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Wener ER, McLennan JD, Papsin BC, Cushing SL, Stavropoulos DJ, Mendoza-Londono R, Quercia N, Gordon KA. Variants in Genes Associated with Hearing Loss in Children: Prevalence in a Large Canadian Cohort. Laryngoscope 2024. [PMID: 38426810 DOI: 10.1002/lary.31373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 01/17/2024] [Accepted: 02/02/2024] [Indexed: 03/02/2024]
Abstract
OBJECTIVE The objective of this study was to assess the prevalence of genetic variants associated with hearing loss in a large cohort of children in Canada using high throughput next generation sequencing (NGS). METHODS A total of 485 children with hearing loss underwent NGS testing with an 80 gene panel of syndromic and non-syndromic variants known to be associated with hearing loss. Genetic variants were classified as pathogenic, likely pathogenic, likely benign, benign, or variants of uncertain significance (VUS), according to the American College of Medical Genetics and Genomics guidelines. RESULTS Across the 80 genes tested, 923 variants, predominantly in 28 genes, were identified in 324 children. Pathogenic variants occurred in 19/80 (23.8%) of the hearing loss related genes tested and confirmed the etiology of hearing loss in 73/485 (15.1%) of children. GJB2 was the most prevalent gene, affecting 28/73 (38.4%) children with confirmed genetic hearing loss in our cohort. Most identified variants (748/923, 81.0%, in 76/80 genes) were of uncertain significance. CONCLUSION Genetic testing using NGS identified the etiology in approximately 15% of childhood hearing loss in a Canadian cohort which is lower than what is typically reported. GJB2 was the most common genetic cause of hearing loss. VUS are commonly identified, presenting clinical challenges for counseling. LEVEL OF EVIDENCE Level 4 Laryngoscope, 2024.
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Affiliation(s)
- Emily R Wener
- Archie's Cochlear Implant Laboratory, Neuroscience & Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Jacob D McLennan
- Archie's Cochlear Implant Laboratory, Neuroscience & Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Blake C Papsin
- Archie's Cochlear Implant Laboratory, Neuroscience & Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Otolaryngology-Head and Neck Surgery, University of Toronto, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Sharon L Cushing
- Archie's Cochlear Implant Laboratory, Neuroscience & Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Otolaryngology-Head and Neck Surgery, University of Toronto, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Dimitri James Stavropoulos
- Genome Diagnostics Paediatric Laboratory Medicine, Clinical and Metabolic Genetics, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Roberto Mendoza-Londono
- Genome Diagnostics Paediatric Laboratory Medicine, Clinical and Metabolic Genetics, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Nada Quercia
- Division of Clinical & Metabolic Genetics, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Genetic Counselling, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Molecular Genetics, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Karen A Gordon
- Archie's Cochlear Implant Laboratory, Neuroscience & Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Otolaryngology-Head and Neck Surgery, University of Toronto, Hospital for Sick Children, Toronto, Ontario, Canada
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Le Nabec A, Collobert M, Le Maréchal C, Marianowski R, Férec C, Moisan S. Whole-Genome Sequencing Improves the Diagnosis of DFNB1 Monoallelic Patients. Genes (Basel) 2021; 12:1267. [PMID: 34440441 PMCID: PMC8391926 DOI: 10.3390/genes12081267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 08/13/2021] [Accepted: 08/17/2021] [Indexed: 11/16/2022] Open
Abstract
Hearing loss is the most common sensory defect, due in most cases to a genetic origin. Variants in the GJB2 gene are responsible for up to 30% of non-syndromic hearing loss. Today, several deafness genotypes remain incomplete, confronting us with a diagnostic deadlock. In this study, whole-genome sequencing (WGS) was performed on 10 DFNB1 patients with incomplete genotypes. New variations on GJB2 were identified for four patients. Functional assays were realized to explore the function of one of them in the GJB2 promoter and confirm its impact on GJB2 expression. Thus, in this study WGS resolved patient genotypes, thus unlocking diagnosis. WGS afforded progress and bridged some gaps in our research.
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Affiliation(s)
- Anaïs Le Nabec
- Univ Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (M.C.); (C.L.M.); (C.F.)
| | - Mégane Collobert
- Univ Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (M.C.); (C.L.M.); (C.F.)
| | - Cédric Le Maréchal
- Univ Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (M.C.); (C.L.M.); (C.F.)
- Laboratoire de Génétique Moléculaire et d’Histocompatibilité, CHRU Brest, UMR 1078, F-29200 Brest, France
| | - Rémi Marianowski
- Service ORL et Chirurgie Cervicofaciale du CHRU Brest, F-29200 Brest, France;
| | - Claude Férec
- Univ Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (M.C.); (C.L.M.); (C.F.)
- Laboratoire de Génétique Moléculaire et d’Histocompatibilité, CHRU Brest, UMR 1078, F-29200 Brest, France
| | - Stéphanie Moisan
- Univ Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (M.C.); (C.L.M.); (C.F.)
- Laboratoire de Génétique Moléculaire et d’Histocompatibilité, CHRU Brest, UMR 1078, F-29200 Brest, France
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Abstract
BACKGROUND Hearing loss (HL) is a heterogeneous condition that causes partial or complete hearing impairment. Hundreds of variants in more than 60 genes have been reported to be associated with Hereditary HL (HHL). The HHL prevalence is thought to be high in the Arab population; however, the genetic epidemiology of HHL among Arab populations is understudied. This study aimed to systematically analyze the genetic epidemiology of HHL in Arab countries. METHODS We searched four literature databases (PubMed, Scopus, Science Direct, and Web of Science) from the time of inception until January 2019 using broad search terms to capture all the reported epidemiological and genetic data related to Arab patients with HHL. FINDINGS A total of 2,600 citations were obtained; 96 studies met our inclusion criteria. Our search strategy yielded 121,276 individuals who were tested for HL over 52 years (1966-2018), of whom 8,099 were clinically diagnosed with HL and belonged to 16 Arab countries. A total of 5,394 patients and 61 families with HHL were genotyped, of whom 336 patients and 6 families carried 104 variants in 44 genes and were from 17/22 Arab countries. Of these variants, 72 (in 41 genes) were distinctive to Arab patients. Arab patients manifested distinctive clinical phenotypes. The incidence of HHL in the captured studies ranged from 1.20 to 18 per 1,000 births per year, and the prevalence was the highest in Iraq (76.3%) and the lowest in Jordan (1.5%). INTERPRETATION This is the first systematic review to capture the prevalence and spectrum of variants associated with HHL in an Arab population. There appears to be a distinctive clinical picture for Arab patients with HHL, and the range and distribution of variants among Arab patients differ from those noted in other affected ethnic groups.
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Moisan S, Le Nabec A, Quillévéré A, Le Maréchal C, Férec C. Characterization of GJB2 cis-regulatory elements in the DFNB1 locus. Hum Genet 2019; 138:1275-1286. [PMID: 31586237 DOI: 10.1007/s00439-019-02068-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 09/29/2019] [Indexed: 11/28/2022]
Abstract
Although most disease-causing variants are within coding region of genes, it is now well established that cis-acting regulatory sequences, depending on 3D-chromatin organization, are required for temporal and spatial control of gene expression. Disruptions of such regulatory elements and/or chromatin conformation are likely to play a critical role in human genetic disease. Hence, recurrent monoallelic cases, who present the most common hereditary type of nonsyndromic hearing loss (i.e., DFNB1), carry only one identified pathogenic allele. This strongly suggests the presence of uncharacterized distal cis-acting elements in the missing allele. Here within, we study the spatial organization of a large DFNB1 locus encompassing the gap junction protein beta 2 (GJB2) gene, the most frequently mutated gene in this inherited hearing loss phenotype, with the chromosome conformation capture carbon copy technology (5C). By combining this approach with functional activity reporter assays and mapping of CCCTC-binding factor (CTCF) along the DFNB1 locus, we identify a novel set of cooperating GJB2 cis-acting elements and suggest a DFNB1 three-dimensional looping regulation model.
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Affiliation(s)
- Stéphanie Moisan
- Laboratoire de Génétique Moléculaire et d'Histocompatibilité, CHRU de Brest, Bretagne, Brest, France. .,Univ Brest, Inserm, EFS UMR 1078, GGB, 29200, Brest, France.
| | - Anaïs Le Nabec
- Univ Brest, Inserm, EFS UMR 1078, GGB, 29200, Brest, France
| | | | - Cédric Le Maréchal
- Laboratoire de Génétique Moléculaire et d'Histocompatibilité, CHRU de Brest, Bretagne, Brest, France.,Univ Brest, Inserm, EFS UMR 1078, GGB, 29200, Brest, France
| | - Claude Férec
- Laboratoire de Génétique Moléculaire et d'Histocompatibilité, CHRU de Brest, Bretagne, Brest, France. .,Univ Brest, Inserm, EFS UMR 1078, GGB, 29200, Brest, France.
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5
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Azadegan‐Dehkordi F, Ahmadi R, Koohiyan M, Hashemzadeh‐Chaleshtori M. Update of spectrum c.35delG and c.‐23+1G>A mutations on the
GJB2
gene in individuals with autosomal recessive nonsyndromic hearing loss. Ann Hum Genet 2018; 83:1-10. [DOI: 10.1111/ahg.12284] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Revised: 08/01/2018] [Accepted: 08/06/2018] [Indexed: 12/31/2022]
Affiliation(s)
- Fatemeh Azadegan‐Dehkordi
- Cellular and Molecular Research Center, Basic Health Sciences Institute Shahrekord University of Medical Sciences Shahrekord Iran
| | - Reza Ahmadi
- Clinical Biochemistry Research Center, Basic Health Sciences Institute Shahrekord University of Medical Sciences Shahrekord Iran
| | - Mahbobeh Koohiyan
- Medical Plants Research Center, Basic Health Sciences Institute Shahrekord University of Medical Sciences Shahrekord Iran
| | - Morteza Hashemzadeh‐Chaleshtori
- Cellular and Molecular Research Center, Basic Health Sciences Institute Shahrekord University of Medical Sciences Shahrekord Iran
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Felix F, Ribeiro MG, Tomita S, Zalis MG. Frequency of GJB2 mutations in patients with nonsyndromic hearing loss from an ethnically characterized Brazilian population. Braz J Otorhinolaryngol 2018; 85:92-98. [PMID: 29773520 PMCID: PMC9442831 DOI: 10.1016/j.bjorl.2017.10.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 09/25/2017] [Accepted: 10/27/2017] [Indexed: 11/24/2022] Open
Abstract
Introduction In different parts of the world, mutations in the GJB2 gene are associated with nonsyndromic hearing loss, and the homozygous 35delG mutation (p.Gly12Valfs*2) is a major cause of hereditary hearing loss. However, the 35delG mutation is not equally prevalent across ethnicities, making it important to study other mutations, especially in multiethnic countries such as Brazil. Objective This study aimed to identify different mutations in the GJB2 gene in patients with severe to profound nonsyndromic sensorineural hearing loss of putative genetic origin, and who were negative or heterozygote for the 35delG mutation. Methods Observational study that analyzed 100 ethnically characterized Brazilian patients with nonsyndromic severe to profound sensorineural hearing loss, who were negative or heterozygote for the 35delG mutation. GJB2 mutations were detected by DNA-based sequencing in this population. Participants’ ethnicities were identified as Latin European, Non-Latin European, Jewish, Native, Turkish, Afro-American, Asian and Others. Results Sixteen participants were heterozygote for the 35delG mutation; 14 participants, including three 35delG heterozygote's, had nine different alterations in the GJB2 gene. One variant, p.Ser199Glnfs*9, detected in two participants, was previously unreported. Three variants were pathogenic (p.Trp172*, p.Val167Met, and p.Arg75Trp), two were non-pathogenic (p.Val27Ile and p.Ile196Thr), and three variants were indeterminate (p.Met34Thr, p.Arg127Leu, and p.Lys168Arg). Three cases of compound heterozygosity were detected: p.[(Gly12Valfs*2)];[(Trp172*)], p.[(Gly12Valfs*2)](;)[(Met34Thr)], and p.[(Gly12Valfs*2)(;)[(Ser199Glnfs*9)]). Conclusion This study detected previously unclassified variants and one case of previously unreported compound heterozygosity.
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Affiliation(s)
- Felippe Felix
- Universidade Federal do Rio de Janeiro (UFRJ), Hospital Universitário Clementino Fraga Filho (HUCFF), Rio de Janeiro, RJ, Brazil.
| | - Marcia Gonçalves Ribeiro
- Universidade Federal do Rio de Janeiro (UFRJ), Hospital Universitário Clementino Fraga Filho (HUCFF), Rio de Janeiro, RJ, Brazil
| | - Shiro Tomita
- Universidade Federal do Rio de Janeiro (UFRJ), Hospital Universitário Clementino Fraga Filho (HUCFF), Rio de Janeiro, RJ, Brazil
| | - Mariano Gustavo Zalis
- Universidade Federal do Rio de Janeiro (UFRJ), Hospital Universitário Clementino Fraga Filho (HUCFF), Rio de Janeiro, RJ, Brazil
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Huang B, Han M, Wang G, Huang S, Zeng J, Yuan Y, Dai P. Genetic mutations in non-syndromic deafness patients in Hainan Province have a different mutational spectrum compared to patients from Mainland China. Int J Pediatr Otorhinolaryngol 2018; 108:49-54. [PMID: 29605365 DOI: 10.1016/j.ijporl.2018.02.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 01/18/2018] [Accepted: 02/11/2018] [Indexed: 10/18/2022]
Abstract
OBJECTIVES To provide appropriate genetic testing and counseling for non-syndromic hearing impairment patients in Hainan Province, an island in the South China Sea. METHODS 299 unrelated students with non-syndromic hearing loss who attended a special education school in Hainan Province were enrolled in this study. Three prominent deafness-related genes (GJB2, SLC26A4, and mtDNA 12S rRNA) were analyzed using Sanger sequencing. RESULTS GJB2 mutations were detected in 32.78% (98/299) of the entire cohort; however, only 5.69% (17/299) had two confirmed pathogenic mutations. The most common mutation observed in this population was c.109G > A in the GJB2 gene, with an allelic frequency of 15.05% (90/598), which is significantly higher than that reported in previous cohorts. A total of 16 patients had two confirmed pathogenic SLC26A4 gene mutations, and 16 patients had one. The IVS7-2A > G mutation was the most commonly observed, with an allelic frequency of 3.51% (21/598). Three patients had a m.1555A > G mutation in the mtDNA 12S rRNA gene. CONCLUSIONS These results reveal that genetic etiology occurred in 11.71% (35/299) of patients, suggesting that Hainan province have a different mutational spectrum compare to Mainland China in non-syndromic deafness patients, which provide useful information to genetic counseling in Hainan province.
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Affiliation(s)
- Bangqing Huang
- Department of Otorhinolaryngology, Hainan Branch of PLA General Hospital, Sanya 572013, PR China
| | - Mingyu Han
- Department of Otorhinolaryngology, Hainan Branch of PLA General Hospital, Sanya 572013, PR China; Department of Otolaryngology and Genetic Testing Center for Deafness, Chinese PLA General Hospital, Beijing 100853, PR China
| | - Guojian Wang
- Department of Otolaryngology and Genetic Testing Center for Deafness, Chinese PLA General Hospital, Beijing 100853, PR China
| | - ShaSha Huang
- Department of Otolaryngology and Genetic Testing Center for Deafness, Chinese PLA General Hospital, Beijing 100853, PR China
| | - Jialing Zeng
- Department of Otorhinolaryngology, Hainan Branch of PLA General Hospital, Sanya 572013, PR China
| | - Yongyi Yuan
- Department of Otolaryngology and Genetic Testing Center for Deafness, Chinese PLA General Hospital, Beijing 100853, PR China.
| | - Pu Dai
- Department of Otolaryngology and Genetic Testing Center for Deafness, Chinese PLA General Hospital, Beijing 100853, PR China.
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8
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Baux D, Vaché C, Blanchet C, Willems M, Baudoin C, Moclyn M, Faugère V, Touraine R, Isidor B, Dupin-Deguine D, Nizon M, Vincent M, Mercier S, Calais C, García-García G, Azher Z, Lambert L, Perdomo-Trujillo Y, Giuliano F, Claustres M, Koenig M, Mondain M, Roux AF. Combined genetic approaches yield a 48% diagnostic rate in a large cohort of French hearing-impaired patients. Sci Rep 2017; 7:16783. [PMID: 29196752 PMCID: PMC5711943 DOI: 10.1038/s41598-017-16846-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 11/17/2017] [Indexed: 11/22/2022] Open
Abstract
Hearing loss is the most common sensory disorder and because of its high genetic heterogeneity, implementation of Massively Parallel Sequencing (MPS) in diagnostic laboratories is greatly improving the possibilities of offering optimal care to patients. We present the results of a two-year period of molecular diagnosis that included 207 French families referred for non-syndromic hearing loss. Our multi-step strategy involved (i) DFNB1 locus analysis, (ii) MPS of 74 genes, and (iii) additional approaches including Copy Number Variations, in silico analyses, minigene studies coupled when appropriate with complete gene sequencing, and a specific assay for STRC. This comprehensive screening yielded an overall diagnostic rate of 48%, equally distributed between DFNB1 (24%) and the other genes (24%). Pathogenic genotypes were identified in 19 different genes, with a high prevalence of GJB2, STRC, MYO15A, OTOF, TMC1, MYO7A and USH2A. Involvement of an Usher gene was reported in 16% of the genotyped cohort. Four de novo variants were identified. This study highlights the need to develop several molecular approaches for efficient molecular diagnosis of hearing loss, as this is crucial for genetic counselling, audiological rehabilitation and the detection of syndromic forms.
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Affiliation(s)
- D Baux
- Laboratoire de Génétique Moléculaire, CHU Montpellier, Montpellier, France
| | - C Vaché
- Laboratoire de Génétique Moléculaire, CHU Montpellier, Montpellier, France
| | - C Blanchet
- Service ORL, CHU Montpellier, Montpellier, France.,Centre National de Référence Maladies Rares "Affections Sensorielles Génétiques", CHU Montpellier, Montpellier, France
| | - M Willems
- Génétique Médicale, CHU Montpellier, Montpellier, France
| | - C Baudoin
- Laboratoire de Génétique Moléculaire, CHU Montpellier, Montpellier, France
| | - M Moclyn
- Laboratoire de Génétique Moléculaire, CHU Montpellier, Montpellier, France
| | - V Faugère
- Laboratoire de Génétique Moléculaire, CHU Montpellier, Montpellier, France
| | - R Touraine
- Service de Génétique, CHU-Hôpital Nord, Saint-Etienne, France
| | - B Isidor
- Service de Génétique Médicale, CHU Nantes, Nantes, France
| | - D Dupin-Deguine
- Service de Génétique Médicale, CHU Toulouse, Toulouse, France.,Service d'ORL, Otoneurologie et ORL pédiatrique CHU Toulouse, Toulouse, France
| | - M Nizon
- Service de Génétique Médicale, CHU Nantes, Nantes, France
| | - M Vincent
- Service de Génétique Médicale, CHU Nantes, Nantes, France
| | - S Mercier
- Service de Génétique Médicale, CHU Nantes, Nantes, France
| | - C Calais
- Service d'ORL, CHU Nantes, Nantes, France
| | - G García-García
- Laboratoire de Génétique de Maladies Rares (LGMR) EA7402, Université de Montpellier, Montpellier, France
| | - Z Azher
- Laboratoire de Génétique de Maladies Rares (LGMR) EA7402, Université de Montpellier, Montpellier, France
| | - L Lambert
- Génétique Médicale, Centre de Compétence des Surdités Génétiques, site constitutif du Centre de Référence des Anomalies du Développement et Syndromes Malformatifs de l'Est, CHRU Nancy, Nancy, France
| | - Y Perdomo-Trujillo
- Service de Génétique Médicale, Centre de Référence pour les Affections Rares en Génétique Ophtalmologique (CARGO), Hôpital Civil, Strasbourg, France
| | - F Giuliano
- Service de Génétique Médicale, CHU Nice, Nice, France
| | - M Claustres
- Laboratoire de Génétique Moléculaire, CHU Montpellier, Montpellier, France.,Laboratoire de Génétique de Maladies Rares (LGMR) EA7402, Université de Montpellier, Montpellier, France
| | - M Koenig
- Laboratoire de Génétique Moléculaire, CHU Montpellier, Montpellier, France.,Laboratoire de Génétique de Maladies Rares (LGMR) EA7402, Université de Montpellier, Montpellier, France
| | - M Mondain
- Service ORL, CHU Montpellier, Montpellier, France.,Centre National de Référence Maladies Rares "Affections Sensorielles Génétiques", CHU Montpellier, Montpellier, France
| | - A F Roux
- Laboratoire de Génétique Moléculaire, CHU Montpellier, Montpellier, France. .,Laboratoire de Génétique de Maladies Rares (LGMR) EA7402, Université de Montpellier, Montpellier, France.
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Leclère JC, Le Gac MS, Le Maréchal C, Ferec C, Marianowski R. GJB2 mutations: Genotypic and phenotypic correlation in a cohort of 690 hearing-impaired patients, toward a new mutation? Int J Pediatr Otorhinolaryngol 2017; 102:80-85. [PMID: 29106882 DOI: 10.1016/j.ijporl.2017.09.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 09/10/2017] [Accepted: 09/11/2017] [Indexed: 10/18/2022]
Abstract
OBJECTIVES To analyze the clinical features of hearing impairment and to search for correlations with the genotype in patients with GJB2 mutations. DESIGN Case series. SETTING Collaborative study in referral centers, institutional practice. PATIENTS A total of 690 hearing-impaired patients were genotypically and phenotypically described. The mutations of GJB2 and GJB6 were studied. Heterozygous patients were searched for another mutation by microsatellite approach. MAIN OUTCOME MEASURES Prevalence of GJB2 mutations, microsatellite approach, hearing-impairment. RESULTS In 498 patients (72,17% of the cohort), no mutation was found. Homozygotous patients were 59 (8,55%), with 51 for c.35delG, 6 for p.M34T and 2 for GJB6. Compound heterozygous were 64 (9,28%) with 56 c.35delG-others mutations. Genotypes with biallelic non sense mutations had a high risk of severe to profound hearing impairment. It was frequently milder in compound heterozygotes than in c.35delG homozygotes. Heterozygous patients were 69 (10%) with 21 c.35delG, 20 p.M34T and 28 others mutations. We selected patients with a complete historical medical file (clinical and audiometric data). Then, we performed a microsatellite approach (multiplex PCR of short DNA fragments) to localize a new pathologic allele. Seventeen heterozygous patients were studied. Six patients (35%) showed the same haplotype. They were compound heterozygous bearing a new pathologic allele. CONCLUSION Genotype may affect deafness severity, but environmental and other genetic factors may also modulate the severity and evolution of GJB2-GJB6 deafness. A new haplotype for GJB2 is described but the exact mutation remains unknown.
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Affiliation(s)
- Jean-Christophe Leclère
- Department of Otorhinolaryngology-Head and Neck Surgery, University Hospital CHU Brest, France
| | - Marie-Suzanne Le Gac
- Department of Otorhinolaryngology-Head and Neck Surgery, University Hospital CHU Brest, France
| | | | - Claude Ferec
- Genetic Department, University Hospital CHU Brest, France
| | - Rémi Marianowski
- Department of Otorhinolaryngology-Head and Neck Surgery, University Hospital CHU Brest, France.
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10
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Tlili A, Al Mutery A, Kamal Eddine Ahmad Mohamed W, Mahfood M, Hadj Kacem H. Prevalence of GJB2 Mutations in Affected Individuals from United Arab Emirates with Autosomal Recessive Nonsyndromic Hearing Loss. Genet Test Mol Biomarkers 2017; 21:686-691. [PMID: 29016196 DOI: 10.1089/gtmb.2017.0130] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
AIM Mutations in the gap junction protein beta 2 (GJB2) gene are responsible for more cases of nonsyndromic recessive hearing loss than any other gene. The purpose of our study was to evaluate the prevalence of GJB2 mutations among affected individuals from United Arab Emirates (UAE). METHODS There were 50 individuals diagnosed with hereditary hearing loss and 120 healthy individuals enrolled in the study. The Sanger sequencing method was used to screen the GJB2 coding region in all affected individuals. The c.-1G>A variant was determined by the polymerase chain reaction-restriction fragment length polymorphism method in normal individuals. RESULTS AND DISCUSSION Nine cases with bi-allelic mutations and three cases with mono-allelic mutations were detected in 12 out of 50 patients (24%). The homozygous mutation c.35delG was identified as the cause of hearing loss in six participants (12%). The mutation c.506G>A was identified in three affected individuals (6%). The allelic frequency (14%) and low percentage of individuals that were homozygous (2%) for the c.35delG mutation suggest that there are other genes responsible for nonsyndromic deafness in the UAE population. The results reported here are a preliminary step in collecting epidemiological data regarding autosomal recessive nonsyndromic hearing loss related to GJB2 gene mutations among the UAE population. CONCLUSION The c.35delG mutation of the GJB2 gene is the most frequently seen causative mutation in the UAE and is followed by the p.Cys169Tyr mutation.
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Affiliation(s)
- Abdelaziz Tlili
- 1 Department of Applied Biology, College of Sciences, University of Sharjah , Sharjah, United Arab Emirates .,2 Human Genetics and Stem Cell Laboratory, Research Institute of Sciences and Engineering, University of Sharjah , Sharjah, United Arab Emirates
| | - Abdullah Al Mutery
- 1 Department of Applied Biology, College of Sciences, University of Sharjah , Sharjah, United Arab Emirates
| | | | - Mona Mahfood
- 1 Department of Applied Biology, College of Sciences, University of Sharjah , Sharjah, United Arab Emirates
| | - Hassen Hadj Kacem
- 1 Department of Applied Biology, College of Sciences, University of Sharjah , Sharjah, United Arab Emirates .,2 Human Genetics and Stem Cell Laboratory, Research Institute of Sciences and Engineering, University of Sharjah , Sharjah, United Arab Emirates
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Carrier re-sequencing reveals rare but benign variants in recessive deafness genes. Sci Rep 2017; 7:11355. [PMID: 28900111 PMCID: PMC5595904 DOI: 10.1038/s41598-017-10099-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 08/03/2017] [Indexed: 11/24/2022] Open
Abstract
For recessive Mendelian disorders, determining the pathogenicity of rare, non-synonymous variants in known causative genes can be challenging without expanded pedigrees and/or functional analysis. In this study, we proposed to establish a database of rare but benign variants in recessive deafness genes by systematic carrier re-sequencing. As a pilot study, 30 heterozygous carriers of pathogenic variants for deafness were identified from unaffected family members of 18 deaf probands. The entire coding regions of the corresponding genes were re-sequenced in those carriers by targeted next-generation sequencing or Sanger sequencing. A total of 32 non-synonymous variants were identified in the normal-hearing carriers in trans with the pathogenic variant and therefore were classified as benign. Among them were five rare (minor allele frequencies less than 0.005) variants that had previously undefined, disputable or even misclassified function: p.A434T (c.1300 G > A) in SLC26A4, p.R266Q (c.797 G > A) in LOXHD1, p.K96Q (c.286 A > C) in MYO15A, p.T123N (c.368 C > A) in GJB2 and p.V1299I (c.797 G > A) in CDH23. Our results suggested that large scale carrier re-sequencing may be warranted to establish a database of rare but benign variants in causative genes in order to reduce false positive genetic diagnosis of recessive Mendelian disorders.
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First report of prevalence c.IVS1+1G>A and del (GJB6-13S1854) mutations in Syrian families with non-syndromic sensorineural hearing loss. Int J Pediatr Otorhinolaryngol 2017; 92:82-87. [PMID: 28012540 DOI: 10.1016/j.ijporl.2016.11.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 11/13/2016] [Accepted: 11/14/2016] [Indexed: 11/23/2022]
Abstract
OBJECTIVE Mutations in GJB2 and GJB6 genes are a frequent cause of congenital non-syndromic hearing loss (NSHL). Mutational screening has usually focused on coding region of GJB2 gene. A few studies have been conducted on the non-coding region and exon 1. c.IVS1+1G>A (a splice site mutation in GJB2 gene have been detected as disruptive mutation. Del (GJB6 D13S1830) is found in many populations, but del (GJB6 D13S1854) is reported from a few restricted countries. This study was carried out to investigate the prevalence of splice site mutation c.IVS1+1G>A and two common deletions in GJB6 gene as the genetic etiology of hearing impairment in 70 Syrian families. METHODS The frequency of the c.IVS1+1G>A mutation and two deletions were determined by PCR-RFLP and A multiplex PCR assay. RESULT Our results showed a high prevalence of IVS1+1G>A mutation (20%) and del(GJB6-D13S1854) (15.7%) in deaf families. The homozygous genotype (c.IVS1+1G>A/c.IVS1+1G>A) was observed in one family and the compound heterozygous genotypes (c.35delG/c.IVS1+1G>A) and (c.IVS1+1G>A/V153I) were observed in 7 families and one family respectively. Also, the heterozygous state (c.IVS1+1G>A/unknown) was detected in 5 families. The study of del((GJB6-D13S1854) was showed a compound heterozygous genotype del((GJB6-D13S1854)/c.IVS1+1G>A) in the same families (5 families) having heterozygous genotype of c.IVS1+1G>A mutation. Also, del(GJB6-D13S1854) is combined with c.35delG mutation in 2 families and it was observed in the heterozygous state del(GJB6-D13S1854)/unknown) in 4 families. In contrast, the del(GJB6-D13S1830) described in many population was absent in our patients. CONCLUSION Our findings indicate to significant contribution of the splice site mutation and del(GJB6-D13S1854) in our deaf families and these mutations were important causes of hearing impairment.
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Application of SNPscan in Genetic Screening for Common Hearing Loss Genes. PLoS One 2016; 11:e0165650. [PMID: 27792752 PMCID: PMC5085070 DOI: 10.1371/journal.pone.0165650] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 10/14/2016] [Indexed: 11/19/2022] Open
Abstract
The current study reports the successful application of a fast and efficient genetic screening system for common hearing loss (HL) genes based on SNPscan genotyping technology. Genetic analysis of 115 variants in common genes related to HL, GJB2, SLC26A4 and MT-RNR, was performed on 695 subjects with non-syndromic hearing loss (NSHL) from the Northern China. The results found that 38.7% (269/695) of cases carried bi-allelic pathogenic variants in GJB2 and SLC26A4 and 0.7% (5/695) of cases carried homoplasmic MT-RNR1 variants. The variant allele frequency of GJB2, SLC26A4 and MT-RNR1 was 19.8% (275/1390), 21.9% (304/1390), and 0.86% (6/695), respectively. This approach can explain ~40% of NSHL cases and thus is a useful tool for establishing primary molecular diagnosis of NSHL in clinical genetics.
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Barashkov NA, Pshennikova VG, Posukh OL, Teryutin FM, Solovyev AV, Klarov LA, Romanov GP, Gotovtsev NN, Kozhevnikov AA, Kirillina EV, Sidorova OG, Vasilyevа LM, Fedotova EE, Morozov IV, Bondar AA, Solovyevа NA, Kononova SK, Rafailov AM, Sazonov NN, Alekseev AN, Tomsky MI, Dzhemileva LU, Khusnutdinova EK, Fedorova SA. Spectrum and Frequency of the GJB2 Gene Pathogenic Variants in a Large Cohort of Patients with Hearing Impairment Living in a Subarctic Region of Russia (the Sakha Republic). PLoS One 2016; 11:e0156300. [PMID: 27224056 PMCID: PMC4880331 DOI: 10.1371/journal.pone.0156300] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 05/12/2016] [Indexed: 11/29/2022] Open
Abstract
Pathogenic variants in the GJB2 gene, encoding connexin 26, are known to be a major cause of hearing impairment (HI). More than 300 allelic variants have been identified in the GJB2 gene. Spectrum and allelic frequencies of the GJB2 gene vary significantly among different ethnic groups worldwide. Until now, the spectrum and frequency of the pathogenic variants in exon 1, exon 2 and the flanking intronic regions of the GJB2 gene have not been described thoroughly in the Sakha Republic (Yakutia), which is located in a subarctic region in Russia. The complete sequencing of the non-coding and coding regions of the GJB2 gene was performed in 393 patients with HI (Yakuts—296, Russians—51, mixed and other ethnicities—46) and in 187 normal hearing individuals of Yakut (n = 107) and Russian (n = 80) populations. In the total sample (n = 580), we revealed 12 allelic variants of the GJB2 gene, 8 of which were recessive pathogenic variants. Ten genotypes with biallelic recessive pathogenic variants in the GJB2 gene (in a homozygous or a compound heterozygous state) were found in 192 out of 393 patients (48.85%). We found that the most frequent GJB2 pathogenic variant in the Yakut patients was c.-23+1G>A (51.82%) and that the second most frequent was c.109G>A (2.37%), followed by c.35delG (1.64%). Pathogenic variants с.35delG (22.34%), c.-23+1G>A (5.31%), and c.313_326del14 (2.12%) were found to be the most frequent among the Russian patients. The carrier frequencies of the c.-23+1G>A and с.109G>A pathogenic variants in the Yakut control group were 10.20% and 2.80%, respectively. The carrier frequencies of с.35delG and c.101T>C were identical (2.5%) in the Russian control group. We found that the contribution of the GJB2 gene pathogenic variants in HI in the population of the Sakha Republic (48.85%) was the highest among all of the previously studied regions of Asia. We suggest that extensive accumulation of the c.-23+1G>A pathogenic variant in the indigenous Yakut population (92.20% of all mutant chromosomes in patients) and an extremely high (10.20%) carrier frequency in the control group may indicate a possible selective advantage for the c.-23+1G>A carriers living in subarctic climate.
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Affiliation(s)
- Nikolay A. Barashkov
- Department of Molecular Genetics, Federal State Budgetary Scientific Institution “Yakut Science Centre of Complex Medical Problems,” Yakutsk, Russian Federation
- Laboratory of Molecular Biology, Institute of Natural Sciences, M.K. Ammosov North-Eastern Federal University, Yakutsk, Russian Federation
- * E-mail:
| | - Vera G. Pshennikova
- Department of Molecular Genetics, Federal State Budgetary Scientific Institution “Yakut Science Centre of Complex Medical Problems,” Yakutsk, Russian Federation
- Laboratory of Molecular Biology, Institute of Natural Sciences, M.K. Ammosov North-Eastern Federal University, Yakutsk, Russian Federation
| | - Olga L. Posukh
- Laboratory of Human Molecular Genetics, Federal Research Center, Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russian Federation
- Novosibirsk State University, Novosibirsk, Russian Federation
| | - Fedor M. Teryutin
- Department of Molecular Genetics, Federal State Budgetary Scientific Institution “Yakut Science Centre of Complex Medical Problems,” Yakutsk, Russian Federation
- Laboratory of Molecular Biology, Institute of Natural Sciences, M.K. Ammosov North-Eastern Federal University, Yakutsk, Russian Federation
| | - Aisen V. Solovyev
- Department of Molecular Genetics, Federal State Budgetary Scientific Institution “Yakut Science Centre of Complex Medical Problems,” Yakutsk, Russian Federation
- Laboratory of Molecular Biology, Institute of Natural Sciences, M.K. Ammosov North-Eastern Federal University, Yakutsk, Russian Federation
| | - Leonid A. Klarov
- Department of Molecular Genetics, Federal State Budgetary Scientific Institution “Yakut Science Centre of Complex Medical Problems,” Yakutsk, Russian Federation
- Department of Radiology, Republican Hospital # 2 –Center of Emergency Medicine, Ministry of Public Health of the Sakha Republic, Yakutsk, Russian Federation
| | - Georgii P. Romanov
- Department of Molecular Genetics, Federal State Budgetary Scientific Institution “Yakut Science Centre of Complex Medical Problems,” Yakutsk, Russian Federation
- Laboratory of Molecular Biology, Institute of Natural Sciences, M.K. Ammosov North-Eastern Federal University, Yakutsk, Russian Federation
| | - Nyurgun N. Gotovtsev
- Department of Molecular Genetics, Federal State Budgetary Scientific Institution “Yakut Science Centre of Complex Medical Problems,” Yakutsk, Russian Federation
- Laboratory of Molecular Biology, Institute of Natural Sciences, M.K. Ammosov North-Eastern Federal University, Yakutsk, Russian Federation
| | - Andrey A. Kozhevnikov
- Republican Centre of Professional Pathology, Republican Hospital # 2 –Center of Emergency Medicine, Ministry of Public Health of the Sakha Republic, Yakutsk, Russian Federation
| | - Elena V. Kirillina
- Institute of Foreign Philology and Regional Studies, M.K. Ammosov North-Eastern Federal University, Yakutsk, Russian Federation
| | - Oksana G. Sidorova
- Department of Molecular Genetics, Federal State Budgetary Scientific Institution “Yakut Science Centre of Complex Medical Problems,” Yakutsk, Russian Federation
| | - Lena M. Vasilyevа
- Audiology-Logopaedic Centre, Republican Hospital #1– National Medical Centre, Ministry of Public Health of the Sakha Republic, Yakutsk, Russian Federation
| | - Elvira E. Fedotova
- Audiology-Logopaedic Centre, Republican Hospital #1– National Medical Centre, Ministry of Public Health of the Sakha Republic, Yakutsk, Russian Federation
| | - Igor V. Morozov
- Novosibirsk State University, Novosibirsk, Russian Federation
- SB RAS Genomics Core Facility, Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russian Federation
| | - Alexander A. Bondar
- SB RAS Genomics Core Facility, Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russian Federation
| | - Natalya A. Solovyevа
- Department of Molecular Genetics, Federal State Budgetary Scientific Institution “Yakut Science Centre of Complex Medical Problems,” Yakutsk, Russian Federation
- Laboratory of Molecular Biology, Institute of Natural Sciences, M.K. Ammosov North-Eastern Federal University, Yakutsk, Russian Federation
| | - Sardana K. Kononova
- Department of Molecular Genetics, Federal State Budgetary Scientific Institution “Yakut Science Centre of Complex Medical Problems,” Yakutsk, Russian Federation
- Laboratory of Molecular Biology, Institute of Natural Sciences, M.K. Ammosov North-Eastern Federal University, Yakutsk, Russian Federation
| | - Adyum M. Rafailov
- Laboratory of Molecular Biology, Institute of Natural Sciences, M.K. Ammosov North-Eastern Federal University, Yakutsk, Russian Federation
| | - Nikolay N. Sazonov
- Department of Biochemistry and Biotechnology, Institute of Natural Sciences, M.K. Ammosov North-Eastern Federal University, Yakutsk, Russian Federation
| | - Anatoliy N. Alekseev
- Institute of Humanitarian Research and Indigenous Peoples of the North, Siberian Branch of the Russian Academy of Sciences, Yakutsk, Russian Federation
| | - Mikhail I. Tomsky
- Department of Molecular Genetics, Federal State Budgetary Scientific Institution “Yakut Science Centre of Complex Medical Problems,” Yakutsk, Russian Federation
| | - Lilya U. Dzhemileva
- Laboratory of Human Molecular Genetics, Institute of Biochemistry and Genetics, Ufa Scientific Centre, Russian Academy of Sciences, Ufa, Russian Federation
- Department of Immunology and Human Reproductive Health, Bashkir State Medical University, Ufa, Russian Federation
| | - Elza K. Khusnutdinova
- Laboratory of Human Molecular Genetics, Institute of Biochemistry and Genetics, Ufa Scientific Centre, Russian Academy of Sciences, Ufa, Russian Federation
- Department of Genetics and Fundamental Medicine, Bashkir State University, Ufa, Russian Federation
| | - Sardana A. Fedorova
- Department of Molecular Genetics, Federal State Budgetary Scientific Institution “Yakut Science Centre of Complex Medical Problems,” Yakutsk, Russian Federation
- Laboratory of Molecular Biology, Institute of Natural Sciences, M.K. Ammosov North-Eastern Federal University, Yakutsk, Russian Federation
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Mikstiene V, Jakaitiene A, Byckova J, Gradauskiene E, Preiksaitiene E, Burnyte B, Tumiene B, Matuleviciene A, Ambrozaityte L, Uktveryte I, Domarkiene I, Rancelis T, Cimbalistiene L, Lesinskas E, Kucinskas V, Utkus A. The high frequency of GJB2 gene mutation c.313_326del14 suggests its possible origin in ancestors of Lithuanian population. BMC Genet 2016; 17:45. [PMID: 26896187 PMCID: PMC4761217 DOI: 10.1186/s12863-016-0354-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 02/15/2016] [Indexed: 12/30/2022] Open
Abstract
Background Congenital hearing loss (CHL) is diagnosed in 1 – 2 newborns in 1000, genetic factors contribute to two thirds of CHL cases in industrialised countries. Mutations of the GJB2 gene located in the DFNB1 locus (13q11-12) are a major cause of CHL worldwide. The aim of this cross-sectional study was to assess the contribution of the DFNB1 locus containing the GJB2 and GJB6 genes in the development of early onset hearing loss in the affected group of participants, to determine the population-specific mutational profile and DFNB1-related HL burden in Lithuanian population. Methods Clinical data were obtained from a collection of 158 affected participants (146 unrelated probands) with early onset non-syndromic HL. GJB2 and GJB6 gene sequencing and GJB6 gene deletion testing were performed. The data of GJB2 and GJB6 gene sequencing in 98 participants in group of self-reported healthy Lithuanian inhabitants were analysed. Statistic summary, homogeneity tests, and logistic regression analysis were used for the assessment of genotype-phenotype correlation. Results Our findings show 57.5 % of affected participants with two pathogenic GJB2 gene mutations identified. The most prevalent GJB2 mutations were c.35delG, p. (Gly12Valfs*2) (rs80338939) and c.313_326del14, p. (Lys105Glyfs*5) (rs111033253) with allele frequencies 64.7 % and 28.3 % respectively. GJB6 gene mutations were not identified in the affected group of participants. The statistical analysis revealed significant differences between GJB2(−) and GJB2(+) groups in disease severity (p = 0.001), and family history (p = 0.01). The probability of identification of GJB2 mutations in patients with various HL characteristics was estimated. The carrier rate of GJB2 gene mutations – 7.1 % (~1 in 14) was identified in the group of healthy participants and a high frequency of GJB2-related hearing loss was estimated in our population. Discussion The results show a very high proportion of GJB2-positive individuals in the research group affected with sensorineural HL. The allele frequency of c.35delG mutation (64.7 %) is consistent with many previously published studies in groups of affected individuals of Caucasian populations. The high frequency of the c.313_326del14 (28.3 % of pathogenic alleles) mutation in affected group of participants was an unexpected finding in our study suggesting not only a high frequency of carriers of this mutation in our population but also its possible origin in Lithuanian ancestors. The high frequency of carriers of the c.313_326del14 mutation in the entire Lithuanian population is supported by it being identified twice in the ethnic Lithuanian group of healthy participants (a frequency 2.0 % of carriers in the study group). Conclusion Analysis of the allele frequency of GJB2 gene mutations revealed a high proportion of c. 313_326del14 (rs111033253) mutations in the GJB2-positive group suggesting its possible origin in Lithuanian forebears. The high frequency of carriers of GJB2 gene mutations in the group of healthy participants corresponds to the substantial frequency of GJB2-associated HL in Lithuania. The observations of the study indicate the significant contribution of GJB2 gene mutations to the pathogenesis of the disorder in the Lithuanian population and will contribute to introducing principles to predict the characteristics of the disease in patients. Electronic supplementary material The online version of this article (doi:10.1186/s12863-016-0354-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Violeta Mikstiene
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
| | - Audrone Jakaitiene
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
| | - Jekaterina Byckova
- Centre of Ear, Nose and Throat Diseases, Vilnius University Hospital Santariskiu clinics, Vilnius, Lithuania.
| | - Egle Gradauskiene
- Centre of Ear, Nose and Throat Diseases, Vilnius University Hospital Santariskiu clinics, Vilnius, Lithuania.
| | - Egle Preiksaitiene
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
| | - Birute Burnyte
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
| | - Birute Tumiene
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
| | - Ausra Matuleviciene
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
| | - Laima Ambrozaityte
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
| | - Ingrida Uktveryte
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
| | - Ingrida Domarkiene
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
| | - Tautvydas Rancelis
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
| | - Loreta Cimbalistiene
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
| | - Eugenijus Lesinskas
- Centre of Ear, Nose and Throat Diseases, Vilnius University Hospital Santariskiu clinics, Vilnius, Lithuania.
| | - Vaidutis Kucinskas
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
| | - Algirdas Utkus
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
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Detection of Connexion 26 GENE (GJB2) Mutations in Cases of Congenital Non Syndromic Deafness. Indian J Otolaryngol Head Neck Surg 2015; 68:248-53. [PMID: 27340645 DOI: 10.1007/s12070-015-0950-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Accepted: 12/10/2015] [Indexed: 10/22/2022] Open
Abstract
Hearing loss is most common form of genetic hearing disorder. Non-syndromic sensory neural autosomal recessive deafness (NSRD) is the most common form of genetic hearing loss. Mutations in GJB2 gene, which encodes the connexin 26 protein, are major cause of NSRD. The aim of this study is directed towards the mutations caused along the connexin 26 gene using blood samples from nonsyndromic deaf children. The study was conducted on 36 congenitally hearing impaired children who visited to our department with complains of hearing loss and reduced speech and whose age was <10 years with no other congenital anomaly. After a thorough history, clinical examination and all audiological and radiological assessment, blood samples are collected and DNA extraction, PCR and sequencing were done for further genetic analysis. Annotated and documented autosomal recessive (pathogenic) mutations were observed in 57 % of NSRD cases. The frequency of pathogenic mutation was commonest for Ins G between nucleotide 30-35 (40 % of cases) followed by Del T at nucleotide 59(20 % of cases).These two common mutations (singly or doubly) were present in 51.4 % of cases. Present study helps to screen the families with hearing impaired children, which will facilitate the development of strategies for diagnosis and treatment of these common genetic disorders.
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Dória M, Neto AP, Santos AC, Barros H, Fernandes S, Moura CP. Prevalence of 35delG and Met34Thr GJB2 variants in Portuguese samples. Int J Pediatr Otorhinolaryngol 2015; 79:2187-90. [PMID: 26482070 DOI: 10.1016/j.ijporl.2015.09.046] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 09/25/2015] [Accepted: 09/30/2015] [Indexed: 10/22/2022]
Abstract
OBJECTIVE To estimate the prevalence of 35delG and Met34Thr variants in a Portuguese children's community sample and to compare these frequencies with nonsyndromic hearing-loss patients. METHODS 502 children were randomly selected among the 8647 participants of the Portuguese birth cohort Generation XXI, and screened for Met34Thr and 35delG variants in the GJB2 gene. These variants were also studied on 89 index-cases, observed in the Clinic of "Hereditary Hearing-loss" in Saint John's Hospital Center, presenting a mild to profound nonsyndromic hearing-loss. RESULTS Among the 502 children from Generation XXI, 10 were heterozygous for the 35delG variant (95% Confidence Interval 1.03-3.68) and 1 homozygous (95% Confidence Interval 0.01-1.24). Other 10 children presented heterozygosity for the Met34Thr variant (95% Confidence Interval 1.03-3.68). No homozygous for the Met34Thr or compound heterozygotes (35delG/Met34Thr) were found. In the total of 89 nonsyndromic hearing-loss patients, 5 (95% Confidence Interval 2.11-12.8) were heterozygous and 7 (95% Confidence Interval 3.61-15.6) were homozygous for the 35delG variant. The Met34Thr variant was found in 4 patients, 2 heterozygous (95% Confidence Interval 0.13-8.31) and 2 homozygous (95% Confidence Interval 0.13-8.31). CONCLUSION The carrier frequency of 35delG and Met34Thr variants in a Portuguese sample was 1 in 50. Our data suggests that the 35delG mutation has an association with deafness. For the Met34Thr variant, no association was observed. However, Met34Thr seemed to conform to an additive model in hearing-loss.
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Affiliation(s)
- Mariana Dória
- Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal.
| | - Ana Paula Neto
- Department of Human Genetics, Faculty of Medicine, University of Porto, Centro Hospitalar São João, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal; Institute for Research and Innovation in Health/Instituto de Investigação e Inovação em Saúde, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Ana Cristina Santos
- Department of Clinical Epidemiology, Predictive Medicine and Public Health, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal; EPI Unit-Institute of Public Health, University of Porto, Rua das Taipas no. 135, 4050-600 Porto, Portugal
| | - Henrique Barros
- Department of Clinical Epidemiology, Predictive Medicine and Public Health, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal; EPI Unit-Institute of Public Health, University of Porto, Rua das Taipas no. 135, 4050-600 Porto, Portugal
| | - Susana Fernandes
- Department of Human Genetics, Faculty of Medicine, University of Porto, Centro Hospitalar São João, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal; Institute for Research and Innovation in Health/Instituto de Investigação e Inovação em Saúde, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Carla Pinto Moura
- Department of Human Genetics, Faculty of Medicine, University of Porto, Centro Hospitalar São João, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal; Institute for Research and Innovation in Health/Instituto de Investigação e Inovação em Saúde, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal; Department of Otorhinolaryngology, Centro Hospitalar São João, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
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Yan D, Kannan-Sundhari A, Vishwanath S, Qing J, Mittal R, Kameswaran M, Liu XZ. The Genetic Basis of Nonsyndromic Hearing Loss in Indian and Pakistani Populations. Genet Test Mol Biomarkers 2015; 19:512-27. [PMID: 26186295 DOI: 10.1089/gtmb.2015.0023] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Deafness encompasses a series of etiologically heterogeneous disorders with mutations in more than 400 independent genes. However, several studies indicate that a large proportion of both syndromic and nonsyndromic forms of deafness in the racially diverse Indian and Pakistani populations are caused by defects in just a few genes. In these countries, there is a strong cultural preference for consanguineous marriage and an associated relatively high prevalence of genetic disorders. The current Indian population is approximately 1.2 billion and it is estimated that 30,000 infants are born with congenital sensorineural hearing loss (HL) each year. The estimated rate of profound bilateral HL is 1.6 per 1000 in Pakistan and 70% of this HL arises in consanguineous families. Knowledge of the genetic cause of deafness within a distinct population is important for accurate genetic counseling and early diagnosis for timely intervention and treatment options. Many sources and technologies are now available for the testing of hearing efficiency. Population-based screening has been proposed as one of the major strategies for translating genetic and genomic advances into population health gains. This review of the genetics of deafness in Indian and Pakistani populations deals with the major causes of deafness in these countries and prospectives for reducing the incidence of inherited deafness.
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Affiliation(s)
- Denise Yan
- 1 Departments of Otolaryngology-Head and Neck Surgery, Leonard M. Miller School of Medicine, University of Miami , Miami, Florida
| | - Abhiraami Kannan-Sundhari
- 1 Departments of Otolaryngology-Head and Neck Surgery, Leonard M. Miller School of Medicine, University of Miami , Miami, Florida.,2 SRM University , SRM Nagar, Chennai, India
| | - Subramanian Vishwanath
- 1 Departments of Otolaryngology-Head and Neck Surgery, Leonard M. Miller School of Medicine, University of Miami , Miami, Florida.,2 SRM University , SRM Nagar, Chennai, India
| | - Jie Qing
- 1 Departments of Otolaryngology-Head and Neck Surgery, Leonard M. Miller School of Medicine, University of Miami , Miami, Florida
| | - Rahul Mittal
- 1 Departments of Otolaryngology-Head and Neck Surgery, Leonard M. Miller School of Medicine, University of Miami , Miami, Florida
| | | | - Xue Zhong Liu
- 1 Departments of Otolaryngology-Head and Neck Surgery, Leonard M. Miller School of Medicine, University of Miami , Miami, Florida
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Adhikary B, Ghosh S, Paul S, Bankura B, Pattanayak AK, Biswas S, Maity B, Das M. Spectrum and frequency of GJB2, GJB6 and SLC26A4 gene mutations among nonsyndromic hearing loss patients in eastern part of India. Gene 2015; 573:239-45. [PMID: 26188157 DOI: 10.1016/j.gene.2015.07.050] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 07/08/2015] [Accepted: 07/14/2015] [Indexed: 11/16/2022]
Abstract
Genetically caused nonsyndromic hearing loss is highly heterogeneous. Inspite of this large heterogeneity, mutations in the genes GJB2, GJB6 and SLC26A4 are major contributors. The mutation spectrum of these genes varies among different ethnic groups. Only a handful of studies focused on the altered genetic signature of these genes in different demographic regions of India but never focused on the eastern part of the country. Our study for the first time aimed to characterize the mutation profile of these genes in hearing loss patients of West Bengal state, India. Mutations in GJB2, GJB6 and SLC26A4 genes were screened by bidirectional sequencing from 215 congenital nonsyndromic hearing loss patients. Radiological diagnosis was performed in patients with SLC26A4 mutations by temporal bone CT scan. The study revealed that 4.65% and 6.97% patients had monoallelic and biallelic GJB2 mutations respectively. Six mutations were identified, p.W24X being the most frequent one accounting for 71.05% of the mutated alleles. Mutations in GJB6 including the previously identified deletion mutation (GJB6-D13S1830) were not identified in our study. Further, no patients harbored biallelic mutations in the SLC26A4 gene or the common inner ear malformation Enlarged Vestibular Aqueduct (EVA). The mutation profile of GJB2 in our study is distinct from other parts of India, suggesting that the mutation spectrum of this gene varies with ethnicity and geographical origin. The absence of GJB6 mutations and low frequency of SLC26A4 mutations suggest that additional genetic factors may also contribute to this disease.
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Affiliation(s)
- Bidisha Adhikary
- Department of Zoology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata 700 019, West Bengal, India
| | - Sudakshina Ghosh
- Department of Zoology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata 700 019, West Bengal, India
| | - Silpita Paul
- Department of Zoology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata 700 019, West Bengal, India
| | - Biswabandhu Bankura
- Department of Zoology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata 700 019, West Bengal, India
| | - Arup Kumar Pattanayak
- Department of Zoology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata 700 019, West Bengal, India
| | - Subhradev Biswas
- Department of E.N.T., Institute of Post Graduate Medical Education & Research, 244 A J C Bose Road, Kolkata 700 020, West Bengal, India
| | - Biswanath Maity
- Department of Zoology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata 700 019, West Bengal, India
| | - Madhusudan Das
- Department of Zoology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata 700 019, West Bengal, India.
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Carrier frequency of the GJB2 mutations that cause hereditary hearing loss in the Japanese population. J Hum Genet 2015; 60:613-7. [PMID: 26178431 PMCID: PMC4635169 DOI: 10.1038/jhg.2015.82] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 06/22/2015] [Accepted: 06/11/2015] [Indexed: 11/08/2022]
Abstract
Hearing impairment is one of the most common sensory disorders that affect ~1 in 1000 children, and half of them are considered to be hereditary. Information about the carrier frequencies of mutations that underlie autosomal recessive disorders is indispensable for accurate genetic counseling to predict the probability of patients' children's disease. However, there have been few reports specific to the Japanese population. GJB2 mutations are reported to be the most frequent cause of hereditary hearing loss, and the mutation spectrum and frequency of GJB2 mutations were reported to vary among different ethnic groups. In this study, we investigated the carrier frequency of GJB2 mutations and the mutation spectrum in 509 individuals randomly selected from the general Japanese population. We show that the carrier frequencies of the two most common pathogenic mutations are 1.57% (8/509) for c.235delC and 1.77% (9/509) for p.Val37Ile. In addition to these mutations, we found two pathogenic variants (p.[Gly45Glu;Tyr136*] and p.Arg143Trp), and the total carrier frequency was estimated to be around 3.73% (19/509). We also detected six unclassified variants, including two novel variants (p.Cys60Tyr and p.Phe106Leu), with the former predicted to be pathogenic. These findings will provide indispensable information for genetic counseling in the Japanese population.
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Zaidieh T, Habbal W, Monem F. Screening of GJB6 Gene Large Deletions Among Syrians with Congenital Hearing Impairment. Genet Test Mol Biomarkers 2015; 19:405-7. [PMID: 25989237 DOI: 10.1089/gtmb.2015.0019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Tarek Zaidieh
- Department of Biochemistry and Microbiology, Faculty of Pharmacy, Damascus University, Damascus, Syria
| | - Wafa Habbal
- Clinical Laboratories Department, Al-Assad Hospital, Damascus University, Damascus, Syria
| | - Fawza Monem
- Department of Biochemistry and Microbiology, Faculty of Pharmacy, Damascus University, Damascus, Syria
- Clinical Laboratories Department, Al-Assad Hospital, Damascus University, Damascus, Syria
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Amorini M, Romeo P, Bruno R, Galletti F, Di Bella C, Longo P, Briuglia S, Salpietro C, Rigoli L. Prevalence of Deafness-Associated Connexin-26 (GJB2) and Connexin-30 (GJB6) Pathogenic Alleles in a Large Patient Cohort from Eastern Sicily. Ann Hum Genet 2015; 79:341-349. [PMID: 26096904 DOI: 10.1111/ahg.12120] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 03/24/2015] [Indexed: 11/28/2022]
Abstract
Mutations in the gene encoding the gap junction protein connexin 26 (GJB2) and connexin 30 (GJB6) have been shown to be a major contributor to prelingual, sensorineural, nonsyndromic deafness. The aim of this study was to characterize and establish the prevalence of GJB2 and GJB6 gene alterations in 196 patients affected by sensorineural, nonsyndromic hearing loss, from Eastern Sicily. We performed sequence analysis of GJB2 and identified sequence variants in 68 out of 196 patients (34.7%); (28 homozygous for c.35delG, 22 compound heterozygous and 11 with only one variant allele). We found 12 different allelic variants, the most prevalent being c.35delG, which was found on 89 chromosomes (65.5%), followed by other alleles with different frequencies (p.E47X, c.-23+1G>A, p.L90P, p.R184W, p.M34T, c.167delT, p.R127H, p.M163V, p.V153I, p.W24X, and p.T8M). Importantly, for the first time we present the frequency and spectrum of GJB2 mutations in NSHL patients from Eastern Sicily. No alterations were found in the GJB6 gene, confirming that alterations in this gene are uncommon in our geographic area. Note that 65.3% and 23.5% of our patients, respectively were found to be negative or carriers by GJB2 molecular screening. This emphasizes the need to broaden the genetic analysis to other genes involved in hearing loss.
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Affiliation(s)
- Maria Amorini
- Department of Paediatrics, University of Messina, Italy
| | | | - Rocco Bruno
- Department of Experimental Medical-Surgery, Specialist and Odontostomatological Science, Otorhinolaringology and Auditory Microsurgery Unit, University of Messina, Italy
| | - Francesco Galletti
- Department of Experimental Medical-Surgery, Specialist and Odontostomatological Science, Otorhinolaringology and Auditory Microsurgery Unit, University of Messina, Italy
| | | | - Patrizia Longo
- Department of Experimental Medical-Surgery, Specialist and Odontostomatological Science, Otorhinolaringology and Auditory Microsurgery Unit, University of Messina, Italy
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Ridal M, Outtasi N, Taybi Z, Boulouiz R, Chaouki S, Boubou M, Maaroufi M, Benmansour N, Zaki Z, Ouldim K, Barakat H, Hida M, Tizniti S, El Alami MN. [Etiologic profile of severe and profound sensorineural hearing loss in children in the region of north-central Morocco]. Pan Afr Med J 2014; 17:100. [PMID: 25018837 PMCID: PMC4081148 DOI: 10.11604/pamj.2014.17.100.2331] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 11/28/2013] [Indexed: 11/24/2022] Open
Abstract
Introduction Le diagnostic d'une surdité profonde est possible dès les premiers jours de vie. Or, le développement du langage et l'intégration scolaire et professionnelle ne sont pas possible que si la surdité est prise en charge précocement. L’établissement d'un diagnostc étiologique a des implications pronostiques et thérapeutiques. Méthodes C'est une étude rétrospective allant de Juin 2009 au mois de Janvier 2012 ayant recensé 250 cas d'enfants porteurs d'une surdité sévère et profonde. Résultats La moyenne d’âge au moment de l'annonce du diagnostic est de 3.7 ans. Les étiologies prédominantes sont les surdités génétiques dans 35.6% suivies des surdités acquises dans 30.8% des cas. Dans 34.4% des cas aucune étiologie n'a pu être retrouvée. Conclusion Cette étude met en évidence la prédominance éventuelle de causes génétiques de la surdité neurosensorielle de l'enfant au Maroc, et souligne la nécessité d'améliorer les politiques de prévention des maladies infectieuses et de dépistage de la surdité néonatale. Cependant, des analyses moléculaires plus ciblées et la réalisation d'un scanner des rochers systématiques sont nécessaires pour évaluer plus précisément la contribution des étiologies génétiques.
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Affiliation(s)
- Mohammed Ridal
- Service d'Oto-Rhino-Laryngologie, CHU Hassan II Fés et faculté de médecine de Fès, Maroc
| | - Naouar Outtasi
- Service d'Oto-Rhino-Laryngologie, CHU Hassan II Fés et faculté de médecine de Fès, Maroc
| | - Zainab Taybi
- Service d'Oto-Rhino-Laryngologie, CHU Hassan II Fés et faculté de médecine de Fès, Maroc
| | - Redouan Boulouiz
- Laboratoire de biologie moléculaire, Institut Pasteur Casablanca, Maroc
| | | | | | | | - Najib Benmansour
- Service d'Oto-Rhino-Laryngologie, CHU Hassan II Fés et faculté de médecine de Fès, Maroc
| | - Zouheir Zaki
- Service d'Oto-Rhino-Laryngologie, CHU Hassan II Fés et faculté de médecine de Fès, Maroc
| | - Karim Ouldim
- Laboraoire de génétique médicale, CHU Hassan II Fès, Maroc
| | - Hamid Barakat
- Laboratoire de biologie moléculaire, Institut Pasteur Casablanca, Maroc
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Sipeky C, Matyas P, Melegh M, Janicsek I, Szalai R, Szabo I, Varnai R, Tarlos G, Ganczer A, Melegh B. Lower carrier rate of GJB2 W24X ancestral Indian mutation in Roma samples from Hungary: implication for public health intervention. Mol Biol Rep 2014; 41:6105-10. [PMID: 24969484 DOI: 10.1007/s11033-014-3488-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 06/17/2014] [Indexed: 11/29/2022]
Abstract
The purpose of this work was to characterise the W24X mutation of the GJB2 gene in order to provide more representative and geographicaly relevant carrier rates of healthy Roma subisolates and the Hungarian population. 493 Roma and 498 Hungarian healthy subjects were genotyped for the GJB2 c.71G>A (rs104894396, W24X) mutation by PCR-RFLP assay and direct sequencing. This is the first report on GJB2 W24X mutation in geographically subisolated Roma population of Hungary compared to local Hungarians. Comparing the genotype and allele frequencies of GJB2 rs104894396 mutation, significant difference was found in GG (98.4 vs. 99.8 %), GA (1.62 vs. 0.20 %) genotypes and A (0.8 vs. 0.1 %) allele between the Roma and Hungarian populations, respectively (p < 0.02). None of the subjects of Roma and Hungarian samples carried the GJB2 W24X AA genotype. Considerable result of our study, that the proportion of GJB2 W24X GA heterozygotes and the A allele frequency was eight times higher in Roma than in Hungarians. Considering the results, the mutant allele frequency both in Roma (0.8 %) and in Hungarian (0.1 %) populations is lower than expected from previous results, likely reflecting local differentiated subisolates of these populations and a suspected lower risk for GJB2 mutation related deafness. However, the significant difference in GJB2 W24X carrier rates between the Roma and Hungarians may initiate individual diagnostic investigations and effective public health interventions.
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Affiliation(s)
- Csilla Sipeky
- Department of Medical Genetics, Clinical Centre, University of Pecs, Szigeti 12, Pecs, 7624, Hungary,
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Javidnia H, Carson N, Awubwa M, Byaruhanga R, Mack D, Vaccani JP. Connexin gene mutations among Ugandan patients with nonsyndromic sensorineural hearing loss. Laryngoscope 2014; 124:E373-6. [PMID: 24706568 DOI: 10.1002/lary.24697] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 03/31/2014] [Accepted: 04/02/2014] [Indexed: 11/06/2022]
Abstract
OBJECTIVES/HYPOTHESIS Congenital deafness occurs in approximately 1 in 1,000 live births, and 50% of these cases are hereditary. Connexin mutations have been identified as the most common cause of hereditary hearing loss in many populations. The prevalence of this mutation in African patients has not been adequately studied. The objective of this study was to determine the prevalence of connexin 26 and 30 mutations in a population of hearing-impaired patients from Uganda. STUDY DESIGN This is an observational study. METHODS Coding regions of both GJB2 and GJB6, noncoding exon 1 of GJB2, and 30 nucleotides of intronic sequence bordering the exons were analyzed in 126 subjects from Uganda with confirmed bilateral, severe-to-profound sensorineural hearing loss. All variants were analyzed for possible clinical significance using a combination of database searches and in silico tools. RESULTS Complete sequence data were obtained on 115/126 individuals; 11 had only partial or no results. Only one reported pathogenic variant was found in GJB2 (c.208C>G; p.Pro70Ala) and none in GJB6. Three reported variants and two novel variants within intron 1 of GJB2 and two variants within exon 3 of GJB6 were also found. CONCLUSIONS None of the most common types of deletions in the GJB2 gene (c.35delG, c.167delT or c.235delC) were found in this large cohort of deaf children from Uganda. This prompts a search for genetic causes of deafness among this and other previously studied African populations.
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Affiliation(s)
- Hedyeh Javidnia
- Department of Otolaryngology, Head and Neck Surgery, The Ottawa Hospital, Ottawa, Ontario, Canada
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Chen T, Jiang L, Liu C, Shan H, Chen J, Yang B, Ou Q. Update of the spectrum of GJB2 mutations in 107 patients with nonsyndromic hearing loss in the Fujian population of China. Ann Hum Genet 2014; 78:235-42. [PMID: 24645897 DOI: 10.1111/ahg.12062] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Accepted: 02/13/2014] [Indexed: 01/15/2023]
Abstract
Mutations in the GJB2 gene, encoding connexin26, which is expressed in the inner ear, have been shown to be responsible for the majority of nonsyndromic hearing loss (NSHL) cases. To update and evaluate the spectrum and prevalence of GJB2 mutations in the Fujian population, we screened exon 2 (coding), exon 1, and flanking introns of GJB2 in 107 NSHL probands and 61 individuals with normal hearing. Twelve different variants were identified, including three pathogenic mutations (c.235delC, c.299_300delAT, and c.508insAACG), one hypomorphic allele (p.V37I), three polymorphic variants (p.V27I, p.E114G, and p.I230T), and five rare variants (p.N62N, p.F115C, p.T123N, p.G21E, and p.F142I). The p.G21E and p.F142I variants were potentially pathogenic as predicted by PolyPhen-2, SIFT, and PROVEAN. The most common mutation was c.235delC with allele frequency 12.6% (27/214). The most common polymorphisms in the Fujian population were p.V27I and p.E114G, both detected at high frequency in probands and controls. The p.E114G variant was always in cis with p.V27I, and formed the haplotype, p.[V27I; E114G] in the Fujian population. Interestingly, only 17.76% (19/107) of NSHL probands had clearly defined pathogenic mutations in GJB2, indicating that the pathogenesis of NSHL in the Fujian population is heterogenous, and that further analysis of other NSHL genes is necessary.
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Affiliation(s)
- Tianbin Chen
- Department of Laboratory Medicine, The 1st Affiliated Hospital of Fujian Medical University, Fuzhou, China
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Martines F, Salvago P, Bartolotta C, Cocuzza S, Fabiano C, Ferrara S, La Mattina E, Mucia M, Sammarco P, Sireci F, Martines E. A genotype-phenotype correlation in Sicilian patients with GJB2 biallelic mutations. Eur Arch Otorhinolaryngol 2014; 272:1857-65. [PMID: 24627074 DOI: 10.1007/s00405-014-2970-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 02/20/2014] [Indexed: 11/29/2022]
Abstract
The aim of this work was to study the genotype distribution of Sicilian patients with biallelic GJB2 mutations; to correlate genotype classes and/or specific mutations of GJB2 gene (35delG-non-35delG) with audiologic profiles. A total of 10 different mutations and 11 different genotypes were evidenced in 73 SNHL subjects; 35delG (90.36 % of cases) and IVS1+1 (13.69 %) were the most common mutations found in the cohort with a significant difference in the distribution between North and South Sicily. Audiological evaluation revealed a severe (16/73) to profound (47/73) hearing loss (HL) in 86.13 % of cases without significant difference between the degree of HL and the province of origin of the subjects (P = 0.727). The homozygous truncating (T/T) genotype was the most widespread (89.04 % of cases), with a severe-to-profound hearing impairment in 90.36 % of T/T class with respect to truncating/non-truncating (T/NT) and non-truncating/non-truncating (NT/NT) genotypes (P = 0.012). From the comparison of homozygous 35delG and 35delG/non-35delG genotypes, a more profound HL in the homozygous 35delG than in compound heterozygous 35delG/non-35delG (p < 0.0001) resulted. This study confirms that 35delG is the most common mutation in the Mediterranean area with a heterogeneous distribution of the genotypes between North and South Sicily; probands homozygotes for 35delG or presenting a T/T genotype are more apt to have a severe-to-profound HL.
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Affiliation(s)
- Francesco Martines
- Dipartimento di Biomedicina Sperimentale e Neuroscienze Cliniche (BioNeC), Sezione di Otorinolaringoiatria, Università degli Studi di Palermo, Via del Vespro, 129, 90127, Palermo, Italy,
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Chan DK, Chang KW. GJB2-associated hearing loss: Systematic review of worldwide prevalence, genotype, and auditory phenotype. Laryngoscope 2013; 124:E34-53. [DOI: 10.1002/lary.24332] [Citation(s) in RCA: 183] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/10/2013] [Indexed: 12/17/2022]
Affiliation(s)
- Dylan K. Chan
- Department of Otolaryngology-Head and Neck Surgery; University of California; San Francisco U.S.A
| | - Kay W. Chang
- Department of Otolaryngology-Head and Neck Surgery; Stanford University School of Medicine; Stanford California U.S.A
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A novel splice-site mutation in the GJB2 gene causing mild postlingual hearing impairment. PLoS One 2013; 8:e73566. [PMID: 24039984 PMCID: PMC3765306 DOI: 10.1371/journal.pone.0073566] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 07/19/2013] [Indexed: 11/26/2022] Open
Abstract
The DFNB1 subtype of autosomal recessive, nonsyndromic hearing impairment, caused by mutations affecting the GJB2 (connection-26) gene, is highly prevalent in most populations worldwide. DFNB1 hearing impairment is mostly severe or profound and usually appears before the acquisition of speech (prelingual onset), though a small number of hypomorphic missense mutations result in mild or moderate deafness of postlingual onset. We identified a novel GJB2 splice-site mutation, c. -22-2A>C, in three siblings with mild postlingual hearing impairment that were compound heterozygous for c. -22-2A>C and c.35delG. Reverse transcriptase-PCR experiments performed on total RNA extracted from saliva samples from one of these siblings confirmed that c. -22-2A>C abolished the acceptor splice site of the single GJB2 intron, resulting in the absence of normally processed transcripts from this allele. However, we did isolate transcripts from the c. -22-2A>C allele that keep an intact GJB2 coding region and that were generated by use of an alternative acceptor splice site previously unknown. The residual expression of wild-type connection-26 encoded by these transcripts probably underlies the mild severity and late onset of the hearing impairment of these subjects.
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Riahi Z, Chahed H, Jaafoura H, Zainine R, Messaoud O, Naili M, Nagara M, Hammami H, Laroussi N, Bouyacoub Y, Kefi R, Bonnet C, Besbes G, Abdelhak S. A novel frameshift mutation (c.405delC) in the GJB2 gene associated with autosomal recessive hearing loss in two Tunisian families. Int J Pediatr Otorhinolaryngol 2013; 77:1485-8. [PMID: 23856379 DOI: 10.1016/j.ijporl.2013.06.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 06/17/2013] [Accepted: 06/18/2013] [Indexed: 10/26/2022]
Abstract
OBJECTIVES Mutations in GJB2 are found to be responsible for 50% of congenital autosomal recessive non-syndromic hearing loss, one of the most important mutations in this gene is the c.35delG, which is responsible for the majority of GJB2 related deafness in the Tunisian population. The aim of this study was to determine the molecular etiology of hearing loss in two Tunisian individuals. METHODS We screened two Tunisian individuals affected by congenital, bilateral, profound, sensorineural hearing loss for mutations in GJB2 gene using PCR and direct sequencing. RESULTS We identified a novel frameshift mutation in the GJB2 gene, the c.405delC resulting in a truncated protein (p.Tyr136Thrfs*32). It was found in compound heterozygosity with the c.35delG in two non-consanguineous unrelated families from Tunisia. One patient underwent a cochlear implant at 4 years. Initial evaluations post-implantation indicate a successful cochlear implant outcome since the patient began to acquire language abilities and auditory sensation. CONCLUSIONS With this novel GJB2 mutation, the mutational spectrum of this gene continues to broaden in our population. The occurrence of biallelic GJB2 mutations for the other deaf girl, despite the neonatal pain and hypotension due to complicated delivery, led us to confirm the importance of GJB2 screening for cochlear implant candidates regardless of the etiology of deafness in populations with a relatively high frequency of GJB2 mutation carriers.
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Affiliation(s)
- Zied Riahi
- Laboratoire de Génomique Biomédicale et Oncogénétique, Institut Pasteur de Tunis, BP 74, 13 Place Pasteur, Tunis 1002, Tunisia
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Manzoli GN, Abe-Sandes K, Bittles AH, da Silva DSD, Fernandes LDC, Paulon RMC, de Castro ICS, Padovani CMCA, Acosta AX. Non-syndromic hearing impairment in a multi-ethnic population of Northeastern Brazil. Int J Pediatr Otorhinolaryngol 2013; 77:1077-82. [PMID: 23684175 DOI: 10.1016/j.ijporl.2013.04.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2012] [Revised: 03/30/2013] [Accepted: 04/01/2013] [Indexed: 01/28/2023]
Abstract
OBJECTIVE There are many hearing impaired individuals in Monte Santo, a rural municipality in the state of Bahia, Brazil, including multiple familial cases strongly suggestive of a genetic aetiology. METHODS The present study investigated 81 subjects with hearing impairment (HI) recruited from 36 families. Mutations often associated with HI, i.e. the DFNB1 mutations c.35delG in GJB2, deletions del(GJB6-D13S1830) and del(GJB6-D13S1854), and A1555G in the mitochondrial gene MTRNR1 were initially analyzed, with additional mutations in GJB2 identified by sequencing the coding region of the gene. RESULTS Seven different mutations were present in GJB2 with mutations c.35delG and p.Arg75Gln, which are known to be pathogenic, identified in 37.0% of the subjects. Individuals homozygous for the c.35delG mutation were diagnosed in eight families, corresponding to 24.7% of unrelated individuals with nonsyndromic hearing impairment (NSHI), and an additional heterozygote for this mutation was present in a single family. Ten individuals (12.4%) in another family were heterozygous for the mutation p.Arg75Gln. CONCLUSIONS Significant heterogeneity was observed in the alleles and patterns of NSHI inheritance among the subjects studied, probably due to the extensive inter-ethnic admixture that characterizes the peoples of Brazil, together with a high prevalence of community endogamy and consanguineous marriage.
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Affiliation(s)
- Gabrielle N Manzoli
- Advanced Laboratory of Public Health/Gonçalo Moniz Research Center (CPqGM), Oswaldo Cruz Foundation (FIOCRUZ), Salvador, Bahia, Brazil
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EMQN Best Practice guidelines for diagnostic testing of mutations causing non-syndromic hearing impairment at the DFNB1 locus. Eur J Hum Genet 2013; 21:1325-9. [PMID: 23695287 PMCID: PMC3798855 DOI: 10.1038/ejhg.2013.83] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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Matos TD, Simões-Teixeira H, Caria H, Gonçalves AC, Chora J, Correia MDC, Moura C, Rosa H, Monteiro L, O'Neill A, Dias Ó, Andrea M, Fialho G. Spectrum and frequency of GJB2 mutations in a cohort of 264 Portuguese nonsyndromic sensorineural hearing loss patients. Int J Audiol 2013; 52:466-71. [PMID: 23668481 DOI: 10.3109/14992027.2013.783719] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE To assess the spectrum and prevalence of mutations in the GJB2 gene in Portuguese nonsyndromic sensorineural hearing loss (NSSHL) patients. DESIGN Sequencing of the coding region, basal promoter, exon 1, and donor splice site of the GJB2 gene; screening for the presence of the two common GJB6 deletions. STUDY SAMPLE A cohort of 264 Portuguese NSSHL patients. RESULTS At least one out of 21 different GJB2 variants was identified in 80 (30.2%) of the 264 patients analysed. Two mutant alleles were found in 53 (20%) of these probands, of which 83% (44/53) harboured at least one c.35delG allele. Twenty-seven (10.2%) of the probands harboured only one mutant allele. Subsequent analysis revealed that the GJB6 deletion del(GJB6-D13S1854) was present in at least 7.4% (2/27) of the patients carrying only one mutant GJB2 allele. Overall, one in five (55/264) of the patients were diagnosed as having DFNB1-related NSSHL, of which the vast majority (53/55) harboured only GJB2 mutations. CONCLUSIONS This study provides clear demonstration that mutations in the GJB2 gene are an important cause of NSSHL in Portugal, thus representing a valuable indicator as regards therapeutical and rehabilitation options, as well as genetic counseling of these patients and their families.
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Affiliation(s)
- Tiago Daniel Matos
- Centre for Biodiversity, Functional, and Integrative Genomics BioFIG, Faculty of Science, University of Lisbon, Lisboa, Portugal
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Zainal SA, Md Daud MK, Abd Rahman N, Zainuddin Z, Alwi Z. Mutation detection in GJB2 gene among Malays with non-syndromic hearing loss. Int J Pediatr Otorhinolaryngol 2012; 76:1175-9. [PMID: 22613756 DOI: 10.1016/j.ijporl.2012.04.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 04/26/2012] [Accepted: 04/27/2012] [Indexed: 11/25/2022]
Abstract
OBJECTIVES To identify the mutations in the GJB2 gene and to determine its association with non-syndromic hearing loss in Malays. METHODS A comparative cross sectional study was conducted on a group of children from the deaf schools and the normal schools. A total of 91 buccal cell samples of non-syndromic hearing loss and 91 normal hearing children were taken. Polymerase chain reaction was used to amplify the coding region of GJB2 gene. The PCR product of GJB2 coding region was preceded with screening for mutations using denaturing high performance liquid chromatography (dHPLC) and mutations detected were confirmed by DNA sequencing. RESULTS Twelve sequence variations including mutations and polymorphisms were found in 32 patients and 37 control subjects. The variations were G4D, V27I, E114G, T123N, V37I and R127H in both groups, W24X, R32H, 257_259 del CGC and M34L in patients only and I203T and V153I in control subjects only. There were no association between homozygous (P=0.368) or heterozygous (P=0.164) GJB2 gene and non-syndromic hearing loss. CONCLUSIONS The types of GJB2 gene mutation were different and vary in Malay non-syndromic hearing loss as compared to the other races. Furthermore, the mutation did not associate with hearing loss in the population. Other related genes are believed to be involved and need to be sought in this group of patients.
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Affiliation(s)
- Siti Aishah Zainal
- Human Genome Center, School of Medical Sciences, Health Campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
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Löppönen T, Dietz A, Väisänen ML, Valtonen H, Kosunen A, Hyvärinen A, Ignatius J, Löppönen H. Homozygous M34T mutation of the GJB2 gene associates with an autosomal recessive nonsyndromic sensorineural hearing impairment in Finnish families. Acta Otolaryngol 2012; 132:862-73. [PMID: 22668073 DOI: 10.3109/00016489.2012.669498] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONCLUSION The genetic and audiological data support the hypothesis that the p.M34T is a pathogenic mutation in the Finnish population. The p.M34T mutation displays an autosomal recessive pattern of inheritance and is associated with mild to moderate nonsyndromic sensorineural hearing impairment (SNHI) in the homozygous state. The audiograms often display a hearing impairment notch at 2-4 kHz in young patients, which may aid in the early diagnosis. OBJECTIVES The aim of the study was to assess whether the p.M34T mutation in the GJB2 gene may associate with nonsyndromic SNHI. METHODS We systematically reviewed the families with children diagnosed with nonsyndromic SNHI caused by a homozygous p.M34T mutation at the Kuopio and Oulu University Hospital Clinics. The children were re-examined and audiological and genetic data were obtained from their parents and healthy siblings to study genotype-phenotype correlation. RESULTS We describe 11 patients from 6 families including 5 sibling pairs from 6 to 23 years of age with homozygous p.M34T genotype all having mild nonsyndromic SNHI. In addition, we found three patients with compound p.M34T mutation also exhibiting mild to moderate SNHI.
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Affiliation(s)
- Tuija Löppönen
- Department of Paediatrics, Child Neurology, Kuopio University Hospital, Finland
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Yuan Y, Zhang X, Huang S, Zuo L, Zhang G, Song Y, Wang G, Wang H, Huang D, Han D, Dai P. Common molecular etiologies are rare in nonsyndromic Tibetan Chinese patients with hearing impairment. PLoS One 2012; 7:e30720. [PMID: 22389666 PMCID: PMC3289614 DOI: 10.1371/journal.pone.0030720] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Accepted: 12/20/2011] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Thirty thousand infants are born every year with congenital hearing impairment in mainland China. Racial and regional factors are important in clinical diagnosis of genetic deafness. However, molecular etiology of hearing impairment in the Tibetan Chinese population living in the Tibetan Plateau has not been investigated. To provide appropriate genetic testing and counseling to Tibetan families, we investigated molecular etiology of nonsyndromic deafness in this population. METHODS A total of 114 unrelated deaf Tibetan children from the Tibet Autonomous Region were enrolled. Five prominent deafness-related genes, GJB2, SLC26A4, GJB6, POU3F4, and mtDNA 12S rRNA, were analyzed. Inner ear development was evaluated by temporal CT. A total of 106 Tibetan hearing normal individuals were included as genetic controls. For radiological comparison, 120 patients, mainly of Han ethnicity, with sensorineural hearing loss were analyzed by temporal CT. RESULTS None of the Tibetan patients carried diallelic GJB2 or SLC26A4 mutations. Two patients with a history of aminoglycoside usage carried homogeneous mtDNA 12S rRNA A1555G mutation. Two controls were homozygous for 12S rRNA A1555G. There were no mutations in GJB6 or POU3F4. A diagnosis of inner ear malformation was made in 20.18% of the Tibetan patients and 21.67% of the Han deaf group. Enlarged vestibular aqueduct, the most common inner ear deformity, was not found in theTibetan patients, but was seen in 18.33% of the Han patients. Common molecular etiologies, GJB2 and SLC26A4 mutations, were rare in the Tibetan Chinese deaf population. CONCLUSION The mutation spectrum of hearing loss differs significantly between Chinese Tibetan patients and Han patients. The incidence of inner ear malformation in Tibetans is almost as high as that in Han deaf patients, but the types of malformation vary greatly. Hypoxia and special environment in plateau may be one cause of developmental inner ear deformity in this population.
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Affiliation(s)
- Yongyi Yuan
- Department of Otolaryngology, PLA General Hospital, Beijing, People's Republic of China
- Department of Otolaryngology, Hainan Branch of PLA General Hospital, Sanya, People's Republic of China
| | - Xun Zhang
- Department of Otolaryngology, 3rd hospital of Hebei Medical University, Shijiazhuang, Hebei Province, People's Republic of China
| | - Shasha Huang
- Department of Otolaryngology, PLA General Hospital, Beijing, People's Republic of China
| | - Lujie Zuo
- Department of Otolaryngology, PLA General Hospital, Beijing, People's Republic of China
- Department of Otolaryngology, 3rd hospital of Hebei Medical University, Shijiazhuang, Hebei Province, People's Republic of China
| | - Guozheng Zhang
- Department of Otolaryngology, PLA General Hospital, Beijing, People's Republic of China
- Department of Otolaryngology, 3rd hospital of Hebei Medical University, Shijiazhuang, Hebei Province, People's Republic of China
| | - Yueshuai Song
- Department of Otolaryngology, PLA General Hospital, Beijing, People's Republic of China
| | - Guojian Wang
- Department of Otolaryngology, PLA General Hospital, Beijing, People's Republic of China
- Department of Otolaryngology, Hainan Branch of PLA General Hospital, Sanya, People's Republic of China
| | - Hongtian Wang
- Department of Otolaryngology, PLA General Hospital, Beijing, People's Republic of China
| | - Deliang Huang
- Department of Otolaryngology, PLA General Hospital, Beijing, People's Republic of China
| | - Dongyi Han
- Department of Otolaryngology, PLA General Hospital, Beijing, People's Republic of China
| | - Pu Dai
- Department of Otolaryngology, PLA General Hospital, Beijing, People's Republic of China
- Department of Otolaryngology, Hainan Branch of PLA General Hospital, Sanya, People's Republic of China
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Chen P, Chen H, Fu S, Chen G, Dong J. Prevalence of GJB6 mutations in Chinese patients with non-syndromic hearing loss. Int J Pediatr Otorhinolaryngol 2012; 76:265-7. [PMID: 22186156 DOI: 10.1016/j.ijporl.2011.11.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Revised: 11/18/2011] [Accepted: 11/19/2011] [Indexed: 10/14/2022]
Abstract
OBJECTIVE To investigate the distribution of GJB6 mutations in Central Chinese population with non-syndromic hearing loss. METHOD Totally 655 hearing impaired patients in Hubei province of China were screened for del(GJB6-D13S1830) deletions by using multiplex PCR and sequencing of GJB6 whole coding region. RESULT The del(GJB6-D13S1830) and other mutations in GJB6 gene were not observed in our study cohort. CONCLUSION The results suggest that GJB6 mutations is not a common cause among Central Chinese population and screening for the mutations of GJB6 can be ranked as unconventional deaf gene test for this population.
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Affiliation(s)
- Peiwei Chen
- Department of Pediatrics, Central Hospital of Enshi Tujia and Miao Autonomous Prefecture, 445000 Enshi, Hubei Province, China
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Liss J, Mirecka A, Kitowska K, Łukaszuk K. Diagnostyka preimplantacyjna w kierunku niedosłuchu wrodzonego z mutacją 35delG w genie GJB2 – doniesienie wstępne. Otolaryngol Pol 2011; 65:443-6. [DOI: 10.1016/s0030-6657(11)70738-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Accepted: 08/24/2011] [Indexed: 11/28/2022]
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Chinetti V, Iossa S, Auletta G, Corvino V, De Luca M, De Falco F, Giannini P, Lilli G, Malesci R, Riccardi P, Marciano E, Franzè A. Mutational analysis forGJB2, GJB6, andGJB3genes in Campania within a universal neonatal hearing screening programme. Int J Audiol 2011; 50:866-70. [DOI: 10.3109/14992027.2011.603757] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Zhao FF, Ji YB, Wang DY, Lan L, Han MK, Li Q, Zhao Y, Rao S, Han D, Wang QJ. Phenotype-genotype correlation in 295 Chinese deaf subjects with biallelic causative mutations in the GJB2 gene. Genet Test Mol Biomarkers 2011; 15:619-25. [PMID: 21488715 DOI: 10.1089/gtmb.2010.0192] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
AIMS The connexin 26 coding gene (GJB2) is the primary causative gene for nonsyndromic sensorineural hearing impairment (NSSHI). More than 100 mutations in this gene have been reported to be linked to hearing impairment (HI), from mild to profound hearing loss. To precisely estimate the impact of GJB2 mutations in the Chinese population, a cross-sectional study was performed to analyze the auditory data of Chinese patients with NSSHI. RESULTS Two hundred ninety-five unrelated patients with NSSHI with biallelic mutations in GJB2 were recruited from seven provinces in Northern China from 2004 to 2008. The levels of HI and average pure tone audiometry were compared across different genotypes by χ(2) testing. The subjects with the genotypes of combined truncating mutations had more cases of severe HI than the subjects with a genotype of several nontruncating mutations. It was also revealed that subjects carrying either c.[79G>A; 341A>G]+[79G>A; 341A>G] or c.[109G>A]+[79G>A; 341A>G] had significantly fewer cases of severe HI than the reference group of homozygous c.235delC, whereas the subjects carrying c.[235delC]+[176_191del16] had more cases of severe HI than the homozygous c.235delC group. CONCLUSIONS This is the first study to clarify the correlations between different GJB2 biallelic genotypes and NSSHI phenotype in the Chinese population. The Chinese subjects with two truncating mutations in GJB2 were shown to correlate with more severe HI.
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Affiliation(s)
- Fei-Fan Zhao
- Department of Otorhinolaryngology/Head and Neck Surgery, Chinese People's Liberation Army Institute of Otolaryngology, Chinese People's Liberation Army General Hospital, Beijing, China
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Choi SY, Lee KY, Kim HJ, Kim HK, Chang Q, Park HJ, Jeon CJ, Lin X, Bok J, Kim UK. Functional evaluation of GJB2 variants in nonsyndromic hearing loss. Mol Med 2011; 17:550-6. [PMID: 21298213 DOI: 10.2119/molmed.2010.00183] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2010] [Accepted: 01/07/2011] [Indexed: 11/06/2022] Open
Abstract
Mutations in the gap junction β2 (GJB2) gene, encoding the connexin26 (CX26) protein, are the most common cause of non-syndromic hearing loss (HL) in many populations. In the East Asian population, two variants, p.V27I (c.79G>A) and p.E114G (c.341G>A), are considered benign polymorphisms since these variants have been identified in both HL patients and normal hearing controls. However, some studies have postulated that homozygotes carrying both p.V27I and p.E114G variants could cause HL. To elucidate possible roles of these variants, we used in vitro approaches to directly assess the pathogenicity of four haplotypes generated by the two polymorphisms: VE (wild type), I*E (p.V27I variant only), VG* (p.E114G variant only), I*G* (both variants). In biochemical coupling assays, the gap junctions (GJs) composed of VG* and I*G* types displayed defective channel activities compared with those of VE wild types or I*E types, which showed normal channel activities. Interestingly, the defect in hemichannel activity was a bit less severe in I*G* type than VG* type, suggesting that I* variant (p.V27I) may compensate for the deleterious effect of G* variant (p.E114G) in hemichannel activities. Our population studies using 412 Korean individuals showed that I*G* type was detected at around 20% in both HL patients and normal controls, suggesting that I*G* type may not be a pathogenic polymorphism. In contrast, VG* type was very rare (3/824) and detected only in HL patients, suggesting that VG* homozygotes (VG*/VG*) or compound heterozygotes carrying VG* type with other mutations may cause HL.
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Affiliation(s)
- Soo-Young Choi
- Department of Biology, College of Natural Sciences, Kyungpook National University, Daegu, Korea
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Yuan Y, Yu F, Wang G, Huang S, Yu R, Zhang X, Huang D, Han D, Dai P. Prevalence of the GJB2 IVS1+1G >A mutation in Chinese hearing loss patients with monoallelic pathogenic mutation in the coding region of GJB2. J Transl Med 2010; 8:127. [PMID: 21122151 PMCID: PMC3014891 DOI: 10.1186/1479-5876-8-127] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Accepted: 12/02/2010] [Indexed: 11/10/2022] Open
Abstract
Background Mutations in the GJB2 gene are the most common cause of nonsyndromic recessive hearing loss in China. In about 6% of Chinese patients with severe to profound sensorineural hearing impairment, only monoallelic GJB2 mutations known to be either recessive or of unclear pathogenicity have been identified. This paper reports the prevalence of the GJB2 IVS1+1G>A mutation in a population of Chinese hearing loss patients with monoallelic pathogenic mutation in the coding region of GJB2. Methods Two hundred and twelve patients, screened from 7133 cases of nonsyndromic hearing loss in China, with monoallelic mutation (mainly frameshift and nonsense mutation) in the coding region of GJB2 were examined for the GJB2 IVS1+1G>A mutation and mutations in the promoter region of this gene. Two hundred and sixty-two nonsyndromic hearing loss patients without GJB2 mutation and 105 controls with normal hearing were also tested for the GJB2 IVS1+1G>A mutation by sequencing. Results Four patients with monoallelic mutation in the coding region of GJB2 were found carrying the GJB2 IVS1+1G>A mutation on the opposite allele. One patient with the GJB2 c.235delC mutation carried one variant, -3175 C>T, in exon 1 of GJB2. Neither GJB2 IVS1+1G>A mutation nor any variant in exon 1 of GJB2 was found in the 262 nonsyndromic hearing loss patients without GJB2 mutation or in the 105 normal hearing controls. Conclusion Testing for the GJB2 IVS 1+1 G to A mutation explained deafness in 1.89% of Chinese GJB2 monoallelic patients, and it should be included in routine testing of patients with GJB2 monoallelic pathogenic mutation.
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Affiliation(s)
- Yongyi Yuan
- Department of Otolaryngology, PLA General Hospital, Beijing, People's Republic of China
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Teek R, Kruustük K, Zordania R, Joost K, Reimand T, Möls T, Oitmaa E, Kahre T, Tõnisson N, Ounap K. Prevalence of c.35delG and p.M34T mutations in the GJB2 gene in Estonia. Int J Pediatr Otorhinolaryngol 2010; 74:1007-12. [PMID: 20708129 DOI: 10.1016/j.ijporl.2010.05.026] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Revised: 05/18/2010] [Accepted: 05/23/2010] [Indexed: 10/19/2022]
Abstract
OBJECTIVE The purpose of this study was to determine the prevalence of c.35delG and p.M34T mutations in the GJB2 gene among children with early onset hearing loss and within a general population of Estonia. METHODS Using an arrayed primer extension assay, we screened 233 probands with early childhood onset hearing loss for 107 different mutations in the GJB2 gene. We then looked for the two most common mutations, c.35delG and p.M34T, in a population of 998 consecutively born Estonian neonates to determine the frequency of these mutations in the general population. RESULTS In 115 (49%) of the patients with early onset hearing loss, we found a mutation in at least one allele of the GJB2 gene. Seventy-three (31%) were homozygous for the c.35delG mutation, seven (3%) were homozygous for the p.M34T mutation, and five (2%) had c35delG/p.M34T compound heterozygosity. Other six identified mutations in GJB2 gene occurred rarely. Among the 998 anonymous newborn samples, we detected 45 who were heterozygous for c.35delG, 2 individuals homozygous for c.35delG, and 58 who were heterozygous for p.M34T. Additionally, we detected two c.35delG/p.M34T compound heterozygotes. CONCLUSION The most common GJB2 gene mutations in Estonian children with early onset hearing loss were c.35delG and p.M34T, with c.35delG accounting for 75% of GJB2 alleles. The carrier frequency for c.35delG and p.M34T in a general population of Estonia was 1 in 22 and 1 in 17, respectively, and was higher than in most other countries.
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Affiliation(s)
- Rita Teek
- Department of Genetics, United Laboratories, Tartu University Hospital, Tartu, Estonia
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Mahdieh N, Rabbani B, Wiley S, Akbari MT, Zeinali S. Genetic causes of nonsyndromic hearing loss in Iran in comparison with other populations. J Hum Genet 2010; 55:639-48. [PMID: 20739942 DOI: 10.1038/jhg.2010.96] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Bozhkova VP, Khashaev ZH, Umanskaya TM. Frequence and the mutation spectrum of GJB2-related hearing loss in children of Dagestan as compared with the central European part of Russia. Biophysics (Nagoya-shi) 2010. [DOI: 10.1134/s0006350910030176] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Yan D, Liu XZ. Modifiers of hearing impairment in humans and mice. Curr Genomics 2010; 11:269-78. [PMID: 21119891 PMCID: PMC2930666 DOI: 10.2174/138920210791233054] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Revised: 04/03/2010] [Accepted: 04/07/2010] [Indexed: 02/04/2023] Open
Abstract
Lack of penetrance and variability of expression are common findings in nonsyndromic hearing loss with autosomal dominant mode of inheritance, but are also seen with recessive inheritance. Now we know that genotype cannot necessarily predict phenotype due to the complexity of the genome, the proteome interacting with the transcriptome, and the dynamically coupled systems that are involved. The contribution of genetic background to phenotypic diversity reflects the additive and interactive (epistasis) effects of multiple genes. Because, individual genes do not act alone but rather in concert with many other genes, it is not surprising that, modifier genes are common source of phenotypic variation in human populations. They can affect the phenotypic outcome of a given genotype by interacting in the same or in a parallel biological pathway as the disease gene. These modifier genes modulate penetrance, dominance, pleiotropy or expressivity in individuals with Mendelian traits and can also be exerted by influencing the severity, the penetrance, the age of onset and the progression of a disease. In this review, we focus on modifier genes that specifically affect hearing loss phenotypes in humans as well as those described in mice. We also include examples of digenic inheritance of deafness, because additive or interactive effects can also result from interaction between two mutant genes.
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Affiliation(s)
| | - Xue-Zhong Liu
- Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
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Matos TD, Simões-Teixeira H, Caria H, Rosa H, O'Neill A, Fialho G. The controversial p.Arg127His mutation in GJB2: report on three Portuguese hearing loss family cases. Genet Test Mol Biomarkers 2010; 14:141-4. [PMID: 19929408 DOI: 10.1089/gtmb.2009.0103] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Mutations in the GJB2 gene account for up to 50% of hereditary nonsyndromic hearing loss in several populations. Over 200 mutations are already described in this gene, and three of them, c.35delG, c.167delT, and c.235delC, are the most frequent in Caucasians, Ashkenazi Jews, and Asians, respectively. Most of GJB2 hearing loss-related mutations are recessive, but a few dominant alleles have also been described. Apart from the clearly pathogenic mutations, there are some other variants whose pathogenicity is still controversial, such as p.Met34Thr, p.Val37Ile, p.Arg127His, and p.Val153Ile. The p.Arg127His allele has been found in some mono- and biallelic hearing-impaired patients from several countries. In this article we report on some Portuguese patients harboring this mutation. Taking into consideration the analysis of these Portuguese cases as well as the genetic and functional data regarding p.Arg127His available in the literature, we conclude that this variant may be a cause of hearing loss depending on environmental factors and/or genetic background.
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Affiliation(s)
- Tiago D Matos
- Faculty of Science, Centre for Biodiversity, Functional, and Integrative Genomics (BioFIG), University of Lisbon, Lisbon, Portugal
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Al-Qahtani MH, Baghlab I, Chaudhary AG, Abuzenadah AM, Bamanie A, Daghistani KJ, Safieh M, Fida L, Dallol A. Spectrum of GJB2 mutations in a cohort of nonsyndromic hearing loss cases from the Kingdom of Saudi Arabia. Genet Test Mol Biomarkers 2010; 14:79-83. [PMID: 19929407 DOI: 10.1089/gtmb.2009.0111] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Nonsyndromic hearing loss (NSHL) affects a substantial proportion of newborns in the world every year. This proportion increases proportionally with the degree of consanguineous marriages in any society. In the Kingdom of Saudi Arabia, consanguineous marriages are common practice and this is associated with a noticeably high frequency of inherited conditions affecting the resulting progeny, including NSHL. Until now there is no published data on the genetic causes of NSHL in Saudi Arabia, which greatly hindered the ability of local genetic counseling and family planning centers to distinguish between hereditary and nonhereditary forms of NSHL and subsequently could not give information on the possible inheritance of deafness. In addition, the lack of validated genetic tests for NSHL delayed the detection of deafness in affected individuals and may have lowered the efficiency of later medical interventions. Further, the population covered in this study is likely to have a multiethnic background caused by decades of religious and economic migration to this region. To address such problems, we undertook the task of unraveling the genetic causes of hearing loss in Saudi Arabia, starting with identifying the GJB2/DFNB1 mutation spectrum in a cohort of unrelated individuals suffering from mild to profound NSHL. A total of 12 reported GJB2 mutations were identified in 17 out of 109 (15.59%) NSHL cases. Biallelic GJB2 mutations were identified in 11 out of the 109 NSHL cases (10.09%), with c.35delG being the most common (7/11, 63.63%). The remaining six patients were found to have monoallelic GJB2 mutations. Interestingly, biallelic GJB2 mutations were not detected in patients of Arab tribal origins, reflecting the genetic heterogeneity of the western area of the Kingdom of Saudi Arabia. Therefore, ethnically targeted genetic screening for GJB2 mutations could be a useful tool toward the management of NSHL in this area.
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Affiliation(s)
- Mohammed H Al-Qahtani
- Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia.
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Chinetti V, Iossa S, Auletta G, Laria C, de Luca M, Di Leva F, Riccardi P, Giannini P, Gasparini P, Ciccodicola A, Marciano E, Franzè A. Screening forGJB2andGJB6gene mutations in patients from Campania region with sensorineural hearing loss. Int J Audiol 2010; 49:326-31. [DOI: 10.3109/14992021003601756] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Prevalence of DFNB1 mutations in Argentinean children with non-syndromic deafness. Report of a novel mutation in GJB2. Int J Pediatr Otorhinolaryngol 2010; 74:250-4. [PMID: 20022641 DOI: 10.1016/j.ijporl.2009.11.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2009] [Revised: 11/16/2009] [Accepted: 11/20/2009] [Indexed: 11/20/2022]
Abstract
OBJECTIVE Mutations in DFNB1 locus, containing GJB2 (connexin 26) and GJB6 (connexin 30) genes, are the most common cause of autosomal recessive non-syndromic hearing loss. More than 100 mutations in GJB2 have been reported worldwide. Two deletions in GJB6, del(GJB6-D13S1830) and del(GJB6-D13S1854), have been found to be frequent in the Spanish population. The aim of this study was to determine the prevalence of GJB2 mutations and both GJB6 deletions in Argentinean children with non-syndromic deafness. METHODS This study included 94 unrelated children with moderate to profound non-syndromic sensorineural hearing impairment. Molecular analysis was performed using a tiered approach. All DNA samples were screened for c.35delG mutation by PCR/RFLP. Samples from patients who were not homozygous for c.35delG were analysed for the presence of GJB6 deletions by PCR multiplex. The samples that remained unresolved after screening were further analysed by direct sequencing of GJB2 coding region. Finally, the splice site mutation IVS1+1G-->A was analysed by PCR/RFLP. RESULTS Sequence variations in the GJB2 and GJB6 genes were found in 49 of the 94 unrelated patients. The most prevalent GJB2 mutation, c.35delG, was found in 40 of the 68 pathogenic alleles with the second most common allele being p.R143W (4/68). Fourteen sequence variations other than c.35delG were identified. Seven already described mutations were present in more than one allele; among them, IVS1+1G-->A, the rare splice site mutation flanking exon 1. In addition to known disease-related alterations, a novel GJB2 mutation, c.262G>C (p.A88P), was also identified. Six alleles were identified carrying GJB6 deletions; the most prevalent was del(GJB6-D13S1830). The frequency of the latter was found to be as high as that found in Spain from where Argentina has received one of its major immigration waves. CONCLUSIONS The overall frequency of GJB2/GJB6 mutations in the present sample is in agreement with other Caucasian populations. As expected, c.35delG was the most prevalent mutation. The deletion del(GJB6-D13S1830) was the second most common mutation. These findings reinforce the importance of the study of GJB2/GJB6 genes in diagnosis to provide early treatment and genetic counselling.
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