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Sharma N, Kumari D, Panigrahi I, Khetarpal P. A systematic review of the monogenic causes of Non-Syndromic Hearing Loss (NSHL) and discussion of Current Diagnosis and Treatment options. Clin Genet 2023; 103:16-34. [PMID: 36089522 DOI: 10.1111/cge.14228] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 09/02/2022] [Accepted: 09/06/2022] [Indexed: 12/13/2022]
Abstract
Hearing impairment is one of the most widespread inheritable sensory disorder affecting at least 1 in every 1000 born. About two-third of hereditary hearing loss (HHL) disorders are non-syndromic. To provide comprehensive update of monogenic causes of non-syndromic hearing loss (NSHL), literature search has been carried out with appropriate keywords in the following databases-PubMed, Google Scholar, Cochrane library, and Science Direct. Out of 2214 papers, 271 papers were shortlisted after applying inclusion and exclusion criterion. Data extracted from selected papers include information about gene name, identified pathogenic variants, ethnicity of the patient, age of onset, gender, title, authors' name, and year of publication. Overall, pathogenic variants in 98 different genes have been associated with NSHL. These genes have important role to play during early embryonic development in ear structure formation and hearing development. Here, we also review briefly the recent information about diagnosis and treatment approaches. Understanding pathogenic genetic variants are helpful in the management of affected and may offer targeted therapies in future.
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Affiliation(s)
- Nandita Sharma
- Department of Human Genetics and Molecular Medicine, School of Health Sciences, Central University of Punjab, Bathinda, India
| | - Divya Kumari
- Department of Pediatrics Medicine, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Inusha Panigrahi
- Department of Pediatrics Medicine, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Preeti Khetarpal
- Department of Human Genetics and Molecular Medicine, School of Health Sciences, Central University of Punjab, Bathinda, India
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2
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Shen N, Peng J, Wang X, Zhu Y, Liu W, Liu A, Lu Y. Association between the p.V37I variant of GJB2 and hearing loss: a pedigree and meta-analysis. Oncotarget 2018; 8:46681-46690. [PMID: 28489599 PMCID: PMC5542302 DOI: 10.18632/oncotarget.17325] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 03/19/2017] [Indexed: 12/31/2022] Open
Abstract
Pathogenic variants in the gap junction protein beta-2 (GJB2) gene are the most common cause of hearing loss. Of these, the p.V37I variant of GJB2 has a high allele frequency (up to 10%) in East Asians. Characterization of the phenotypic spectrum associated with p.V37I, as well as the role of this variant in the onset of hearing loss could have a remarkable effect on future diagnostic strategies. Here, we performed a pedigree analysis of unrelated families exhibiting various hearing phenotypes, and then conducted a meta-analysis to comprehensively assess the association between the p.V37I and the risk of hearing loss. Pedigree analyses showed that both homozygous p.V37I variants, as well as compound heterozygous p.V37I with other GJB2 pathogenic variants, contributed to various phenotypes of hearing loss. Meanwhile, meta-analysis demonstrated that, compared with those in the wild type group, both p.V37I homozygotes and compound heterozygous p.V37I variants were at significantly higher risk of developing hearing loss (odds ratios = 7.14 and 3.63; 95% confidence intervals = 3.01-16.95 and 1.38–9.54, respectively). Conversely, heterozygous p.V37I variants alone did not increase the risk of hearing loss. Given the high allele carriage rate of p.V37I (up to 10%) within the general population, our work not only provides information that might influence future genetic screening policies, but also offers insight into clinical risk evaluation and genetic counseling regarding hearing loss.
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Affiliation(s)
- Na Shen
- Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Jing Peng
- Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xiong Wang
- Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yaowu Zhu
- Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Weiyong Liu
- Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Aiguo Liu
- Department of Otorhinolaryngology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yanjun Lu
- Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
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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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Ghasemnejad T, Shekari Khaniani M, Zarei F, Farbodnia M, Mansoori Derakhshan S. An update of common autosomal recessive non-syndromic hearing loss genes in Iranian population. Int J Pediatr Otorhinolaryngol 2017; 97:113-126. [PMID: 28483220 DOI: 10.1016/j.ijporl.2017.04.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2016] [Revised: 04/03/2017] [Accepted: 04/04/2017] [Indexed: 11/16/2022]
Abstract
Autosomal-recessive genes are responsible for about 80% of the hereditary non-syndromic hearing loss (NSHL) cases. In Iran, due to consanguineous marriages, NSHL is the second most frequent disability after intellectual disability, occurring one in 16 individuals. Enormous heterogeneity in the genetic pathology of hearing loss causes a major challenge in identification of responsible genes. In Iran, GJB2 is responsible for the most cases of pre-lingual and non-syndromic hearing loss (with frequency of 16.7%) which followed by other genes with lower frequency. Although several studies have indicated that a large proportion of both syndromic and non-syndromic hearing loss in Iranian populations are caused by defects in just a few genes, new detection strategies such as NGS (Next-generation sequencing) have increased the spectrum of responsible mutations. However, by applying this technique in Iran patients screening, the role of lots of novel related genes have been reported. In this review, we aim to describe function of these genes and their contribution to non-syndromic genetic hearing loss in Iranian population and we classify the genes by their functions.
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Affiliation(s)
- Tohid Ghasemnejad
- Neurosciences Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Department of Medical Genetic, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Fatemeh Zarei
- Department of Stem Cells and Developmental Biology at Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran
| | - Mina Farbodnia
- Department of Cellular and Molecular Biology, Faculty of Sciences, Saba University, Urmia, Iran
| | - Sima Mansoori Derakhshan
- Neurosciences Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Department of Medical Genetic, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
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Zheng J, Ying Z, Cai Z, Sun D, He Z, Gao Y, Zhang T, Zhu Y, Chen Y, Guan MX. GJB2 Mutation Spectrum and Genotype-Phenotype Correlation in 1067 Han Chinese Subjects with Non-Syndromic Hearing Loss. PLoS One 2015; 10:e0128691. [PMID: 26043044 PMCID: PMC4456361 DOI: 10.1371/journal.pone.0128691] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 04/29/2015] [Indexed: 11/17/2022] Open
Abstract
Mutations in Gap Junction Beta 2 (GJB2) have been reported to be a major cause of non-syndromic hearing loss in many populations worldwide. The spectrums and frequencies of GJB2 variants vary substantially among different ethnic groups, and the genotypes among these populations remain poorly understood. In the present study, we carried out a systematic and extended mutational screening of GJB2 gene in 1067 Han Chinese subjects with non-syndromic hearing loss, and the resultant GJB2 variants were evaluated by phylogenetic, structural and bioinformatic analysis. A total of 25 (23 known and 2 novel) GJB2 variants were identified, including 6 frameshift mutations, 1 nonsense mutation, 16 missense mutations and 2 silent mutations. In this cohort, c.235delC is the most frequently observed pathogenic mutation. The phylogenetic, structural and bioinformatic analysis showed that 2 novel variants c.127G>T (p.V43L), c.293G>C (p.R98P) and 2 known variants c. 107T>C (p.L36P) and c.187G>T (p.V63L) are localized at highly conserved amino acids. In addition, these 4 mutations are absent in 203 healthy individuals, therefore, they are probably the most likely candidate pathogenic mutations. In addition, 66 (24 novel and 42 known) genotypes were identified, including 6 homozygotes, 20 compound heterozygotes, 18 single heterozygotes, 21 genotypes harboring only polymorphism(s) and the wild type genotype. Among these, 153 (14.34%) subjects were homozygous for pathogenic mutations, 63 (5.91%) were compound heterozygotes, and 157 (14.71%) carried single heterozygous mutation. Furthermore, 65.28% (141/216) of these cases with two pathogenic mutations exhibited profound hearing loss. These data suggested that mutations in GJB2 gene are responsible for approximately 34.96% of non-syndromic hearing loss in Han Chinese population from Zhejiang Province in eastern China. In addition, our results also strongly supported the idea that other factors such as alterations in regulatory regions, additional genes, and environmental factors may contribute to the clinical manifestation of deafness.
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Affiliation(s)
- Jing Zheng
- Institute of Genetics, School of Medicine, Zhejiang University, Hangzhou, China
| | - Zhengbiao Ying
- Department of Otolaryngology, Wenling People’s Hospital, Wenzhou Medical University, Taizhou, China
| | - Zhaoyang Cai
- Department of Otolaryngology, Wenling People’s Hospital, Wenzhou Medical University, Taizhou, China
| | - Dongmei Sun
- Department of Laboratory Medicine, Jinhua Municipal Central Hospital, Jinhua, China
| | - Zheyun He
- Attardi Institute of Mitochondrial Biomedicine, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Yinglong Gao
- Attardi Institute of Mitochondrial Biomedicine, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Ting Zhang
- Department of Otolaryngology, Wenling People’s Hospital, Wenzhou Medical University, Taizhou, China
| | - Yi Zhu
- Department of Otolaryngology, the First Affiliated Hospital, Wenzhou Medical University, Wenzhou, China
| | - Ye Chen
- Institute of Genetics, School of Medicine, Zhejiang University, Hangzhou, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou, China
| | - Min-Xin Guan
- Institute of Genetics, School of Medicine, Zhejiang University, Hangzhou, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou, China
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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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Al-Sebeih K, Al-Kandari M, Al-Awadi SA, Hegazy FF, Al-Khamees GA, Naguib KK, Al-Dabbous RM. Connexin 26 gene mutations in non-syndromic hearing loss among Kuwaiti patients. Med Princ Pract 2014; 23:74-9. [PMID: 24080506 PMCID: PMC5586821 DOI: 10.1159/000348304] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 01/22/2013] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE To study connexin 26 (Cx26) gene mutations among autosomal recessive non-syndromal hearing loss in Kuwaiti patients and evaluate their effect on phenotypes. SUBJECTS AND METHODS This cross sectional study included 100 patients aged between 6 months and 18 years, who were referred to the Sheikh Salem Al-Ali Centre for audiology and speech evaluation of autosomal recessive non-syndromic sensorineural hearing loss confirmed by clinico-genetic evaluation and a battery of diagnostic tests. Gene profiling and sequencing were performed to detect the presence and nature of Cx26 mutation. RESULTS Of the 100 patients, mutation of Cx26 gene was detected in 15 patients (15%) of which 9 (60%) cases were heterozygous and 6 cases (40%) were homozygous. Eighty per cent of the 15 Cx26 positive cases resulted from the 35delG mutation. Among the heterozygous cases, 6 (66.6%) were positive for 35delG. All 6 homozygous patients were positive for the 35delG mutation. A significant correlation was found between genetic findings (p = 0.013) and family history (p = 0.029), as well as the onset (p = 0.015), course (p = 0.033), degree and configuration of hearing loss (p = 0.001). CONCLUSION Among the selected Kuwaiti population sample, the Cx26 gene mutation was responsible for 15% of autosomal recessive non-syndromic sensorineural hearing loss. We recommend that screening for Cx26 gene mutation be considered in the screening strategy of patients with non-syndromic childhood hearing loss for counselling and management purposes. .
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Affiliation(s)
- Khalid Al-Sebeih
- Department of Surgery, Faculty of Medicine, Health Science Center, Kuwait University, Kuwait City, Kuwait
- Department of Otolaryngology, Zain Hospital, Kuwait City, Kuwait
- *Khalid H. Al-Sebeih, MD, FRCSC, FACS, Department of Surgery – Otolaryngology Division, Faculty of Medicine, Kuwait University, PO Box 17228 Khalidiya, 72453 Kuwait City (Kuwait), E-Mail
| | | | | | - Fatma F. Hegazy
- Kuwait Medical Genetics Centre, Sabah Hospital, Kuwait City, Kuwait
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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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Castro LSSD, Marinho ANDR, Rodrigues EMR, Marques GCT, Carvalho TAAD, Silva LCSD, dos Santos SEB. A study of GJB2 and delGJB6-D13S1830 mutations in Brazilian non-syndromic deaf children from the Amazon region. Braz J Otorhinolaryngol 2013; 79:95-9. [PMID: 23503914 PMCID: PMC9450865 DOI: 10.5935/1808-8694.20130016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 11/02/2012] [Indexed: 12/12/2022] Open
Abstract
Objective Method Results Conclusion
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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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Yao J, Lu Y, Wei Q, Cao X, Xing G. A systematic review and meta-analysis of 235delC mutation of GJB2 gene. J Transl Med 2012; 10:136. [PMID: 22747691 PMCID: PMC3443034 DOI: 10.1186/1479-5876-10-136] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2011] [Accepted: 06/15/2012] [Indexed: 12/17/2022] Open
Abstract
Background The 235delC mutation of GJB2 gene is considered as a risk factor for the non-syndromic hearing loss (NSHL), and a significant difference in the frequency and distribution of the 235delC mutation has been described world widely. Methods A systematic review was performed by means of a meta-analysis to evaluate the influence of the 235delC mutation on the risk of NSHL. A literature search in electronic databases using keywords “235delC”, “GJB2” associated with “carrier frequency” was conducted to include all papers from January 1999 to June 2011. A total of 36 papers were included and there contained 13217 cases and 6521 controls derived from Oceania, American, Europe and Asian. Results A remarkable heterogeneity between these studies was observed. The combined results of meta-analysis showed that the 235delC mutant increased the risk of NSHL (OR = 7.9, 95%CI 4.77 ~ 13.11, P <0.00001). Meanwhile, heterogeneity of genetic effect was also observed due to the ethnic specificity and regional disparity. Therefore, the stratified meta-analysis was subsequently conducted and the results indicated that the 235delC mutation was significantly correlated with the risk of NHSL in the East Asian and South-east Asian populations (OR = 12.05, 95%CI 8.33~17.44, P <0.00001), but not significantly in the Oceania and European populations (OR = 10.36, 95%CI: 4.68~22.96, Z = 1.68, P >0.05). Conclusions The 235delC mutation of GJB2 gene increased the risk of NHSL in the East Asian and South-east Asian populations, but non-significantly associated with the NSHL susceptibility in Oceania and European populations, suggesting a significant ethnic specificity of this NSHL-associated mutation.
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Affiliation(s)
- Jun Yao
- Department of Biotechnology, School of Basic Medical Science, Nanjing Medical University, Nanjing 210029, People’s Republic of China
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12
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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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Homøe P, Koch A, Rendtorff ND, Lodahl M, Andersen T, Andersen S, Eiberg H, Nielsen IM, Tranebjærg L. GJB2(Connexin-26) mutations are not frequent among hearing impaired patients in East Greenland. Int J Audiol 2012; 51:433-6. [DOI: 10.3109/14992027.2012.660575] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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14
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Estimation of carrier frequencies of six autosomal-recessive Mendelian disorders in the Korean population. J Hum Genet 2011; 57:139-44. [PMID: 22170460 DOI: 10.1038/jhg.2011.144] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Although many studies have been performed to identify mutations in Korean patients with various autosomal-recessive Mendelian disorders (AR-MDs), little is known about the carrier frequencies of AR-MDs in the Korean population. Twenty common mutations from six AR-MDs, including Wilson disease (WD), non-syndromic hearing loss (NSHL), glycogen storage disease type Ia (GSD Ia), phenylketonuria (PKU), congenital hypothyroidism (CH), and congenital lipoid adrenal hyperplasia (CLAH) were selected to screen for based on previous studies. A total of 3057 Koreans were genotyped by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry followed by confirmation using the Sanger sequencing. We found 201 and 8 carriers with either one or two mutations in different genes, respectively, yielding a total carrier frequency of 1 in 15 (6.7%). Of the six AR-MDs, NSHL has the highest carrier frequency followed by WD, CH, CLAH, GSD Ia, and PKU. As carrier screening tests are becoming prevalent and the number of mutations known and tested is rising, a priori data on the carrier frequencies in different ethnic groups is mandatory to plan a population screening program and to estimate its efficiency. In light of this, the present results can be used as a basis to establish a screening policy for common AR-MRs in the Korean population.
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Kim SY, Lee BY, Lim JH, Ryu HM, Yang JH, Chung JH, Han HW, Park SY. Determination of the carrier frequencies of selectedGJB2mutations in the Korean population. Int J Audiol 2011; 50:694-8. [DOI: 10.3109/14992027.2011.563247] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [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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Fu S, Dong J, Wang C, Chen G. Parental attitudes toward genetic testing for prelingual deafness in China. Int J Pediatr Otorhinolaryngol 2010; 74:1122-5. [PMID: 20637511 DOI: 10.1016/j.ijporl.2010.06.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Revised: 06/17/2010] [Accepted: 06/19/2010] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Recent advances in molecular biology of hearing and deafness have made genetic testing an option for deaf individuals and their families. In China, DNA microarray and other genetic testing method has been applied to rapid genetic diagnosis of non-syndromic hearing loss. However, there is no information about the interests in such testing in China. The purpose of this study is to document the attitudes of parents with normal hearing who have one or more deaf children toward diagnostic, carrier, and prenatal genetic testing for deafness. METHODS A structured, self-completion questionnaire was given to delegates at a conference held at Hubei Rehabilitation Research Center for Deaf Children, Wuhan, China on March 3, 2010. Of 366 surveys distributed, 290 were completed and returned. RESULTS Ninety-four percent of the respondents had a positive attitude toward genetic testing. Seventy-two percent stated that they were interested in genetic testing of deaf child. Of the individuals who were interested in such testing, 69% would consider having prenatal genetic testing for deafness. CONCLUSION The present study provided evidence of a predominantly positive attitude toward genetics. Appropriate genetic counseling can help parents to understand the risk, benefits, and limitations of genetic testing for prelingual deafness.
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Affiliation(s)
- Siqing Fu
- Department of Medical Genetics, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
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Sequence Variations and Haplotypes of the GJB2 Gene Revealed by Resequencing of 192 Chromosomes from the General Population in Korea. Clin Exp Otorhinolaryngol 2010; 3:65-9. [PMID: 20607074 PMCID: PMC2896735 DOI: 10.3342/ceo.2010.3.2.65] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Accepted: 05/04/2010] [Indexed: 11/08/2022] Open
Abstract
Objectives Hearing impairment (HI) is the most common sensory deficit in human. The Gap Junction Protein, Beta-2 (GJB2) gene encodes the protein connexin 26, and this gene accounts for up to half of the cases of autosomal recessive nonsyndromic HI. This study was conducted to obtain a set of sequence variations (SVs) of the GJB2 gene among Koreans from the general population for making molecular genetic diagnoses and performing genetic counseling. Methods We resequenced the GJB2 gene in 192 chromosomes from 96 adult individuals of Korean descent and who were without a history of hearing difficulty. The data of the SVs was obtained and the haplotypes were reconstructed from the data. Results Five SVs were observed, including a novel one (c.558G>A; p.T186T), with the allele frequencies ranging from 0.5% (1/192) to 41% (79/192). The linkage disequilibrium study and haplotype construction showed that some of the SVs are in tight linkage, resulting in a limited number of haplotypes. Conclusion We observed SVs of the GJB2 gene with different allele frequencies, and a limited number of haplotypes were constructed. The data from this study can be used as reference data for GJB2-related hearing genetic studies, including studies on the founder effect and population genetics, and this data is particularly relevant to people of East Asian decent.
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Tsukada K, Nishio S, Usami S. A large cohort study ofGJB2mutations in Japanese hearing loss patients. Clin Genet 2010; 78:464-70. [DOI: 10.1111/j.1399-0004.2010.01407.x] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Yuan Y, You Y, Huang D, Cui J, Wang Y, Wang Q, Yu F, Kang D, Yuan H, Han D, Dai P. Comprehensive molecular etiology analysis of nonsyndromic hearing impairment from typical areas in China. J Transl Med 2009; 7:79. [PMID: 19744334 PMCID: PMC2754984 DOI: 10.1186/1479-5876-7-79] [Citation(s) in RCA: 127] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Accepted: 09/10/2009] [Indexed: 12/04/2022] Open
Abstract
Background Every year, 30,000 babies are born with congenital hearing impairment in China. The molecular etiology of hearing impairment in the Chinese population has not been investigated thoroughly. To provide appropriate genetic testing and counseling to families, we performed a comprehensive investigation of the molecular etiology of nonsyndromic deafness in two typical areas from northern and southern China. Methods A total of 284 unrelated school children with hearing loss who attended special education schools in China were enrolled in this study, 134 from Chifeng City in Inner Mongolia and the remaining 150 from Nangtong City in JiangSu Province. Screening was performed for GJB2, GJB3, GJB6, SLC26A4, 12S rRNA, and tRNAser(UCN) genes in this population. All patients with SLC26A4 mutations or variants were subjected to high-resolution temporal bone CT scan to verify the enlarged vestibular aqueduct. Results Mutations in the GJB2 gene accounted for 18.31% of the patients with nonsyndromic hearing loss, 1555A>G mutation in mitochondrial DNA accounted for 1.76%, and SLC26A4 mutations accounted for 13.73%. Almost 50% of the patients with nonsyndromic hearing loss in these typical Chinese areas carried GJB2 or SLC26A4 mutations. No significant differences in mutation spectrum or prevalence of GJB2 and SLC26A4 were found between the two areas. Conclusion In this Chinese population, 54.93% of cases with hearing loss were related to genetic factors. The GJB2 gene accounted for the etiology in about 18.31% of the patients with hearing loss, SLC26A4 accounted for about 13.73%, and mtDNA 1555A>G mutation accounted for 1.76%. Mutations in GJB3, GJB6, and mtDNA tRNAser(UCN) were not common in this Chinese cohort. Conventionally, screening is performed for GJB2, SLC26A4, and mitochondrial 12S rRNA in the Chinese deaf population.
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Affiliation(s)
- Yongyi Yuan
- Department of Otolaryngology, PLA General Hospital, Beijing, PR China.
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GJB2 mutation spectrum in 2,063 Chinese patients with nonsyndromic hearing impairment. J Transl Med 2009; 7:26. [PMID: 19366456 PMCID: PMC2679712 DOI: 10.1186/1479-5876-7-26] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Accepted: 04/14/2009] [Indexed: 11/10/2022] Open
Abstract
Background Mutations in GJB2 are the most common molecular defects responsible for autosomal recessive nonsyndromic hearing impairment (NSHI). The mutation spectra of this gene vary among different ethnic groups. Methods In order to understand the spectrum and frequency of GJB2 mutations in the Chinese population, the coding region of the GJB2 gene from 2063 unrelated patients with NSHI was PCR amplified and sequenced. Results A total of 23 pathogenic mutations were identified. Among them, five (p.W3X, c.99delT, c.155_c.158delTCTG, c.512_c.513insAACG, and p.Y152X) are novel. Three hundred and seven patients carry two confirmed pathogenic mutations, including 178 homozygotes and 129 compound heterozygotes. One hundred twenty five patients carry only one mutant allele. Thus, GJB2 mutations account for 17.9% of the mutant alleles in 2063 NSHI patients. Overall, 92.6% (684/739) of the pathogenic mutations are frame-shift truncation or nonsense mutations. The four prevalent mutations; c.235delC, c.299_c.300delAT, c.176_c.191del16, and c.35delG, account for 88.0% of all mutantalleles identified. The frequency of GJB2 mutations (alleles) varies from 4% to 30.4% among different regions of China. It also varies among different sub-ethnic groups. Conclusion In some regions of China, testing of the three most common mutations can identify at least one GJB2 mutant allele in all patients. In other regions such as Tibet, the three most common mutations account for only 16% the GJB2 mutant alleles. Thus, in this region, sequencing of GJB2 would be recommended. In addition, the etiology of more than 80% of the mutant alleles for NSHI in China remains to be identified. Analysis of other NSHI related genes will be necessary.
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Abidi O, Boulouiz R, Nahili H, Bakhouch K, Wakrim L, Rouba H, Chafik A, Hassar M, Barakat A. Carrier frequencies of mutations/polymorphisms in the connexin 26 gene (GJB2) in the Moroccan population. ACTA ACUST UNITED AC 2009; 12:569-74. [PMID: 19072567 DOI: 10.1089/gte.2008.0063] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Mutations in the Connexin 26 gene (GJB2/Cx26) are responsible for more than half of all cases of prelingual nonsyndromic recessive deafness in Caucasians. The carrier frequency of the 35delG-GJB2 mutation was found to be as high as 2-4% in the Mediterranean populations. Different GJB2 mutations were reported in the Moroccan patients with autosomal recessive nonsyndromic hearing loss; however, rare studies were carried out on the carrier frequencies of these mutations in the healthy populations. The aim of this study was to estimate the carrier frequencies of the GJB2 mutations in the Moroccan population. The molecular analysis of the 35delG mutation and other GJB2 sequence variations was performed in 386 healthy unrelated Moroccan individuals with no known hearing loss. Five GJB2 sequence variations at heterozygous state were found: two mutations, 35delG and 109G > A (V37I), and three polymorphisms, 79G > A (V27I), 341G > A (E114G), and 457G > A (V153I). The carrier frequency of the 35delG mutation was the highest with 2.07% [95% confidence interval (0.90-4.04%)], followed by that of the V37I mutation with 1.43% (0.06-5.39). The carrier frequency of V27I, E114G, and V153I changes was estimated to be 0.71% (0.01-4.34). This finding shows that the 35delG carrier frequency found here is similar to the one observed in Mediterranean populations. It provides new information about GJB2 carrier rates facilitating the diagnosis and the genetic counseling in the Moroccan population.
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Affiliation(s)
- Omar Abidi
- Laboratory of Human Genetics, Department of Scientific Research, Pasteur Institute, Casablanca, Morocco
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Carrier frequency of GJB2 (connexin-26) mutations causing inherited deafness in the Korean population. J Hum Genet 2008; 53:1022-1028. [DOI: 10.1007/s10038-008-0342-7] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2008] [Accepted: 10/19/2008] [Indexed: 10/21/2022]
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Dai P, Yuan Y, Huang D, Zhu X, Yu F, Kang D, Yuan H, Wu B, Han D, Wong LJC. Molecular etiology of hearing impairment in Inner Mongolia: mutations in SLC26A4 gene and relevant phenotype analysis. J Transl Med 2008; 6:74. [PMID: 19040761 PMCID: PMC2630943 DOI: 10.1186/1479-5876-6-74] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2008] [Accepted: 11/30/2008] [Indexed: 11/15/2022] Open
Abstract
Background The molecular etiology of hearing impairment in Chinese has not been thoroughly investigated. Study of GJB2 gene revealed that 30.4% of the patients with hearing loss in Inner Mongolia carried GJB2 mutations. The SLC26A4 gene mutations and relevant phenotype are analyzed in this study. Methods One hundred and thirty-five deaf patients were included. The coding exons of SLC26A4 gene were sequence analyzed in 111 patients, not including 22 patients carrying bi-allelic GJB2 mutations or one patient carrying a known GJB2 dominant mutation as well as one patient with mtDNA 1555A>G mutation. All patients with SLC26A4 mutations or variants were subjected to high resolution temporal bone CT scan and those with confirmed enlarged vestibular aqueduct and/or other inner ear malformation were then given further ultrasound scan of thyroid and thyroid hormone assays. Results Twenty-six patients (19.26%, 26/135) were found carrying SLC26A4 mutation. Among them, 17 patients with bi-allelic SLC26A4 mutations were all confirmed to have EVA or other inner ear malformation by CT scan. Nine patients were heterozygous for one SLC26A4 mutation, including 3 confirmed to be EVA or EVA and Mondini dysplasia by CT scan. The most common mutation, IVS7-2A>G, accounted for 58.14% (25/43) of all SLC26A4 mutant alleles. The shape and function of thyroid were confirmed to be normal by thyroid ultrasound scan and thyroid hormone assays in 19 of the 20 patients with EVA or other inner ear malformation except one who had cystoid change in the right side of thyroid. No Pendred syndrome was diagnosed. Conclusion In Inner Mongolia, China, mutations in SLC26A4 gene account for about 12.6% (17/135) of the patients with hearing loss. Together with GJB2 (23/135), SLC26A4 are the two most commonly mutated genes causing deafness in this region. Pendred syndrome is not detected in this deaf population. We established a new strategy that detects SLC26A4 mutations prior to the temporal bone CT scan to find EVA and inner ear malformation patients. This model has a unique advantage in epidemiologic study of large deaf population.
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Affiliation(s)
- Pu Dai
- Department of Otolaryngology and Genetic Testing Center for Deafness, Chinese PLA General Hospital, Beijing, PR China.
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Abidi O, Boulouiz R, Nahili H, Imken L, Rouba H, Chafik A, Barakat A. The analysis of three markers flanking GJB2 gene suggests a single origin of the most common 35delG mutation in the Moroccan population. Biochem Biophys Res Commun 2008; 377:971-4. [PMID: 18952066 DOI: 10.1016/j.bbrc.2008.10.086] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2008] [Accepted: 10/20/2008] [Indexed: 11/28/2022]
Abstract
In Caucasian populations a single mutation, 35delG, accounts for the majority of GJB2 gene mediated hearing loss, with carrier frequencies estimated between 2-4%, possibly resulting from a founder effect rather than from a mutational hot spot. In Moroccan population, the 35delG mutation accounts for 90.8% of all GJB2 mutated alleles in deaf patients with a carrier frequency of 2.65%. The aim of this study was to evaluate whether the 35delG mutation has derived from a single origin in the Moroccan population. We enrolled 30 unrelated deaf patients homozygous for the 35delG mutation and 165 unrelated control individuals negative for this mutation, and genotyped three microsatellite markers flanking the GJB2 region: D13S141, D13S175 and D13S143. Data analysis revealed that the 35delG mutation is associated with particular alleles of these markers, with significant linkage disequilibrium for the 125 and 105 nucleotide long alleles of D13S141 and D13S175, and that a single specific haplotype accounts for 68% of the chromosomes carrying the 35delG mutation. The estimate age of 35delG mutation is 135 generations or approximately 2700 years old. Like in other Mediterranean populations, our results suggest that in the Moroccan population the 35delG mutation has derived from a single origin in a common founder process.
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Affiliation(s)
- Omar Abidi
- Laboratoire de Génétique Humaine, Département des Recherches Scientifiques, Institut Pasteur, Morocco. 1, Place Louis Pasteur, Casablanca 20100, Morocco.
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Niceta M, Fabiano C, Sammarco P, Piccione M, Antona V, Giuffrè M, Corsello G. Epidemiological study of nonsyndromic hearing loss in Sicilian newborns. Am J Med Genet A 2007; 143A:1666-70. [PMID: 17568408 DOI: 10.1002/ajmg.a.31836] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- M Niceta
- Laboratorio di Genetica Molecolare, Ospedale V. Cervello, Palermo, Sicily, Italy.
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Ramsebner R, Volker R, Lucas T, Hamader G, Weipoltshammer K, Baumgartner WD, Wachtler FJ, Kirschhofer K, Frei K. High Incidence of GJB2 Mutations During Screening of Newborns for Hearing Loss in Austria. Ear Hear 2007; 28:298-301. [PMID: 17485979 DOI: 10.1097/aud.0b013e318047932d] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES The aim of the present study was to evaluate gap junction protein beta2 (GJB2) genetic testing within a national neonate screening program for hearing loss (HL) in a European population. DESIGN Neonatal cases of nonsyndromic HL (N = 21) were identified by postpartal otoacoustic emissions (OAE) and brain stem electric response audiometry (BERA) analysis. GJB2 testing was performed by direct sequencing. RESULTS Mutations in GJB2 were found in 15 of 21 children (71.4%) identified by neonatal audiological screening. The 35delG mutation in GJB2 was found homozygous in 10 cases (47.6%) and also as a clear cause of HL as the heterozygous alterations 35delG/del311-324 and 35delG/L90P. In a single case, L90P/R143Q was also identified as a cause of HL. In 3 HL cases that were not identifiable during initial OAE testing, homozygous 35delG and 35delG/R184P defined the genetic basis for HL in 2 cases, whereas one case had wild-type GJB2. CONCLUSIONS Our findings of the high mutation rate in the Austrian population, especially in neonates identified during the newborn screening program, confirm the importance of screening for mutations in GJB2.
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Affiliation(s)
- Reinhard Ramsebner
- Department of Otorhinolaryngology, Medical University of Vienna, Austria
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Huculak C, Bruyere H, Nelson TN, Kozak FK, Langlois S. V37I connexin 26 allele in patients with sensorineural hearing loss: evidence of its pathogenicity. Am J Med Genet A 2007; 140:2394-400. [PMID: 17036313 DOI: 10.1002/ajmg.a.31486] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Sensorineural hearing loss (SNHL) is the most common inherited sensory disorder, reported in 1-3 of every 1,000 births. It has been estimated that 50% of all cases of prelingual SNHL are genetically determined. There is tremendous genetic heterogeneity, with multiple dominant and recessive loci. Mutations of the gap junction beta-2 gene (GJB2) emerge as a leading cause of autosomal recessive non-syndromic SNHL. Over 90 sequence alterations have been reported, the pathogenicity of some of them being unknown or unclear. The status of the V37I allele of connexin 26 (GJB2 amino acid product) with regards to its association with SNHL has been controversial. This study examines the pathogenicity of V37I by comparing the frequency of this allele in 40 patients with SNHL of Chinese and Caucasian descent with the frequency of the allele in 100 anonymized, ethnically matched controls. The V37I allele was identified in 43.75 and 11.5% of the patient and control alleles of Chinese ethnicity, respectively, but was not found in either Caucasian cohort. We also compiled the audiograms of 15 individuals with SNHL homozygous for the V37I allele, and showed that these individuals present with a mild to moderate SNHL. These results indicate that (1) the V37I allele is common in individuals of Chinese descent but rarely present in individuals of Caucasian decent; and (2) the V37I allele is pathogenic, but produces milder hearing loss compared to nonsense mutations of connexin 26 such as the 35delG mutation.
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Affiliation(s)
- C Huculak
- Department of Medical Genetics, University of British Columbia, Vancouver, Canada
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Tang HY, Fang P, Ward PA, Schmitt E, Darilek S, Manolidis S, Oghalai JS, Roa BB, Alford RL. DNA sequence analysis of GJB2, encoding connexin 26: observations from a population of hearing impaired cases and variable carrier rates, complex genotypes, and ethnic stratification of alleles among controls. Am J Med Genet A 2007; 140:2401-15. [PMID: 17041943 PMCID: PMC3623690 DOI: 10.1002/ajmg.a.31525] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Mutations in GJB2 are associated with hereditary hearing loss. DNA sequencing of GJB2 in a cohort of hearing impaired patients and a multi-ethnic control group is reported. Among 610 hearing impaired cases, 43 DNA sequence variations were identified in the coding region of GJB2 including 24 mutations, 8 polymorphisms, 3 unclassified variants (G4D, R127C, M163V), 1 controversial variant (V37I), and 7 novel variants (G12C, N14D, V63A, T86M, L132V, D159, 592_600delinsCAGTGTTCATGACATTC). Sixteen non-coding sequence variations were also identified among cases including the IVS1+1A>G mutation, 2 polymorphisms, and 13 novel variants. A diagnosis of GJB2-associated hearing loss was confirmed for 63 cases (10.3%). Heterozygous mutations were found in 39 cases (6.4%). Eleven cases carrying novel or unclassified variants (1.8 %) and 18 cases carrying the controversial V37I variant were identified (3%). In addition, 294 control subjects from 4 ethnic groups were sequenced for GJB2. Thirteen sequence variations in the coding region of GJB2 were identified among controls including 2 mutations, 6 polymorphisms, 2 unclassified variants (G4D, T123N), 1 controversial variant (V37I), and 2 novel variants (R127L, V207L). Nine sequence variations were identified among controls in the non-coding regions in and around GJB2 exon 2. Of particular interest among controls were the variability in carrier rates and ethnic stratification of alleles, and the complex genotypes among Asians, 47% of whom carried two to four sequence variations in the coding region of GJB2. These data provide new information about carrier rates for GJB2-based hearing loss in various ethnic groups and contribute to evaluation of the pathogenicity of the controversial V37I variant.
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Affiliation(s)
- Hsiao-Yuan Tang
- Bobby R. Alford Department of Otolaryngology—Head and Neck Surgery, Baylor College of Medicine, Houston, Texas
| | - Ping Fang
- Medical Genetics Laboratories, Baylor College of Medicine, Houston, Texas
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Patricia A. Ward
- Medical Genetics Laboratories, Baylor College of Medicine, Houston, Texas
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Eric Schmitt
- Medical Genetics Laboratories, Baylor College of Medicine, Houston, Texas
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Sandra Darilek
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Spiros Manolidis
- Department of Otolaryngology—Head and Neck Surgery, Columbia University, New York, New York
| | - John S. Oghalai
- Bobby R. Alford Department of Otolaryngology—Head and Neck Surgery, Baylor College of Medicine, Houston, Texas
| | - Benjamin B. Roa
- Medical Genetics Laboratories, Baylor College of Medicine, Houston, Texas
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Raye Lynn Alford
- Bobby R. Alford Department of Otolaryngology—Head and Neck Surgery, Baylor College of Medicine, Houston, Texas
- Correspondence to: Raye Lynn Alford, Ph.D., F.A.C.M.G., Bobby R. Alford Department of Otolaryngology—Head and Neck Surgery, Baylor College of Medicine, One Baylor Plaza, NA102, Houston 77030, TX.
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Pu D, Yi-wen Y, Jing-hong C, Fei Y, Bing H, Dong-yang K, Hui-jun Y, Dong-yi H. GJB2 mutation spectrum in deaf population in a typical southeastern area of China. J Otol 2006. [DOI: 10.1016/s1672-2930(06)50020-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Pagarkar W, Bitner-Glindzicz M, Knight J, Sirimanna T. Late postnatal onset of hearing loss due to GJB2 mutations. Int J Pediatr Otorhinolaryngol 2006; 70:1119-24. [PMID: 16469394 DOI: 10.1016/j.ijporl.2005.10.026] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2005] [Revised: 10/22/2005] [Accepted: 10/27/2005] [Indexed: 10/25/2022]
Abstract
GJB2 mutations account for approximately 50% of recessive non-syndromic deafness, with 35delG being the most prevalent. Homozygous 35delG mutations cause pre-lingual, non-progressive hearing loss that is detected on newborn hearing screening programmes. We present a sibling pair with homozygous 35delG mutations, who passed hearing tests in early infancy and developed progressive sensorineural hearing loss, one requiring a cochlear implant. These cases illustrate that deafness due to such mutations may have a late onset and consequently be missed on neonatal screening programmes and they may present an argument to consider neonatal screening for GJB2 mutations in order to aid early intervention.
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Affiliation(s)
- Waheeda Pagarkar
- Department of Audiology, Great Ormond Street Hospital for Children, Great Ormond Street, London, WC1N 3JH, UK
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Noguchi Y, Yashima T, Hatanaka A, Uzawa M, Yasunami M, Kimura A, Kitamura K. A mutation in Wolfram syndrome type 1 gene in a Japanese family with autosomal dominant low-frequency sensorineural hearing loss. Acta Otolaryngol 2005; 125:1189-94. [PMID: 16353398 DOI: 10.1080/00016480510044232] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
CONCLUSION Our findings suggest that Wolfram syndrome type 1 gene (WFS1) mutation is an important cause of autosomal dominant low-frequency sensorineural hearing loss (LFSNHL) in Japan. OBJECTIVE DFNA6/14 is caused by a heterozygous mutation of WFS1 and is a common cause of autosomal dominant LFSNHL among populations in both Europe and the US. The purpose of this study was to investigate WFS1 mutations among Japanese patients whose phenotypes were consistent with those of DFNA6/14. MATERIAL AND METHODS Using audiometry and genetic analysis, we searched for WFS1 mutations in three unrelated Japanese patients with LFSNHL and a familial history of autosomal dominant hearing loss. RESULTS One patient carried a heterozygous G2700A mutation at codon 844 in exon 8, resulting in substitution of a threonine for an alanine (A844T). Genetic analysis of the available members of the patient's family showed that the A844T mutation segregated with LFSNHL, but was not detected in any of 140 control chromosomes. It thus appears likely that the A844T mutation is causative for hearing loss in this group. Speech audiometry, self-recording audiometry and auditory brainstem responses showed the patient to have cochlear deafness without retrocochlear dysfunction. No mutation was found in the other two patients.
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Affiliation(s)
- Yoshihiro Noguchi
- Department of Otolaryngology, Graduate School, Medical Research Institute and Laboratory of Genomic Diversity, School of Biomedical Science, Tokyo Medical and Dental University, Tokyo, Japan.
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