In a variant form of CGD with X-linked inheritance, affected males have a normal visible absorbance spectrum of cytochrome b, yet fail to generate superoxide (X+ CGD). The size and abundance of the mRNA for the 91-kD subunit and its encoded protein were examined and appeared normal. To search for a putative mutation in the coding sequence of the 91-kD subunit gene, the corresponding RNA from an affected X+ male was amplified by the polymerase chain reaction and sequenced. A single nucleotide change, a C----A transversion, was identified that predicts a nonconservative Pro----His substitution at residue 415 of the encoded protein. Hybridization of amplified genomic DNA with allele-specific oligonucleotide probes demonstrated the mutation to be specific to affected X+ males and the carrier state. These results strengthen the concept that all X-linked CGD relates to mutations affecting the expression or structure of the 91-kD cytochrome b subunit. The mechanism by which the Pro 415----His mutation renders the oxidase nonfunctional is unknown, but may involve an impaired interaction with other components of the oxidase. Images PMID:2556453

  19. Biallelic mutations in the autophagy regulator DRAM2 cause retinal dystrophy with early macular involvement.

    PubMed

    El-Asrag, Mohammed E; Sergouniotis, Panagiotis I; McKibbin, Martin; Plagnol, Vincent; Sheridan, Eamonn; Waseem, Naushin; Abdelhamed, Zakia; McKeefry, Declan; Van Schil, Kristof; Poulter, James A; Johnson, Colin A; Carr, Ian M; Leroy, Bart P; De Baere, Elfride; Inglehearn, Chris F; Webster, Andrew R; Toomes, Carmel; Ali, Manir

    2015-06-01

    Retinal dystrophies are an overlapping group of genetically heterogeneous conditions resulting from mutations in more than 250 genes. Here we describe five families affected by an adult-onset retinal dystrophy with early macular involvement and associated central visual loss in the third or fourth decade of life. Affected individuals were found to harbor disease-causing variants in DRAM2 (DNA-damage regulated autophagy modulator protein 2). Homozygosity mapping and exome sequencing in a large, consanguineous British family of Pakistani origin revealed a homozygous frameshift variant (c.140delG [p.Gly47Valfs(∗)3]) in nine affected family members. Sanger sequencing of DRAM2 in 322 unrelated probands with retinal dystrophy revealed one European subject with compound heterozygous DRAM2 changes (c.494G>A [p.Trp165(∗)] and c.131G>A [p.Ser44Asn]). Inspection of previously generated exome sequencing data in unsolved retinal dystrophy cases identified a homozygous variant in an individual of Indian origin (c.64_66del [p.Ala22del]). Independently, a gene-based case-control association study was conducted via an exome sequencing dataset of 18 phenotypically similar case subjects and 1,917 control subjects. Using a recessive model and a binomial test for rare, presumed biallelic, variants, we found DRAM2 to be the most statistically enriched gene; one subject was a homozygote (c.362A>T [p.His121Leu]) and another a compound heterozygote (c.79T>C [p.Tyr27His] and c.217_225del [p.Val73_Tyr75del]). DRAM2 encodes a transmembrane lysosomal protein thought to play a role in the initiation of autophagy. Immunohistochemical analysis showed DRAM2 localization to photoreceptor inner segments and to the apical surface of retinal pigment epithelial cells where it might be involved in the process of photoreceptor renewal and recycling to preserve visual function. PMID:25983245

  20. Biallelic Mutations in the Autophagy Regulator DRAM2 Cause Retinal Dystrophy with Early Macular Involvement

    PubMed Central

    El-Asrag, Mohammed E.; Sergouniotis, Panagiotis I.; McKibbin, Martin; Plagnol, Vincent; Sheridan, Eamonn; Waseem, Naushin; Abdelhamed, Zakia; McKeefry, Declan; Van Schil, Kristof; Poulter, James A.; Black, Graeme; Hall, Georgina; Ingram, Stuart; Gillespie, Rachel; Ramsden, Simon; Manson, Forbes; Hardcastle, Alison; Michaelides, Michel; Cheetham, Michael; Arno, Gavin; Thomas, Niclas; Bhattacharya, Shomi; Moore, Tony; Nemeth, Andrea; Downes, Susan; Lise, Stefano; Lord, Emma; Johnson, Colin A.; Carr, Ian M.; Leroy, Bart P.; De Baere, Elfride; Inglehearn, Chris F.; Webster, Andrew R.; Toomes, Carmel; Ali, Manir

    2015-01-01

    Retinal dystrophies are an overlapping group of genetically heterogeneous conditions resulting from mutations in more than 250 genes. Here we describe five families affected by an adult-onset retinal dystrophy with early macular involvement and associated central visual loss in the third or fourth decade of life. Affected individuals were found to harbor disease-causing variants in DRAM2 (DNA-damage regulated autophagy modulator protein 2). Homozygosity mapping and exome sequencing in a large, consanguineous British family of Pakistani origin revealed a homozygous frameshift variant (c.140delG [p.Gly47Valfs∗3]) in nine affected family members. Sanger sequencing of DRAM2 in 322 unrelated probands with retinal dystrophy revealed one European subject with compound heterozygous DRAM2 changes (c.494G>A [p.Trp165∗] and c.131G>A [p.Ser44Asn]). Inspection of previously generated exome sequencing data in unsolved retinal dystrophy cases identified a homozygous variant in an individual of Indian origin (c.64_66del [p.Ala22del]). Independently, a gene-based case-control association study was conducted via an exome sequencing dataset of 18 phenotypically similar case subjects and 1,917 control subjects. Using a recessive model and a binomial test for rare, presumed biallelic, variants, we found DRAM2 to be the most statistically enriched gene; one subject was a homozygote (c.362A>T [p.His121Leu]) and another a compound heterozygote (c.79T>C [p.Tyr27His] and c.217_225del [p.Val73_Tyr75del]). DRAM2 encodes a transmembrane lysosomal protein thought to play a role in the initiation of autophagy. Immunohistochemical analysis showed DRAM2 localization to photoreceptor inner segments and to the apical surface of retinal pigment epithelial cells where it might be involved in the process of photoreceptor renewal and recycling to preserve visual function. PMID:25983245

  1. A Point Mutation in the Gene for Asparagine-Linked Glycosylation 10B (Alg10b) Causes Nonsyndromic Hearing Impairment in Mice (Mus musculus)

    PubMed Central

    Probst, Frank J.; Corrigan, Rebecca R.; del Gaudio, Daniela; Salinger, Andrew P.; Lorenzo, Isabel; Gao, Simon S.; Chiu, Ilene; Xia, Anping

    2013-01-01

    The study of mouse hearing impairment mutants has led to the identification of a number of human hearing impairment genes and has greatly furthered our understanding of the physiology of hearing. The novel mouse mutant neurological/sensory 5 (nse5) demonstrates a significantly reduced or absent startle response to sound and is therefore a potential murine model of human hearing impairment. Genetic analysis of 500 intercross progeny localized the mutant locus to a 524 kilobase (kb) interval on mouse chromosome 15. A missense mutation in a highly-conserved amino acid was found in the asparagine-linked glycosylation 10B gene (Alg10b), which is within the critical interval for the nse5 mutation. A 20.4 kb transgene containing a wildtype copy of the Alg10b gene rescued the mutant phenotype in nse5/nse5 homozygous animals, confirming that the mutation in Alg10b is responsible for the nse5/nse5 mutant phenotype. Homozygous nse5/nse5 mutants had abnormal auditory brainstem responses (ABRs), distortion product otoacoustic emissions (DPOAEs), and cochlear microphonics (CMs). Endocochlear potentials (EPs), on the other hand, were normal. ABRs and DPOAEs also confirmed the rescue of the mutant nse5/nse5 phenotype by the wildtype Alg10b transgene. These results suggested a defect in the outer hair cells of mutant animals, which was confirmed by histologic analysis. This is the first report of mutation in a gene involved in the asparagine (N)-linked glycosylation pathway causing nonsyndromic hearing impairment, and it suggests that the hearing apparatus, and the outer hair cells in particular, are exquisitely sensitive to perturbations of the N-linked glycosylation pathway. PMID:24303013

  2. A novel mutation of the HNF1B gene associated with hypoplastic glomerulocystic kidney disease and neonatal renal failure: a case report and mutation update.

    PubMed

    Alvelos, Maria Inês; Rodrigues, Magda; Lobo, Luísa; Medeira, Ana; Sousa, Ana Berta; Simão, Carla; Lemos, Manuel Carlos

    2015-02-01

    Hepatocyte nuclear factor 1 beta (HNF1B) plays an important role in embryonic development, namely in the kidney, pancreas, liver, genital tract, and gut. Heterozygous germline mutations of HNF1B are associated with the renal cysts and diabetes syndrome (RCAD). Affected individuals may present a variety of renal developmental abnormalities and/or maturity-onset diabetes of the young (MODY). A Portuguese 19-month-old male infant was evaluated due to hypoplastic glomerulocystic kidney disease and renal dysfunction diagnosed in the neonatal period that progressed to stage 5 chronic renal disease during the first year of life. His mother was diagnosed with a solitary hypoplastic microcystic left kidney at age 20, with stage 2 chronic renal disease established at age 35, and presented bicornuate uterus, pancreatic atrophy, and gestational diabetes. DNA sequence analysis of HNF1B revealed a novel germline frameshift insertion (c.110_111insC or c.110dupC) in both the child and the mother. A review of the literature revealed a total of 106 different HNF1B mutations, in 236 mutation-positive families, comprising gross deletions (34%), missense mutations (31%), frameshift deletions or insertions (15%), nonsense mutations (11%), and splice-site mutations (8%). The study of this family with an unusual presentation of hypoplastic glomerulocystic kidney disease with neonatal renal dysfunction identified a previously unreported mutation of the HNF1B gene, thereby expanding the spectrum of known mutations associated with renal developmental disorders. PMID:25700310

  3. The Association of Pre-S/S Gene Mutations and Hepatitis B Virus Vertical Transmission

    PubMed Central

    Yin, Yuzhu; Zhang, Peizhen; Tan, Zhangmin; Zhou, Jin; Wu, Lingling; Hou, Hongying

    2016-01-01

    Background HBV Pre-S/S gene mutations can occur before or after implementation of combined vaccination program. HBV Prs-S/S gene mutation is a risk factor of vaccination failure and frequently causes HBV vertical transfection. Objectives To assess the association of hepatitis B virus (HBV) S gene mutations with vertical transmission. Patients and Methods In this prospective nested case-control study, a total of 60 pregnant women with positive serum HBsAg and HBV DNA ≥ 107 IU/mL were divided into a case group (15 cases with vaccination failure) and a control group (45 cases with vaccination success) according to whether their infants tested positive for HBV infection. Mothers and their children in the case group were further sub-divided into groups including mothers, newborns and infant (the same newborns at age of seven months). The pre-S/S gene mutations were detected by PCR and sequenced and its association with vertical transmission of HBV was analyzed. Results HBV genotype B was the dominant genotype in the both groups’ mothers. Each mother-child pair in case group had the same HBV genotype. There were no significant differences in mutation frequencies of HBV Pre-S/S gene between case and control groups’ mothers (Fragment 1 (M): 2 vs. 4, P > 0.05; Fragment 2 (M): 10 vs. 10, P > 0.05), or among the mothers, newborns and infants in the case group (Fragment 1 (M): 2, 2, and 3, respectively, P > 0.05; Fragment 2 (M): 10, 10 and 10 respectively, P > 0.05). Mutation site analysis of the both groups’ mothers demonstrated 108 different mutation sites in the HBV pre-S/S gene, with 105 silent mutations and 5 missense mutations including ntA826G, ntC531T, ntT667C, ntC512T and ntC546A. Among 15 mother-newborn-infant pairs with successful PCR and sequence in case group, 7 (41.17%) mother-newborn pairs, 9 (60.00%) mother-infant pairs and 3 (20.00%) infant-newborn pairs had different mutation sites. Conclusions HBV in children due to vaccination failure was resulted

  4. An Agrobacterium VirB10 Mutation Conferring a Type IV Secretion System Gating Defect▿

    PubMed Central

    Banta, Lois M.; Kerr, Jennifer E.; Cascales, Eric; Giuliano, Meghan E.; Bailey, Megan E.; McKay, Cedar; Chandran, Vidya; Waksman, Gabriel; Christie, Peter J.

    2011-01-01

    Agrobacterium VirB7, VirB9, and VirB10 form a “core complex” during biogenesis of the VirB/VirD4 type IV secretion system (T4SS). VirB10 spans the cell envelope and, in response to sensing of ATP energy consumption by the VirB/D4 ATPases, undergoes a conformational change required for DNA transfer across the outer membrane (OM). Here, we tested a model in which VirB10 regulates substrate passage by screening for mutations that allow for unregulated release of the VirE2 secretion substrate to the cell surface independently of target cell contact. One mutation, G272R, conferred VirE2 release and also rendered VirB10 conformationally insensitive to cellular ATP depletion. Strikingly, G272R did not affect substrate transfer to target cells (Tra+) but did block pilus production (Pil−). The G272R mutant strain displayed enhanced sensitivity to vancomycin and SDS but did not nonspecifically release periplasmic proteins or VirE2 truncated of its secretion signal. G272 is highly conserved among VirB10 homologs, including pKM101 TraF, and in the TraF X-ray structure the corresponding Gly residue is positioned near an α-helical domain termed the antenna projection (AP), which is implicated in formation of the OM pore. A partial AP deletion mutation (ΔAP) also confers a Tra+ Pil− phenotype; however, this mutation did not allow VirE2 surface exposure but instead allowed the release of pilin monomers or short oligomers to the milieu. We propose that (i) G272R disrupts a gating mechanism in the core chamber that regulates substrate passage across the OM and (ii) the G272R and ΔAP mutations block pilus production at distinct steps of the pilus biogenesis pathway. PMID:21421757

  5. Mutational analysis of the DTDST gene in a fetus with achondrogenesis type 1B.

    PubMed

    Cai, G; Nakayama, M; Hiraki, Y; Ozono, K

    1998-06-16

    We describe a diastrophic dysplasia (DTDST) gene mutation in a Japanese male fetus with achondrogenesis type 1B and his relatives. Diagnosis in the fetus was based on roentgenographic data and pathological findings of bones and cartilage. Nucleotide sequencing of the DTDST gene demonstrated that the fetus was homozygous for both delVal340 and Thr689Ser and his parents and a healthy brother were heterozygous for the mutations. The former mutation was reported previously in patients with achondrogenesis type 1B, and the latter was detected in 5 alleles of 26 healthy Japanese individuals. These data suggest that delVal340 is associated with achondrogenesis type 1B in the Japanese, whereas a serine to threonine substitution is most likely polymorphic. PMID:9637425

  6. Hepatitis B surface antigen escape mutations: Indications for initiation of antiviral therapy revisited

    PubMed Central

    Leong, Jennifer; Lin, Derek; Nguyen, Mindie H

    2016-01-01

    Approximately 240 million people are chronically infected with hepatitis B. The implementation of rigorous vaccination programs has led to an overall decrease in the prevalence of this disease worldwide but this may also have led to emergence of viral mutations that can escape the protection of hepatitis B surface antibody. As this phenomenon is increasingly recognized, concern for transmission to vaccinated individuals has also been raised. Herein, we describe two cases where the suspected presence of a hepatitis B surface antigen escape mutation impacted the decision to initiate early antiviral therapy, as well as provide a brief review of these mutations. Our findings described here suggest that a lower threshold for initiating therapy in these individuals should be considered in order to reduce the risk of transmission, as vaccination does not provide protection. PMID:26989671

  7. The B cell mutator AID promotes B lymphoid blast crisis and drug-resistance in chronic myeloid leukemia

    PubMed Central

    Klemm, Lars; Duy, Cihangir; Iacobucci, Ilaria; Kuchen, Stefan; von Levetzow, Gregor; Feldhahn, Niklas; Henke, Nadine; Li, Zhiyu; Hoffmann, Thomas K.; Kim, Yong-mi; Hofmann, Wolf-Karsten; Jumaa, Hassan; Groffen, John; Heisterkamp, Nora; Martinelli, Giovanni; Lieber, Michael R; Casellas, Rafael; Müschen, Markus

    2009-01-01

    Summary Chronic myeloid leukemia (CML) is induced by BCR-ABL1 and can be effectively treated for many years with Imatinib until leukemia cells acquire drug resistance through BCR-ABL1 mutations and progress into fatal B lymphoid blast crisis (LBC). Despite its clinical significance, the mechanism of progression into LBC is unknown. Here we show that LBC but not CML cells express the B cell-specific mutator enzyme AID. We demonstrate that AID expression in CML cells promotes overall genetic instability by hypermutation of tumor suppressor and DNA repair genes. Importantly, our data uncover a causative role of AID activity in the acquisition of BCR-ABL1 mutations leading to Imatinib-resistance, thus providing a rationale for the rapid development of drug resistance and blast crisis progression. PMID:19732723

  8. IDH1 p.R132 mutations may not be actively involved in the carcinogenesis of hepatocellular carcinoma

    PubMed Central

    Lu, Jun; Zou, Yang; Xu, Ling; Yang, Run-Xiang; Fan, Yu; Zhang, Wen; Yu, Dandan; Yao, Yong-Gang

    2014-01-01

    Background Recent studies have identified prevalent isocitrate dehydrogenase 1 (IDH1) codon 132 mutations (p.R132) in gliomas and acute myeloid leukemia (AML). The IDH1 mutations lead to a loss of its normal enzymatic activity and acquisition of neomorphic activity in production of α-ketoglutarate (α-KG) and 2-hydroxyglutarate (2-HG), which finally cause alterations of multiple gene expression of tumorigenesis-associated α-KG-dependent enzymes. The aim of this study was to determine whether IDH1 p.R132 mutations are involved in the carcinogenesis of hepatocellular carcinoma. Material/Methods A total of 87 Han Chinese patients with primary hepatocellular carcinoma (HCC) were analyzed by direct DNA sequencing for IDH1 p.R132 mutations. The expression levels of multiple α-KG-dependent enzymes and associated genes were quantified in HepG2 cells overexpressing IDH1 p.R132 mutants by Western blotting and real-time PCR. Results None of 87 Han Chinese patients with HCC harbored any IDH1 p.R132 mutations. The protein levels of HIF-1α and histone methylation marker (H3K4me3 and H3K79me2) were determined in HepG2 cells overexpressing IDH1 p.R132 mutants, but we discerned no difference. Measurement of mRNA expression levels of VEGF, GLUT1, and HOXA genes also showed no significant difference between cells overexpressing IDH1 wild-type and p.R132 mutants. Conclusions Our negative results, together with some previous reports of the absence of IDH1 p.R132 mutations in HCC tissues, suggests that IDH1 p.R132 mutations are not actively involved in the development of HCC. PMID:24531386

  9. Mutations in WNT10B Are Identified in Individuals with Oligodontia.

    PubMed

    Yu, Ping; Yang, Wenli; Han, Dong; Wang, Xi; Guo, Sen; Li, Jinchen; Li, Fang; Zhang, Xiaoxia; Wong, Sing-Wai; Bai, Baojing; Liu, Yao; Du, Jie; Sun, Zhong Sheng; Shi, Songtao; Feng, Hailan; Cai, Tao

    2016-07-01

    Tooth agenesis is one of the most common developmental anomalies in humans. Oligodontia, a severe form of tooth agenesis, is genetically and phenotypically a heterogeneous condition. Although significant efforts have been made, the genetic etiology of dental agenesis remains largely unknown. In the present study, we performed whole-exome sequencing to identify the causative mutations in Chinese families in whom oligodontia segregates with dominant inheritance. We detected a heterozygous missense mutation (c.632G>A [p.Arg211Gln]) in WNT10B in all affected family members. By Sanger sequencing a cohort of 145 unrelated individuals with non-syndromic oligodontia, we identified three additional mutations (c.569C>G [p.Pro190Arg], c.786G>A [p.Trp262(∗)], and c.851T>G [p.Phe284Cys]). Interestingly, analysis of genotype-phenotype correlations revealed that mutations in WNT10B affect the development of permanent dentition, particularly the lateral incisors. Furthermore, a functional assay demonstrated that each of these mutants could not normally enhance the canonical Wnt signaling in HEPG2 epithelial cells, in which activity of the TOPFlash luciferase reporter was measured. Notably, these mutant WNT10B ligands could not efficiently induce endothelial differentiation of dental pulp stem cells. Our findings provide the identification of autosomal-dominant WNT10B mutations in individuals with oligodontia, which increases the spectrum of congenital tooth agenesis and suggests attenuated Wnt signaling in endothelial differentiation of dental pulp stem cells. PMID:27321946

  10. Vps33b pathogenic mutations preferentially affect VIPAS39/SPE-39-positive endosomes.

    PubMed

    Tornieri, Karine; Zlatic, Stephanie A; Mullin, Ariana P; Werner, Erica; Harrison, Robert; L'hernault, Steven W; Faundez, Victor

    2013-12-20

    Mutations in Vps33 isoforms cause pigment dilution in mice (Vps33a, buff) and Drosophila (car) and the neurogenic arthrogryposis, renal dysfunction and cholestasis syndrome in humans (ARC1, VPS33B). The later disease is also caused by mutations in VIPAS39, (Vps33b interacting protein, apical-basolateral polarity regulator, SPE-39 homolog; ARC2), a protein that interacts with the HOmotypic fusion and Protein Sorting (HOPS) complex, a tether necessary for endosome-lysosome traffic. These syndromes offer insight into fundamental endosome traffic processes unique to metazoans. However, the molecular and cellular mechanisms underlying these mutant phenotypes remain poorly understood. Here we investigate interactions of wild-type and disease-causing mutations in VIPAS39/SPE-39 and Vps33b by yeast two hybrid, immunoprecipitation and quantitative fluorescent microscopy. We find that although few mutations prevent interaction between VIPAS39/SPE-39 and Vps33b, some mutants fragment VIPAS39/SPE-39-positive endosomes, but all mutants alter the subcellular localization of Vps33b to VIPAS39/SPE-39-positive endosomes. Our data suggest that the ARC syndrome may result through impaired VIPAS39/SPE-39 and Vps33b-dependent endosomal maturation or fusion. PMID:23918659

  11. Vps33b pathogenic mutations preferentially affect VIPAS39/SPE-39-positive endosomes

    PubMed Central

    Tornieri, Karine; Zlatic, Stephanie A.; Mullin, Ariana P.; Werner, Erica; Harrison, Robert; L'Hernault, Steven W.; Faundez, Victor

    2013-01-01

    Mutations in Vps33 isoforms cause pigment dilution in mice (Vps33a, buff) and Drosophila (car) and the neurogenic arthrogryposis, renal dysfunction and cholestasis syndrome in humans (ARC1, VPS33B). The later disease is also caused by mutations in VIPAS39, (Vps33b interacting protein, apical-basolateral polarity regulator, SPE-39 homolog; ARC2), a protein that interacts with the HOmotypic fusion and Protein Sorting (HOPS) complex, a tether necessary for endosome–lysosome traffic. These syndromes offer insight into fundamental endosome traffic processes unique to metazoans. However, the molecular and cellular mechanisms underlying these mutant phenotypes remain poorly understood. Here we investigate interactions of wild-type and disease-causing mutations in VIPAS39/SPE-39 and Vps33b by yeast two hybrid, immunoprecipitation and quantitative fluorescent microscopy. We find that although few mutations prevent interaction between VIPAS39/SPE-39 and Vps33b, some mutants fragment VIPAS39/SPE-39-positive endosomes, but all mutants alter the subcellular localization of Vps33b to VIPAS39/SPE-39-positive endosomes. Our data suggest that the ARC syndrome may result through impaired VIPAS39/SPE-39 and Vps33b-dependent endosomal maturation or fusion. PMID:23918659

  12. Genetic and Proteomic Characterization of rpoB Mutations and Their Effect on Nematicidal Activity in Photorhabdus luminescens LN2

    PubMed Central

    Qiu, Xuehong; Yan, Xun; Liu, Mingxing; Han, Richou

    2012-01-01

    Rifampin resistant (RifR) mutants of the insect pathogenic bacterium Photorhabdus luminescens LN2 from entomopathogenic nematode Heterorhabditis indica LN2 were genetically and proteomically characterized. The RifR mutants showed typical phase one characters of Photorhabdus bacteria, and insecticidal activity against Galleria mellonella larvae, but surprisingly influenced their nematicidal activity against axenic infective juveniles (IJs) of H. bacteriophora H06, an incompatible nematode host. 13 out of 34 RifR mutants lost their nematicidal activity against H06 IJs but supported the reproduction of H06 nematodes. 7 nematicidal-producing and 7 non-nematicidal-producing RifR mutants were respectively selected for rpoB sequence analysis. rpoB mutations were found in all 14 RifR mutants. The rpoB (P564L) mutation was found in all 7 mutants which produced nematicidal activity against H06 nematodes, but not in the mutants which supported H06 nematode production. Allelic exchange assays confirmed that the Rif-resistance and the impact on nematicidal activity of LN2 bacteria were conferred by rpoB mutation(s). The non-nematicidal-producing RifR mutant was unable to colonize in the intestines of H06 IJs, but able to colonize in the intestines of its indigenous LN2 IJs. Proteomic analysis revealed different protein expression between wild-type strain and RifR mutants, or between nematicidal-producing and non nematicidal-producing mutants. At least 7 putative proteins including DsbA, HlpA, RhlE, RplC, NamB (a protein from T3SS), and 2 hypothetical proteins (similar to unknown protein YgdH and YggE of Escherichia coli respectively) were probably involved in the nematicidal activity of LN2 bacteria against H06 nematodes. This hypothesis was further confirmed by creating insertion-deletion mutants of three selected corresponding genes (the downregulated rhlE and namB, and upregualted dsbA). These results indicate that the rpoB mutations greatly influence the symbiotic

  13. Mutations of the human interferon alpha-2b (hIFNα-2b) gene in cancer patients receiving radiotherapy

    PubMed Central

    Shahid, Saman; Chaudhry, Muhammad Nawaz; Mahmood, Nasir

    2015-01-01

    This research aimed to find out the impact of ionizing radiations on the hIFNα-2b gene of radiotherapy treated cancer patients. The gene hIFNα-2b synthesizes a protein which is an important anticancerous and antiviral protein. The cancer patients (breast, lung, thyroid, oral and prostate) who were undergoing a radiotherapy treatment were selected. A molecular analysis was performed for DNA isolation and gene amplification through PCR, to identify gene mutations. Further, by bioinformatics tools we concluded that how mutations identified in gene sequences have led to the alterations in the hINFα-2b protein in radiotherapy receiving cancer patients. The 32% mutations in the hINFα-2b gene were identified and all were frameshift mutations. Radiotherapy can impact the immune system and cancer patients may modulate their immunity. Understaning the mechanisms of radiotherapy-elicited immune response may be helpful in the development of those therapeutic interventions that can enhance the efficacy of radiotherapy. PMID:26396921

  14. ASXL1 and DNMT3A mutation in a cytogenetically normal B3 thymoma.

    PubMed

    Belani, R; Oliveira, G; Erikson, G A; Ra, S; Schechter, M S; Lee, J K; Shipman, W J; Haaser, S M; Torkamani, A

    2014-01-01

    The molecular drivers of thymoma are poorly understood. Outside of the identification of rarely occurring epidermal growth factor receptor and v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog mutations via candidate gene sequencing, mutations in common cancer genes have yet to be observed. Only a single thymoma genome sequence has been previously reported, with no mutations in known cancer genes identified. Thus, we attempted to identify somatic driver mutations in a cytogenetically normal thymoma. A stage IVB type B3 thymoma from a 47-year-old male of Asian descent with no history of myasthenia gravis or other autoimmune condition was genomically evaluated. Exome sequencing and low-pass whole-genome sequencing was performed to identify somatic point mutations, copy number changes and structural variants. Mutations in known tumor suppressors DNMT3A (p.G728D) and ASXL1 (p.E657fs), consistent with mutations of known consequence in acute myeloid leukemia, were identified. Contrary to a previous report, this finding suggests the genetic etiology of thymomas may not be fundamentally distinct from other tumor types. Rather, these findings suggest that further sequencing of cytogenetically normal thymoma samples should reveal the specific molecular drivers of thymoma. PMID:25000259

  15. Characterization of mutations in streptomycin-resistant Mycobacterium tuberculosis isolates in Sichuan, China and the association between Beijing-lineage and dual-mutation in gidB.

    PubMed

    Sun, Honghu; Zhang, Congcong; Xiang, Ling; Pi, Rui; Guo, Zhen; Zheng, Chao; Li, Song; Zhao, Yuding; Tang, Ke; Luo, Mei; Rastogi, Nalin; Li, Yuqing; Sun, Qun

    2016-01-01

    Mutations in rpsL, rrs, and gidB are well linked to streptomycin (STR) resistance, some of which are suggested to be potentially associated with Mycobacterium tuberculosis genotypic lineages in certain geographic regions. In this study, we aimed to investigate the mutation characteristics of streptomycin resistance and the relationship between the polymorphism of drug-resistant genes and the lineage of M. tuberculosis isolates in Sichuan, China. A total of 227 M. tuberculosis clinical isolates, including 180 STR-resistant and 47 pan-susceptible isolates, were analyzed for presence of mutations in the rpsL, rrs and gidB loci. Mutation K43R in rpsL was strongly associated with high-level streptomycin resistance (P < 0.01), while mutations in rrs and gidB potentially contributed to low-level resistance (P < 0.05). No general association was exhibited between STR resistance and Beijing genotype, however, in STR-resistant strains, Beijing genotype was significantly correlated with high-level STR resistance, as well as the rpsL mutation K43R (P < 0.01), indicating that Beijing genotype has an evolutionary advantage under streptomycin pressure. Notably, in all isolates of Beijing genotype, a dual mutation E92D (a276c) and A205A (a615g) in gidB was detected, suggesting a highly significant association between this dual mutation and Beijing genotype. PMID:26786661

  16. Analysis of regulatory mechanism after ErbB4 gene mutation based on local modeling methodology.

    PubMed

    Chen, C L; Zhao, J W

    2016-01-01

    ErbB4 is an oncogene belonging to the epidermal growth factor receptor family and contributes to the occurrence and development of multiple cancers, such as gastric, breast, and colorectal cancers. Therefore, studies of the regulation of ErbB4 in cancerigenic pathway will advance molecular targeted therapy. Advanced bioinformatic analysis softwares, such as ExPASy, Predictprotei, QUARK, and I-TASSER, were used to analyze the regulatory mechanism after ErbB4 gene mutation in terms of amino acid sequence, primary, secondary, and tertiary structure of the protein and upstream-downstream receptor/ligands. Mutation of the 19th and 113th amino acids at the carboxyl terminus of ErbB4 protein did not affect its biological nature, but its secondary structure changed and protein binding sites were near 2 mutational sites; moreover, after mutation introduction, additional binding sites were observed. Tertiary structure modeling indicated that local structure of ErbB4 was changed from an α helical conformation into a β chain folding structure; the α helical conformation is the functional site of protein, while active sites are typically near junctions between helical regions, thus the helical structures are easily destroyed and change into folding structures or other structures after stretching. Mutable sites of ErbB4 is exact binding sites where dimer formed with other epidermal growth factor family proteins; mutation enabled the ErbB4 receptor to bind to neuregulin 1 ligand without dimer formation, disrupting the signal transduction pathway and affecting ErbB4 function. PMID:27323039

  17. Proteomic Analysis Reveals a Novel Mutator S (MutS) Partner Involved in Mismatch Repair Pathway.

    PubMed

    Chen, Zhen; Tran, Mykim; Tang, Mengfan; Wang, Wenqi; Gong, Zihua; Chen, Junjie

    2016-04-01

    The mismatch repair (MMR) family is a highly conserved group of proteins that function in correcting base-base and insertion-deletion mismatches generated during DNA replication. Disruption of this process results in characteristic microsatellite instability (MSI), repair defects, and susceptibility to cancer. However, a significant fraction of MSI-positive cancers express MMR genes at normal levels and do not carry detectable mutation in known MMR genes, suggesting that additional factors and/or mechanisms may exist to explain these MSI phenotypes in patients. To systematically investigate the MMR pathway, we conducted a proteomic analysis and identified MMR-associated protein complexes using tandem-affinity purification coupled with mass spectrometry (TAP-MS) method. The mass spectrometry data have been deposited to the ProteomeXchange with identifier PXD003014 and DOI 10.6019/PXD003014. We identified 230 high-confidence candidate interaction proteins (HCIPs). We subsequently focused on MSH2, an essential component of the MMR pathway and uncovered a novel MSH2-binding partner, WDHD1. We further demonstrated that WDHD1 forms a stable complex with MSH2 and MSH3 or MSH6,i.e.the MutS complexes. The specific MSH2/WDHD1 interaction is mediated by the second lever domain of MSH2 and Ala(1123)site of WDHD1. Moreover, we showed that, just like MSH2-deficient cells, depletion of WDHD1 also led to 6-thioguanine (6-TG) resistance, indicating that WDHD1 likely contributes to the MMR pathway. Taken together, our study uncovers new components involved in the MMR pathway, which provides candidate genes that may be responsible for the development of MSI-positive cancers. PMID:27037360

  18. Syncytium-inducing mutations localize to two discrete regions within the cytoplasmic domain of herpes simplex virus type 1 glycoprotein B.

    PubMed Central

    Gage, P J; Levine, M; Glorioso, J C

    1993-01-01

    Herpes simplex virus type 1 glycoprotein B (gB) is essential for virus entry, an event involving fusion of the virus envelope with the cell surface membrane, and virus-induced cell-cell fusion, resulting in polykaryocyte, or syncytium, formation. The experiments described in this report employed a random mutagenesis strategy to develop a more complete genetic map of mutations resulting in the syn mutant phenotype. The results indicate that syn mutations occur within two essential and highly conserved hydrophilic, alpha-helical regions of the gB cytoplasmic domain. Region I is immediately proximal to the transmembrane domain and includes residues R796 to E816/817. Region II is localized centrally in the cytoplasmic domain and includes residues A855 and R858. Positively charged residues were particularly affected in both regions, suggesting that charge interactions may be required to suppress the syn mutant phenotype. No syn mutations were identified within the transmembrane domain. A virus containing a rate of entry (roe) mutation at residue A851, either within or immediately proximal to syn region II, was isolated. Since roe mutations have also been discovered in the external domain of gB, it appears likely that the external and cytoplasmic domains cooperate in virus penetration. Moreover, the observation that both roe and syn mutations occur in the cytoplasmic domain further suggests that gB functions in an analogous manner in both membrane fusion events. It might be predicted from these observations that membrane fusion involves transduction of a fusion signal along the gB molecule through the transmembrane domain. Communication between the external and cytoplasmic domain may thus be required for gB-mediated membrane fusion events. Images PMID:8383236

  19. Extracellular Paracoccidioides brasiliensis phospholipase B involvement in alveolar macrophage interaction

    PubMed Central

    2010-01-01

    Background Phospholipase B (PLB) has been reported to be one of the virulence factors for human pathogenic fungi and has also been described as necessary for the early events in infection. Based on these data, we investigated the role of PLB in virulence and modulation of the alveolar pulmonary immune response during infection using an in-vitro model of host-pathogen interaction, i.e. Paracoccidioides brasiliensis yeast cells infecting alveolar macrophage (MH-S) cells. Results The effect of PLB was analyzed using the specific inhibitor alexidine dihydrochloride (0.25 μM), and pulmonary surfactant (100 μg mL-1), during 6 hours of co-cultivation of P. brasiliensis and MH-S cells. Alexidine dihydrochloride inhibited PLB activity by 66% and significantly decreased the adhesion and internalization of yeast cells by MH-S cells. Genes involved in phagocytosis (trl2, cd14) and the inflammatory response (nfkb, tnf-α, il-1β) were down-regulated in the presence of this PLB inhibitor. In contrast, PLB activity and internalization of yeast cells significantly increased in the presence of pulmonary surfactant; under this condition, genes such as clec2 and the pro-inflammatory inhibitor (nkrf) were up-regulated. Also, the pulmonary surfactant did not alter cytokine production, while alexidine dihydrochloride decreased the levels of interleukin-10 (IL-10) and increased the levels of IL-12 and tumor necrosis factor-α (TNF-α). In addition, gene expression analysis of plb1, sod3 and icl1 suggests that P. brasiliensis gene re-programming is effective in facilitating adaptation to this inhospitable environment, which mimics the lung-environment interaction. Conclusion P. brasiliensis PLB activity is involved in the process of adhesion and internalization of yeast cells at the MH-S cell surface and may enhance virulence and subsequent down-regulation of macrophage activation. PMID:20843362

  20. DNA replication is altered in Immunodeficiency Centromeric instability Facial anomalies (ICF) cells carrying DNMT3B mutations

    PubMed Central

    Lana, Erica; Mégarbané, André; Tourrière, Hélène; Sarda, Pierre; Lefranc, Gérard; Claustres, Mireille; De Sario, Albertina

    2012-01-01

    ICF syndrome is a rare autosomal recessive disorder that is characterized by Immunodeficiency, Centromeric instability, and Facial anomalies. In all, 60% of ICF patients have mutations in the DNMT3B (DNA methyltransferase 3B) gene, encoding a de novo DNA methyltransferase. In ICF cells, constitutive heterochromatin is hypomethylated and decondensed, metaphase chromosomes undergo rearrangements (mainly involving juxtacentromeric regions), and more than 700 genes are aberrantly expressed. This work shows that DNA replication is also altered in ICF cells: (i) heterochromatic genes replicate earlier in the S-phase; (ii) global replication fork speed is higher; and (iii) S-phase is shorter. These replication defects may result from chromatin changes that modify DNA accessibility to the replication machinery and/or from changes in the expression level of genes involved in DNA replication. This work highlights the interest of using ICF cells as a model to investigate how DNA methylation regulates DNA replication in humans. PMID:22378288

  1. Novel mutation detection IN rpoB OF rifampicin-resistant Mycobacterium Tuberculosis using pyroseouencing.

    PubMed

    Htike Min, Pyar Kyi; Pitaksajjakul, Pannamthip; Tipkrua, Natthakan; Wongwit, Waranya; Jintaridh, Pornrutsami; Ramasoota, Pongrama

    2014-07-01

    Tuberculosis (TB) remains a major global public health problem particularly severe in parts of Asia and Africa, where often it is present in HIV-AIDS patients. Although rifampicin-resistant (RIFr) TB is slow to emerge due to the low rate of mutation of its target leading to RIFE being a marker of TB that is already resistant to other anti-TB drugs, and such cases are prone to treatment failure. More than 95% of rifampicin resistance is associated with mutations in Mycobacterium tuberculosis (MTB) rpoB, with 97% of mutations occurring within the 81 bp rifampicin-resistant determining region (RRDR) of this gene. In this study, we employed pyrosequencing technique to identify mutations in RRDR and 5 codons beyond of 39 MTB strains, comprising of 14 multi-drug resistance TB (MDRTB) and 3 RIF susceptible (RIFs) MTB from the Center of Disease Control (CDC), Ratchaburi Province, and 19 mono RIFr MTB, 1 MDRTB and 2 poly-drug resistant MTB from the Chest Institute, Ministry of Public Health, Thailand. Mu- tations in 8/22 samples from the Chest Institute and 13/14 from CDC were able to be identified. Six point mutations were detected, with Ser531Leu mutation accounting for 13, the silent mutation at Gly536 for 4, deletion of Gly523 for 2, combination of His526Cys and novel Leu533Arg for 1, and a novel Leu538Arg for 1. Mutation analysis of the 81 bp fragment and 5 codons beyond in MTB rpoB using pyrosequencing provides a useful approach in predicting RIFr phenotype allowing early diagnosis and appropriate drug therapy. PMID:25507602

  2. Novel mutation detection IN rpoB OF rifampicin-resistant Mycobacterium tuberculosis using pyrosequencing.

    PubMed

    Htike Min, Pyar Kyi; Pitaksajjakul, Pannamthip; Tipkrua, Natthakan; Wongwit, Waranya; Jintaridh, Pornrutsami; Ramasoota, Pongrama

    2014-07-01

    Tuberculosis (TB) remains a major global public health problem particularly severe in parts of Asia and Africa, where often it is present in HIV-AIDS patients. Although rifampicin-resistant (RIFr) TB is slow to emerge due to the low rate of mutation of its target leading to RIFE being a marker of TB that is already resistant to other anti-TB drugs, and such cases are prone to treatment failure. More than 95% of rifampicin resistance is associated with mutations in Mycobacterium tuberculosis (MTB) rpoB, with 97% of mutations occurring within the 81 bp rifampicin-resistant determining region (RRDR) of this gene. In this study, we employed pyrosequencing technique to identify mutations in RRDR and 5 codons beyond of 39 MTB strains, comprising of 14 multi-drug resistance TB (MDRTB) and 3 RIF susceptible (RIFs) MTB from the Center of Disease Control (CDC), Ratchaburi Province, and 19 mono RIFr MTB, 1 MDRTB and 2 poly-drug resistant MTB from the Chest Institute, Ministry of Public Health, Thailand. Mu- tations in 8/22 samples from the Chest Institute and 13/14 from CDC were able to be identified. Six point mutations were detected, with Ser531Leu mutation accounting for 13, the silent mutation at Gly536 for 4, deletion of Gly523 for 2, combination of His526Cys and novel Leu533Arg for 1, and a novel Leu538Arg for 1. Mutation analysis of the 81 bp fragment and 5 codons beyond in MTB rpoB using pyrosequencing provides a useful approach in predicting RIFr phenotype allowing early diagnosis and appropriate drug therapy. PMID:25427352

  3. Molecular basis of the attenuated phenotype of human APOBEC3B DNA mutator enzyme

    PubMed Central

    Caval, Vincent; Bouzidi, Mohamed S.; Suspène, Rodolphe; Laude, Hélène; Dumargne, Marie-Charlotte; Bashamboo, Anu; Krey, Thomas; Vartanian, Jean-Pierre; Wain-Hobson, Simon

    2015-01-01

    The human APOBEC3A and APOBEC3B genes (A3A and A3B) encode DNA mutator enzymes that deaminate cytidine and 5-methylcytidine residues in single-stranded DNA (ssDNA). They are important sources of mutations in many cancer genomes which show a preponderance of CG->TA transitions. Although both enzymes can hypermutate chromosomal DNA in an experimental setting, only A3A can induce double strand DNA breaks, even though the catalytic domains of A3B and A3A differ by only 9% at the protein level. Accordingly we sought the molecular basis underlying A3B attenuation through the generation of A3A-A3B chimeras and mutants. It transpires that the N-terminal domain facilitates A3B activity while a handful of substitutions in the catalytic C-terminal domain impacting ssDNA binding serve to attenuate A3B compared to A3A. Interestingly, functional attenuation is also observed for the rhesus monkey rhA3B enzyme compared to rhA3A indicating that this genotoxic dichotomy has been selected for and maintained for some 38 million years. Expression of all human ssDNA cytidine deaminase genes is absent in mature sperm indicating they contribute to somatic mutation and cancer but not human diversity. PMID:26384561

  4. Cathepsin F mutations cause Type B Kufs disease, an adult-onset neuronal ceroid lipofuscinosis

    PubMed Central

    Smith, Katherine R.; Dahl, Hans-Henrik M.; Canafoglia, Laura; Andermann, Eva; Damiano, John; Morbin, Michela; Bruni, Amalia C.; Giaccone, Giorgio; Cossette, Patrick; Saftig, Paul; Grötzinger, Joachim; Schwake, Michael; Andermann, Frederick; Staropoli, John F.; Sims, Katherine B.; Mole, Sara E.; Franceschetti, Silvana; Alexander, Noreen A.; Cooper, Jonathan D.; Chapman, Harold A.; Carpenter, Stirling; Berkovic, Samuel F.; Bahlo, Melanie

    2013-01-01

    Kufs disease, an adult-onset neuronal ceroid lipofuscinosis, is challenging to diagnose and genetically heterogeneous. Mutations in CLN6 were recently identified in recessive Kufs disease presenting as progressive myoclonus epilepsy (Type A), whereas the molecular basis of cases presenting with dementia and motor features (Type B) is unknown. We performed genome-wide linkage mapping of two families with recessive Type B Kufs disease and identified a single region on chromosome 11 to which both families showed linkage. Exome sequencing of five samples from the two families identified homozygous and compound heterozygous missense mutations in CTSF within this linkage region. We subsequently sequenced CTSF in 22 unrelated individuals with suspected recessive Kufs disease, and identified an additional patient with compound heterozygous mutations. CTSF encodes cathepsin F, a lysosomal cysteine protease, dysfunction of which is a highly plausible candidate mechanism for a storage disorder like ceroid lipofuscinosis. In silico modeling suggested the missense mutations would alter protein structure and function. Moreover, re-examination of a previously published mouse knockout of Ctsf shows that it recapitulates the light and electron-microscopic pathological features of Kufs disease. Although CTSF mutations account for a minority of cases of type B Kufs, CTSF screening should be considered in cases with early-onset dementia and may avoid the need for invasive biopsies. PMID:23297359

  5. New novel mutation of the ATP7B gene in a family with Wilson disease.

    PubMed

    Lee, Jun-Young; Kim, Young-Hyun; Kim, Tae-Woo; Oh, Sun-Young; Kim, Dal-Sik; Shin, Byoung-Soo

    2012-02-15

    Wilson disease (WD) is an autosomal recessive disorder of copper metabolism. The WD gene codes for a copper transporting P-type ATPase (ATP7B) are located on chromosome 13q14.3. Mutation of this gene disrupts copper homeostasis, resulting in the accumulation of copper in the liver, brain, kidneys and corneas and copper toxication at these sites. Since the detection of the WD gene in 1993, approximately 300 disease-specific muations have been identified. We recently evaluated a Korean family with WD. The proband, a 17-year-old boy, visited our hospital due to abnormal behaviors including generalized slow movement, dysphagia, drooling and ataxia. Laboratory results revealed decreases in serum copper and ceruloplasmin and an increase in urinary excretion of copper. He had liver cirrhosis, brain lesions and Kayser-Fleischer corenal rings. Molecular genetic analysis of the ATP7B gene demonstrated that he was heterozygous for deletion mutation c.2697_2723del27 in exon 11. Further study of family members revealed that his father and younger brother had the same mutation. The c.2697_2723del27 deletion mutation in exon 11 has not yet been reported as a causative muation of WD and is an in-frame deletion not expected to lead to a frame shift. Therefore, we report a novel mutation of the ATP7B gene in a family with WD. PMID:22075048

  6. Mutations in the PDE6B gene in autosomal recessive retinitis pigmentosa

    SciTech Connect

    Danciger, M.; Blaney, J.; Gao, Y.Q.; Zhao, D.Y.

    1995-11-01

    We have studied 24 small families with presumed autosomal recessive inheritance of retinitis pigmentosa by a combination of haplotype analysis and exon screening. Initial analysis of the families was made with a dinucleotide repeat polymorphism adjacent to the gene for rod cGMP-phosphodiesterase (PDE6B). This was followed by denaturing gradient gel electrophoresis (DGGE) and single-strand conformation polymorphism electrophoresis (SSCPE) of the 22 exons and a portion of the 5{prime} untranslated region of the PDE6B gene in the probands of each family in which the PDE6B locus could not be ruled out from segregating with disease. Two probands were found with compound heterozygous mutations: Gly576Asp and His620(1-bp del) mutations were present in one proband, and a Lys706X null mutation and an AG to AT splice acceptor site mutation in intron 2 were present in the other. Only the affecteds of each of the two families carried both corresponding mutations. 29 refs., 3 figs., 1 tab.

  7. Mutations in KAT6B, Encoding a Histone Acetyltransferase, Cause Genitopatellar Syndrome

    PubMed Central

    Campeau, Philippe M.; Kim, Jaeseung C.; Lu, James T.; Schwartzentruber, Jeremy A.; Abdul-Rahman, Omar A.; Schlaubitz, Silke; Murdock, David M.; Jiang, Ming-Ming; Lammer, Edward J.; Enns, Gregory M.; Rhead, William J.; Rowland, Jon; Robertson, Stephen P.; Cormier-Daire, Valérie; Bainbridge, Matthew N.; Yang, Xiang-Jiao; Gingras, Marie-Claude; Gibbs, Richard A.; Rosenblatt, David S.; Majewski, Jacek; Lee, Brendan H.

    2012-01-01

    Genitopatellar syndrome (GPS) is a skeletal dysplasia with cerebral and genital anomalies for which the molecular basis has not yet been determined. By exome sequencing, we found de novo heterozygous truncating mutations in KAT6B (lysine acetyltransferase 6B, formerly known as MYST4 and MORF) in three subjects; then by Sanger sequencing of KAT6B, we found similar mutations in three additional subjects. The mutant transcripts do not undergo nonsense-mediated decay in cells from subjects with GPS. In addition, human pathological analyses and mouse expression studies point to systemic roles of KAT6B in controlling organismal growth and development. Myst4 (the mouse orthologous gene) is expressed in mouse tissues corresponding to those affected by GPS. Phenotypic differences and similarities between GPS, the Say-Barber-Biesecker variant of Ohdo syndrome (caused by different mutations of KAT6B), and Rubinstein-Taybi syndrome (caused by mutations in other histone acetyltransferases) are discussed. Together, the data support an epigenetic dysregulation of the limb, brain, and genital developmental programs. PMID:22265014

  8. Mutations in COX7B Cause Microphthalmia with Linear Skin Lesions, an Unconventional Mitochondrial Disease

    PubMed Central

    Indrieri, Alessia; van Rahden, Vanessa Alexandra; Tiranti, Valeria; Morleo, Manuela; Iaconis, Daniela; Tammaro, Roberta; D’Amato, Ilaria; Conte, Ivan; Maystadt, Isabelle; Demuth, Stephanie; Zvulunov, Alex; Kutsche, Kerstin; Zeviani, Massimo; Franco, Brunella

    2012-01-01

    Microphthalmia with linear skin lesions (MLS) is an X-linked dominant male-lethal disorder associated with mutations in holocytochrome c-type synthase (HCCS), which encodes a crucial player of the mitochondrial respiratory chain (MRC). Unlike other mitochondrial diseases, MLS is characterized by a well-recognizable neurodevelopmental phenotype. Interestingly, not all clinically diagnosed MLS cases have mutations in HCCS, thus suggesting genetic heterogeneity for this disorder. Among the possible candidates, we analyzed the X-linked COX7B and found deleterious de novo mutations in two simplex cases and a nonsense mutation, which segregates with the disease, in a familial case. COX7B encodes a poorly characterized structural subunit of cytochrome c oxidase (COX), the MRC complex IV. We demonstrated that COX7B is indispensable for COX assembly, COX activity, and mitochondrial respiration. Downregulation of the COX7B ortholog (cox7B) in medaka (Oryzias latipes) resulted in microcephaly and microphthalmia that recapitulated the MLS phenotype and demonstrated an essential function of complex IV activity in vertebrate CNS development. Our results indicate an evolutionary conserved role of the MRC complexes III and IV for the proper development of the CNS in vertebrates and uncover a group of mitochondrial diseases hallmarked by a developmental phenotype. PMID:23122588

  9. Mutations in KAT6B, encoding a histone acetyltransferase, cause Genitopatellar syndrome.

    PubMed

    Campeau, Philippe M; Kim, Jaeseung C; Lu, James T; Schwartzentruber, Jeremy A; Abdul-Rahman, Omar A; Schlaubitz, Silke; Murdock, David M; Jiang, Ming-Ming; Lammer, Edward J; Enns, Gregory M; Rhead, William J; Rowland, Jon; Robertson, Stephen P; Cormier-Daire, Valérie; Bainbridge, Matthew N; Yang, Xiang-Jiao; Gingras, Marie-Claude; Gibbs, Richard A; Rosenblatt, David S; Majewski, Jacek; Lee, Brendan H

    2012-02-10

    Genitopatellar syndrome (GPS) is a skeletal dysplasia with cerebral and genital anomalies for which the molecular basis has not yet been determined. By exome sequencing, we found de novo heterozygous truncating mutations in KAT6B (lysine acetyltransferase 6B, formerly known as MYST4 and MORF) in three subjects; then by Sanger sequencing of KAT6B, we found similar mutations in three additional subjects. The mutant transcripts do not undergo nonsense-mediated decay in cells from subjects with GPS. In addition, human pathological analyses and mouse expression studies point to systemic roles of KAT6B in controlling organismal growth and development. Myst4 (the mouse orthologous gene) is expressed in mouse tissues corresponding to those affected by GPS. Phenotypic differences and similarities between GPS, the Say-Barber-Biesecker variant of Ohdo syndrome (caused by different mutations of KAT6B), and Rubinstein-Taybi syndrome (caused by mutations in other histone acetyltransferases) are discussed. Together, the data support an epigenetic dysregulation of the limb, brain, and genital developmental programs. PMID:22265014

  10. Bcl-6 mutation status provides clinically valuable information in early-stage B-cell chronic lymphocytic leukemia.

    PubMed

    Sarsotti, E; Marugan, I; Benet, I; Terol, M J; Sanchez-Izquierdo, D; Tormo, M; Rubio-Moscardo, F; Martinez-Climent, J A; García-Conde, J

    2004-04-01

    In B-cell chronic lymphocytic leukemia (B-CLL), somatic mutation of IgVH genes defines a subgroup with favorable prognosis, whereas the absence of IgVH mutations is correlated with a worse outcome. Mutations of the BCL-6 gene are also observed in a subset of B-CLL, but the clinical significance of this molecular alteration remains uncertain. We examined the distribution of IgVH and BCL-6 gene mutations in 95 well-characterized patients with Binet stage A B-CLL, and correlated them with clinical, laboratory, cytogenetic findings and disease progression. Mutations of the BCL-6 gene were observed only in cases harboring mutated IgVH. Unexpectedly, coexistence of IgVH and BCL-6 mutations was correlated with shorter treatment-free interval (TFI) compared to cases harboring only IgVH mutation (median, 55 months vs not reached; P=0.01), resembling the clinical course of unmutated IgVH cases (median TFI, 44 months). As expected, deletions of 17p13 (P53 locus) and 11q22 (ATM locus) were observed in cases with unmutated IgVH, except one patient who showed mutations of both IgVH and BCL-6. No other statistically significant differences were observed among the genetic subgroups. Our data indicate that BCL-6 mutations identify a subgroup of Binet stage A B-CLL patients with a high risk of progression despite the presence of mutated IgVH gene. PMID:14961033

  11. Mutation Profiling of the Hepatitis B Virus Strains Circulating in North Indian Population

    PubMed Central

    Tuteja, Amit; Siddiqui, Abu Baker; Madan, Kaushal; Goyal, Rohit; Shalimar; Sreenivas, Vishnubhatla; Kaur, Navkiran; Panda, Subrat K.; Narayanasamy, Krishnamoorthy; Subodh, Swati; Acharya, Subrat K.

    2014-01-01

    Aims The aim of this study was to investigate the genomic mutations in the circulating Hepatitis B virus strains causing infection in the Indian population. Further, we wanted to analyze the biological significance of these mutations in HBV mediated disease. Methods 222 HBsAg positive patients were enrolled in the study. The genotype and mutation profile was determined for the infecting HBV isolate by sequencing overlapping fragments. These sequences were analyzed by using different tools and compared with previously available HBV sequence information. Mutation Frequency Index (MFI) for the Genes and Diagnosis group was also calculated. Results HBV Genotype D was found in 55% (n = 121) of the patient group and genotype A was found in 30% (n = 66) of samples. The majority (52%) of the HBV-infected individuals in the present study were HBeAg-negative in all the age groups studied. Spontaneous drug associated mutations implicated in resistance to antiviral therapy were also identified in about quarter of our patients, which is of therapeutic concern. The MFI approach used in the study indicated that Core peptide was the most conserved region in both genotypes and Surface peptide had highest mutation frequency. Few mutations in X gene (T36A and G50R) showed high frequency of association with HCC. A rare recombinant strain of HBV genotype A and D was also identified in the patient group. Conclusions HBV genotype D was found out to be most prevalent. More than half of the patients studied had HBeAg negative disease. Core region was found to be most conserved. Drug Associated mutations were detected in 22% of the patient group and T36A and G50R mutations in X gene were found to be associated with HCC. PMID:24637457

  12. Mutations in the Promoter Region of the Aldolase B Gene that cause Hereditary Fructose Intolerance

    PubMed Central

    Coffee, Erin M.; Tolan, Dean R.

    2010-01-01

    SUMMARY Hereditary fructose intolerance (HFI) is a potentially fatal inherited metabolic disease caused by a deficiency of aldolase B activity in the liver and kidney. Over 40 disease-causing mutations are known in the protein-coding region of ALDOB. Mutations upstream of the protein-coding portion of ALDOB are reported here for the first time. DNA sequence analysis of 61 HFI patients revealed single base mutations in the promoter, intronic enhancer, and the first exon, which is entirely untranslated. One mutation, g.–132G>A, is located within the promoter at an evolutionarily conserved nucleotide within a transcription factor-binding site. A second mutation, IVS1+1G>C, is at the donor splice site of the first exon. In vitro electrophoretic mobility shift assays show a decrease in nuclear extract-protein binding at the g.–132G>A mutant site. The promoter mutation results in decreased transcription using luciferase reporter plasmids. Analysis of cDNA from cells transfected with plasmids harboring the IVS1+1G>C mutation results in aberrant splicing leading to complete retention of the first intron (~ 5 kb). The IVS1+1G>C splicing mutation results in loss of luciferase activity from a reporter plasmid. These novel mutations in ALDOB represent 2% of alleles in American HFI patients, with IVS1+1G>C representing a significantly higher allele frequency (6%) among HFI patients of Hispanic and African-American ethnicity. PMID:20882353

  13. Mutations in epigenetic regulators are involved in acute lymphoblastic leukemia relapse following allogeneic hematopoietic stem cell transplantation

    PubMed Central

    Lai, Xiaoyu; Li, Caihua; Shi, Jimin; Tan, Yamin; Fu, Shan; Wang, Yebo; Zhu, Ni; He, Jingsong; Zheng, Weiyan; Yu, Xiaohong; Cai, Zhen; Huang, He

    2016-01-01

    Although steady improvements to chemotherapeutic treatments has helped cure 80% of childhood acute lymphoblastic leukemia (ALL) cases, chemotherapy has proven to be less effective in treating the majority of adult patients, leaving allogeneic hematopoietic stem cell transplantation (allo-HSCT) as the primary adult treatment option. Nevertheless relapse are the leading cause of death following allo-HSCT. The genetic pathogenesis of relapse following allo-HSCT in Philadelphia chromosome- negative ALL (Ph− ALL) remains unexplored. We performed longitudinal whole-exome sequencing analysis in three adult patients with Ph− B-cell ALL (Ph− B-ALL) on samples collected from diagnosis to relapse after allo-HSCT. Based on these data, we performed target gene sequencing on 23 selected genes in 58 adult patients undergoing allo-HSCT with Ph− B-ALL. Our results revealed a significant enrichment of mutations in epigenetic regulators from relapsed samples, with recurrent somatic mutations in SETD2, CREBBP, KDM6A and NR3C1. The relapsed samples were also enriched in signaling factor mutations, including KRAS, PTPN21, MYC and USP54. Furthermore, we are the first to reveal the clonal evolution patterns during leukemia relapse after allo-HSCT. Cells present in relapsed specimens were genetically related to the diagnosed tumor, these cells therefore arose from either an existing subclone that was not eradicated by allo-HSCT therapy, or from the same progenitor that acquired new mutations. In some cases, however, it is possible that leukemia recurrence following allo-HSCT could result from a secondary malignancy with a distinct set of mutations. We identified novel genetic causes of leukemia relapse after allo-HSCT using the largest generated data set to date from adult patients with Ph− B-ALL. PMID:26527318

  14. Identification and characterization of mutations in housefly (Musca domestica) acetylcholinesterase involved in insecticide resistance.

    PubMed

    Walsh, S B; Dolden, T A; Moores, G D; Kristensen, M; Lewis, T; Devonshire, A L; Williamson, M S

    2001-10-01

    Acetylcholinesterase (AChE) insensitive to organophosphate and carbamate insecticides has been identified as a major resistance mechanism in numerous arthropod species. However, the associated genetic changes have been reported in the AChE genes from only three insect species; their role in conferring insecticide insensitivity has been confirmed, using functional expression, only for those in Drosophila melanogaster. The housefly, Musca domestica, was one of the first insects shown to have this mechanism; here we report the occurrence of five mutations (Val-180-->Leu, Gly-262-->Ala, Gly-262-->Val, Phe-327-->Tyr and Gly-365-->Ala) in the AChE gene of this species that, either singly or in combination, confer different spectra of insecticide resistance. The baculovirus expression of wild-type and mutated housefly AChE proteins has confirmed that the mutations each confer relatively modest levels of insecticide insensitivity except the novel Gly-262-->Val mutation, which results in much stronger resistance (up to 100-fold) to certain compounds. In all cases the effects of mutation combinations are additive. The mutations introduce amino acid substitutions that are larger than the corresponding wild-type residues and are located within the active site of the enzyme, close to the catalytic triad. The likely influence of these substitutions on the accessibility of the different types of inhibitor and the orientation of key catalytic residues are discussed in the light of the three-dimensional structures of the AChE protein from Torpedo californica and D. melanogaster. PMID:11563981

  15. Pathogenic mechanism of an autism-associated neuroligin mutation involves altered AMPA-receptor trafficking.

    PubMed

    Chanda, S; Aoto, J; Lee, S-J; Wernig, M; Südhof, T C

    2016-02-01

    Neuroligins are postsynaptic cell-adhesion molecules that bind to presynaptic neurexins. Although the general synaptic role of neuroligins is undisputed, their specific functions at a synapse remain unclear, even controversial. Moreover, many neuroligin gene mutations were associated with autism, but the pathophysiological relevance of these mutations is often unknown, and their mechanisms of action uninvestigated. Here, we examine the synaptic effects of an autism-associated neuroligin-4 substitution (called R704C), which mutates a cytoplasmic arginine residue that is conserved in all neuroligins. We show that the R704C mutation, when introduced into neuroligin-3, enhances the interaction between neuroligin-3 and AMPA receptors, increases AMPA-receptor internalization and decreases postsynaptic AMPA-receptor levels. When introduced into neuroligin-4, conversely, the R704C mutation unexpectedly elevated AMPA-receptor-mediated synaptic responses. These results suggest a general functional link between neuroligins and AMPA receptors, indicate that both neuroligin-3 and -4 act at excitatory synapses but perform surprisingly distinct functions, and demonstrate that the R704C mutation significantly impairs the normal function of neuroligin-4, thereby validating its pathogenicity. PMID:25778475

  16. GEFS+ is not related to the most common mutations of SCN1B, SCN1A and GABRG2 in two Tunisian families.

    PubMed

    Mrabet, H; Belhedi, N; Bouchlaka, S; El Gaaied, A; Mrabet, A

    2007-12-01

    The objective was to investigate whether the described mutations of the SCN1A, SCN1B and GABRG2 genes are associated to generalised epilepsy with febrile seizure plus (GEFS+) in two Tunisian families. We performed a genetic study of two multigenerational Tunisian families with GEFS+ spectrum. The molecular analysis included a PCR amplification of SCN1B, SCN1A and GAGRG2 exons, then a screening of the known SCN1B, SCN1A and GABRG2 gene mutations by direct sequencing. The data excluded the involvement of all known published mutations. However, an insertion of a T nucleotide at a heterozygous state within the intron 12 of the SCN1A gene has been identified in two probands and their parents. Our results corroborate the genetic heterogeneity of GEFS+ predominantly in epilepsy patients of different countries and ethnic groups. PMID:18175077

  17. New AP4B1 mutation in an African-American child associated with intellectual disability

    PubMed Central

    Lamichhane, Dronacharya

    2013-01-01

    Prevalence of intellectual disability (ID) varies from 1–3%. Genetic causes of ID are being increasingly recognized. Although multiple mutations have been identified as a cause of syndromic ID, the genetic etiology of non-syndromic ID is poorly understood. However, more than 100 loci have been mapped that are associated with non-syndromic ID. There have been a couple of reports of AP4B1 gene mutation causing severe intellectual disability, absent speech, shy character, stereotypic laughter, muscular hypotonia that progressed to spastic paraplegia, microcephaly, foot deformity, decreased muscle mass of the lower limbs, inability to walk, and growth retardation. They had structural brain abnormalities and seizures. The reported cases were from Arab families where consanguineous marriage is common. We encountered an African-American child who presented first at the age of 24 mo with language difficulties and was subsequently found to have moderate to severe intellectual disability by standardized tests. Shortly, he started to have seizures and problems with ambulation. Although he was hypotonic at the time of presentation, legs slowly became spastic at the age of 4 yr. After a thorough work up, he was found to have heterozygous mutation in the AP4B1 gene along with another missense mutation in the same gene. There has been no report of mutation in this gene in the North American population. Although AP4B1 typically is said to be an autosomal recessive disease-causing gene, our case is different in the sense that there are two mutations in the same gene one of which has never been reported before and co-exists with a known disease causing mutation. Yet, the phenotype of the case closely resembles those published previously.

  18. Mutations Associated With Occult Hepatitis B in HIV-Positive South Africans

    PubMed Central

    Powell, Eleanor A.; Gededzha, Maemu P.; Rentz, Michael; Rakgole, Nare J.; Selabe, Selokela G.; Seleise, Tebogo A.; Mphahlele, M. Jeffrey; Blackard, Jason T.

    2015-01-01

    Occult hepatitis B is characterized by the absence of hepatitis B surface antigen (HBsAg) but the presence of HBV DNA. Because diagnosis of hepatitis B virus (HBV) typically includes HBsAg detection, occult HBV remains largely undiagnosed. Occult HBV is associated with increased risk of hepatocellular carcinoma, reactivation to chronic HBV during immune suppression, and transmission during blood transfusion and liver transplant. The mechanisms leading to occult HBV infection are unclear, although viral mutations are likely a significant factor. In this study, sera from 394 HIV-positive South Africans were tested for HBV DNA and HBsAg. For patients with detectable HBV DNA, the overlapping surface and polymerase open reading frames (ORFs) were sequenced. Occult-associated mutations—those mutations found exclusively in individuals with occult HBV infection but not in individuals with chronic HBV infection from the same cohort or GenBank references—were identified. Ninety patients (22.8%) had detectable HBV DNA. Of these, 37 had detectable HBsAg, while 53 lacked detectable surface antigen. The surface and polymerase ORFs were cloned successfully for 19 patients with chronic HBV and 30 patients with occult HBV. In total, 235 occult-associated mutations were identified. Ten occult-associated mutations were identified in more than one patient. Additionally, 15 amino acid positions had two distinct occult-associated mutations at the same residue. Occult-associated mutations were common and present in all regions of the surface and polymerase ORFs. Further study is underway to determine the effects of these mutations on viral replication and surface antigen expression in vitro. PMID:25164924

  19. A mutation of the start codon in the X region of hepatitis B virus DNA in a patient with non-B, non-C chronic hepatitis.

    PubMed

    Fujise, Kiyotaka; Tatsuzawa, Keiko; Kono, Midori; Hoshina, Sadayori; Tsubota, Akihito; Niiya, Minoru; Namiki, Yoshihisa; Tada, Norio; Tajiri, Hisao

    2011-02-27

    There are cases of hepatitis involving occult hepatitis B virus (HBV) infection in which, even though the HB surface antigen (HBsAg) is negative, HBV-DNA is detected by a polymerase chain reaction (PCR). We conducted a sequence analysis of the entire HBV region in a case of non-B non-C chronic hepatitis in a 46-year-old female. A diagnosis of non-B non-C chronic hepatitis was made. Although HBV markers, such as HBs antibody (anti-HBs), anti-HBc, HBeAg and anti-HBe, were negative, HBV-DNA was positive. Nested PCR was performed to amplify the precore region of HBV-DNA and all remaining regions by long nested PCR. Sequence analysis of the two obtained bands was conducted by direct sequencing. Compared with the control strains, the ATG (Methionine) start codon in the X region had mutated to GTG (Valine). It is assumed that a mutation at the start codon in the X region may be the reason why HBV markers are negative in some cases of hepatitis that involve occult HBV infection. PMID:21423595

  20. Congenital Recessive Methemoglobinemia Revealed in Adulthood: Description of a New Mutation in Cytochrome b5 Reductase Gene.

    PubMed

    Forestier, Alexandra; Pissard, Serge; Cretet, Justine; Mambie, Adeline; Pascal, Laurent; Cliquennois, Manuel; Cambier, Nathalie; Rose, Christian

    2015-01-01

    Methemoglobinemia can be acquired (oxidizing drugs or chemicals products) or inherited either by mutations affecting globin chains [M hemoglobins (M Hbs)] or by defects in the enzymatic system involved in the reduction of spontaneous Hb oxidation: nicotinamide adenine dinucleotide (NADH)-cytochrome b5 reductase. It is encoded by the CYB5R3 gene: there are two phenotypes of autosomal recessive congenital methemoglobinemia, in type II CYB5R deficiency is generalized and affects all cells, leading to an early onset, whereas in type I, the enzyme deficiency is restricted to erythrocytes, usually discovered in infancy but not exclusively. We report a new case of methemoglobinemia discovered in a patient from Bahrain who exhibited an unknown dyspnea at the age of 37 years without trigger events or oxidizing products. We discovered a new mutation in the CYB5R3 gene: exon 9, codon 266 (delGAG) (GLU) (CYB5R3: c.726_729delGAG) in the homozygous state. Appearance of methemoglobinemia in an adult usually suggests an acquired cause but our case illustrated that it could also reveal a type I mutation of cytochrome b5 reductase. PMID:26291966

  1. A Case of Congenital Central Hypoventilation Syndrome with PHOX2B Gene Mutation in a Korean Neonate

    PubMed Central

    Kwon, Kyoung-Ah; Byun, Shin-Yun; Kim, Shine-Young; Hwang, Sang-Hyoun

    2010-01-01

    Congenital central hypoventilation syndrome (CCHS) is a life-threatening disorder with apnea and cyanosis during sleep requiring immediate endotracheal intubation during the first day of life. The PHOX2B gene has been identified as the major gene involved in CCHS. This is the first report of a Korean neonate with CCHS confirmed to have a PHOX2B mutation with expanded alleles containing 20 polyalanine repeats that is a relatively small number compared to previous cases. The patient required intermittent ventilator support during sleep only and did not suffer from any other disorders of the autonomic nerve system. He consistently needs ventilator support during sleep and remains alive. Analysis of PHOX2B gene is useful for diagnosis and appropriate therapeutic intervention of CCHS patients. PMID:20676341

  2. A recurrent dominant negative E47 mutation causes agammaglobulinemia and BCR(-) B cells.

    PubMed

    Boisson, Bertrand; Wang, Yong-Dong; Bosompem, Amma; Ma, Cindy S; Lim, Annick; Kochetkov, Tatiana; Tangye, Stuart G; Casanova, Jean-Laurent; Conley, Mary Ellen

    2013-11-01

    Approximately 90% of patients with isolated agammaglobulinemia and failure of B cell development have mutations in genes required for signaling through the pre–B cell and B cell receptors. The nature of the gene defect in the majority of remaining patients is unknown. We recently identified 4 patients with agammaglobulinemia and markedly decreased numbers of peripheral B cells. The B cells that could be detected had an unusual phenotype characterized by the increased expression of CD19 but the absence of a B cell receptor. Genetic studies demonstrated that all 4 patients had the exact same de novo mutation in the broadly expressed transcription factor E47. The mutant protein (E555K) was stable in patient-derived EBV-transformed cell lines and cell lines transfected with expression vectors. E555K in the transfected cells localized normally to the nucleus and resulted in a dominant negative effect when bound to DNA as a homodimer with wild-type E47. Mutant E47 did permit DNA binding by a tissue-specific heterodimeric DNA-binding partner, myogenic differentiation 1 (MYOD). These findings document a mutational hot-spot in E47 and represent an autosomal dominant form of agammaglobulinemia. Further, they indicate that E47 plays a critical role in enforcing the block in development of B cell precursors that lack functional antigen receptors. PMID:24216514

  3. Carrier Frequency of CYP1B1 Mutations in the United States (An American Ophthalmological Society Thesis)

    PubMed Central

    Wiggs, Janey L.; Langgurth, Anne M.; Allen, Keri F.

    2014-01-01

    Purpose: CYP1B1 mutations cause autosomal recessive congenital glaucoma. Disease risk assessment for families with CYP1B1 mutations requires knowledge of the population mutation carrier frequency. The purpose of this study is to determine the CYP1B1 mutation carrier frequency in clinically normal individuals residing in the United States. Because CYP1B1 mutations can exhibit variable expressivity, we hypothesize that the mutation carrier frequency is higher than expected. Methods: Two hundred fifty individuals without glaucoma or a family history of glaucoma were enrolled. CYP1B1 mutations were identified by DNA sequencing, and pathogenicity was estimated by PolyPhen-2 or a previous report of disease causality. Results: Based on the disease frequency (1 in 10,000) and prevalence of CYP1B1-related congenital glaucoma (15% to 20%), the frequency of CYP1B1-related congenital glaucoma in the United States is approximately 1 in 50,000. Assuming Hardy-Weinberg equilibrium, the expected CYP1B1 mutation carrier frequency would be 1 in 112, or 0.89%. Among the 250 study participants, 11 (4.4%) are carriers of a single pathogenic mutation, representing a carrier frequency of 1 in 22, which is 5.1 times the expected frequency. A higher-than-expected carrier frequency (1 in 33, 3.0%) was also observed in 4300 white individuals sequenced by the National Heart Lung and Blood Institute Exome Sequencing Project. Conclusions: Our results show that the CYP1B1 mutation carrier frequency in the US population is between 1 in 22 and 1 in 33, which is 5.1 to 3.4 times the expected frequency. These results suggest that more individuals than expected are carriers of a deleterious CYP1B1 mutation, and that the prevalence of CYP1B1-related disease may be higher than expected. PMID:25646030

  4. Promiscuous Mutations Activate the Non-Canonical NF-kB Pathway in Multiple Myeloma

    PubMed Central

    Keats, Jonathan J.; Fonseca, Rafael; Chesi, Marta; Schop, Roelandt; Baker, Angela; Chng, Wee-Joo; Van Wier, Scott; Tiedemann, Rodger; Shi, Chang-Xin; Sebag, Michael; Braggio, Esteban; Henry, Travis; Zhu, Yuan-Xiao; Fogle, Homer; Price-Troska, Tammy; Ahmann, Gregory; Mancini, Catherine; Brents, Leslie A.; Kumar, Shaji; Greipp, Philip; Dispenzieri, Angela; Bryant, Barb; Mulligan, George; Bruhn, Laurakay; Barrett, Michael; Valdez, Riccardo; Trent, Jeff; Stewart, A. Keith; Carpten, John; Bergsagel, P. Leif

    2007-01-01

    Summary Activation of NF-kB has been noted in many tumor types, however only rarely has this been linked to an underlying genetic mutation. An integrated analysis of high-density oligonucleotide array CGH and gene expression profiling data from 155 multiple myeloma samples identified a promiscuous array of abnormalities contributing to the dysregulation of NF-kB in approximately 20% of patients. We report mutations in ten genes causing the inactivation of TRAF2, TRAF3, CYLD, cIAP1/cIAP2, and activation of NFKB1, NFKB2, CD40, LTBR, TACI, and NIK that result primarily in constitutive activation of the non-canonical NF-kB pathway, with the single most common abnormality being inactivation of TRAF3. These results highlight the critical importance of the NF-kB pathway in the pathogenesis of multiple myeloma. PMID:17692805

  5. A Form of the Metabolic Syndrome Associated with Mutations in DYRK1B

    PubMed Central

    Choi, Murim; Faramarzi, Saeed; Mane, Shrikant; Kasaei, Mohammad; Sarajzadeh-Fard, Kazem; Hwa, John; Kidd, Kenneth K.; Babaee Bigi, Mohammad A.; Malekzadeh, Reza; Hosseinian, Adallat; Babaei, Masoud; Lifton, Richard P.; Mani, Arya

    2014-01-01

    BACKGROUND Genetic analysis has been successful in identifying causative mutations for individual cardiovascular risk factors. Success has been more limited in mapping susceptibility genes for clusters of cardiovascular risk traits, such as those in the metabolic syndrome. METHODS We identified three large families with coinheritance of early-onset coronary artery disease, central obesity, hypertension, and diabetes. We used linkage analysis and whole-exome sequencing to identify the disease-causing gene. RESULTS A founder mutation was identified in DYRK1B, substituting cysteine for arginine at position 102 in the highly conserved kinase-like domain. The mutation precisely cosegregated with the clinical syndrome in all the affected family members and was absent in unaffected family members and unrelated controls. Functional characterization of the disease gene revealed that nonmutant protein encoded by DYRK1B inhibits the SHH (sonic hedgehog) and Wnt signaling pathways and consequently enhances adipogenesis. Furthermore, DYRK1B promoted the expression of the key gluconeogenic enzyme glucose-6-phosphatase. The R102C allele showed gain-offunction activities by potentiating these effects. A second mutation, substituting proline for histidine 90, was found to cosegregate with a similar clinical syndrome in an ethnically distinct family. CONCLUSIONS These findings indicate a role for DYRK1B in adipogenesis and glucose homeostasis and associate its altered function with an inherited form of the metabolic syndrome. (Funded by the National Institutes of Health.) PMID:24827035

  6. Precore/core region mutations of hepatitis B virus related to clinical severity

    PubMed Central

    Kim, Hong; Lee, Seoung-Ae; Do, Seung Yeon; Kim, Bum-Joon

    2016-01-01

    Despite the availability of an effective vaccine, hepatitis B virus (HBV) infection remains a major health problem, with more than 350 million chronically infected people worldwide and over 1 million annual deaths due to cirrhosis and liver cancer. HBV mutations are primarily generated due both to a lack of proofreading capacity by HBV polymerase and to host immune pressure, which is a very important factor for predicting disease progression and therapeutic outcomes. Several types of HBV precore/core (preC/C) mutations have been described to date. The host immune response against T cells drives mutation in the preC/C region. Specifically, preC/C mutations in the MHC class II restricted region are more common than in other regions and are significantly related to hepatocellular carcinoma. Certain mutations, including preC G1896A, are also significantly related to HBeAg-negative chronic infection. This review article mainly focuses on the HBV preC/C mutations that are related to disease severity and on the HBeAg serostatus of chronically infected patients. PMID:27158197

  7. EGFR-activating mutations, DNA copy number abundance of ErbB family, and prognosis in lung adenocarcinoma

    PubMed Central

    Chen, Hsuan-Yu; Liu, Chia-Hsin; Chang, Ya-Hsuan; Yu, Sung-Liang; Ho, Bing-Ching; Hsu, Chung-Ping; Yang, Tsung-Ying; Chen, Kun-Chieh; Hsu, Kuo-Hsuan; Tseng, Jeng-Sen; Hsia, Jiun-Yi; Chuang, Cheng-Yen; Chang, Chi-Sheng; Li, Yu-Cheng; Li, Ker-Chau; Chang, Gee-Chen; Yang, Pan-Chyr

    2016-01-01

    In this study, EGFR-activating mutation status and DNA copy number abundances of members of ErbB family were measured in 261 lung adenocarcinomas. The associations between DNA copy number abundances of ErbB family, EGFR-activating mutation status, and prognosis were explored. Results showed that DNA copy number abundances of EGFR, ERBB2, ERBB3, and ERBB4 had associations with overall survival in lung adenocarcinoma with EGFR-activating mutations. In the stratification analysis, only ERBB2 showed significant discrepancy in patients carrying wild type EGFR and other members of ErbB family in patients carrying EGFR-activating mutation. This indicated that CNAs of ErbB family had effect modifications of EGFR-activating mutation status. Findings of this study demonstrate potential molecular guidance of patient management of lung adenocarcinoma with or without EGFR-activating mutations. PMID:26824984

  8. Lipoprotein profiles in human heterozygote carriers of a functional mutation P297S in scavenger receptor class B1.

    PubMed

    Ljunggren, Stefan A; Levels, Johannes H M; Hovingh, Kees; Holleboom, Adriaan G; Vergeer, Menno; Argyri, Letta; Gkolfinopoulou, Christina; Chroni, Angeliki; Sierts, Jeroen A; Kastelein, John J; Kuivenhoven, Jan Albert; Lindahl, Mats; Karlsson, Helen

    2015-12-01

    The scavenger receptor class B type 1 (SR-B1) is an important HDL receptor involved in cholesterol uptake and efflux, but its physiological role in human lipoprotein metabolism is not fully understood. Heterozygous carriers of the SR-B1(P297S) mutation are characterized by increased HDL cholesterol levels, impaired cholesterol efflux from macrophages and attenuated adrenal function. Here, the composition and function of lipoproteins were studied in SR-B1(P297S) heterozygotes.Lipoproteins from six SR-B1(P297S) carriers and six family controls were investigated. HDL and LDL/VLDL were isolated by ultracentrifugation and proteins were separated by two-dimensional gel electrophoresis and identified by mass spectrometry. HDL antioxidant properties, paraoxonase 1 activities, apoA-I methionine oxidations and HDL cholesterol efflux capacity were assessed.Multivariate modeling separated carriers from controls based on lipoprotein composition. Protein analyses showed a significant enrichment of apoE in LDL/VLDL and of apoL-1 in HDL from heterozygotes compared to controls. The relative distribution of plasma apoE was increased in LDL and in lipid-free form. There were no significant differences in paraoxonase 1 activities, HDL antioxidant properties or HDL cholesterol efflux capacity but heterozygotes showed a significant increase of oxidized methionines in apoA-I.The SR-B1(P297S) mutation affects both HDL and LDL/VLDL protein compositions. The increase of apoE in carriers suggests a compensatory mechanism for attenuated SR-B1 mediated cholesterol uptake by HDL. Increased methionine oxidation may affect HDL function by reducing apoA-I binding to its targets. The results illustrate the complexity of lipoprotein metabolism that has to be taken into account in future therapeutic strategies aiming at targeting SR-B1. PMID:26454245

  9. Mutation of fibulin-1 causes a novel syndrome involving the central nervous system and connective tissues

    PubMed Central

    Bohlega, Saeed; Al-Ajlan, Huda; Al-Saif, Amr

    2014-01-01

    Fibulin-1 is an extracellular matrix protein that has an important role in the structure of elastic fibers and basement membranes of various tissues. Using homozygosity mapping and exome sequencing, we discovered a missense mutation, p.(Cys397Phe), in fibulin-1 in three patients from a consanguineous family presented with a novel syndrome of syndactyly, undescended testes, delayed motor milestones, mental retardation and signs of brain atrophy. The mutation discovered segregated with the phenotype and was not found in 374 population-matched alleles. The affected cysteine is highly conserved across vertebrates and its mutation is predicted to abolish a disulfide bond that defines the tertiary structure of fibulin-1. Our findings emphasize the crucial role fibulin-1 has in development of the central nervous system and various connective tissues. PMID:24084572

  10. Diversity and Convergence of Sodium Channel Mutations Involved in Resistance to Pyrethroids

    PubMed Central

    Rinkevich, Frank D.; Du, Yuzhe; Dong, Ke

    2013-01-01

    Pyrethroid insecticides target voltage-gated sodium channels, which are critical for electrical signaling in the nervous system. The intensive use of pyrethroids in controlling arthropod pests and disease vectors has led to many instances of pyrethroid resistance around the globe. In the past two decades, studies have identified a large number of sodium channel mutations that are associated with resistance to pyrethroids. The purpose of this review is to summarize both common and unique sodium channel mutations that have been identified in arthropod pests of importance to agriculture or human health. Identification of these mutations provides valuable molecular markers for resistance monitoring in the field and helped the discovery of the elusive pyrethroid receptor site(s) on the sodium channel. PMID:24019556

  11. Human Immunoglobulin (Ig)M+IgD+ Peripheral Blood B Cells Expressing the CD27 Cell Surface Antigen Carry Somatically Mutated Variable Region Genes: CD27 as a General Marker for Somatically Mutated (Memory) B Cells

    PubMed Central

    Klein, Ulf; Rajewsky, Klaus; Küppers, Ralf

    1998-01-01

    Immunoglobulin (Ig)M+IgD+ B cells are generally assumed to represent antigen-inexperienced, naive B cells expressing variable (V) region genes without somatic mutations. We report here that human IgM+IgD+ peripheral blood (PB) B cells expressing the CD27 cell surface antigen carry mutated V genes, in contrast to CD27-negative IgM+IgD+ B cells. IgM+IgD+CD27+ B cells resemble class-switched and IgM-only memory cells in terms of cell phenotype, and comprise ∼15% of PB B lymphocytes in healthy adults. Moreover, a very small population (<1% of PB B cells) of highly mutated IgD-only B cells was detected, which likely represent the PB counterpart of IgD-only tonsillar germinal center and plasma cells. Overall, the B cell pool in the PB of adults consists of ∼40% mutated memory B cells and 60% unmutated, naive IgD+CD27− B cells (including CD5+ B cells). In the somatically mutated B cells, VH region genes carry a two- to threefold higher load of somatic mutation than rearranged Vκ genes. This might be due to an intrinsically lower mutation rate in κ light chain genes compared with heavy chain genes and/or result from κ light chain gene rearrangements in GC B cells. A common feature of the somatically mutated B cell subsets is the expression of the CD27 cell surface antigen which therefore may represent a general marker for memory B cells in humans. PMID:9802980

  12. Differential Pathogenesis of Lung Adenocarcinoma Subtypes Involving Sequence Mutations, Copy Number, Chromosomal Instability, and Methylation

    PubMed Central

    Wilkerson, Matthew D.; Yin, Xiaoying; Walter, Vonn; Zhao, Ni; Cabanski, Christopher R.; Hayward, Michele C.; Miller, C. Ryan; Socinski, Mark A.; Parsons, Alden M.; Thorne, Leigh B.; Haithcock, Benjamin E.; Veeramachaneni, Nirmal K.; Funkhouser, William K.; Randell, Scott H.; Bernard, Philip S.; Perou, Charles M.; Hayes, D. Neil

    2012-01-01

    Background Lung adenocarcinoma (LAD) has extreme genetic variation among patients, which is currently not well understood, limiting progress in therapy development and research. LAD intrinsic molecular subtypes are a validated stratification of naturally-occurring gene expression patterns and encompass different functional pathways and patient outcomes. Patients may have incurred different mutations and alterations that led to the different subtypes. We hypothesized that the LAD molecular subtypes co-occur with distinct mutations and alterations in patient tumors. Methodology/Principal Findings The LAD molecular subtypes (Bronchioid, Magnoid, and Squamoid) were tested for association with gene mutations and DNA copy number alterations using statistical methods and published cohorts (n = 504). A novel validation (n = 116) cohort was assayed and interrogated to confirm subtype-alteration associations. Gene mutation rates (EGFR, KRAS, STK11, TP53), chromosomal instability, regional copy number, and genomewide DNA methylation were significantly different among tumors of the molecular subtypes. Secondary analyses compared subtypes by integrated alterations and patient outcomes. Tumors having integrated alterations in the same gene associated with the subtypes, e.g. mutation, deletion and underexpression of STK11 with Magnoid, and mutation, amplification, and overexpression of EGFR with Bronchioid. The subtypes also associated with tumors having concurrent mutant genes, such as KRAS-STK11 with Magnoid. Patient overall survival, cisplatin plus vinorelbine therapy response and predicted gefitinib sensitivity were significantly different among the subtypes. Conclusions/ Significance The lung adenocarcinoma intrinsic molecular subtypes co-occur with grossly distinct genomic alterations and with patient therapy response. These results advance the understanding of lung adenocarcinoma etiology and nominate patient subgroups for future evaluation of treatment response

  13. Chronic bacterial infection activates autoreactive B cells and induces isotype switching and autoantigen-driven mutations.

    PubMed

    Jung, Sophie; Schickel, Jean-Nicolas; Kern, Aurélie; Knapp, Anne-Marie; Eftekhari, Pierre; Da Silva, Sylvia; Jaulhac, Benoît; Brink, Robert; Soulas-Sprauel, Pauline; Pasquali, Jean-Louis; Martin, Thierry; Korganow, Anne-Sophie

    2016-01-01

    The links between infections and the development of B-cell-mediated autoimmune diseases are still unclear. In particular, it has been suggested that infection-induced stimulation of innate immune sensors can engage low affinity autoreactive B lymphocytes to mature and produce mutated IgG pathogenic autoantibodies. To test this hypothesis, we established a new knock-in mouse model in which autoreactive B cells could be committed to an affinity maturation process. We show that a chronic bacterial infection allows the activation of such B cells and the production of nonmutated IgM autoantibodies. Moreover, in the constitutive presence of their soluble antigen, some autoreactive clones are able to acquire a germinal center phenotype, to induce Aicda gene expression and to introduce somatic mutations in the IgG heavy chain variable region on amino acids forming direct contacts with the autoantigen. Paradoxically, only lower affinity variants are detected, which strongly suggests that higher affinity autoantibodies secreting B cells are counterselected. For the first time, we demonstrate in vivo that a noncross-reactive infectious agent can activate and induce autoreactive B cells to isotype switching and autoantigen-driven mutations, but on a nonautoimmune background, tolerance mechanisms prevent the formation of consequently dangerous autoimmunity. PMID:26474536

  14. A Naturally Occurring Mutation in ropB Suppresses SpeB Expression and Reduces M1T1 Group A Streptococcal Systemic Virulence

    PubMed Central

    Hollands, Andrew; Aziz, Ramy K.; Kansal, Rita; Kotb, Malak; Nizet, Victor; Walker, Mark J.

    2008-01-01

    Epidemiological studies of group A streptococcus (GAS) have noted an inverse relationship between SpeB expression and invasive disease. However, the role of SpeB in the course of infection is still unclear. In this study we utilize a SpeB-negative M1T1 clinical isolate, 5628, with a naturally occurring mutation in the gene encoding the regulator RopB, to elucidate the role of RopB and SpeB in systemic virulence. Allelic exchange mutagenesis was used to replace the mutated ropB allele in 5628 with the intact allele from the well characterized isolate 5448. The inverse allelic exchange was also performed to replace the intact ropB in 5448 with the mutated allele from 5628. An intact ropB was found to be essential for SpeB expression. While the ropB mutation was shown to have no effect on hemolysis of RBC's, extracellular DNase activity or survival in the presence of neutrophils, strains with the mutated ropB allele were less virulent in murine systemic models of infection. An isogenic SpeB knockout strain containing an intact RopB showed similarly reduced virulence. Microarray analysis found genes of the SpeB operon to be the primary target of RopB regulation. These data show that an intact RopB and efficient SpeB production are necessary for systemic infection with GAS. PMID:19116661

  15. A naturally occurring mutation in ropB suppresses SpeB expression and reduces M1T1 group A streptococcal systemic virulence.

    PubMed

    Hollands, Andrew; Aziz, Ramy K; Kansal, Rita; Kotb, Malak; Nizet, Victor; Walker, Mark J

    2008-01-01

    Epidemiological studies of group A streptococcus (GAS) have noted an inverse relationship between SpeB expression and invasive disease. However, the role of SpeB in the course of infection is still unclear. In this study we utilize a SpeB-negative M1T1 clinical isolate, 5628, with a naturally occurring mutation in the gene encoding the regulator RopB, to elucidate the role of RopB and SpeB in systemic virulence. Allelic exchange mutagenesis was used to replace the mutated ropB allele in 5628 with the intact allele from the well characterized isolate 5448. The inverse allelic exchange was also performed to replace the intact ropB in 5448 with the mutated allele from 5628. An intact ropB was found to be essential for SpeB expression. While the ropB mutation was shown to have no effect on hemolysis of RBC's, extracellular DNase activity or survival in the presence of neutrophils, strains with the mutated ropB allele were less virulent in murine systemic models of infection. An isogenic SpeB knockout strain containing an intact RopB showed similarly reduced virulence. Microarray analysis found genes of the SpeB operon to be the primary target of RopB regulation. These data show that an intact RopB and efficient SpeB production are necessary for systemic infection with GAS. PMID:19116661

  16. Hypogonadotropic Hypogonadism due to a Novel Missense Mutation in the First Extracellular Loop of the Neurokinin B Receptor

    PubMed Central

    Bereket, Abdullah; Rocha, Nuno; Porter, Keith; Turan, Serap; Gribble, Fiona M.; Kotan, L. Damla; Akcay, Teoman; Atay, Zeynep; Canan, Husniye; Serin, Ayse; O’Rahilly, Stephen; Reimann, Frank; Semple, Robert K.; Topaloglu, A. Kemal

    2015-01-01

    Context The neurokinin B (NKB) receptor, encoded by TACR3, is widely expressed within the central nervous system, including hypothalamic nuclei involved in regulating GnRH release. We have recently reported two mutations in transmembrane segments of the receptor and a missense mutation in NKB in patients with normosmic isolated hypogonadotropic hypogonadism (nIHH). Patients and Methods We sequenced the TACR3 gene in a family in which three siblings had nIHH. The novel mutant receptor thus identified was studied in a heterologous expression system using calcium flux as the functional readout. Results All affected siblings were homozygous for the His148Leu mutation, in the first extracellular loop of the NKB receptor. The His148Leu mutant receptor exhibited profoundly impaired signaling in response to NKB (EC50 = 3 ± 0.1 nm and >5 μm for wild-type and His148Leu, respectively). The location of the mutation in an extracellular part of the receptor led us also to test whether senktide, a synthetic NKB analog, may retain ability to stimulate the mutant receptor. However, the signaling activity of the His148Leu receptor in response to senktide was also severely impaired (EC50 = 1 ± 1 nm for wild-type and no significant response of His148Leu to 10 μm). Conclusions Homozygosity for the TACR3 His148Leu mutation leads to failure of sexual maturation in humans, whereas signaling by the mutant receptor in vitro in response to either NKB or senktide is severely impaired. These observations further strengthen the link between NKB, the NKB receptor, and regulation of human reproductive function. PMID:19755480

  17. RAB39B gene mutations are not a common cause of Parkinson's disease or dementia with Lewy bodies.

    PubMed

    Hodges, Kyndall; Brewer, Sheridan S; Labbé, Catherine; Soto-Ortolaza, Alexandra I; Walton, Ronald L; Strongosky, Audrey J; Uitti, Ryan J; van Gerpen, Jay A; Ertekin-Taner, Nilüfer; Kantarci, Kejal; Lowe, Val J; Parisi, Joseph E; Savica, Rodolfo; Graff-Radford, Jonathan; Jones, David T; Knopman, David S; Petersen, Ronald C; Murray, Melissa E; Graff-Radford, Neill R; Ferman, Tanis J; Dickson, Dennis W; Wszolek, Zbigniew K; Boeve, Bradley F; Ross, Owen A; Lorenzo-Betancor, Oswaldo

    2016-09-01

    Mutations in Ras-related protein Rab-39B (RAB39B) gene have been linked to X-linked early-onset Parkinsonism with intellectual disabilities. The aim of this study was to address the genetic contribution of RAB39B to Parkinson's disease (PD), dementia with Lewy bodies (DLB), and pathologically confirmed Lewy body dementia (pLBD) cases. A cohort of 884 PD, 399 DLB, and 379 pLBD patients were screened for RAB39B mutations, but no coding variants were found, suggesting RAB39B mutations are not a common cause of PD, DLB, or pLBD in Caucasian population. PMID:27459931

  18. Novel mutations of the arylsulphatase B (ARSB) gene in Indian patients with mucopolysaccharidosis type VI

    PubMed Central

    Uttarilli, Anusha; Ranganath, Prajnya; Jain, S. Jamal Md Nurul; Krishna, Prasad C.; Sinha, Anupam; Verma, Ishwar C.; Phadke, Shubha R.; Puri, Ratna D.; Danda, Sumita; Muranjan, Mamta N.; Jevalikar, Ganesh; Nagarajaram, H. A.; Dalal, Ashwin B.

    2015-01-01

    Background & objectives: Mucopolysaccharidosis type VI (MPS VI) is a rare, autosomal recessive lysosomal storage disorder caused by deficient enzymatic activity of N-acetyl galactosamine-4-sulphatase resulting from mutations in the arylsulphatase B (ARSB) gene. The ARSB gene is located on chromosome 5q11-q13 and is composed of eight exons. More than hundred ARSB mutations have been reported so far, but the mutation spectrum of MPS VI in India is still unknown. Hence, the aim of the present study was to identify the mutational spectrum in patients with MPS VI in India and to study the genotype-phenotype association and functional outcomes of these mutations. Methods: Molecular characterization of the ARSB gene by Sanger sequencing was done for 15 patients (aged 15 months to 11 yr) who were enzymatically confirmed to have MPS VI. Age of onset, clinical progression and enzyme activity levels in each patient were studied to look for genotype-phenotype association. Haplotype analysis performed for unrelated patients with the recurring mutation W450C, was suggestive of a founder effect. Sequence and structural analyses of the ARSB protein using standard software were carried out to determine the impact of detected mutations on the function of the ARSB protein. Results: A total of 12 mutations were identified, of which nine were novel mutations namely, p.D53N, p.L98R, p.Y103SfsX9, p.W353X, p.H393R, p.F166fsX18, p.I220fsX5, p.W450L, and p.W450C, and three were known mutations (p.D54N, p.A237D and p.S320R). The nine novel sequence variants were confirmed not to be polymorphic variants by performing sequencing in 50 unaffected individuals from the same ethnic population. Interpretation & conclusions: Nine novel mutations were identified in MPS VI cases from India in the present study. The study also provides some insights into the genotype-phenotype association in MPS VI. PMID:26609033

  19. Expanding the clinical spectrum of B4GALT7 deficiency: homozygous p.R270C mutation with founder effect causes Larsen of Reunion Island syndrome.

    PubMed

    Cartault, François; Munier, Patrick; Jacquemont, Marie-Line; Vellayoudom, Jeannine; Doray, Bérénice; Payet, Christine; Randrianaivo, Hanitra; Laville, Jean-Marc; Munnich, Arnold; Cormier-Daire, Valérie

    2015-01-01

    First described as a variant of Larsen syndrome in Reunion Island (LRS) in the southern Indian Ocean, 'Larsen of Reunion Island syndrome' is characterized by dwarfism, hyperlaxity, multiple dislocations and distinctive facial features. It overlaps with Desbuquois dysplasia, Larsen syndrome and spondyloepiphyseal dysplasia with dislocations ascribed to CANT1, FLNB and CHST3 mutations, respectively. We collected the samples of 22 LRS cases. After exclusion of CANT1, FLNB and CHST3 genes, an exome sequencing was performed in two affected second cousins and one unaffected sister. We identified a homozygous missense mutation in B4GALT7, NM_007255.2: c.808C>T p.(Arg270Cys) named p.R270C, in the two affected cases, not present in the unaffected sister. The same homozygous mutation was subsequently identified in the remaining 20 LRS cases. Our findings demonstrate that B4GALT7 is the causative gene for LRS. The identification of a unique homozygous mutation argues in favor of a founder effect. B4GALT7 encodes a galactosyltransferase, required for the initiation of glycoaminoglycan side chain synthesis of proteoglycans. This study expands the phenotypic spectrum of B4GALT7 mutations, initially described as responsible for the progeroid variant of Ehlers-Danlos syndrome. It further supports a common physiopathological basis involving proteoglycan synthesis in skeletal disorders with dislocations. PMID:24755949

  20. Involvement of c-KIT mutation in the development of gastrointestinal stromal tumors through proliferation promotion and apoptosis inhibition

    PubMed Central

    Ma, Ying-Yu; Yu, Sheng; He, Xu-Jun; Xu, Yuan; Wu, Fang; Xia, Ying-Jie; Guo, Kun; Wang, Hui-Ju; Ye, Zai-Yuan; Zhang, Wei; Tao, Hou-Quan

    2014-01-01

    The aim of this study was to discuss the role of c-KIT mutation in the pathogenesis of gastrointestinal stromal tumors (GISTs) and analyze its correlation with proliferation and apoptosis. c-KIT and PDGFRA genotypes were examined by deoxyribonucleic acid sequencing. Immunohistochemistry was performed to determine the expression levels of Kit, Ki-67 (proliferation marker), and apoptotic protease-activating factor (APAF)-1 (apoptosis marker) and the relationship between their three genes. In the 68 cases examined, 44 cases (64.7%) showed mutations in one of the four exons of c-KIT. The mutations were most frequently found in exon 11 (30 cases [44.1%]), followed by exon 9 (ten cases [14.7%]) and exon 13 (four cases [5.9%]). c-KIT mutation showed no association with prognostic factors using the classification of risk of aggressive behavior in GIST proposed by Fletcher et al. No cases had mutated exon 17 of c-KIT, and neither did exon 12, 14, or 18 of PDGFRA in our present study. There was a positive correlation between the expression level of Kit and Ki-67 (R=0.282, P=0.020). Conversely, a negative correlation was found between the expression levels of Kit and APAF1 (R=−0.243, P=0.046). In conclusion, most GISTs with Kit expression showed c-KIT mutation. Kit expression has a positive correlation with Ki-67 and a negative correlation with APAF1, showing that c-KIT is involved in GIST occurrence and development through proliferation promotion and apoptosis inhibition. PMID:24833907

  1. Germline BRCA Mutations Are Associated With Higher Risk of Nodal Involvement, Distant Metastasis, and Poor Survival Outcomes in Prostate Cancer

    PubMed Central

    Castro, Elena; Goh, Chee; Olmos, David; Saunders, Ed; Leongamornlert, Daniel; Tymrakiewicz, Malgorzata; Mahmud, Nadiya; Dadaev, Tokhir; Govindasami, Koveela; Guy, Michelle; Sawyer, Emma; Wilkinson, Rosemary; Ardern-Jones, Audrey; Ellis, Steve; Frost, Debra; Peock, Susan; Evans, D. Gareth; Tischkowitz, Marc; Cole, Trevor; Davidson, Rosemarie; Eccles, Diana; Brewer, Carole; Douglas, Fiona; Porteous, Mary E.; Donaldson, Alan; Dorkins, Huw; Izatt, Louise; Cook, Jackie; Hodgson, Shirley; Kennedy, M. John; Side, Lucy E.; Eason, Jacqueline; Murray, Alex; Antoniou, Antonis C.; Easton, Douglas F.; Kote-Jarai, Zsofia; Eeles, Rosalind

    2013-01-01

    Purpose To analyze the baseline clinicopathologic characteristics of prostate tumors with germline BRCA1 and BRCA2 (BRCA1/2) mutations and the prognostic value of those mutations on prostate cancer (PCa) outcomes. Patients and Methods This study analyzed the tumor features and outcomes of 2,019 patients with PCa (18 BRCA1 carriers, 61 BRCA2 carriers, and 1,940 noncarriers). The Kaplan-Meier method and Cox regression analysis were used to evaluate the associations between BRCA1/2 status and other PCa prognostic factors with overall survival (OS), cause-specific OS (CSS), CSS in localized PCa (CSS_M0), metastasis-free survival (MFS), and CSS from metastasis (CSS_M1). Results PCa with germline BRCA1/2 mutations were more frequently associated with Gleason ≥ 8 (P = .00003), T3/T4 stage (P = .003), nodal involvement (P = .00005), and metastases at diagnosis (P = .005) than PCa in noncarriers. CSS was significantly longer in noncarriers than in carriers (15.7 v 8.6 years, multivariable analyses [MVA] P = .015; hazard ratio [HR] = 1.8). For localized PCa, 5-year CSS and MFS were significantly higher in noncarriers (96% v 82%; MVA P = .01; HR = 2.6%; and 93% v 77%; MVA P = .009; HR = 2.7, respectively). Subgroup analyses confirmed the poor outcomes in BRCA2 patients, whereas the role of BRCA1 was not well defined due to the limited size and follow-up in this subgroup. Conclusion Our results confirm that BRCA1/2 mutations confer a more aggressive PCa phenotype with a higher probability of nodal involvement and distant metastasis. BRCA mutations are associated with poor survival outcomes and this should be considered for tailoring clinical management of these patients. PMID:23569316

  2. Exome and deep sequencing of clinically aggressive neuroblastoma reveal somatic mutations that affect key pathways involved in cancer progression.

    PubMed

    Lasorsa, Vito Alessandro; Formicola, Daniela; Pignataro, Piero; Cimmino, Flora; Calabrese, Francesco Maria; Mora, Jaume; Esposito, Maria Rosaria; Pantile, Marcella; Zanon, Carlo; De Mariano, Marilena; Longo, Luca; Hogarty, Michael D; de Torres, Carmen; Tonini, Gian Paolo; Iolascon, Achille; Capasso, Mario

    2016-04-19

    The spectrum of somatic mutation of the most aggressive forms of neuroblastoma is not completely determined. We sought to identify potential cancer drivers in clinically aggressive neuroblastoma.Whole exome sequencing was conducted on 17 germline and tumor DNA samples from high-risk patients with adverse events within 36 months from diagnosis (HR-Event3) to identify somatic mutations and deep targeted sequencing of 134 genes selected from the initial screening in additional 48 germline and tumor pairs (62.5% HR-Event3 and high-risk patients), 17 HR-Event3 tumors and 17 human-derived neuroblastoma cell lines.We revealed 22 significantly mutated genes, many of which implicated in cancer progression. Fifteen genes (68.2%) were highly expressed in neuroblastoma supporting their involvement in the disease. CHD9, a cancer driver gene, was the most significantly altered (4.0% of cases) after ALK.Other genes (PTK2, NAV3, NAV1, FZD1 and ATRX), expressed in neuroblastoma and involved in cell invasion and migration were mutated at frequency ranged from 4% to 2%.Focal adhesion and regulation of actin cytoskeleton pathways, were frequently disrupted (14.1% of cases) thus suggesting potential novel therapeutic strategies to prevent disease progression.Notably BARD1, CHEK2 and AXIN2 were enriched in rare, potentially pathogenic, germline variants.In summary, whole exome and deep targeted sequencing identified novel cancer genes of clinically aggressive neuroblastoma. Our analyses show pathway-level implications of infrequently mutated genes in leading neuroblastoma progression. PMID:27009842

  3. Exome and deep sequencing of clinically aggressive neuroblastoma reveal somatic mutations that affect key pathways involved in cancer progression

    PubMed Central

    Lasorsa, Vito Alessandro; Formicola, Daniela; Pignataro, Piero; Cimmino, Flora; Calabrese, Francesco Maria; Mora, Jaume; Esposito, Maria Rosaria; Pantile, Marcella; Zanon, Carlo; De Mariano, Marilena; Longo, Luca; Hogarty, Michael D.; de Torres, Carmen; Tonini, Gian Paolo; Iolascon, Achille; Capasso, Mario

    2016-01-01

    The spectrum of somatic mutation of the most aggressive forms of neuroblastoma is not completely determined. We sought to identify potential cancer drivers in clinically aggressive neuroblastoma. Whole exome sequencing was conducted on 17 germline and tumor DNA samples from high-risk patients with adverse events within 36 months from diagnosis (HR-Event3) to identify somatic mutations and deep targeted sequencing of 134 genes selected from the initial screening in additional 48 germline and tumor pairs (62.5% HR-Event3 and high-risk patients), 17 HR-Event3 tumors and 17 human-derived neuroblastoma cell lines. We revealed 22 significantly mutated genes, many of which implicated in cancer progression. Fifteen genes (68.2%) were highly expressed in neuroblastoma supporting their involvement in the disease. CHD9, a cancer driver gene, was the most significantly altered (4.0% of cases) after ALK. Other genes (PTK2, NAV3, NAV1, FZD1 and ATRX), expressed in neuroblastoma and involved in cell invasion and migration were mutated at frequency ranged from 4% to 2%. Focal adhesion and regulation of actin cytoskeleton pathways, were frequently disrupted (14.1% of cases) thus suggesting potential novel therapeutic strategies to prevent disease progression. Notably BARD1, CHEK2 and AXIN2 were enriched in rare, potentially pathogenic, germline variants. In summary, whole exome and deep targeted sequencing identified novel cancer genes of clinically aggressive neuroblastoma. Our analyses show pathway-level implications of infrequently mutated genes in leading neuroblastoma progression. PMID:27009842

  4. Further defining the phenotypic spectrum of B4GALT7 mutations.

    PubMed

    Salter, Claire G; Davies, Justin H; Moon, Rebecca J; Fairhurst, Joanna; Bunyan, David; Foulds, Nicola

    2016-06-01

    Proteoglycans are components of the extracellular matrix with diverse biological functions. Defects in proteoglycan synthesis have been linked to several human diseases with common features of short stature, hypermobility, joint dislocations, and skeletal dysplasia. B4GALT7 encodes galactosyltransferase-I that catalyzes the addition of a galactose moiety to a xylosyl group in the tetrasaccharide linker of proteoglycans. Mutations in this gene have been associated with the rare progeroid form of Ehlers Danlos syndrome and in addition more recently found to underlie Larsen of Reunion Island syndrome. Nine individuals have been reported with a diagnosis of the progeroid form of Ehlers Danlos syndrome, four of whom have had molecular characterization showing homozygous or compound heterozygous mutations in B4GALT7. We report two newly described patients with compound heterozygous mutations in B4GALT7, and show that the six individuals with confirmed mutations do not have the progeroid features described in the original five patients with a clinical diagnosis of the progeroid form of Ehlers Danlos syndrome. We suggest that galactosyltransferase-I deficiency does not cause the progeroid form of Ehlers Danlos syndrome, but instead results in a clinically recognizable syndrome comprising short stature, joint hypermobility, radioulnar synostosis, and severe hypermetropia. This group of syndromic patients are on a phenotypic spectrum with individuals who have Larsen of Reunion Island syndrome, although the key features of osteopenia, fractures and hypermetropia have not been reported in patients from Reunion Island. © 2016 Wiley Periodicals, Inc. PMID:26940150

  5. Gain-of-function mutations in complement factor B are associated with atypical hemolytic uremic syndrome

    PubMed Central

    de Jorge, Elena Goicoechea; Harris, Claire L.; Esparza-Gordillo, Jorge; Carreras, Luis; Arranz, Elena Aller; Garrido, Cynthia Abarrategui; López-Trascasa, Margarita; Sánchez-Corral, Pilar; Morgan, B. Paul; de Córdoba, Santiago Rodríguez

    2007-01-01

    Hemolytic uremic syndrome (HUS) is an important cause of acute renal failure in children. Mutations in one or more genes encoding complement-regulatory proteins have been reported in approximately one-third of nondiarrheal, atypical HUS (aHUS) patients, suggesting a defect in the protection of cell surfaces against complement activation in susceptible individuals. Here, we identified a subgroup of aHUS patients showing persistent activation of the complement alternative pathway and found within this subgroup two families with mutations in the gene encoding factor B (BF), a zymogen that carries the catalytic site of the complement alternative pathway convertase (C3bBb). Functional analyses demonstrated that F286L and K323E aHUS-associated BF mutations are gain-of-function mutations that result in enhanced formation of the C3bBb convertase or increased resistance to inactivation by complement regulators. These data expand our understanding of the genetic factors conferring predisposition to aHUS, demonstrate the critical role of the alternative complement pathway in the pathogenesis of aHUS, and provide support for the use of complement-inhibition therapies to prevent or reduce tissue damage caused by dysregulated complement activation. PMID:17182750

  6. Mutation of chromatin modifiers; an emerging hallmark of germinal center B-cell lymphomas

    PubMed Central

    Lunning, M A; Green, M R

    2015-01-01

    Subtypes of non-Hodgkin's lymphomas align with different stages of B-cell development. Germinal center B-cell (GCB)-like diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL) and Burkitt's lymphoma (BL) each share molecular similarities with normal GCB cells. Recent next-generation sequencing studies have gained insight into the genetic etiology of these malignancies and revealed a high frequency of mutations within genes encoding proteins that modifying chromatin. These include activating and inactivating mutations of genes that perform post-translational modification of histones and organize chromatin structure. Here, we discuss the function of histone acetyltransferases (CREBBP, EP300), histone methyltransferases (KDM2C/D, EZH2) and regulators of higher order chromatin structure (HIST1H1C/D/E, ARID1A and SMARCA4) that have been reported to be mutated in ⩾5% of DLBCL, FL or BL. Mutations of these genes are an emerging hallmark of lymphomas with GCB-cell origins, and likely represent the next generation of therapeutic targets for these malignancies. PMID:26473533

  7. Mutational analysis of the major soybean UreF paralogue involved in urease activation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In soybean, mutation at Eu2 or Eu3 eliminates the urease activities of both the embryo-specific and the tissue-ubiquitous (assimilatory) isozymes, encoded by Eu1 and Eu4, respectively. Eu3 encodes UreG, a GTP’ase necessary for proper emplacement of Ni and carbon dioxide in the urease active site. ...

  8. A functional null mutation of SCN1B in a patient with Dravet syndrome.

    PubMed

    Patino, Gustavo A; Claes, Lieve R F; Lopez-Santiago, Luis F; Slat, Emily A; Dondeti, Raja S R; Chen, Chunling; O'Malley, Heather A; Gray, Charles B B; Miyazaki, Haruko; Nukina, Nobuyuki; Oyama, Fumitaka; De Jonghe, Peter; Isom, Lori L

    2009-08-26

    Dravet syndrome (also called severe myoclonic epilepsy of infancy) is one of the most severe forms of childhood epilepsy. Most patients have heterozygous mutations in SCN1A, encoding voltage-gated sodium channel Na(v)1.1 alpha subunits. Sodium channels are modulated by beta1 subunits, encoded by SCN1B, a gene also linked to epilepsy. Here we report the first patient with Dravet syndrome associated with a recessive mutation in SCN1B (p.R125C). Biochemical characterization of p.R125C in a heterologous system demonstrated little to no cell surface expression despite normal total cellular expression. This occurred regardless of coexpression of Na(v)1.1 alpha subunits. Because the patient was homozygous for the mutation, these data suggest a functional SCN1B null phenotype. To understand the consequences of the lack of beta1 cell surface expression in vivo, hippocampal slice recordings were performed in Scn1b(-/-) versus Scn1b(+/+) mice. Scn1b(-/-) CA3 neurons fired evoked action potentials with a significantly higher peak voltage and significantly greater amplitude compared with wild type. However, in contrast to the Scn1a(+/-) model of Dravet syndrome, we found no measurable differences in sodium current density in acutely dissociated CA3 hippocampal neurons. Whereas Scn1b(-/-) mice seize spontaneously, the seizure susceptibility of Scn1b(+/-) mice was similar to wild type, suggesting that, like the parents of this patient, one functional SCN1B allele is sufficient for normal control of electrical excitability. We conclude that SCN1B p.R125C is an autosomal recessive cause of Dravet syndrome through functional gene inactivation. PMID:19710327

  9. SF3B1 mutations correlated to cytogenetics and mutations in NOTCH1, FBXW7, MYD88, XPO1 and TP53 in 1160 untreated CLL patients.

    PubMed

    Jeromin, S; Weissmann, S; Haferlach, C; Dicker, F; Bayer, K; Grossmann, V; Alpermann, T; Roller, A; Kohlmann, A; Haferlach, T; Kern, W; Schnittger, S

    2014-01-01

    We analyzed a large cohort of 1160 untreated CLL patients for novel genetic markers (SF3B1, NOTCH1, FBXW7, MYD88, XPO1) in the context of molecular, immunophenotypic and cytogenetic data. NOTCH1 mutations (mut) (12.3%), SF3B1mut (9.0%) and TP53mut (7.1%) were more frequent than XPO1mut (3.4%), FBXW7mut (2.5%) and MYD88mut (1.5%). SF3B1mut, NOTCH1mut, TP53mut and XPO1mut were highly correlated to unmutated, whereas MYD88mut were associated with mutated IGHV status. Associations of diverse cytogenetic aberrations and mutations emerged: (1) SF3B1mut with del(11q), (2) NOTCH1mut and FBXW7mut with trisomy 12 and nearly exclusiveness of SF3B1mut, (3) MYD88mut with del(13q) sole and low frequencies of SF3B1mut, NOTCH1mut and FBXW7mut. In patients with normal karyotype only SF3B1mut were frequent, whereas NOTCH1mut rarely occurred. An adverse prognostic impact on time to treatment (TTT) and overall survival (OS) was observed for SF3B1mut, NOTCH1mut and TP53 disruption. In multivariate analyses SF3B1mut, IGHV mutational status and del(11q) were the only independent genetic markers for TTT, whereas for OS SF3B1mut, IGHV mutational status and TP53 disruption presented with significant impact. Finally, our data suggest that analysis of gene mutations refines the risk stratification of cytogenetic prognostic subgroups and confirms data of a recently proposed model integrating molecular and cytogenetic data. PMID:24113472

  10. Primary Diffuse Large B-cell Lymphoma involving the Mandible.

    PubMed

    Alshahrani, Faleh Ali A; Aljabab, Abdulsalam S; Motabi, Ibraheem Hm; Alrashed, Abdullah; Anil, Sukumaran

    2015-10-01

    Lymphomas of the oral cavity are rare and typically present as intraosseous lesions that are most commonly diffuse large B-cell type. Diffuse large B-cell lymphoma (DLBCL) is an aggressive B-cell lymphoma histologically characterized by diffuse proliferation of large neoplastic B-lymphoid cells with a nuclear size equal to or exceeding normal histiocytic nuclei. A case of DLBCL of the mandible in an 18 years old male patient is presented. This report discusses this rare malignancy, including clinical presentation, histopathologic features, immunologic profile, treatment and prognosis. Though lymphoma of mandible is rare, it must be considered in differential diagnosis of swellings arising in the region. PMID:26581467

  11. Analysis of differential β variable region of T cell receptor expression and NAV3/TNFRSF1B gene mutation in mycosis fungoides

    PubMed Central

    Li, Li; Ren, Jingyu; Guo, Shuping; Bai, Li

    2016-01-01

    Objective This study aimed to analyze the predominant expression of the variable region of T cell receptor (TRBV) and determine whether NAV3 or TNFRSF1B gene mutation involved in the pathogenesis of MF. Results TRBV5-7 expression increased from the normal, early-stage to advanced-stage lesion in MF patient. By contrast, TRBV2 decreased with the lesion developed. We found no mutations of NAV3 or TNFRSF1B in the lesions from this study. Materials and Methods Real-time PCR were used to screen differential expression of TRBV in different lesions. Mutational analyses were used to validate genetic alterations in the skin lesions. Conclusions The identification of TRBV gene expression differences between normal and different stages of MF lesions provide insight into promising new diagnostic and prognostic biomarkers. None of the reported genetic abnormalities suggests complexity of progress from a primary cytogenetic event to an advanced stage with poor prognosis in MF. PMID:26918607

  12. Seizures Due to a KCNQ2 Mutation: Treatment with Vitamin B6.

    PubMed

    Reid, Emma S; Williams, Hywel; Stabej, Polona Le Quesne; James, Chela; Ocaka, Louise; Bacchelli, Chiara; Footitt, Emma J; Boyd, Stewart; Cleary, Maureen A; Mills, Philippa B; Clayton, Peter T

    2016-01-01

    There is increasing evidence that vitamin B6, given either as pyridoxine or pyridoxal 5'-phosphate, can sometimes result in improved seizure control in idiopathic epilepsy. Whole-exome sequencing was used to identify a de novo mutation (c.629G>A; p.Arg210His) in KCNQ2 in a 7-year-old patient whose neonatal seizures showed a response to pyridoxine and who had a high plasma to CSF pyridoxal 5'-phosphate ratio, usually indicative of an inborn error of vitamin B6 metabolism. This mutation has been described in three other patients with neonatal epileptic encephalopathy. A review of the literature was performed to assess the effectiveness of vitamin B6 treatment in patients with a KCNQ2 channelopathy. Twenty-three patients have been reported to have been trialled with B6; in three of which B6 treatment was used alone or in combination with other antiepileptic drugs to control seizures. The anticonvulsant effect of B6 vitamers may be propagated by multiple mechanisms including direct antagonist action on ion channels, antioxidant action on excess reactive oxygen species generated by increased neuronal firing and replenishing the pool of pyridoxal 5'-phosphate needed for the synthesis of some inhibitory neurotransmitters. Vitamin B6 may be a promising adjunctive treatment for patients with channelopathies and the wider epileptic population. This report also demonstrates that an abnormal plasma to CSF pyridoxal 5'-phosphate ratio may not be exclusive to inborn errors of vitamin B6 metabolism. PMID:26446091

  13. Conspicuous involvement of desmin tail mutations in diverse cardiac and skeletal myopathies.

    PubMed

    Bär, Harald; Goudeau, Bertrand; Wälde, Sarah; Casteras-Simon, Monique; Mücke, Norbert; Shatunov, Alexey; Goldberg, Y Paul; Clarke, Charles; Holton, Janice L; Eymard, Bruno; Katus, Hugo A; Fardeau, Michel; Goldfarb, Lev; Vicart, Patrick; Herrmann, Harald

    2007-04-01

    Myofibrillar myopathy (MFM) encompasses a genetically heterogeneous group of human diseases caused by mutations in genes coding for structural proteins of muscle. Mutations in the intermediate filament (IF) protein desmin (DES), a major cytoskeletal component of myocytes, lead to severe forms of "desminopathy," which affects cardiac, skeletal, and smooth muscle. Most mutations described reside in the central alpha-helical rod domain of desmin. Here we report three novel mutations--c.1325C>T (p.T442I), c.1360C>T (p.R454W), and c.1379G>T (p.S460I)--located in desmin's non-alpha-helical carboxy-terminal "tail" domain. We have investigated the impact of these and four--c.1237G>A (p.E413K), c.1346A>C (p.K449T), c.1353C>G (p.I451M), and c.1405G>A (p.V469M)--previously described "tail" mutations on in vitro filament formation and on the generation of ordered cytoskeletal arrays in transfected myoblasts. Although all but two mutants (p.E413K, p.R454W) assembled into IFs in vitro and all except p.E413K were incorporated into IF arrays in transfected C2C12 cells, filament properties differed significantly from wild-type desmin as revealed by viscometric assembly assays. Most notably, when coassembled with wild-type desmin, these mutants revealed a severe disturbance of filament-formation competence and filament-filament interactions, indicating an inherent incompatibility of mutant and wild-type protein to form mixed filaments. The various clinical phenotypes observed may reflect altered interactions of desmin's tail domain with different components of the myoblast cytoskeleton leading to diminished biomechanical properties and/or altered metabolism of the individual myocyte. Our in vitro assembly regimen proved to be a very sensible tool to detect if a particular desmin mutation is able to cause filament abnormalities. PMID:17221859

  14. Mutations, kataegis, and translocations in B lymphocytes: towards a mechanistic understanding of AID promiscuous activity

    PubMed Central

    Casellas, Rafael; Basu, Uttiya; Yewdell, William T.; Chaudhuri, Jayanta; Robbiani, Davide F.; Di Noia, Javier M.

    2016-01-01

    As B cells engage in the immune response they express the deaminase AID to initiate the hypermutation and recombination of immunoglobulin genes, which are crucial processes for the efficient recognition and disposal of pathogens, However, AID must be tightly controlled in B cells to minimize off-targeting mutations, which can drive chromosomal translocations and the development of B cell malignancies, such as lymphomas. Recent genomic and biochemical analyses have begun to unravel the crucial question of how AID-mediated deamination is targeted outside immunoglobulin genes. Here, we discuss the transcriptional and topological features that are emerging as key drivers of AID promiscuous activity. PMID:26898111

  15. Compensatory variances of drug-induced hepatitis B virus YMDD mutations.

    PubMed

    Cai, Ying; Wang, Ning; Wu, Xiaomei; Zheng, Kai; Li, Yan

    2016-01-01

    Although the drug-induced mutations of HBV have been ever documented, the evolutionary mechanism is still obscure. To deeply reveal molecular characters of HBV evolution under the special condition, here we made a comprehensive investigation of the molecular variation of the 3432 wild-type sequences and 439 YMDD variants from HBV genotype A, B, C and D, and evaluated the co-variant patterns and the frequency distribution in the different YMDD mutation types and genotypes, by using the naïve Bayes classification algorithm and the complete induction method based on the comparative sequence analysis. The data showed different compensatory changes followed by the rtM204I/V. Although occurrence of the YMDD mutation itself was not related to the HBV genotypes, the subsequence co-variant patterns were related to the YMDD variant types and HBV genotypes. From the hierarchy view, we clarified that historical mutations, drug-induced mutation and compensatory variances, and displayed an inter-conditioned relationship of amino acid variances during multiple evolutionary processes. This study extends the understanding of the polymorphism and fitness of viral protein. PMID:27588233

  16. Cerebral involvement in axonal Charcot-Marie-Tooth neuropathy caused by mitofusin2 mutations.

    PubMed

    Brockmann, Knut; Dreha-Kulaczewski, Steffi; Dechent, Peter; Bönnemann, Carsten; Helms, Gunther; Kyllerman, Marten; Brück, Wolfgang; Frahm, Jens; Huehne, Kathrin; Gärtner, Jutta; Rautenstrauss, Bernd

    2008-07-01

    Mutations in the mitofusin 2 (MFN2) gene are a major cause of primary axonal Charcot- Marie-Tooth (CMT) neuropathy. This study aims at further characterization of cerebral white matter alterations observed in patients with MFN2 mutations. Molecular genetic, magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), and diffusion tensor imaging (DTI) investigations were performed in four unrelated patients aged 7 to 38 years with early onset axonal CMT neuropathy. Three distinct and so far undescribed MFN2 mutations were detected. Two patients had secondary macrocephaly and mild diffuse predominantly periventricular white matter alterations on MRI. In addition, one boy had symmetrical T2-hyperintensities in both thalami. Two patients had optic atrophy, one of them with normal MRI. In three patients proton MRS revealed elevated concentrations of total N-acetyl compounds (neuronal marker), total creatine (found in all cells) and myo-inositol (astrocytic marker) in cerebral white and gray matter though with regional variation. These alterations were most pronounced in the two patients with abnormal MRI. DTI of these patients revealed mild reductions of fractional anisotropy and mild increase of mean diffusivity in white matter. The present findings indicate an enhanced cellular density in cerebral white matter of MFN2 neuropathy which is primarily due to a reactive gliosis without axonal damage and possibly accompanied by mild demyelination. PMID:18425620

  17. Mutations in core nucleotide sequence of hepatitis B virus correlate with fulminant and severe hepatitis.

    PubMed Central

    Ehata, T; Omata, M; Chuang, W L; Yokosuka, O; Ito, Y; Hosoda, K; Ohto, M

    1993-01-01

    Infection with hepatitis B virus leads to a wide spectrum of liver injury, including self-limited acute hepatitis, fulminant hepatitis, and chronic hepatitis with progression to cirrhosis or acute exacerbation to liver failure, as well as an asymptomatic chronic carrier state. Several studies have suggested that the hepatitis B core antigen could be an immunological target of cytotoxic T lymphocytes. To investigate the reason why the extreme immunological attack occurred in fulminant hepatitis and severe exacerbation patients, the entire precore and core region of hepatitis B virus DNA was sequenced in 24 subjects (5 fulminant, 10 severe fatal exacerbation, and 9 self-limited acute hepatitis patients). No significant change in the nucleotide sequence and deduced amino acid residue was noted in the nine self-limited acute hepatitis patients. In contrast, clustering changes in a small segment of 16 amino acids (codon 84-99 from the start of the core gene) in all seven adr subtype infected fulminant and severe exacerbation patients was found. A different segment with clustering substitutions (codon 48-60) was also found in seven of eight adw subtype infected fulminant and severe exacerbation patients. Of the 15 patients, 2 lacked precore stop mutation which was previously reported to be associated with fulminant hepatitis. These data suggest that these core regions with mutations may play an important role in the pathogenesis of hepatitis B viral disease, and such mutations are related to severe liver damage. Images PMID:8450049

  18. Rapid Detection of rpoB Gene Mutations Conferring Rifampin Resistance in Mycobacterium tuberculosis

    PubMed Central

    Ao, Wanyuan; Aldous, Stephen; Woodruff, Evelyn; Hicke, Brian; Rea, Larry; Kreiswirth, Barry

    2012-01-01

    Multidrug-resistant Mycobacterium tuberculosis strains are widespread and present a challenge to effective treatment of this infection. The need for a low-cost and rapid detection method for clinically relevant mutations in Mycobacterium tuberculosis that confer multidrug resistance is urgent, particularly for developing countries. We report here a novel test that detects the majority of clinically relevant mutations in the beta subunit of the RNA polymerase (rpoB) gene that confer resistance to rifampin (RIF), the treatment of choice for tuberculosis (TB). The test, termed TB ID/R, combines a novel target and temperature-dependent RNase H2-mediated cleavage of blocked DNA primers to initiate isothermal helicase-dependent amplification of a rpoB gene target sequence. Amplified products are detected by probes arrayed on a modified silicon chip that permits visible detection of both RIF-sensitive and RIF-resistant strains of M. tuberculosis. DNA templates of clinically relevant single-nucleotide mutations in the rpoB gene were created to validate the performance of the TB ID/R test. Except for one rare mutation, all mutations were unambiguously detected. Additionally, 11 RIF-sensitive and 25 RIF-resistant clinical isolates were tested by the TB ID/R test, and 35/36 samples were classified correctly (96.2%). This test is being configured in a low-cost test platform to provide rapid diagnosis and drug susceptibility information for TB in the point-of-care setting in the developing world, where the need is acute. PMID:22518852

  19. Mutation of POC1B in a severe syndromic retinal ciliopathy

    PubMed Central

    Beck, Bodo B.; Phillips, Jennifer B.; Bartram, Malte P.; Wegner, Jeremy; Thoenes, Michaela; Pannes, Andrea; Sampson, Josephina; Heller, Raoul; Göbel, Heike; Koerber, Friederike; Neugebauer, Antje; Hedergott, Andrea; Nürnberg, Gudrun; Nürnberg, Peter; Thiele, Holger; Altmüller, Janine; Toliat, Mohammad R.; Staubach, Simon; Boycott, Kym M.; Valente, Enza Maria; Janecke, Andreas R.; Eisenberger, Tobias; Bergmann, Carsten; Tebbe, Lars; Wang, Yang; Wu, Yundong; Fry, Andrew M.; Westerfield, Monte; Wolfrum, Uwe; Bolz, Hanno J.

    2014-01-01

    We describe a consanguineous Iraqi family with Leber congenital amaurosis (LCA), Joubert syndrome (JBTS), and polycystic kidney disease. Targeted NGS for excluding mutations in known LCA and JBTS genes, homozygosity mapping and whole-exome sequencing identified a homozygous missense variant, c.317G>C (p.Arg106Pro), in POC1B, a gene essential for ciliogenesis, basal body and centrosome integrity. In silico modeling suggested a requirement of p.Arg106 for formation of the third WD40 repeat and a protein interaction interface. In human and mouse retina, POC1B localized to the basal body and centriole adjacent to the connecting cilium of photoreceptors and in synapses of the outer plexiform layer. Knockdown of Poc1b in zebrafish caused cystic kidneys and retinal degeneration with shortened and reduced photoreceptor connecting cilia, compatible with the human syndromic ciliopathy. A recent study describes homozygosity for p.Arg106ProPOC1B in a family with non-syndromic cone-rod dystrophy. The phenotype associated with homozygous p.Arg106ProPOC1B may thus be highly variable, analogous to homozygous p.Leu710Ser in WDR19 causing either isolated retinitis pigmentosa or Jeune syndrome. Our study indicates that POC1B is required for retinal integrity, and we propose POC1B mutations as a probable cause for JBTS with severe polycystic kidney disease. PMID:25044745

  20. Germline Mutation in EXPH5 Implicates the Rab27B Effector Protein Slac2-b in Inherited Skin Fragility

    PubMed Central

    McGrath, John A.; Stone, Kristina L.; Begum, Rumena; Simpson, Michael A.; Dopping-Hepenstal, Patricia J.; Liu, Lu; McMillan, James R.; South, Andrew P.; Pourreyron, Celine; McLean, W.H. Irwin; Martinez, Anna E.; Mellerio, Jemima E.; Parsons, Maddy

    2012-01-01

    The Rab GTPase Rab27B and one of its effector proteins, Slac2-b (also known as EXPH5, exophilin-5), have putative roles in intracellular vesicle trafficking but their relevance to human disease is not known. By using whole-exome sequencing, we identified a homozygous frameshift mutation in EXPH5 in three siblings with inherited skin fragility born to consanguineous Iraqi parents. All three individuals harbor the mutation c.5786delC (p.Pro1929Leufs∗8) in EXPH5, which truncates the 1,989 amino acid Slac2-b protein by 52 residues. The clinical features comprised generalized scale-crusts and occasional blisters, mostly induced by trauma, as well as mild diffuse pigmentary mottling on the trunk and proximal limbs. There was no increased bleeding tendency, no neurologic abnormalities, and no increased incidence of infection. Analysis of an affected person's skin showed loss of Slac2-b immunostaining (C-terminal antibody), disruption of keratinocyte adhesion within the lower epidermis, and an increased number of perinuclear vesicles. A role for Slac2-b in keratinocyte biology was supported by findings of cytoskeletal disruption (mainly keratin intermediate filaments) and decreased keratinocyte adhesion in both keratinocytes from an affected subject and after shRNA knockdown of Slac2-b in normal keratinocytes. Slac2-b was also shown to colocalize with Rab27B and β4 integrin to early adhesion initiation sites in spreading normal keratinocytes. Collectively, our findings identify an unexpected role for Slac2-b in inherited skin fragility and expand the clinical spectrum of human disorders of GTPase effector proteins. PMID:23176819

  1. Different spectra of recurrent gene mutations in subsets of chronic lymphocytic leukemia harboring stereotyped B-cell receptors

    PubMed Central

    Sutton, Lesley-Ann; Young, Emma; Baliakas, Panagiotis; Hadzidimitriou, Anastasia; Moysiadis, Theodoros; Plevova, Karla; Rossi, Davide; Kminkova, Jana; Stalika, Evangelia; Pedersen, Lone Bredo; Malcikova, Jitka; Agathangelidis, Andreas; Davis, Zadie; Mansouri, Larry; Scarfò, Lydia; Boudjoghra, Myriam; Navarro, Alba; Muggen, Alice F.; Yan, Xiao-Jie; Nguyen-Khac, Florence; Larrayoz, Marta; Panagiotidis, Panagiotis; Chiorazzi, Nicholas; Niemann, Carsten Utoft; Belessi, Chrysoula; Campo, Elias; Strefford, Jonathan C.; Langerak, Anton W.; Oscier, David; Gaidano, Gianluca; Pospisilova, Sarka; Davi, Frederic; Ghia, Paolo; Stamatopoulos, Kostas; Rosenquist, Richard

    2016-01-01

    We report on markedly different frequencies of genetic lesions within subsets of chronic lymphocytic leukemia patients carrying mutated or unmutated stereotyped B-cell receptor immunoglobulins in the largest cohort (n=565) studied for this purpose. By combining data on recurrent gene mutations (BIRC3, MYD88, NOTCH1, SF3B1 and TP53) and cytogenetic aberrations, we reveal a subset-biased acquisition of gene mutations. More specifically, the frequency of NOTCH1 mutations was found to be enriched in subsets expressing unmutated immunoglobulin genes, i.e. #1, #6, #8 and #59 (22–34%), often in association with trisomy 12, and was significantly different (P<0.001) to the frequency observed in subset #2 (4%, aggressive disease, variable somatic hypermutation status) and subset #4 (1%, indolent disease, mutated immunoglobulin genes). Interestingly, subsets harboring a high frequency of NOTCH1 mutations were found to carry few (if any) SF3B1 mutations. This starkly contrasts with subsets #2 and #3 where, despite their immunogenetic differences, SF3B1 mutations occurred in 45% and 46% of cases, respectively. In addition, mutations within TP53, whilst enriched in subset #1 (16%), were rare in subsets #2 and #8 (both 2%), despite all being clinically aggressive. All subsets were negative for MYD88 mutations, whereas BIRC3 mutations were infrequent. Collectively, this striking bias and skewed distribution of mutations and cytogenetic aberrations within specific chronic lymphocytic leukemia subsets implies that the mechanisms underlying clinical aggressiveness are not uniform, but rather support the existence of distinct genetic pathways of clonal evolution governed by a particular stereotyped B-cell receptor selecting a certain molecular lesion(s). PMID:27198719

  2. Mutation at position 791 in Escherichia coli 16S ribosomal RNA affects processes involved in the initiation of protein synthesis.

    PubMed Central

    Tapprich, W E; Goss, D J; Dahlberg, A E

    1989-01-01

    A single base was mutated from guanine to adenine at position 791 in 16S rRNA in the Escherichia coli rrnB operon on the multicopy plasmid pKK3535. The plasmid-coded rRNA was processed and assembled into 30S ribosomal subunits in E. coli and caused a retardation of cell growth. The mutation affected crucial functional roles of the 30S subunit in the initiation of protein synthesis. The affinity of the mutant 30S subunits for 50S subunits was reduced and the association equilibrium constant for initiation factor 3 was decreased by a factor of 10 compared to wild-type 30S subunits. The interrelationship among the region of residue 790 in 16S rRNA, subunit association, and initiation factor 3 binding during initiation complex formation, as revealed by this study, offers insights into the functional role of rRNA in protein synthesis. PMID:2662189

  3. A functional null mutation of SCN1B in a patient with Dravet Syndrome

    PubMed Central

    Patino, Gustavo A.; Claes, Lieve R.F.; Lopez-Santiago, Luis; Slat, Emily A.; Dondeti, Raja S. R.; Chen, Chunling; O'Malley, Heather A.; Gray, Charles B.B.; Miyazaki, Haruko; Nukina, Nobuyuki; Oyama, Fumitaka; Jonghe, Peter De; Isom, Lori L.

    2009-01-01

    Dravet syndrome (also called Severe Myoclonic Epilepsy of Infancy) is one of the most severe forms of childhood epilepsy. Most patients have heterozygous mutations in SCN1A, encoding voltage-gated sodium channel Nav1.1 α subunits. Sodium channels are modulated by β1 subunits, encoded by SCN1B, a gene also linked to epilepsy. Here we report the first patient with Dravet Syndrome associated with a recessive mutation in SCN1B (p.R125C). Biochemical characterization of p.R125C in a heterologous system demonstrated little to no cell surface expression despite normal total cellular expression. This occurred regardless of co-expression of Nav1.1 α subunits. Because the patient was homozygous for the mutation, these data suggest a functional SCN1B null phenotype. To understand the consequences of the lack of β1 cell surface expression in vivo, hippocampal slice recordings were performed in Scn1b−/− vs. Scn1b+/+ mice. Scn1b−/− CA3 neurons fired evoked action potentials with a significantly higher peak voltage and significantly greater amplitude compared to wildtype. However, in contrast to the Scn1a+/− model of Dravet syndrome, we found no measurable differences in sodium current density in acutely dissociated CA3 hippocampal neurons. While Scn1b−/− mice seize spontaneously, the seizure susceptibility of Scn1b+/− mice was similar to wildtype, suggesting that, like the parents of this patient, one functional SCN1B allele is sufficient for normal control of electrical excitability. We conclude that SCN1B p.R125C is an autosomal recessive cause of Dravet syndrome through functional gene inactivation. PMID:19710327

  4. Rodriguez syndrome with SF3B4 mutation: a severe form of Nager syndrome?

    PubMed

    McPherson, Elizabeth; Zaleski, Christina; Ye, Zhan; Lin, Simon

    2014-07-01

    We report on the findings of a novel heterozygous de novo SF3B4 mutation in a long-surviving patient with clinical features of Rodriguez syndrome including severe acrofacial dysostosis, phocomelia with pre- and post-axial limb defects, fibular agenesis, rib, and shoulder girdle anomalies. Since SF3B4 mutations have been recently associated with Nager syndrome, this suggests that at least some cases of Rodriguez syndrome are either allelic to or represent unusually severe manifestations of Nager syndrome. Although clinical overlap is obvious, this is somewhat surprising given the presumed autosomal recessive inheritance of Rodriguez syndrome. Investigation of other Rodriguez syndrome patients is needed to clarify the genetic mechanism and possible heterogeneity in patients with clinical features of Rodriguez syndrome. PMID:24715698

  5. Anxiety and Methylenetetrahydrofolate Reductase Mutation Treated With S-Adenosyl Methionine and Methylated B Vitamins.

    PubMed

    Anderson, Shanna; Panka, Jacob; Rakobitsch, Robin; Tyre, Kaitlin; Pulliam, Kerry

    2016-04-01

    This case report highlights challenges faced in the clinical management of patients with methylenetetrahydrofolate reductase (MTHFR) gene mutations and the importance of precise dosage when recommending methylated B vitamins to compensate for deficiencies caused by the polymorphism or symptoms related to the polymorphism. It also underscores the importance of obtaining ongoing objective assessments of anxiety (eg, Patient Reported Outcomes Measurement Information System, or PROMIS) to help gauge patient response. PMID:27330489

  6. ATP8B1 mutations in British cases with intrahepatic cholestasis of pregnancy

    PubMed Central

    Müllenbach, R; Bennett, A; Tetlow, N; Patel, N; Hamilton, G; Cheng, F; Chambers, J; Howard, R; Taylor-Robinson, S D; Williamson, C

    2005-01-01

    Background: Intrahepatic cholestasis of pregnancy (ICP) affects approximately 0.7% of pregnancies in the UK and is associated with prematurity, fetal distress, and intrauterine death. Homozygous mutations in the ATP8B1 gene cause cholestasis with a normal serum gamma-glutamyl transpeptidase (γ-GT), and have been reported in two forms of cholestasis: progressive familial intrahepatic cholestasis type 1 (PFIC1) and benign recurrent intrahepatic cholestasis (BRIC). Aims: To establish whether mutations in ATP8B1 are associated with ICP in British cases Patients: Sixteen well phenotyped women with ICP without raised γ-GT were selected for sequence analysis. Subsequently, 182 patients and 120 controls were examined for the presence of the variants detected. Methods: All coding exons were sequenced in 16 cases. Eight ICP cases, including two women carrying a mutation, were investigated using in vivo hepatic 31P magnetic resonance spectroscopy (MRS) Results: Two heterozygous ATP8B1 transitions (208G>A and 2599C>T) that resulted in amino acid substitutions were identified; 208G>A was identified in three cases. MRS revealed an increased phosphodiester signal (Mann-Whitney U test, p = 0.03) and a decreased phosphomonoester/phosphodiester ratio (p = 0.04) in ICP cases compared with controls. Conclusions: We were able to demonstrate ATP8B1 mutations in ICP. MRS studies suggest that susceptibility to ICP is associated with a relative rise in biliary phospholipid. These data also suggest that MRS may be used for non-invasive assessment of the liver and biliary constituents in cholestasis. PMID:15888793

  7. Identification and characterization of SMPD1 mutations causing Niemann-Pick types A and B in Spanish Patients

    PubMed Central

    Rodríguez-Pascau, Laura; Gort, Laura; Schuchman, Edward H.; Vilageliu, Lluïsa; Grinberg, Daniel; Chabás, Amparo

    2009-01-01

    Niemann-Pick disease (NPD) types A/B are both caused by a deficiency of lysosomal acid sphingomyelinase and display autosomal recessive inheritance. These two types of the disease were described according to the presence (type A) or absence (type B) of neurological symptoms. We present a molecular analysis of 19 Spanish NPD A/B patients and two from Maghreb. Eight of the patients had type A and 13 had type B NPD. All mutant SMPD1 alleles were identified, including 17 different mutations, 10 of which were novel. The only frequent mutations in the 21 NPD patients were c.1823_1825delGCC (p.R608del) (38%) and c.1445C>A (p.A482E) (9%). Genotype-phenotype correlations were established for most of the mutations and, in particular, the p.R608del-type B association was confirmed. This mutation accounts for 61.5% of the mutant alleles in the type B subgroup of patients. Expression studies performed on six of the identified mutations confirmed them to be disease-causing due to their low enzyme activity. An allele with a mutation affecting a non-canonical donor splice site produced only aberrant mRNAs corresponding to previously reported non-functional SMPD1 minor transcripts. This study is the first exhaustive mutational analysis of Spanish Niemann-Pick A/B disease patients. PMID:19405096

  8. Mutation of L-2,3-diaminopropionic acid synthase genes blocks staphyloferrin B synthesis in Staphylococcus aureus

    PubMed Central

    2011-01-01

    Background Staphylococcus aureus synthesizes two siderophores, staphyloferrin A and staphyloferrin B, that promote iron-restricted growth. Previous work on the biosynthesis of staphyloferrin B has focused on the role of the synthetase enzymes, encoded from within the sbnA-I operon, which build the siderophore from the precursor molecules citrate, alpha-ketoglutarate and L-2,3-diaminopropionic acid. However, no information yet exists on several other enzymes, expressed from the biosynthetic cluster, that are thought to be involved in the synthesis of the precursors (or synthetase substrates) themselves. Results Using mutants carrying insertions in sbnA and sbnB, we show that these two genes are essential for the synthesis of staphyloferrin B, and that supplementation of the growth medium with L-2,3-diaminopropionic acid can bypass the block in staphyloferrin B synthesis displayed by the mutants. Several mechanisms are proposed for how the enzymes SbnA, with similarity to cysteine synthase enzymes, and SbnB, with similarity to amino acid dehydrogenases and ornithine cyclodeaminases, function together in the synthesis of this unusual nonproteinogenic amino acid L-2,3-diaminopropionic acid. Conclusions Mutation of either sbnA or sbnB result in abrogation of synthesis of staphyloferrin B, a siderophore that contributes to iron-restricted growth of S. aureus. The loss of staphyloferrin B synthesis is due to an inability to synthesize the unusual amino acid L-2,3-diaminopropionic acid which is an important, iron-liganding component of the siderophore structure. It is proposed that SbnA and SbnB function together as an L-Dap synthase in the S. aureus cell. PMID:21906287

  9. Mutations in B4GALNT1 (GM2 synthase) underlie a new disorder of ganglioside biosynthesis

    PubMed Central

    Lehman, Anna; Chioza, Barry; Baple, Emma L.; Maroofian, Reza; Cross, Harold; Sreekantan-Nair, Ajith; Priestman, David A.; Al-Turki, Saeed; McEntagart, Meriel E.; Proukakis, Christos; Royle, Louise; Kozak, Radoslaw P.; Bastaki, Laila; Patton, Michael; Wagner, Karin; Coblentz, Roselyn; Price, Joy; Mezei, Michelle; Schlade-Bartusiak, Kamilla; Hurles, Matthew E.

    2013-01-01

    Glycosphingolipids are ubiquitous constituents of eukaryotic plasma membranes, and their sialylated derivatives, gangliosides, are the major class of glycoconjugates expressed by neurons. Deficiencies in their catabolic pathways give rise to a large and well-studied group of inherited disorders, the lysosomal storage diseases. Although many glycosphingolipid catabolic defects have been defined, only one proven inherited disease arising from a defect in ganglioside biosynthesis is known. This disease, because of defects in the first step of ganglioside biosynthesis (GM3 synthase), results in a severe epileptic disorder found at high frequency amongst the Old Order Amish. Here we investigated an unusual neurodegenerative phenotype, most commonly classified as a complex form of hereditary spastic paraplegia, present in families from Kuwait, Italy and the Old Order Amish. Our genetic studies identified mutations in B4GALNT1 (GM2 synthase), encoding the enzyme that catalyzes the second step in complex ganglioside biosynthesis, as the cause of this neurodegenerative phenotype. Biochemical profiling of glycosphingolipid biosynthesis confirmed a lack of GM2 in affected subjects in association with a predictable increase in levels of its precursor, GM3, a finding that will greatly facilitate diagnosis of this condition. With the description of two neurological human diseases involving defects in two sequentially acting enzymes in ganglioside biosynthesis, there is the real possibility that a previously unidentified family of ganglioside deficiency diseases exist. The study of patients and animal models of these disorders will pave the way for a greater understanding of the role gangliosides play in neuronal structure and function and provide insights into the development of effective treatment therapies. PMID:24103911

  10. Mutational analysis of hepatitis B virus pre-S1 (9-24) fusogenic peptide.

    PubMed

    Liu, Qiushi; Somiya, Masaharu; Shimada, Naohiko; Sakamoto, Wakako; Yoshimoto, Nobuo; Iijima, Masumi; Tatematsu, Kenji; Nakai, Tadashi; Okajima, Toshihide; Maruyama, Atsushi; Kuroda, Shuńichi

    2016-05-27

    A hollow nanoparticle known as a bio-nanocapsule (BNC) consisting of hepatitis B virus (HBV) envelope L protein and liposome (LP) can encapsulate drugs and genes and thereby deliver them in vitro and in vivo to human hepatic tissues, specifically by utilizing the HBV-derived infection machinery. Recently, we identified a low pH-dependent fusogenic domain at the N-terminal part of the pre-S1 region of the HBV L protein (amino acid residues 9 to 24; NPLGFFPDHQLDPAFG), which shows membrane destabilizing activity (i.e., membrane fusion, membrane disruption, and payload release) upon interaction with target LPs. In this study, instead of BNC and HBV, we generated LPs displaying a mutated form of the pre-S1 (9-24) peptide, and performed a membrane disruption assay using target LPs containing pyranine (fluorophore) and p-xylene-bis (N-pyridinium bromide) (DPX) as a quencher. The membrane disruption activity was found to correlate with the hydrophobicity of the whole structure, while the peptide retained a random-coil structure even under low pH condition. One large hydrophobic cluster (I) and one small hydrophobic cluster (II) residing in the peptide would be connected by the protonation of residues D16 and D20, and thereby exhibit strong membrane disruption activity in a low pH-dependent manner. Furthermore, the introduction of a positively charged residue enhanced the activity significantly, suggesting that a sole positively charged residue (H17) may be important for the interaction with target LPs by electrostatic interaction. Collectively, these results suggest that the pre-S1 (9-24) peptide may be involved in the endosomal escape of the BNC's payloads, as well as in the HBV uncoating process. PMID:27120459

  11. Mutations in B4GALNT1 (GM2 synthase) underlie a new disorder of ganglioside biosynthesis.

    PubMed

    Harlalka, Gaurav V; Lehman, Anna; Chioza, Barry; Baple, Emma L; Maroofian, Reza; Cross, Harold; Sreekantan-Nair, Ajith; Priestman, David A; Al-Turki, Saeed; McEntagart, Meriel E; Proukakis, Christos; Royle, Louise; Kozak, Radoslaw P; Bastaki, Laila; Patton, Michael; Wagner, Karin; Coblentz, Roselyn; Price, Joy; Mezei, Michelle; Schlade-Bartusiak, Kamilla; Platt, Frances M; Hurles, Matthew E; Crosby, Andrew H

    2013-12-01

    Glycosphingolipids are ubiquitous constituents of eukaryotic plasma membranes, and their sialylated derivatives, gangliosides, are the major class of glycoconjugates expressed by neurons. Deficiencies in their catabolic pathways give rise to a large and well-studied group of inherited disorders, the lysosomal storage diseases. Although many glycosphingolipid catabolic defects have been defined, only one proven inherited disease arising from a defect in ganglioside biosynthesis is known. This disease, because of defects in the first step of ganglioside biosynthesis (GM3 synthase), results in a severe epileptic disorder found at high frequency amongst the Old Order Amish. Here we investigated an unusual neurodegenerative phenotype, most commonly classified as a complex form of hereditary spastic paraplegia, present in families from Kuwait, Italy and the Old Order Amish. Our genetic studies identified mutations in B4GALNT1 (GM2 synthase), encoding the enzyme that catalyzes the second step in complex ganglioside biosynthesis, as the cause of this neurodegenerative phenotype. Biochemical profiling of glycosphingolipid biosynthesis confirmed a lack of GM2 in affected subjects in association with a predictable increase in levels of its precursor, GM3, a finding that will greatly facilitate diagnosis of this condition. With the description of two neurological human diseases involving defects in two sequentially acting enzymes in ganglioside biosynthesis, there is the real possibility that a previously unidentified family of ganglioside deficiency diseases exist. The study of patients and animal models of these disorders will pave the way for a greater understanding of the role gangliosides play in neuronal structure and function and provide insights into the development of effective treatment therapies. PMID:24103911

  12. A Novel Mutation of the HNF1B Gene Associated With Hypoplastic Glomerulocystic Kidney Disease and Neonatal Renal Failure

    PubMed Central

    Alvelos, Maria Inês; Rodrigues, Magda; Lobo, Luísa; Medeira, Ana; Sousa, Ana Berta; Simão, Carla; Lemos, Manuel Carlos

    2015-01-01

    Abstract Hepatocyte nuclear factor 1 beta (HNF1B) plays an important role in embryonic development, namely in the kidney, pancreas, liver, genital tract, and gut. Heterozygous germline mutations of HNF1B are associated with the renal cysts and diabetes syndrome (RCAD). Affected individuals may present a variety of renal developmental abnormalities and/or maturity-onset diabetes of the young (MODY). A Portuguese 19-month-old male infant was evaluated due to hypoplastic glomerulocystic kidney disease and renal dysfunction diagnosed in the neonatal period that progressed to stage 5 chronic renal disease during the first year of life. His mother was diagnosed with a solitary hypoplastic microcystic left kidney at age 20, with stage 2 chronic renal disease established at age 35, and presented bicornuate uterus, pancreatic atrophy, and gestational diabetes. DNA sequence analysis of HNF1B revealed a novel germline frameshift insertion (c.110_111insC or c.110dupC) in both the child and the mother. A review of the literature revealed a total of 106 different HNF1B mutations, in 236 mutation-positive families, comprising gross deletions (34%), missense mutations (31%), frameshift deletions or insertions (15%), nonsense mutations (11%), and splice-site mutations (8%). The study of this family with an unusual presentation of hypoplastic glomerulocystic kidney disease with neonatal renal dysfunction identified a previously unreported mutation of the HNF1B gene, thereby expanding the spectrum of known mutations associated with renal developmental disorders. PMID:25700310

  13. Behavioral phenotype in five individuals with de novo mutations within the GRIN2B gene

    PubMed Central

    2013-01-01

    Background Intellectual disability (ID) is often associated with behavioral problems or disorders. Mutations in the GRIN2B gene (MRD6, MIM613970) have been identified as a common cause of ID (prevalence of 0.5 – 1% in individuals with ID) associated with EEG and behavioral problems. Methods We assessed five GRIN2B mutation carriers aged between 3 and 14 years clinically and via standardized questionnaires to delineate a detailed behavioral phenotype. Parents and teachers rated problem behavior of their affected children by completing the Developmental Behavior Checklist (DBC) and the Conners’ Rating Scales Revised (CRS-R:L). Results All individuals had mild to severe ID and needed guidance in daily routine. They showed characteristic behavior problems with prominent hyperactivity, impulsivity, distractibility and a short attention span. Stereotypies, sleeping problems and a friendly but boundless social behavior were commonly reported. Conclusion Our observations provide an initial delineation of the behavioral phenotype of GRIN2B mutation carriers. PMID:23718928

  14. Skeletal Dysplasia, Global Developmental Delay, and Multiple Congenital Anomalies in a 5 year-old boy– Report of the Second Family with B3GAT3 mutation and Expansion of the Phenotype

    PubMed Central

    von Oettingen, Julia E.; Tan, Wen-Hann; Dauber, Andrew

    2015-01-01

    As a major component of the extracellular matrix, proteoglycans influence the mechanical properties of connective tissue and play an important role in cell-cell and cell-matrix interactions. Genetic defects of proteoglycan biosynthesis lead to multi-system disorders, often most prominently affecting the skeletal system and skin. Specific deficiencies in the enzymes involved in the biosynthesis of the linkage region between the core of the proteoglycan protein and its glycosaminoglycan side chains are known as linkeropathies. We report on a patient from a second family with a homozygous c.830 G>A (p.Arg277Gln) mutation in the B3GAT3 gene. The clinical features expand the previously reported phenotype of B3GAT3 mutations and of linkeropathies in general. This patient has short stature, facial dysmorphisms, skeletal findings, joint laxity, and cardiac manifestations similar to those previously associated with B3GAT3 mutations. However, he also has developmental delay, a visual refractory defect, dental defects, pectus carinatum, and skin abnormalities that have only been associated with linkeropathies caused by mutations in B4GALT6 and B4GALT7. He has bilateral inguinal hernias and atlanto-axial as well as atlanto-occipital instability that have not been previously associated with B3GAT3 mutations. We provide a detailed clinical report and a comparative overview of the phenotypic features of the linkeropathies caused by mutations in B3GAT3, B4GALT6 and B4GALT7. PMID:24668659

  15. Can mutational GC-pressure create new linear B-cell epitopes in herpes simplex virus type 1 glycoprotein B?

    PubMed

    Khrustalev, Vladislav Victorovich

    2009-01-01

    We showed that GC-content of nucleotide sequences coding for linear B-cell epitopes of herpes simplex virus type 1 (HSV1) glycoprotein B (gB) is higher than GC-content of sequences coding for epitope-free regions of this glycoprotein (G + C = 73 and 64%, respectively). Linear B-cell epitopes have been predicted in HSV1 gB by BepiPred algorithm ( www.cbs.dtu.dk/services/BepiPred ). Proline is an acrophilic amino acid residue (it is usually situated on the surface of protein globules, and so included in linear B-cell epitopes). Indeed, the level of proline is much higher in predicted epitopes of gB than in epitope-free regions (17.8% versus 1.8%). This amino acid is coded by GC-rich codons (CCX) that can be produced due to nucleotide substitutions caused by mutational GC-pressure. GC-pressure will also lead to disappearance of acrophobic phenylalanine, isoleucine, methionine and tyrosine coded by GC-poor codons. Results of our "in-silico directed mutagenesis" showed that single nonsynonymous substitutions in AT to GC direction in two long epitope-free regions of gB will cause formation of new linear epitopes or elongation of previously existing epitopes flanking these regions in 25% of 539 possible cases. The calculations of GC-content and amino acid content have been performed by CodonChanges algorithm ( www.barkovsky.hotmail.ru ). PMID:19811425

  16. Effective epitope identification employing phylogenetic, mutational variability, sequence entropy, and correlated mutation analysis targeting NS5B protein of hepatitis C virus: from bioinformatics to therapeutics.

    PubMed

    Meshram, Rohan J; Gacche, Rajesh N

    2015-08-01

    Hepatitis C virus (HCV) is considered as a foremost cause affecting numerous human liver-related disorders. An effective immuno-prophylactic measure (like stable vaccine) is still unavailable for HCV. We perform an in silico analysis of nonstructural protein 5B (NS5B) based CD4 and CD8 epitopes that might be implicated in improvement of treatment strategies for efficient vaccine development programs against HCV. Here, we report on effective utilization of knowledge obtained from multiple sequence alignment and phylogenetic analysis for investigation and evaluation of candidate epitopes that have enormous potential to be used in formulating proficient vaccine, embracing multiple strains prevalent among major geographical locations. Mutational variability data discussed herein focus on discriminating the region under active evolutionary pressure from those having lower mutational potential in existing experimentally verified epitopes, thus, providing a concrete framework for designing an effective peptide-based vaccine against HCV. Additionally, we measured entropy distribution in NS5B residues and pinpoint the positions in epitopes that are more susceptible to mutations and, thus, account for virus strategy to evade the host immune system. Findings from this study are expected to add more details on the sequence and structural aspects of NS5B protein, ultimately facilitating our understanding about the pathophysiology of HCV and assisting advance studies on the function of NS5B antigen on the epitope level. We also report on the mutational crosstalk between functionally important coevolving residues, using correlated mutation analysis, and identify networks of coupled mutations that represent pathways of allosteric communication inside and among NS5B thumb, finger, and palm domains. PMID:25727409

  17. Investigating the Impact of Asp181 Point Mutations on Interactions between PTP1B and Phosphotyrosine Substrate

    NASA Astrophysics Data System (ADS)

    Liu, Mengyuan; Wang, Lushan; Sun, Xun; Zhao, Xian

    2014-05-01

    Protein tyrosine phosphatase 1B (PTP1B) is a key negative regulator of insulin and leptin signaling, which suggests that it is an attractive therapeutic target in type II diabetes and obesity. The aim of this research is to explore residues which interact with phosphotyrosine substrate can be affected by D181 point mutations and lead to increased substrate binding. To achieve this goal, molecular dynamics simulations were performed on wild type (WT) and two mutated PTP1B/substrate complexes. The cross-correlation and principal component analyses show that point mutations can affect the motions of some residues in the active site of PTP1B. Moreover, the hydrogen bond and energy decomposition analyses indicate that apart from residue 181, point mutations have influence on the interactions of substrate with several residues in the active site of PTP1B.

  18. Adaptation of lettuce mosaic virus to Catharanthus roseus involves mutations in the central domain of the VPg.

    PubMed

    Svanella-Dumas, Laurence; Verdin, Eric; Faure, Chantal; German-Retana, Sylvie; Gognalons, Patrick; Danet, Jean Luc; Marais, Armelle; Candresse, Thierry

    2014-05-01

    An isolate of Lettuce mosaic virus (LMV, a Potyvirus) infecting Madagascar periwinckle (Catharanthus roseus) was identified and characterized by Illumina deep sequencing. LMV-Cr has no close affinities to previously sequenced LMV isolates and represents a novel, divergent LMV clade. Inoculation experiments with other representative LMV isolates showed that they are unable to infect C. roseus, which was not known to be a host for LMV. However, three C. roseus variants of one of these isolates, LMV-AF199, could be selected and partially or completely sequenced. These variants are characterized by the accumulation of mutations affecting the C-terminal part of the cylindrical inclusion (CI) helicase and the central part of the VPg. In particular, a serine to proline mutation at amino acid 143 of the VPg was observed in all three independently selected variants and is also present in the LMV-Cr isolate, making it a prime candidate as a host-range determinant. Other mutations at VPg positions 65 and 144 could also contribute to the ability to infect C. roseus. Inoculation experiments involving a recombinant LMV expressing a permissive lettuce eukaryotic translation initiation factor 4E (eIF4E) suggest that eIF4E does not contribute to the interaction of most LMV isolates with C. roseus. PMID:24400938

  19. Infantile spinal muscular atrophy with respiratory distress type I presenting without respiratory involvement: Novel mutations and review of the literature.

    PubMed

    Luan, Xinghua; Huang, Xiaojun; Liu, Xiaoli; Zhou, Haiyan; Chen, Shengdi; Cao, Li

    2016-08-01

    Spinal muscular atrophy with respiratory distress type 1 (SMARD1), also known as distal spinal muscular atrophy 1 (DSMA1) or distal hereditary motor neuropathies type 6 (dHMN6), is a rare autosomal recessive motor neuron disorder that affects infants and is characterized by diaphragmatic palsy, distal muscular weakness and muscle atrophy. The disease is caused by mutations in the gene encoding immunoglobulinm-binding protein 2 (IGHMBP2). We present a female child with novel compound heterozygous mutations in IGHMBP2 gene c.344C>T (p.115T>M) and c.1737C>A (p.579F>L), displaying distal limbs weakness and atrophy without signs of diaphragmatic palsy or respiratory insufficiency. We review 20 reported SMARD1 cases that have no respiratory involvement or have late onsets. We propose that IGHMBP2 gene mutations are characterized by significant phenotypic heterogeneity. Diaphragmatic palsy and respiratory distress may be absent and SMARD1 should be considered in infantile with the onset of peripheral neuropathies. PMID:26922252

  20. Complement Factor B Mutations in Atypical Hemolytic Uremic Syndrome—Disease-Relevant or Benign?

    PubMed Central

    Marinozzi, Maria Chiara; Vergoz, Laura; Rybkine, Tania; Ngo, Stephanie; Bettoni, Serena; Pashov, Anastas; Cayla, Mathieu; Tabarin, Fanny; Jablonski, Mathieu; Hue, Christophe; Smith, Richard J.; Noris, Marina; Halbwachs-Mecarelli, Lise; Donadelli, Roberta; Fremeaux-Bacchi, Veronique

    2014-01-01

    Atypical hemolytic uremic syndrome (aHUS) is a genetic ultrarare renal disease associated with overactivation of the alternative pathway of complement. Four gain-of-function mutations that form a hyperactive or deregulated C3 convertase have been identified in Factor B (FB) ligand binding sites. Here, we studied the functional consequences of 10 FB genetic changes recently identified from different aHUS cohorts. Using several tests for alternative C3 and C5 convertase formation and regulation, we identified two gain-of-function and potentially disease-relevant mutations that formed either an overactive convertase (M433I) or a convertase resistant to decay by FH (K298Q). One mutation (R178Q) produced a partially cleaved protein with no ligand binding or functional activity. Seven genetic changes led to near-normal or only slightly reduced ligand binding and functional activity compared with the most common polymorphism at position 7, R7. Notably, none of the algorithms used to predict the disease relevance of FB mutations agreed completely with the experimental data, suggesting that in silico approaches should be undertaken with caution. These data, combined with previously published results, suggest that 9 of 15 FB genetic changes identified in patients with aHUS are unrelated to disease pathogenesis. This study highlights that functional assessment of identified nucleotide changes in FB is mandatory to confirm disease association. PMID:24652797

  1. Reconstructing a B-Cell Clonal Lineage. II. Mutation, Selection, and Affinity Maturation

    PubMed Central

    Kepler, Thomas B.; Munshaw, Supriya; Wiehe, Kevin; Zhang, Ruijun; Yu, Jae-Sung; Woods, Christopher W.; Denny, Thomas N.; Tomaras, Georgia D.; Alam, S. Munir; Moody, M. Anthony; Kelsoe, Garnett; Liao, Hua-Xin; Haynes, Barton F.

    2014-01-01

    Affinity maturation of the antibody response is a fundamental process in adaptive immunity during which B-cells activated by infection or vaccination undergo rapid proliferation accompanied by the acquisition of point mutations in their rearranged immunoglobulin (Ig) genes and selection for increased affinity for the eliciting antigen. The rate of somatic hypermutation at any position within an Ig gene is known to depend strongly on the local DNA sequence, and Ig genes have region-specific codon biases that influence the local mutation rate within the gene resulting in increased differential mutability in the regions that encode the antigen-binding domains. We have isolated a set of clonally related natural Ig heavy chain–light chain pairs from an experimentally infected influenza patient, inferred the unmutated ancestral rearrangements and the maturation intermediates, and synthesized all the antibodies using recombinant methods. The lineage exhibits a remarkably uniform rate of improvement of the effective affinity to influenza hemagglutinin (HA) over evolutionary time, increasing 1000-fold overall from the unmutated ancestor to the best of the observed antibodies. Furthermore, analysis of selection reveals that selection and mutation bias were concordant even at the level of maturation to a single antigen. Substantial improvement in affinity to HA occurred along mutationally preferred paths in sequence space and was thus strongly facilitated by the underlying local codon biases. PMID:24795717

  2. CACNA1B mutation is linked to unique myoclonus-dystonia syndrome

    PubMed Central

    Groen, Justus L.; Andrade, Arturo; Ritz, Katja; Jalalzadeh, Hamid; Haagmans, Martin; Bradley, Ted E.J.; Jongejan, Aldo; Verbeek, Dineke S.; Nürnberg, Peter; Denome, Sylvia; Hennekam, Raoul C.M.; Lipscombe, Diane; Baas, Frank; Tijssen, Marina A.J.

    2015-01-01

    Using exome sequencing and linkage analysis in a three-generation family with a unique dominant myoclonus-dystonia-like syndrome with cardiac arrhythmias, we identified a mutation in the CACNA1B gene, coding for neuronal voltage-gated calcium channels CaV2.2. This mutation (c.4166G>A;p.Arg1389His) is a disruptive missense mutation in the outer region of the ion pore. The functional consequences of the identified mutation were studied using whole-cell and single-channel patch recordings. High-resolution analyses at the single-channel level showed that, when open, R1389H CaV2.2 channels carried less current compared with WT channels. Other biophysical channel properties were unaltered in R1389H channels including ion selectivity, voltage-dependent activation or voltage-dependent inactivation. CaV2.2 channels regulate transmitter release at inhibitory and excitatory synapses. Functional changes could be consistent with a gain-of-function causing the observed hyperexcitability characteristic of this unique myoclonus-dystonia-like syndrome associated with cardiac arrhythmias. PMID:25296916

  3. Identification and characterization of the Escherichia coli gene dsbB, whose product is involved in the formation of disulfide bonds in vivo.

    PubMed Central

    Missiakas, D; Georgopoulos, C; Raina, S

    1993-01-01

    We have identified and characterized the Escherichia coli gene dsbB, whose product is required for disulfide bond formation of periplasmic proteins, by using two different approaches: (i) screening of a multicopy plasmid library for clones which protect E. coli from the lethal effects of dithiothreitol (DTT), and (ii) screening of insertion libraries of E. coli for DTT-sensitive mutants. Mapping and characterization of mutations conferring a DTT-sensitive phenotype also identified the dsbA, trxA, and trxB genes, whose products are involved in different oxidation-reduction pathways. Null mutations in dsbB conferred pleiotropic phenotypes such as sensitivity to benzylpenicillin and inability to support plaque formation of filamentous phages, and they were shown to severely affect disulfide bond oxidation of secreted proteins such as OmpA and beta-lactamase. These phenotypes resemble the phenotype of bacteria carrying either a null mutation in the dsbA gene or the double mutation dsbA dsbB. Sequencing and expression of the dsbB gene revealed that it encodes a 20-kDa protein predicted to possess an "exchangeable" disulfide bond in -Cys-Val-Leu-Cys-. The dsbB gene maps at 26.5 min on the genetic map of the E. coli chromosome, and its transcription is directed from two promoters, neither of which resembles the canonical E sigma 70-recognized promoter. Images Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:7688471

  4. NF-κB-driven suppression of FOXO3a contributes to EGFR mutation-independent gefitinib resistance.

    PubMed

    Chiu, Ching-Feng; Chang, Yi-Wen; Kuo, Kuang-Tai; Shen, Yu-Shiuan; Liu, Chien-Ying; Yu, Yang-Hao; Cheng, Ching-Chia; Lee, Kang-Yun; Chen, Feng-Chi; Hsu, Min-Kung; Kuo, Tsang-Chih; Ma, Jui-Ti; Su, Jen-Liang

    2016-05-01

    Therapy with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (EGFR-TKIs, such as gefitinib or erlotinib) significantly prolongs survival time for patients with tumors harboring an activated mutation on EGFR; however, up to 40% of lung cancer patients exhibit acquired resistance to EGFR-TKIs with an unknown mechanism. FOXO3a, a transcription factor of the forkhead family, triggers apoptosis, but the mechanistic details involved in EGFR-TKI resistance and cancer stemness remain largely unclear. Here, we observed that a high level of FOXO3a was correlated with EGFR mutation-independent EGFR-TKI sensitivity, the suppression of cancer stemness, and better progression-free survival in lung cancer patients. The suppression of FOXO3a obviously increased gefitinib resistance and enhanced the stem-like properties of lung cancer cells; consistent overexpression of FOXO3a in gefitinib-resistant lung cancer cells reduced these effects. Moreover, we identified that miR-155 targeted the 3'UTR of FOXO3a and was transcriptionally regulated by NF-κB, leading to repressed FOXO3a expression and increased gefitinib resistance, as well as enhanced cancer stemness of lung cancer in vitro and in vivo. Our findings indicate that FOXO3a is a significant factor in EGFR mutation-independent gefitinib resistance and the stemness of lung cancer, and suggest that targeting the NF-κB/miR-155/FOXO3a pathway has potential therapeutic value in lung cancer with the acquisition of resistance to EGFR-TKIs. PMID:27091996

  5. A recurrent synonymous KAT6B mutation causes Say-Barber-Biesecker/Young-Simpson syndrome by inducing aberrant splicing.

    PubMed

    Yilmaz, Rüstem; Beleza-Meireles, Ana; Price, Susan; Oliveira, Renata; Kubisch, Christian; Clayton-Smith, Jill; Szakszon, Katalin; Borck, Guntram

    2015-12-01

    Mutations of the histone acetyltransferase-encoding KAT6B gene cause the Say-Barber-Biesecker/Young-Simpson (SBBYS) type of blepharophimosis-"mental retardation" syndromes and the more severe genitopatellar syndrome. The SBBYS syndrome-causing mutations are clustered in the large exon 18 of KAT6B and almost exclusively lead to predicted protein truncation. An atypical KAT6B mutation, a de novo synonymous variant located in exon 16 (c.3147G>A, p.(Pro1049Pro)) was previously identified in three unrelated patients. This exonic mutation was predicted in silico to cause protein truncation through aberrant splicing. Here, we report three additional unrelated children with typical SBBYS syndrome and the KAT6B c.3147G>A mutation. We show on RNA derived from patient blood that the mutation indeed induces aberrant splicing through the use of a cryptic exonic splice acceptor site created by the sequence variant. Our results thus identify the synonymous variant c.3147G>A as a splice site mutation and a mutational hot spot in SBBYS syndrome. PMID:26334766

  6. Mutational and structural analysis of diffuse large B-cell lymphoma using whole genome sequencing | Office of Cancer Genomics

    Cancer.gov

    Abstract: Diffuse large B-cell lymphoma (DLBCL) is a genetically heterogeneous cancer comprising at least two molecular subtypes that differ in gene expression and distribution of mutations. Recently, application of genome/exome sequencing and RNA-seq to DLBCL has revealed numerous genes that are recurrent targets of somatic point mutation in this disease.

  7. Evolution of multidrug resistance during Staphylococcus aureus infection involves mutation of the essential two component regulator WalKR.

    PubMed

    Howden, Benjamin P; McEvoy, Christopher R E; Allen, David L; Chua, Kyra; Gao, Wei; Harrison, Paul F; Bell, Jan; Coombs, Geoffrey; Bennett-Wood, Vicki; Porter, Jessica L; Robins-Browne, Roy; Davies, John K; Seemann, Torsten; Stinear, Timothy P

    2011-11-01

    Antimicrobial resistance in Staphylococcus aureus is a major public health threat, compounded by emergence of strains with resistance to vancomycin and daptomycin, both last line antimicrobials. Here we have performed high throughput DNA sequencing and comparative genomics for five clinical pairs of vancomycin-susceptible (VSSA) and vancomycin-intermediate ST239 S. aureus (VISA); each pair isolated before and after vancomycin treatment failure. These comparisons revealed a frequent pattern of mutation among the VISA strains within the essential walKR two-component regulatory locus involved in control of cell wall metabolism. We then conducted bi-directional allelic exchange experiments in our clinical VSSA and VISA strains and showed that single nucleotide substitutions within either walK or walR lead to co-resistance to vancomycin and daptomycin, and caused the typical cell wall thickening observed in resistant clinical isolates. Ion Torrent genome sequencing confirmed no additional regulatory mutations had been introduced into either the walR or walK VISA mutants during the allelic exchange process. However, two potential compensatory mutations were detected within putative transport genes for the walK mutant. The minimal genetic changes in either walK or walR also attenuated virulence, reduced biofilm formation, and led to consistent transcriptional changes that suggest an important role for this regulator in control of central metabolism. This study highlights the dramatic impacts of single mutations that arise during persistent S. aureus infections and demonstrates the role played by walKR to increase drug resistance, control metabolism and alter the virulence potential of this pathogen. PMID:22102812

  8. Large Deletions and Point Mutations Involving DOCK8 in the Autosomal Recessive Form of the Hyper-IgE Syndrome

    PubMed Central

    Engelhardt, Karin R.; McGhee, Sean; Winkler, Sabine; Sassi, Atfa; Woellner, Cristina; Lopez-Herrera, Gabriela; Chen, Andrew; Kim, Hong Sook; Lloret, Maria Garcia; Schulze, Ilka; Ehl, Stephan; Thiel, Jens; Pfeifer, Dietmar; Veelken, Hendrik; Niehues, Tim; Siepermann, Kathrin; Weinspach, Sebastian; Reisli, Ismail; Keles, Sevgi; Genel, Ferah; Kütükçüler, Necil; Camcioğlu, Yildiz; Somer, Ayper; Aydiner, Elif Karakoc; Barlan, Isil; Gennery, Andrew; Metin, Ayse; Degerliyurt, Aydan; Pietrogrande, Maria C.; Yeganeh, Mehdi; Baz, Zeina; Al-Tamemi, Salem; Klein, Christoph; Puck, Jennifer M.; Holland, Steven M.; McCabe, Edward R. B.; Grimbacher, Bodo; Chatila, Talal

    2010-01-01

    Background The genetic etiologies of the hyper-IgE syndromes are diverse. Approximately 60-70% of patients with hyper-IgE syndrome have dominant mutations in STAT3, and a single patient was reported to have a homozygous TYK2 mutation. In the remaining hyper-IgE syndrome patients, the genetic etiology has not yet been identified. Methods We performed genome-wide single nucleotide polymorphism analysis for nine subjects with autosomal recessive hyper-IgE syndrome to locate copy number variations and homozygous haplotypes. Homozygosity mapping was performed with twelve subjects from seven additional families. The candidate gene was analyzed by genomic and cDNA sequencing to identify causative alleles in a total of 27 patients with autosomal recessive hyper-IgE syndrome. Findings Subtelomeric microdeletions were identified in six subjects at the terminus of chromosome 9p. In all patients the deleted interval involved DOCK8, encoding a protein implicated in the regulation of the actin cytoskeleton. Sequencing of subjects without large deletions revealed 16 patients from nine unrelated families with distinct homozygous mutations in DOCK8 causing premature termination, frameshift, splice site disruption, single exon- and micro-deletions. DOCK8 deficiency was associated with impaired activation of CD4+ and CD8+ T cells. Interpretation Autosomal recessive mutations in DOCK8 are responsible for many, though not all, cases of autosomal recessive hyper-IgE syndrome. DOCK8 disruption is associated with a phenotype of severe cellular immunodeficiency characterized by susceptibility to viral infections, atopic eczema, defective T cell activation and TH17 cell differentiation; and impaired eosinophil homeostasis and dysregulation of IgE. PMID:20004785

  9. Genotypic Detection of rpoB and katG Gene Mutations Associated with Rifampicin and Isoniazid Resistance in Mycobacterium Tuberculosis Isolates: A Local Scenario (Kelantan)

    PubMed Central

    Ismail, Nurul-Ain; Ismail, Mohd Fazli; Noor, Siti Suraiya MD; Camalxaman, Siti Nazrina

    2016-01-01

    Background Drug resistant tuberculosis (DR-TB) remains a public health issue that is of major concern on a global scale. The characterisation of clinical isolates may provide key information regarding the underlying mechanisms of drug resistance, and helps to augment therapeutic options. This study aims to evaluate the frequency of gene mutations associated with Rifampicin (RIF) and Isoniazid (INH) resistance among nine clinical isolates. Methods A total of nine drug resistant Mycobacterium tuberculosis clinical isolates were screened for genetic mutations in rpoB and katusing polymerase chain reaction (PCR) amplification and DNA sequencing. Genotypic analysis was performed to detect the mutations in the sequence of the target genes. Results Our findings reveal that 80% of the isolates possess mutations at codon 119 (His119Tyr) and 135 (Arg135Trp and Ser135Leu) within the rpoB gene; and 70% possess mutations in the katG gene at codon 238 with amino acid change (Leu238Arg). Conclusion Findings from this study provide an overview of the current situation of RIF and INH resistance in a hospital Universiti Sains Malaysia (HUSM) located in Kelantan, Malaysia, which could facilitate molecular-based detection methods of drug-resistant strains. Further information regarding the molecular mechanisms involved in resistance in RR-/MDR-TB should be addressed in the near future. PMID:27540322

  10. Whole exome sequencing of relapsed/refractory patients expands the repertoire of somatic mutations in diffuse large B-cell lymphoma.

    PubMed

    Mareschal, Sylvain; Dubois, Sydney; Viailly, Pierre-Julien; Bertrand, Philippe; Bohers, Elodie; Maingonnat, Catherine; Jaïs, Jean-Philippe; Tesson, Bruno; Ruminy, Philippe; Peyrouze, Pauline; Copie-Bergman, Christiane; Fest, Thierry; Jo Molina, Thierry; Haioun, Corinne; Salles, Gilles; Tilly, Hervé; Lecroq, Thierry; Leroy, Karen; Jardin, Fabrice

    2016-03-01

    Despite the many efforts already spent to enumerate somatic mutations in diffuse large B-cell lymphoma (DLBCL), previous whole-genome and whole-exome studies conducted on patients of mixed outcomes failed at characterizing the 30% of patients who will relapse or resist current immunochemotherapies. To address this issue, we performed whole-exome sequencing of normal/tumoral DNA pairs in 14 relapsed/refractory (R/R) patients subclassified by full-transcriptome arrays (six activated B-cell like, three germinal center B-cell like, and five primary mediastinal B-cell lymphomas), from the LNH-03 LYSA clinical trial program. Aside from well-known DLBCL features, gene and pathway level recurrence analyses proposed several interesting leads including TBL1XR1 and activating mutations in IRF4 or in the insulin regulation pathway. Sequencing-based copy number analysis defined 23 short recurrently altered regions involving genes such as REL, CDKN2A, HYAL2, and TP53. Moreover, it highlighted mutations in genes such as GNA13, CARD11, MFHAS1, and PCLO as associated with secondary variant allele amplification events. The five primary mediastinal B-cell lymphomas (PMBL), while unexpected in a R/R cohort, showed a significantly higher mutation rate (P = 0.003) and provided many insights on this classical Hodgkin lymphoma related subtype. Novel genes such as XPO1, MFHAS1, and ITPKB were found particularly mutated, along with various cytokine-based signaling pathways. Among these analyses, somatic events in the NF-κB pathway were found preponderant in the three DLBCL subtypes, confirming its major implication in DLBCL aggressiveness and pinpointing several new candidate genes. PMID:26608593

  11. Human genes involved in hepatitis B virus infection

    PubMed Central

    Zeng, Zheng

    2014-01-01

    Persistent hepatitis B virus (HBV) infection is a significant public health problem because it is a major cause of chronic liver disease, cirrhosis, and hepatocellular carcinoma (HCC). Roughly one-third of the world population has been infected with HBV and there are about 350 million (5%-6%) persistent carriers. HBV causes 80% of all liver cancer cases and is the second most important carcinogen, after smoking tobacco. There is an approximate 90% risk of becoming a persistent carrier following perinatal infection in infants born to e antigen positive carrier mothers and a 30% risk in pre-school children. Only 5%-10% of adults become persistent carriers following infection. Of individuals persistently infected with HBV, 10%-30% will develop liver cirrhosis and HCC. These highly variable outcomes in both clearance rates and disease outcomes in persistently infected individuals cannot be fully explained by differences in immunological, viral or environmental factors. Thus, differences in host genetic factors may affect the natural history of hepatitis B. PMID:24976707

  12. Mutations in KCNH1 and ATP6V1B2 cause Zimmermann-Laband syndrome.

    PubMed

    Kortüm, Fanny; Caputo, Viviana; Bauer, Christiane K; Stella, Lorenzo; Ciolfi, Andrea; Alawi, Malik; Bocchinfuso, Gianfranco; Flex, Elisabetta; Paolacci, Stefano; Dentici, Maria Lisa; Grammatico, Paola; Korenke, Georg Christoph; Leuzzi, Vincenzo; Mowat, David; Nair, Lal D V; Nguyen, Thi Tuyet Mai; Thierry, Patrick; White, Susan M; Dallapiccola, Bruno; Pizzuti, Antonio; Campeau, Philippe M; Tartaglia, Marco; Kutsche, Kerstin

    2015-06-01

    Zimmermann-Laband syndrome (ZLS) is a developmental disorder characterized by facial dysmorphism with gingival enlargement, intellectual disability, hypoplasia or aplasia of nails and terminal phalanges, and hypertrichosis. We report that heterozygous missense mutations in KCNH1 account for a considerable proportion of ZLS. KCNH1 encodes the voltage-gated K(+) channel Eag1 (Kv10.1). Patch-clamp recordings showed strong negative shifts in voltage-dependent activation for all but one KCNH1 channel mutant (Gly469Arg). Coexpression of Gly469Arg with wild-type KCNH1 resulted in heterotetrameric channels with reduced conductance at positive potentials but pronounced conductance at negative potentials. These data support a gain-of-function effect for all ZLS-associated KCNH1 mutants. We also identified a recurrent de novo missense change in ATP6V1B2, encoding the B2 subunit of the multimeric vacuolar H(+) ATPase, in two individuals with ZLS. Structural analysis predicts a perturbing effect of the mutation on complex assembly. Our findings demonstrate that KCNH1 mutations cause ZLS and document genetic heterogeneity for this disorder. PMID:25915598

  13. Adult Onset of BRAFV600E-Mutated Langerhans Cell Histiocytosis with Cutaneous Involvement Successfully Diagnosed by Immunohistochemical Staining

    PubMed Central

    Tono, Hisayuki; Fujimura, Taku; Kakizaki, Aya; Furudate, Sadanori; Ishibashi, Masaya; Aiba, Setsuya

    2015-01-01

    Langerhans cell histiocytosis (LCH) is characterized by the clonal proliferation of Langerhans cells; it is categorized as a single-system disease with single or multifocal lesions, and as a multi-system disease with or without the risk of organ involvement. Although the skin is not categorized as a risk organ, the precise diagnosis of skin lesions is necessary to determine the protocol for the treatment of LCH. In this report, we describe a 28-year-old Japanese man with adult onset of BRAFV600E-mutated LCH with cutaneous involvement successfully diagnosed by immunohistochemical staining. Our report suggests that immunohistochemical staining for the BRAFV600E gene could be a diagnostic tool to determine the clinical type of LCH. PMID:26500535

  14. Familial C3 glomerulonephritis associated with mutations in the gene for complement factor B.

    PubMed

    Imamura, Hideaki; Konomoto, Takao; Tanaka, Etsuko; Hisano, Satoshi; Yoshida, Yoko; Fujimura, Yoshihiro; Miyata, Toshiyuki; Nunoi, Hiroyuki

    2015-05-01

    We report the first case of familial C3 glomerulonephritis (C3GN) associated with mutations in the gene for complement factor B (CFB). A 12-year-old girl was diagnosed with biopsy-proven C3GN. Her mother had a history of treatment for membranoproliferative glomerulonephritis, and her brother had hypocomplementemia without urinary abnormalities. DNA analysis revealed heterozygosity for CFB p.S367R in the patient, mother and brother. Evaluation of the structure-function relationship supports that this mutation has gain-of-function effects in CFB. The present case suggests that CFB has an important role in the etiology of C3GN and provides a new insight into anticomplement therapy approaches. PMID:25758434

  15. Activation and Products of the Cryptic Secondary Metabolite Biosynthetic Gene Clusters by Rifampin Resistance (rpoB) Mutations in Actinomycetes

    PubMed Central

    Tanaka, Yukinori; Kasahara, Ken; Hirose, Yutaka; Murakami, Kiriko; Kugimiya, Rie

    2013-01-01

    A subset of rifampin resistance (rpoB) mutations result in the overproduction of antibiotics in various actinomycetes, including Streptomyces, Saccharopolyspora, and Amycolatopsis, with H437Y and H437R rpoB mutations effective most frequently. Moreover, the rpoB mutations markedly activate (up to 70-fold at the transcriptional level) the cryptic/silent secondary metabolite biosynthetic gene clusters of these actinomycetes, which are not activated under general stressful conditions, with the exception of treatment with rare earth elements. Analysis of the metabolite profile demonstrated that the rpoB mutants produced many metabolites, which were not detected in the wild-type strains. This approach utilizing rifampin resistance mutations is characterized by its feasibility and potential scalability to high-throughput studies and would be useful to activate and to enhance the yields of metabolites for discovery and biochemical characterization. PMID:23603745

  16. Regulation of Axonal HCN1 Trafficking in Perforant Path Involves Expression of Specific TRIP8b Isoforms

    PubMed Central

    Lewis, Alan S.; Stoub, Travis R.; Ramos, Elena M.; Brandt, Nicola; Nicholson, Daniel A.; Chetkovich, Dane M.; Bender, Roland A.

    2012-01-01

    The functions of HCN channels in neurons depend critically on their subcellular localization, requiring fine-tuned machinery that regulates subcellular channel trafficking. Here we provide evidence that regulatory mechanisms governing axonal HCN channel trafficking involve association of the channels with specific isoforms of the auxiliary subunit TRIP8b. In the medial perforant path, which normally contains HCN1 channels in axon terminals in immature but not in adult rodents, we found axonal HCN1 significantly increased in adult mice lacking TRIP8b (TRIP8b−/−). Interestingly, adult mice harboring a mutation that results in expression of only the two most abundant TRIP8b isoforms (TRIP8b[1b/2]−/−) exhibited an HCN1 expression pattern similar to wildtype mice, suggesting that presence of one or both of these isoforms (TRIP8b(1a), TRIP8b(1a-4)) prevents HCN1 from being transported to medial perforant path axons in adult mice. Concordantly, expression analyses demonstrated a strong increase of expression of both TRIP8b isoforms in rat entorhinal cortex with age. However, when overexpressed in cultured entorhinal neurons of rats, TRIP8b(1a), but not TRIP8b(1a-4), altered substantially the subcellular distribution of HCN1 by promoting somatodendritic and reducing axonal expression of the channels. Taken together, we conclude that TRIP8b isoforms are important regulators of HCN1 trafficking in entorhinal neurons and that the alternatively-spliced isoform TRIP8b(1a) could be responsible for the age-dependent redistribution of HCN channels out of perforant path axon terminals. PMID:22363812

  17. The mitochondrial calcium uniporter is involved in mitochondrial calcium cycle dysfunction: Underlying mechanism of hypertension associated with mitochondrial tRNA(Ile) A4263G mutation.

    PubMed

    Chen, Xi; Zhang, Yu; Xu, Bin; Cai, Zhongqi; Wang, Lin; Tian, Jinwen; Liu, Yuqi; Li, Yang

    2016-09-01

    Recent studies have shown that the mitochondrial DNA mutations are involved in the pathogenesis of hypertension. Our previous study identified mitochondrial tRNA(Ile) A4263G mutation in a large Chinese Han family with maternally-inherited hypertension. This mutation may contribute to mitochondrial Ca(2+) cycling dysfuntion, but the mechanism is unclear. Lymphoblastoid cell lines were derived from hypertensive and normotensive individuals, either with or without tRNA(Ile) A4263G mutation. The mitochondrial calcium ([Ca(2+)]m) in cells from hypertensive subjects with the tRNA(Ile) A4263G mutation, was lower than in cells from normotension or hypertension without mutation, or normotension with mutation (P<0.05). Meanwhile, cytosolic calcium ([Ca(2+)]c) in hypertensive with mutation cells was higher than another three groups. After exposure to caffeine, which could increase the [Ca(2+)]c by activating ryanodine receptor on endoplasmic reticulum, [Ca(2+)]c/[Ca(2+)]m increased higher than in hypertensive with mutation cells from another three groups. Moreover, MCU expression was decreased in hypertensive with mutation cells compared with in another three groups (P<0.05). [Ca(2+)]c increased and [Ca(2+)]m decreased after treatment with Ru360 (an inhibitor of MCU) or an siRNA against MCU. In this study we found decreased MCU expression in hypertensive with mutation cells contributed to dysregulated Ca(2+) uptake into the mitochondria, and cytoplasmic Ca(2+) overload. This abnormality might be involved in the underlying mechanisms of maternally inherited hypertension in subjects carrying the mitochondrial tRNA(Ile) A4263G mutation. PMID:27471128

  18. Overview of hepatitis B virus mutations and their implications in the management of infection

    PubMed Central

    Caligiuri, Patrizia; Cerruti, Rita; Icardi, Giancarlo; Bruzzone, Bianca

    2016-01-01

    Hepatitis B virus (HBV) affects approximately two billion people worldwide and more than 240 million people in the world are currently chronic carrier that could develop serious complications in the future, like liver cirrhosis and hepatocellular carcinoma. Although an extended HBV immunization program is being carried out since the early ‘80s, representing effective preventive measure, leading to a dramatic reduction of HBV hepatitis incidence, globally HBV infection still represents a major public health problem. The HBV virus is a DNA virus belongs to the Hepadnaviridae family. The HBV-DNA is a circular, partial double strand genome. All coding information is on the minus DNA strand and it is organized into four open reading frames. Despite hepatitis B virus is a DNA virus, it has a high mutation rate due to its replicative strategy, that leads to the production of many non-identical variants at each cycle of replication. In fact, it contains a polymerase without the proofreading activity, and uses an RNA intermediate (pgRNA) during its replication, so error frequencies are comparable to those seen in retroviruses and other RNA viruses rather than in more stable DNA viruses. Due to the low fidelity of the polymerase, the high replication rate and the overlapping reading frames, mutations occur throughout the genome and they have been identified both in the structural and not structural gene. The arise of mutations being to develop of a whole of viral variants called “quasi-species” and the prevalent population, which favors virus replication, was selected by viral fitness, host’s immune pressure and external pressure, i.e., vaccination or antiviral therapy. Naturally occurring mutations were found both in acute and chronic subjects. In the present review we examine and discuss the most recent available data about HBV genetic variability and its significance. PMID:26755866

  19. Investigation of Somatic GNAQ, GNA11, BAP1 and SF3B1 Mutations in Ophthalmic Melanocytomas

    PubMed Central

    Francis, Jasmine H.; Wiesner, Thomas; Milman, Tatyana; Won, Helen H.; Lin, Amy; Lee, Vivian; Albert, Daniel M.; Folberg, Robert; Berger, Michael F.; Char, Devron H.; Marr, Brian; Abramson, David H.

    2016-01-01

    Purpose The aim of this study was to use massively parallel DNA sequencing to identify GNAQ/11, BAP1 and SF3B1 mutations in ophthalmic melanocytoma. Procedures Six ophthalmic melanocytoma specimens (1 iridociliary and 5 optic nerve) were profiled for genomic alterations in GNAQ/11, BAP1 and SF3B1 using a custom deep sequencing assay. This assay uses solution phase hybridization-based exon capture and deep-coverage massively parallel DNA sequencing to interrogate all protein-coding exons and select introns. Results The only iridociliary melanocytoma showed a mutation in GNAQ but not in BAP1. Of the 2 optic-nerve melanocytomas that developed into melanoma, one had a GNAQ mutation and both a BAP1 mutation and monosomy 3. The remaining 3 optic-nerve melanocytomas did not reveal mutations in GNAQ/11 or BAP1. SF3B1 mutations were not detected in any specimen. Conclusions The presence of GNAQ mutation in some iridociliary and optic-nerve melanocytomas suggests a possible relationship between ophthalmic melanocytoma and other ophthalmic melanocytic neoplasms. BAP1 mutation may accompany the transformation of ophthalmic melanocytoma to melanoma. PMID:27239460

  20. CIT, a gene involved in neurogenic cytokinesis, is mutated in human primary microcephaly.

    PubMed

    Basit, Sulman; Al-Harbi, Khalid M; Alhijji, Sabri A M; Albalawi, Alia M; Alharby, Essa; Eldardear, Amr; Samman, Mohammed I

    2016-10-01

    Autosomal recessive primary microcephaly (MCPH) is a static neurodevelopmental disorder characterized by congenital small head circumference and non-progressive intellectual disability without additional severe brain malformations. MCPH is a genetically heterogeneous disorder. Sixteen genes (MCPH1-MCPH16) have been discovered so far, mutations thereof lead to autosomal recessive primary microcephaly. In a family, segregating MCPH in an autosomal recessive manner, genome-wide homozygosity mapping mapped a disease locus to 16.9-Mb region on chromosome 12q24.11-q24.32. Following this, exome sequencing in three affected individuals of the family discovered a splice site variant (c.753+3A>T) in citron kinase (CIT) gene, segregating with the disorder in the family. CIT co-localizes to the midbody ring during cytokinesis, and its loss of expression results in defects in neurogenic cytokinesis in both humans and mice. Splice site variant in CIT, identified in this study, is predicted to abolish splice donor site. cDNA sequence of an affected individual showed retention of an intron next to the splice donor site. The study, presented here, revealed the first variant in the CIT causing MCPH in the family. PMID:27519304

  1. Involvement of ESCRT-II in Hepatitis B Virus Morphogenesis

    PubMed Central

    Stieler, Jens T.; Prange, Reinhild

    2014-01-01

    The hepatitis B virus (HBV) is an enveloped DNA virus that replicates via reverse transcription of its pregenomic RNA (pgRNA). Budding of HBV is supposed to occur at intracellular membranes and requires scission functions of the endosomal sorting complex required for transport (ESCRT) provided by ESCRT-III and VPS4. Here, we have investigated the impact of the upstream-acting ESCRT-I and ESCRT-II complexes in HBV morphogenesis. RNA interference knockdown of the ESCRT-I subunits TSG101 and VPS28 did not block, but rather stimulate virus release. In contrast, RNAi-mediated depletion of the ESCRT-II components EAP20, EAP30 and EAP45 greatly reduced virus egress. By analyzing different steps of the HBV maturation pathway, we find that the knockdown of ESCRT-II not only inhibited the production and/or release of enveloped virions, but also impaired intracellular nucleocapsid formation. Transcription/translation studies revealed that the depletion of ESCRT-II neither affected the synthesis and nuclear export of HBV-specific RNAs nor the expression of the viral core and envelope proteins. Moreover, the absence of ESCRT-II had no effects on the assembly capability and integrity of HBV core/capsids. However, the level of encapsidated pgRNA was significantly reduced in ESCRT-II-depleted cells, implicating that ESCRT-II directs steps accompanying the formation of replication-competent nucleocapsids, like e.g. assisting in RNA trafficking and encapsidation. In support of this, the capsid protein was found to interact and colocalize with ESCRT-II subunits in virus-producing cells. Together, these results indicate an essential role for ESCRT-II in the HBV life cycle and suggest that ESCRT-II functions prior to the final HBV budding reaction. PMID:24614091

  2. Identification of seven novel CYP11B1 gene mutations in Chinese patients with 11β-hydroxylase deficiency.

    PubMed

    Wang, Xiaojing; Nie, Min; Lu, Lin; Tong, Anli; Chen, Shi; Lu, Zhaolin

    2015-08-01

    Steroid 11β-hydroxylase deficiency (11β-OHD), one of common cause of congenital adrenal hyperplasia (CAH), is an autosomal recessive disorder characterized by virilization, precocious pseudo-puberty, and hypertension. It is caused by CYP11B1 gene mutation. We performed molecular genetic analysis of the CYP11B1 gene in six patients with preliminary clinical diagnosis of 11β-OHD and four patients identified as potential 11β-OHD from a CAH cohort in which CYP21A2 gene mutations consecutively screened. Seven novel CYP11B1 mutations, including p.R454H, p.Q472P, p.Q155X, p.K173X, IVS2-1G>A, R454A fs 573X, and g.2704_g.3154del, and six previously described mutations (p.P94L, p.G267S, p.G379V, p.R448H, p.R454C and p.R141X) were identified. These mutations mainly clustered in exons 3 and 8. Eight of twenty alleles carried mutations occurring at the Arg454 position, which is a mutational hot spot for Han Chinese. The pathogenic nature of novel p.R454H mutation was predicted by protein sequence alignment and in silico analysis. All the identified mutations were responsible for the clinical features observed in these ten unrelated Chinese patients. This study expands the CYP11B1 mutation spectrum and provides evidence for prenatal diagnosis and genetic counseling. Genetic analysis is an alternative approach to help clinicians confirm uncertain 11β-OHD diagnosis, facilitating reasonable steroid replacement. PMID:25911436

  3. Absence of Functional LIN28B Mutations in a Large Cohort of Patients with Idiopathic Central Precocious Puberty

    PubMed Central

    Silveira-Neto, Acácio P.; Leal, Leticia Ferro; Emerman, Amy B.; Henderson, Katherine D.; Piskounova, Elena; Henderson, Brian E.; Gregory, Richard I.; Gontijo Silveira, Letícia F.; Hirschhorn, Joel N.; Nguyen, Thutrang T.; Beneduzzi, Daiane; Tusset, Cintia; Reis, Ana Claudia S.; Brito, Vinicius N.; Mendonça, Berenice B.; Palmert, Mark R; Antonini, Sonir R; Latronico, Ana Claudia

    2012-01-01

    Aim To investigate LIN28B gene variants in children with idiopathic central precocious puberty (CPP). Patients and Methods We studied 178 Brazilian children with CPP (171 girls,16.8% familial cases). A large multiethnic group (1599 subjects; MEC cohort) was used as control. DNA analysis and biochemical in vitro studies were performed. Results A heterozygous LIN28B variant, p.H199R, was identified in a girl who developed CPP at 5.2 yrs. This variant was absent in 310 Brazilian control individuals, but it was found in the same allele frequency in women from the MEC cohort, independently of the age of menarche. Functional studies revealed that when ectopically expressed in cells the mutant protein was capable of binding pre-let-7 miRNA and inhibiting let-7 expression to the same extent as wild-type Lin28B protein. Other rare LIN28B variants (p.P173P, c.198+32_33delCT, g.9575731A>C and c.-11C>T) were identified in CPP patients and controls. Therefore, no functional mutation was identified. Conclusion In vitro studies revealed that the rare LIN28B p.H199R variant identified in a girl with CPP does not affect the Lin28B function in the regulation of let-7 expression. Although LIN28B SNPs were associated with normal pubertal timing, rare variations in this gene do not seem to be commonly involved in the molecular pathogenesis of CPP. PMID:22964795

  4. Severe Undervirilisation in a 46,XY Case Due to a Novel Mutation in HSD17B3 Gene.

    PubMed

    Alikaşifoğlu, Ayfer; Vurallı, Doğuş; Hiort, Olaf; Gönç, Nazlı; Özön, Alev; Kandemir, Nurgün

    2015-09-01

    17-β-hydroxysteroid dehydrogenase type 3 (17β-HSD3) is an important enzyme involved in the final steps of androgen synthesis and is required for the development of normal male external genitalia. 46,XY individuals with deficiency of this enzyme present a wide clinical spectrum from a female appearance of the external genitalia through ambiguous genitalia to a predominantly male genitalia with micropenis or hypospadias. This paper reports a one-year-old 46,XY patient with 17β-HSD3 deficiency who presented with female external genitalia and bilaterally palpable gonads in the inguinal region. The low T/Δ4 ratio after human chorionic gonadotropin (hCG) stimulation suggested 17β-HSD3 deficiency. A homozygous mutation, c.761_762delAG, was determined at the intron 9/exon 10 splice site of the HSD17B3 gene. To the best of our knowledge, this mutation has not been reported thus far, but its localization and type would imply a complete disruption of the 17β-HSD3 which may explain the phenotype of our patient. PMID:26831562

  5. Severe Undervirilisation in a 46,XY Case Due to a Novel Mutation in HSD17B3 Gene

    PubMed Central

    Alikaşifoğlu, Ayfer; Vurallı, Doğuş; Hiort, Olaf; Gönç, Nazlı; Özön, Alev; Kandemir, Nurgün

    2015-01-01

    17-β-hydroxysteroid dehydrogenase type 3 (17β-HSD3) is an important enzyme involved in the final steps of androgen synthesis and is required for the development of normal male external genitalia. 46,XY individuals with deficiency of this enzyme present a wide clinical spectrum from a female appearance of the external genitalia through ambiguous genitalia to a predominantly male genitalia with micropenis or hypospadias. This paper reports a one-year-old 46,XY patient with 17β-HSD3 deficiency who presented with female external genitalia and bilaterally palpable gonads in the inguinal region. The low T/Δ4 ratio after human chorionic gonadotropin (hCG) stimulation suggested 17β-HSD3 deficiency. A homozygous mutation, c.761_762delAG, was determined at the intron 9/exon 10 splice site of the HSD17B3 gene. To the best of our knowledge, this mutation has not been reported thus far, but its localization and type would imply a complete disruption of the 17β-HSD3 which may explain the phenotype of our patient. PMID:26831562

  6. Mutation of Fnip1 is associated with B-cell deficiency, cardiomyopathy, and elevated AMPK activity.

    PubMed

    Siggs, Owen M; Stockenhuber, Alexander; Deobagkar-Lele, Mukta; Bull, Katherine R; Crockford, Tanya L; Kingston, Bethany L; Crawford, Greg; Anzilotti, Consuelo; Steeples, Violetta; Ghaffari, Sahar; Czibik, Gabor; Bellahcene, Mohamed; Watkins, Hugh; Ashrafian, Houman; Davies, Benjamin; Woods, Angela; Carling, David; Yavari, Arash; Beutler, Bruce; Cornall, Richard J

    2016-06-28

    Folliculin (FLCN) is a tumor-suppressor protein mutated in the Birt-Hogg-Dubé (BHD) syndrome, which associates with two paralogous proteins, folliculin-interacting protein (FNIP)1 and FNIP2, forming a complex that interacts with the AMP-activated protein kinase (AMPK). Although it is clear that this complex influences AMPK and other metabolic regulators, reports of its effects have been inconsistent. To address this issue, we created a recessive loss-of-function variant of Fnip1 Homozygous FNIP1 deficiency resulted in profound B-cell deficiency, partially restored by overexpression of the antiapoptotic protein BCL2, whereas heterozygous deficiency caused a loss of marginal zone B cells. FNIP1-deficient mice developed cardiomyopathy characterized by left ventricular hypertrophy and glycogen accumulation, with close parallels to mice and humans bearing gain-of-function mutations in the γ2 subunit of AMPK. Concordantly, γ2-specific AMPK activity was elevated in neonatal FNIP1-deficient myocardium, whereas AMPK-dependent unc-51-like autophagy activating kinase 1 (ULK1) phosphorylation and autophagy were increased in FNIP1-deficient B-cell progenitors. These data support a role for FNIP1 as a negative regulator of AMPK. PMID:27303042

  7. X region mutations of hepatitis B virus related to clinical severity

    PubMed Central

    Kim, Hong; Lee, Seoung-Ae; Kim, Bum-Joon

    2016-01-01

    Chronic hepatitis B virus (HBV) infection remains a major health problem, with more than 240 million people chronically infected worldwide and potentially 650000 deaths per year due to advanced liver diseases including liver cirrhosis and hepatocellular carcinoma (HCC). HBV-X protein (HBx) contributes to the biology and pathogenesis of HBV via stimulating virus replication or altering host gene expression related to HCC. The HBV X region contains only 465 bp encoding the 16.5 kDa HBx protein, which also contains several critical cis-elements such as enhancer II, the core promoter and the microRNA-binding region. Thus, mutations in this region may affect not only the HBx open reading frame but also the overlapped cis-elements. Recently, several types of HBx mutations significantly associated with clinical severity have been described, although the functional mechanism in most of these cases remains unsolved. This review article will mainly focus on the HBx mutations proven to be significantly related to clinical severity via epidemiological studies. PMID:27350725

  8. Hepatitis B and Hepatitis C Infection Biomarkers and TP53 Mutations in Hepatocellular Carcinomas from Colombia

    PubMed Central

    Navas, Maria-Cristina; Suarez, Iris; Carreño, Andrea; Uribe, Diego; Rios, Wilson Alfredo; Cortes-Mancera, Fabian; Martel, Ghyslaine; Vieco, Beatriz; Lozano, Diana; Jimenez, Carlos; Gouas, Doriane; Osorio, German; Hoyos, Sergio; Restrepo, Juan Carlos; Correa, Gonzalo; Jaramillo, Sergio; Lopez, Rocio; Bravo, Luis Eduardo; Arbelaez, Maria Patricia; Scoazec, Jean-Yves; Abedi-Ardekani, Behnoush; Santella, Regina M.; Chemin, Isabelle; Hainaut, Pierre

    2011-01-01

    Hepatocellular Carcinoma (HCC) is a leading cause of cancer-related death worldwide. Globally, the most important HCC risk factors are Hepatitis B Virus (HBV) and/or Hepatitis C Virus (HCV), chronic alcoholism, and dietary exposure to aflatoxins. We have described the epidemiological pattern of 202 HCC samples obtained from Colombian patients. Additionally we investigated HBV/HCV infections and TP53 mutations in 49 of these HCC cases. HBV biomarkers were detected in 58.1% of the cases; HBV genotypes F and D were characterized in three of the samples. The HCV biomarker was detected in 37% of the samples while HBV/HCV coinfection was found in 19.2%. Among TP53 mutations, 10.5% occur at the common aflatoxin mutation hotspot, codon 249. No data regarding chronic alcoholism was available from the cases. In conclusion, in this first study of HCC and biomarkers in a Colombian population, the main HCC risk factor was HBV infection. PMID:22114738

  9. X region mutations of hepatitis B virus related to clinical severity.

    PubMed

    Kim, Hong; Lee, Seoung-Ae; Kim, Bum-Joon

    2016-06-28

    Chronic hepatitis B virus (HBV) infection remains a major health problem, with more than 240 million people chronically infected worldwide and potentially 650000 deaths per year due to advanced liver diseases including liver cirrhosis and hepatocellular carcinoma (HCC). HBV-X protein (HBx) contributes to the biology and pathogenesis of HBV via stimulating virus replication or altering host gene expression related to HCC. The HBV X region contains only 465 bp encoding the 16.5 kDa HBx protein, which also contains several critical cis-elements such as enhancer II, the core promoter and the microRNA-binding region. Thus, mutations in this region may affect not only the HBx open reading frame but also the overlapped cis-elements. Recently, several types of HBx mutations significantly associated with clinical severity have been described, although the functional mechanism in most of these cases remains unsolved. This review article will mainly focus on the HBx mutations proven to be significantly related to clinical severity via epidemiological studies. PMID:27350725

  10. Trisomy 19 is associated with trisomy 12 and mutated IGHV genes in B-chronic lymphocytic leukaemia.

    PubMed

    Sellmann, Ludger; Gesk, Stefan; Walter, Christoph; Ritgen, Matthias; Harder, Lana; Martín-Subero, José I; Schroers, Roland; Siemer, Dörte; Nückel, Holger; Dyer, Martin J S; Dührsen, Ulrich; Siebert, Reiner; Dürig, Jan; Küppers, Ralf

    2007-07-01

    The occurrence of trisomy 19 was investigated in 705 cases of B-chronic lymphocytic leukaemia (CLL) by metaphase cytogenetic and/or fluorescence in situ hybridisation analyses. Trisomy 19 was detected in 11 cases (1.6%), all of which also carried a trisomy 12; nine of 10 had mutated IGHV genes. In contrast, B-CLL cases with trisomy 12 lacking trisomy 19 mostly had unmutated IGHV genes. Karyotypes of the present study and the literature identified a strong correlation to trisomy 18 in addition to trisomy 12. Trisomy 19 seems to be a secondary event in B-CLL with trisomy 12, mostly originating from mutated B cells. PMID:17593029