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Chen PY, Yang TW, Tseng YS, Tsai CY, Yeh CS, Lee YH, Lin PH, Lin TC, Wu YJ, Yang TH, Chiang YT, Hsu JSJ, Hsu CJ, Chen PL, Chou CF, Wu CC. Machine learning-based longitudinal prediction for GJB2-related sensorineural hearing loss. Comput Biol Med 2024; 176:108597. [PMID: 38763069 DOI: 10.1016/j.compbiomed.2024.108597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 05/09/2024] [Accepted: 05/10/2024] [Indexed: 05/21/2024]
Abstract
BACKGROUND Recessive GJB2 variants, the most common genetic cause of hearing loss, may contribute to progressive sensorineural hearing loss (SNHL). The aim of this study is to build a realistic predictive model for GJB2-related SNHL using machine learning to enable personalized medical planning for timely intervention. METHOD Patients with SNHL with confirmed biallelic GJB2 variants in a nationwide cohort between 2005 and 2022 were included. Different data preprocessing protocols and computational algorithms were combined to construct a prediction model. We randomly divided the dataset into training, validation, and test sets at a ratio of 72:8:20, and repeated this process ten times to obtain an average result. The performance of the models was evaluated using the mean absolute error (MAE), which refers to the discrepancy between the predicted and actual hearing thresholds. RESULTS We enrolled 449 patients with 2184 audiograms available for deep learning analysis. SNHL progression was identified in all models and was independent of age, sex, and genotype. The average hearing progression rate was 0.61 dB HL per year. The best MAE for linear regression, multilayer perceptron, long short-term memory, and attention model were 4.42, 4.38, 4.34, and 4.76 dB HL, respectively. The long short-term memory model performed best with an average MAE of 4.34 dB HL and acceptable accuracy for up to 4 years. CONCLUSIONS We have developed a prognostic model that uses machine learning to approximate realistic hearing progression in GJB2-related SNHL, allowing for the design of individualized medical plans, such as recommending the optimal follow-up interval for this population.
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Affiliation(s)
- Pey-Yu Chen
- Department of Otolaryngology, MacKay Memorial Hospital, Taipei, Taiwan; Department of Audiology and Speech-Language Pathology, Mackay Medical College, New Taipei City, Taiwan; Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan
| | - Ta-Wei Yang
- Graduate Institute of Networking and Multimedia, National Taiwan University, Taipei, Taiwan
| | - Yi-Shan Tseng
- Department of Computer Science & Information Engineering, National Taiwan University, Taipei, Taiwan
| | - Cheng-Yu Tsai
- Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan; Graduate Institute of Medical Genomics and Proteomics, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Chiung-Szu Yeh
- Department of Computer Science & Information Engineering, National Taiwan University, Taipei, Taiwan
| | - Yen-Hui Lee
- Department of Otolaryngology, National Taiwan University Biomedical Park Hospital, Hsinchu County, Taiwan; Department of Otolaryngology, National Taiwan University Hospital Hsin-Chu Branch, Hsinchu City, Taiwan; Hearing and Speech Center, National Taiwan University Hospital, Taipei, Taiwan
| | - Pei-Hsuan Lin
- Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan; Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ting-Chun Lin
- Department of Computer Science & Information Engineering, National Taiwan University, Taipei, Taiwan
| | - Yu-Jen Wu
- Department of Computer Science & Information Engineering, National Taiwan University, Taipei, Taiwan
| | - Ting-Hua Yang
- Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan
| | - Yu-Ting Chiang
- Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan; Graduate Institute of Medical Genomics and Proteomics, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Jacob Shu-Jui Hsu
- Graduate Institute of Medical Genomics and Proteomics, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Chuan-Jen Hsu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan; Department of Otorhinolaryngology-Head and Neck Surgery, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung, Taiwan; School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Pei-Lung Chen
- Graduate Institute of Medical Genomics and Proteomics, National Taiwan University College of Medicine, Taipei, Taiwan; Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan
| | - Chen-Fu Chou
- Department of Computer Science & Information Engineering, National Taiwan University, Taipei, Taiwan
| | - Chen-Chi Wu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan; Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan; Department of Medical Research, National Taiwan University Hospital Hsin-Chu Branch, Hsin-Chu, Taiwan.
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Franz L, Incognito A, Gallo C, Turolla L, Scquizzato E, Cenedese R, Matarazzo A, Savegnago D, Zanatta P, Genovese E, de Filippis C, Marioni G. Audiological Phenotypes of Connexin Gene Mutation Patterns: A Glance at Different GJB2/GJB6 Gene Mutation Profiles. CHILDREN (BASEL, SWITZERLAND) 2024; 11:194. [PMID: 38397306 PMCID: PMC10887074 DOI: 10.3390/children11020194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 01/28/2024] [Accepted: 02/01/2024] [Indexed: 02/25/2024]
Abstract
GJB2 mutations are the most common cause of autosomal-recessive non-syndromic sensorineural hearing loss (SNHL). The available evidence shows large phenotypic variability across different genotypes and allelic variants. The aim of this study was to investigate the clinical and audiological features of a cohort of subjects with different GJB2/GJB6 gene mutation profiles from a tertiary referral center in Northeastern Italy. We considered 57 patients with GJB2/GJB6 mutations presenting with congenital, non-syndromic SNHL, mainly coming from the Veneto region (Italy). The samples were screened for mutations in exons 1 and 2 of the GJB2 gene and for the GJB6 gene deletion del (GJB6-D13S1830). Free-field and air-conduction frequency-specific thresholds and the pure-tone average (PTA) were considered in the statistical analysis. Five patients (8.87%) had connexin gene mutations in simple heterozygosis, 15 (26.31%) in compound heterozygosis, 34 (59.64%) in homozygosis, and 3 (5.26%) with digenic patterns. The frequency-specific air-conduction thresholds showed significantly different mean values across the different genotypes (Roy's largest-root test, p = 0.0473). Despite the evidence already available on genetic SNHL, many new insights are to be expected. Further large-scale prospective studies including different populations are necessary to confirm these preliminary findings about the clinical and audiological features of patients with different GJB2/GJB6 gene mutation patterns.
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Affiliation(s)
- Leonardo Franz
- Phoniatrics and Audiology Unit, Department of Neuroscience DNS, University of Padova, 35122 Treviso, Italy; (L.F.); (A.I.); (C.G.); (R.C.); (D.S.); (C.d.F.)
| | - Alessandro Incognito
- Phoniatrics and Audiology Unit, Department of Neuroscience DNS, University of Padova, 35122 Treviso, Italy; (L.F.); (A.I.); (C.G.); (R.C.); (D.S.); (C.d.F.)
| | - Chiara Gallo
- Phoniatrics and Audiology Unit, Department of Neuroscience DNS, University of Padova, 35122 Treviso, Italy; (L.F.); (A.I.); (C.G.); (R.C.); (D.S.); (C.d.F.)
| | - Licia Turolla
- Medical Genetics Unit, Treviso Hospital, 31100 Treviso, Italy;
| | - Elisa Scquizzato
- Molecular Pathology Laboratory, Unit of Pathological Anatomy, Treviso Hospital, 31100 Treviso, Italy;
| | - Roberta Cenedese
- Phoniatrics and Audiology Unit, Department of Neuroscience DNS, University of Padova, 35122 Treviso, Italy; (L.F.); (A.I.); (C.G.); (R.C.); (D.S.); (C.d.F.)
| | - Alessandro Matarazzo
- Phoniatrics and Audiology Unit, Department of Neuroscience DNS, University of Padova, 35122 Treviso, Italy; (L.F.); (A.I.); (C.G.); (R.C.); (D.S.); (C.d.F.)
| | - Daniel Savegnago
- Phoniatrics and Audiology Unit, Department of Neuroscience DNS, University of Padova, 35122 Treviso, Italy; (L.F.); (A.I.); (C.G.); (R.C.); (D.S.); (C.d.F.)
| | - Paolo Zanatta
- Department of Anesthesiology and Critical Care, Treviso Hospital, 31100 Treviso, Italy;
| | - Elisabetta Genovese
- Otorhinolaryngology Unit, Department of Medical and Surgical Sciences for Children and Adults, University of Modena and Reggio Emilia, 41121 Modena, Italy;
| | - Cosimo de Filippis
- Phoniatrics and Audiology Unit, Department of Neuroscience DNS, University of Padova, 35122 Treviso, Italy; (L.F.); (A.I.); (C.G.); (R.C.); (D.S.); (C.d.F.)
| | - Gino Marioni
- Phoniatrics and Audiology Unit, Department of Neuroscience DNS, University of Padova, 35122 Treviso, Italy; (L.F.); (A.I.); (C.G.); (R.C.); (D.S.); (C.d.F.)
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3
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Genetic etiology of non-syndromic hearing loss in Europe. Hum Genet 2022; 141:683-696. [PMID: 35044523 DOI: 10.1007/s00439-021-02425-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Accepted: 12/20/2021] [Indexed: 12/17/2022]
Abstract
Hearing impairment not etiologically associated with clinical signs in other organs (non-syndromic) is genetically heterogeneous, so that over 120 genes are currently known to be involved. The frequency of mutations in each gene and the most frequent mutations vary throughout populations. Here we review the genetic etiology of non-syndromic hearing impairment (NSHI) in Europe. Over the years, epidemiological data were scarce because of the large number of involved genes, whose screening was not cost-effective until implementation of massively parallel DNA sequencing. In Europe, the most common form of autosomal recessive NSHI is DFNB1, which accounts for 11-57% of the cases. Mutations in STRC account for 16% of the recessive cases, and only a few more (MYO15A, MYO7A, LOXHD1, USH2A, TMPRSS3, CDH23, TMC1, OTOF, OTOA, SLC26A4, ADGRV1 and TECTA) have contributions higher than 2%. As regards autosomal-dominant NSHI, DFNA22 (MYO6) and DFNA8/12 (TECTA) represent the most common forms, accounting for 21% and 18% of elucidated cases, respectively. The contribution of ACTG1 and WFS1 drops to 9% in both cases, followed by POU4F3 (6.5%), MYO7A (5%), MYH14 and COL11A2 (4% each). Four additional genes contribute 2.5% each one (MITF, KCNQ4, EYA4, SOX10) and the remaining are residually represented. X-linked hearing loss and maternally-inherited NSHI have minor contributions in most countries. Further knowledge on the genetic epidemiology of NSHI in Europe needs a standardization of the experimental approaches and a stratification of the results according to clinical features, familial history and patterns of inheritance, to facilitate comparison between studies.
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Ding Y, Zhang S, Guo Q, Zheng H. Mitochondrial Diabetes is Associated with tRNA Leu(UUR) A3243G and ND6 T14502C Mutations. Diabetes Metab Syndr Obes 2022; 15:1687-1701. [PMID: 35685248 PMCID: PMC9172734 DOI: 10.2147/dmso.s363978] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 05/26/2022] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Mutations in mitochondrial DNA (mtDNA) are associated with type 2 diabetes mellitus (T2DM). In particular, m.A3243G is the most common T2DM-related mtDNA mutation in many families worldwide. However, the clinical features and pathophysiology of m.A3243G-induced T2DM are largely undefined. METHODS Two pedigrees with maternally inherited T2DM were underwent clinical, molecular and biochemical assessments. The mtDNA genes were PCR amplified and sequenced. Mitochondrial adenosine triphosphate (ATP) and reactive oxygen species (ROS) were measured in polymononuclear leukocytes derived from three patients with both the m.A3243G and m.T14502C mutations, three patients with only the m.A3243G mutation and three controls without these mutations. Moreover, GJB2, GJB3 and GJB6 mutations were screened by PCR-Sanger sequencing. RESULTS Members of the two pedigrees manifestated variable clinical phenotypes including diabetes and hearing and vision impairments. The age at onset of T2DM varied from 31 to 66 years, with an average of 41 years. Mutational analysis of mitochondrial genomes indicated the presence of the m.A3243G mutation in both pedigrees. Matrilineal relatives in one of the pedigrees harbored the coexisting of m.A3243G and m.T14502C mutations. Remarkably, the m.T14502C mutation, which causes the substitution of a conserved isoleucine for valine at position 58 in ND6 mRNA, may affect the mitochondrial respiratory chain functions. Biochemical analysis revealed that cell lines bearing both the m.A3243G and m.T14502C mutations exhibited greater reductions in ATP levels and increased ROS production compared with those carrying only the m.A3243G mutation. However, we did not find any mutations in the GJB2, GJB3 and GJB6 genes. CONCLUSION Our study indicated that mitochondrial diabetes is associated with the tRNALeu(UUR) A3243G and ND6 T14502C mutations.
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Affiliation(s)
- Yu Ding
- Central Laboratory, Hangzhou First People’s Hospital, Hangzhou, 310006, Zhejiang, People’s Republic of China
- Correspondence: Yu Ding, Central Laboratory, Hangzhou First People’s Hospital, Hangzhou, 310006, Zhejiang, People’s Republic of China, Tel/Fax +86-571-56005600, Email
| | - Shunrong Zhang
- Department of Geriatrics, Hangzhou First People’s Hospital, Hangzhou, 310006, Zhejiang, People’s Republic of China
| | - Qinxian Guo
- Central Laboratory, Hangzhou First People’s Hospital, Hangzhou, 310006, Zhejiang, People’s Republic of China
| | - Hui Zheng
- Central Laboratory, Hangzhou First People’s Hospital, Hangzhou, 310006, Zhejiang, People’s Republic of China
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5
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Veldman BCF, Kuper WFE, Lilien M, Schuurs-Hoeijmakers JHM, Marcelis C, Phan M, Hettinga Y, Talsma HE, van Hasselt PM, Haijes HA. Beyond nephronophthisis: Retinal dystrophy in the absence of kidney dysfunction in childhood expands the clinical spectrum of CEP83 deficiency. Am J Med Genet A 2021; 185:2204-2210. [PMID: 33938610 PMCID: PMC8252653 DOI: 10.1002/ajmg.a.62225] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 03/31/2021] [Accepted: 04/01/2021] [Indexed: 12/12/2022]
Abstract
The CEP83 protein is an essential part in the first steps of ciliogenesis, causing a ciliopathy if deficient. As a core component of the distal appendages of the centriole, CEP83 is located in almost all cell types and is involved in the primary cilium assembly. Previously reported CEP83 deficient patients all presented with nephronophthisis and kidney dysfunction. Despite retinal degeneration being a common feature in ciliopathies, only one patient also had retinitis. Here, we present two unrelated patients, who both presented with retinitis pigmentosa, without nephronophthisis or any form of kidney dysfunction. Both patients harbor bi‐allelic variants in CEP83. This report expands the current clinical spectrum of CEP83 deficiency. For timely diagnosis of CEP83 deficiency, we advocate that CEP83 should be included in gene panels for inherited retinal diseases.
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Affiliation(s)
- Bram C F Veldman
- Department of Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Willemijn F E Kuper
- Department of Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marc Lilien
- Department of Pediatric Nephrology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Carlo Marcelis
- Department of Clinical Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Milan Phan
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ymkje Hettinga
- Bartiméus Diagnostic Center for Complex Visual Disorders, Zeist, The Netherlands
| | - Herman E Talsma
- Bartiméus Diagnostic Center for Complex Visual Disorders, Zeist, The Netherlands
| | - Peter M van Hasselt
- Department of Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Hanneke A Haijes
- Department of Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
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Küçük Kurtulgan H, Altuntaş EE, Yıldırım ME, Özdemir Ö, Bağcı B, Sezgin İ. The Analysis of GJB2, GJB3, and GJB6 Gene Mutations in Patients with Hereditary Non-Syndromic Hearing Loss Living in Sivas. J Int Adv Otol 2020; 15:373-378. [PMID: 31846914 DOI: 10.5152/iao.2019.5401] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVES The aim of the present study was to investigate the presence of GJB2, GJB3, and GJB6 gene mutations in non-syndromic sensorineural hearing loss (NSHL) cases living in Sivas region, to provide appropriate genetic counseling for cases who were found to have mutation, and to contribute to decrease the frequency of mutant allele in the next generation and plan treatment and rehabilitation with early diagnosis. MATERIALS AND METHODS The study included 53 unrelated cases that were diagnosed with congenital NSHL between June 2009 and March 2010. Multiplex ligation-dependent probe amplification method was used for genotyping of GJB2, GJB3, and GJB6 gene mutations. RESULTS Heterozygous 35delG variant was determined in 1.9% (n=1) of cases, homozygous 35delG in 15.1% (n=8), heterozygous IVS1+1G>A mutation in 1.9% (n=1), compound heterozygous in 3.8% (n=2), and homozygous IVS1+1G>A variant in 3.8% (n=2). None of the cases had mutation in GJB3 and GJB6 genes. Mutated allele frequencies in the present study were found to be 17.9% for 35delG and 6.6% for IVS1+1G>A. CONCLUSION The present study showed that 35delG mutation is the most common variant in the Sivas region, and that IVS1+1G>A mutation should be investigated in hearing loss. Another result of the present study was that genetic analyzes would allow early diagnosis of hearing impairments particularly when infants whose parents have consanguinity do not pass the newborn hearing screening.
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Affiliation(s)
- Hande Küçük Kurtulgan
- Department of Medical Genetics, Cumhuriyet University School of Medicine, Sivas, Turkey
| | | | - Malik Ejder Yıldırım
- Department of Medical Genetics, Cumhuriyet University School of Medicine, Sivas, Turkey
| | - Öztürk Özdemir
- Department of Medical Genetics, Çanakkale 18 Mart University, Çanakkale, Turkey
| | - Binnur Bağcı
- Department of Nutrition and Dietetics, Cumhuriyet University School of Medicine, Sivas, Turkey
| | - İlhan Sezgin
- Department of Medical Genetics, Cumhuriyet University School of Medicine, Sivas, Turkey
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Pandya A, O'Brien A, Kovasala M, Bademci G, Tekin M, Arnos KS. Analyses of del(GJB6-D13S1830) and del(GJB6-D13S1834) deletions in a large cohort with hearing loss: Caveats to interpretation of molecular test results in multiplex families. Mol Genet Genomic Med 2020; 8:e1171. [PMID: 32067424 PMCID: PMC7196463 DOI: 10.1002/mgg3.1171] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 01/24/2020] [Accepted: 01/30/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Mutations involving the closely linked GJB2 and GJB6 at the DFNB1 locus are a common genetic cause of profound congenital hearing loss in many populations. In some deaf GJB2 heterozygotes, a 309 kb deletion involving the GJB6 has been found to be the cause for hearing loss when inherited in trans to a GJB2 mutation. METHODS We screened 2,376 probands from a National DNA Repository of deaf individuals. RESULTS Fifty-two of 318 heterozygous probands with pathogenic GJB2 sequence variants had a GJB6 deletion. Additionally, eight probands had an isolated heterozygous GJB6 deletion that did not explain their hearing loss. In two deaf subjects, including one proband, a homozygous GJB6 deletion was the cause for their hearing loss, a rare occurrence not reported to date. CONCLUSION This study represents the largest US cohort of deaf individuals harboring GJB2 and GJB6 variants, including unique subsets of families with deaf parents. Testing additional members to clarify the phase of GJB2/GJB6 variants in multiplex families was crucial in interpreting clinical significance of the variants in the proband. It highlights the importance of determining the phase of GJB2/GJB6 variants when interpreting molecular test results especially in multiplex families with assortative mating.
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Affiliation(s)
- Arti Pandya
- Department of Pediatrics, Division of Genetics and Metabolism, UNC Chapel Hill, Chapel Hill, NC, USA
| | - Alexander O'Brien
- Department of Pediatrics, Division of Genetics and Metabolism, UNC Chapel Hill, Chapel Hill, NC, USA
| | - Michael Kovasala
- Department of Pediatrics, Division of Genetics and Metabolism, UNC Chapel Hill, Chapel Hill, NC, USA
| | - Guney Bademci
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami, Miami, FL, USA
| | - Mustafa Tekin
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami, Miami, FL, USA
| | - Kathleen S Arnos
- Department of Science, Technology, & Mathematics, Gallaudet University, Washington, DC, USA
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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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9
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Subaşıoğlu A, Duman D, Sırmacı A, Bademci G, Carkıt F, Somdaş MA, Erkan M, Tekin M, Dündar M. Research of genetic bases of hereditary non-syndromic hearing loss. Turk Arch Pediatr 2017; 52:122-132. [PMID: 29062245 DOI: 10.5152/turkpediatriars.2017.4254] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 03/13/2017] [Indexed: 11/22/2022]
Abstract
AIM Hearing loss is the most common sensory disorder that affects approximately one per 1000 live births. With this project, we aimed to identify gene variants that were common causes of hearing loss in Turkey to contribute to the planning of genetic screening programs for hearing loss, as well as to improve genetic counseling to affected families. MATERIAL AND METHODS Twenty-one families with at least two affected individuals and parental consanguinity who presented with non-syndromic severe-to-profound sensorineural hearing loss were included in this study. We first screened for mutations in GJB2 and mitochondrial DNA 12S RNA genes. Subsequently, we genotyped the TMIE c.250C>T and SNP markers flanking the SLC26A4, MYO7A, MYO15A, OTOF, CDH23, TMIE, TECTA, PCDH15, TMC1, TMPRSS3, TMHS genes in the remaining twelve families without mutations in GJB2. RESULTS Screening for mutations in GJB2 gene showed c.[35delG];[35delG] mutation in four families, c.[35delG];[507C>A] mutation in two families, c.[35delG];[-23+1G>A] mutation in one family, and c.457G>A heterozygous mutation in one family. Genotyping SNP markers showed the c.[250C>T];[250C>T] mutation in TMIE in one family. A homozygous region with SNP genotypes was detected with the OTOF gene in one family, the TMPRSS3 gene in another family, and also a homozygous region was detected with TMHS, OTOF, and TMPRSS3 genes in another family. CONCLUSIONS Further research will be required to determine the genetic bases of hearing loss in families with non-syndromic hearing loss.
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Affiliation(s)
- Aslı Subaşıoğlu
- Department of Medical Genetics, Erciyes University Faculty of Medicine, Kayseri, Turkey
| | - Duygu Duman
- Department of Pediatrics, Division of Pediatric Genetic Diseases, Ankara University Faculty of Medicine, Ankara, Turkey
| | - Aslı Sırmacı
- Division of Human Genetics, John T. Macdonald, Miami University Miller Medical Faculty, Miami, USA
| | - Güney Bademci
- Division of Human Genetics, John T. Macdonald, Miami University Miller Medical Faculty, Miami, USA
| | - Fehime Carkıt
- Division of Odiology, Kayseri Education and Research Hospital, Kayseri, Turkey
| | - Mehmet Akif Somdaş
- Department of Otolaryngology, Erciyes University Faculty of Medicine, Kayseri, Turkey
| | - Mustafa Erkan
- Department of Otolaryngology, Erciyes University Faculty of Medicine, Kayseri, Turkey
| | - Mustafa Tekin
- Division of Human Genetics, John T. Macdonald, Miami University Miller Medical Faculty, Miami, USA
| | - Munis Dündar
- Department of Medical Genetics, Erciyes University Faculty of Medicine, Kayseri, Turkey
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10
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Tsukada K, Nishio SY, Hattori M, Usami SI. Ethnic-specific spectrum of GJB2 and SLC26A4 mutations: their origin and a literature review. Ann Otol Rhinol Laryngol 2015; 124 Suppl 1:61S-76S. [PMID: 25999548 DOI: 10.1177/0003489415575060] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The mutation spectrum of the GJB2 and SLC26A4 genes, the 2 most common genes causing deafness, are known to be ethnic specific. In this study, the spectrum of the reported GJB2 and SLC26A4 mutations in different populations are reviewed and considered from a human migration perspective. METHODS Fifty-two and 17 articles on GJB2 and SLC26A4 mutations, respectively, were reviewed through the PubMed database from April 1996 to September 2014. The 4 most prevalent mutations were selected and compared. A cluster analysis was subsequently performed for these selected mutations. RESULTS The present review of frequent mutations shows the ethnic-specific GJB2 and SLC26A4 gene mutation spectrum. A cluster analysis of the GJB2 and SLC26A4 genes revealed similarities between ethnic populations. CONCLUSION The mutation spectrum reviewed in this study clearly indicated that the frequent mutations in the GJB2 and SLC26A4 genes are consistent with the founder mutation hypothesis. A comparison with the Y-chromosome phylogenetic tree indicated that these mutations may have occurred during human migration.
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Affiliation(s)
- Keita Tsukada
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Shin-Ya Nishio
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan Department of Hearing Implant Sciences, Shinshu University School of Medicine, Matsumoto, Japan
| | - Mitsuru Hattori
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Shin-Ichi Usami
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan Department of Hearing Implant Sciences, Shinshu University School of Medicine, Matsumoto, Japan
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Kim SY, Kim AR, Han KH, Kim MY, Jeon EH, Koo JW, Oh SH, Choi BY. Residual Hearing in DFNB1 Deafness and Its Clinical Implication in a Korean Population. PLoS One 2015; 10:e0125416. [PMID: 26061264 PMCID: PMC4464755 DOI: 10.1371/journal.pone.0125416] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 03/23/2015] [Indexed: 11/19/2022] Open
Abstract
Introduction The contribution of Gap junction beta-2 protein (GJB2) to the genetic load of deafness and its mutation spectra vary among different ethnic groups. Objective In this study, the mutation spectrum and audiologic features of patients with GJB2 mutations were evaluated with a specific focus on residual hearing. Methods An initial cohort of 588 subjects from 304 families with varying degrees of hearing loss were collected at the otolaryngology clinics of Seoul National University Hospital and Seoul National University Bundang Hospital from September 2010 through January 2014. GJB2 sequencing was carried out for 130 probands with sporadic or autosomal recessive non syndromic hearing loss. The audiograms were evaluated in the GJB2 mutants. Results Of the 130 subjects, 22 (16.9%) were found to carry at least one mutant allele of GJB2. The c.235delC mutation was shown to have the most common allele frequency (39.0%) among GJB2 mutations, followed by p.R143W (26.8%) and p.V37I (9.8%). Among those probands without the p.V37I allele in a trans configuration who showed some degree of residual hearing, the mean air conduction thresholds at 250 and 500 Hz were 57 dB HL and 77.8 dB HL, respectively. The c.235delC mutation showed a particularly wide spectrum of hearing loss, from mild to profound and significantly better hearing thresholds at 250 Hz and 2k Hz than in the non-p.V37I and non-235delC nonsyndromic hearing loss and deafness 1(DFNB1) subjects. Conclusion Despite its reputation as the cause of severe to profound deafness, c.235delC, the most frequent DFNB1 mutation in our cohort, caused a wide range of hearing loss with some residual hearing in low frequencies. This finding can be of paramount help for prediction of low frequency hearing thresholds in very young DFNB1 patients and highlights the importance of soft surgery for cochlear implantation in these patients.
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Affiliation(s)
- So Young Kim
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Ah Reum Kim
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Kyu Hee Han
- Department of Otorhinolaryngology-Head and Neck Surgery, National Medical Center, Seoul, Korea
| | - Min Young Kim
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Eun-Hee Jeon
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Ja-Won Koo
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
- Sensory Organ Research Institute, Seoul National University Medical Research Center, Seoul, Korea
| | - Seung Ha Oh
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
- Sensory Organ Research Institute, Seoul National University Medical Research Center, Seoul, Korea
| | - Byung Yoon Choi
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
- Sensory Organ Research Institute, Seoul National University Medical Research Center, Seoul, Korea
- * E-mail:
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Salvago P, Martines E, La Mattina E, Mucia M, Sammarco P, Sireci F, Martines F. Distribution and phenotype of GJB2 mutations in 102 Sicilian patients with congenital non syndromic sensorineural hearing loss. Int J Audiol 2014; 53:558-63. [PMID: 24793888 DOI: 10.3109/14992027.2014.905717] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE To evaluate the frequency of GJB2 mutations and their correlation with phenotype in Sicilian non-syndromic sensorineural hearing loss (NSHL) 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 102 Sicilian NSHL patients. RESULTS Fifteen different mutations in GJB2 and seventeen different genotypes were detected. No GJB6 mutations were found. The hearing impairment was profound in the 64.72% of probands (mean PTA0.25-4 kHz of 88.82 ± 26.52 dB HL). A total of 81.37% of patients harboured at least one c.35delG allele; c.167delT and c.-23 + 1G> A were identified in 10.78% and the 9.8% of patients respectively; c.35delG homozygotes presented more severe hearing impairment (75.59% of profound hearing loss) and a higher mean PTA0.25-4 kHz (96.79 ± 21.11 dB HL) with respect to c.35delG/non-c.35delG and c.35delG/Wt patients (P < 0.05). CONCLUSIONS This work underlines the role of c.35delG, c.167delT and c.-23 + 1G> A as the most frequent causes of NSHL in Sicily. The c.35delG frequency found is similar to those reported in other populations of the Mediterranean area. The analysis of genetic and audiologic data confirmed a variability in the phenotype associated to a single genotype.
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Affiliation(s)
- Pietro Salvago
- * Dipartimento di Biomedicina Sperimentale e Neuroscienze Cliniche, (BioNeC), Sezione di Otorinolaringoiatria, Università degli Studi di Palermo , 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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Esteves MCBN, de Lima Isaac M, Francisco AM, da Silva Junior WA, Ferreira CA, Dell'Aringa AHB. Analysis of the presence of the GJB6 mutations in patients heterozygous for GJB2 mutation in Brazil. Eur Arch Otorhinolaryngol 2013; 271:695-9. [PMID: 23553242 DOI: 10.1007/s00405-013-2468-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 03/20/2013] [Indexed: 10/27/2022]
Abstract
Mutations in the GJB2 gene, mainly 35delG, are responsible for most autosomal recessive inherited genetic hearing loss. The audiometric standard of these hearing losses remains inconsistent and other genes, such as GJB6, have been involved in association with GJB2. The objective of the study was to identify the deletions del(GJB6-D13S1830) and del(GJB6-D13S1854) in patients heterozygous for 35delG/GJB2 and analyze the phenotype they present. 101 patients with mild to profound degree of sensorineural hypoacusis were evaluated. The allele-specific PCR technique was used to identify 35delG. The del(GJB6-D13S1830) and del(GJB6-D13S1854) were identified through the PCR multiplex technique. 90% of the subjects presented a normal genotype for the analyzed mutations; 6.93% were shown to be heterozygous for 35delG/GJB2 and 1% presented compound heterozygosis GJB2/GJB6). The data found reinforced the hypothesis of an interaction of more than one gene as the cause of autosomal recessive genetic hearing loss and emphasized the importance of an early diagnosis for appropriate intervention.
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Zhang J, Wang Z, Dai W, Zeng Y, Li H. GJB2 allele variants and the associated audiologic features identified in Chinese patients with less severe idiopathic hearing loss. Genet Test Mol Biomarkers 2011; 15:313-8. [PMID: 21366436 DOI: 10.1089/gtmb.2010.0182] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS To explore possible correlations between the genotype of GJB2, the gene that encodes connexin 26 (Cx26), and its related audiogram features in Chinese patients with less severe nonsyndromic hearing loss (HL), we examined the pure tone audiograms and GJB2 coding region allele variants in 236 patients. RESULTS Twelve of 34 (35.3%) patients with biallelic GJB2 mutations had totally asymmetric HL, a significantly higher prevalence than in patients with wild-type GJB2 (p = 0.027). In patients with biallelic GJB2 mutations, the percentages of cases with sloping, flat, and differently shaped audiograms between ears were 44.1%, 11.8%, and 35.3%, respectively; however, in patients with wild-type GJB2, the percentages were 72.4%, 3.4%, and 21.1%, respectively. Significant differences were found between patients with wild-type GJB2 and those with biallelic GJB2 mutations (p = 0.013) as well as those with single GJB2 mutations (p = 0.043). Threshold differences between ears were significantly higher in patients carrying GJB2 polymorphisms than in patients with wild-type GJB2 at 250-8000 Hz (p < 0.05). The threshold changes at adjacent octaves showed significant differences between groups at each adjacent frequency from 4000 to 8000 Hz (p = 0.04). CONCLUSIONS The patients who carried biallelic pathogenic Cx26 mutations showed asymmetric HL compared with the patients who carried wild-type Cx26. The threshold difference and threshold changes at adjacent octaves between ears were higher in the patients with Cx26 polymorphisms.
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Affiliation(s)
- Jianning Zhang
- Department of Otolaryngology, Eye Ear Nose and Throat Hospital of Fudan University, 83 Fen Yang Road, Shanghai, China
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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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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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Kenna MA, Feldman HA, Neault MW, Frangulov A, Wu BL, Fligor B, Rehm HL. Audiologic phenotype and progression in GJB2 (Connexin 26) hearing loss. ACTA ACUST UNITED AC 2010; 136:81-7. [PMID: 20083784 DOI: 10.1001/archoto.2009.202] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVES To document the audiologic phenotype of children with biallelic GJB2 (connexin 26) mutations, and to correlate it with the genotype. DESIGN Prospective, observational study. SETTING Tertiary care children's hospital. PATIENTS Infants and children with sensorineural hearing loss (SNHL). INTERVENTION Sequencing of the GJB2 (connexin 26) gene. MAIN OUTCOME MEASURES Degree and progression of SNHL. RESULTS From December 1, 1998, through November 30, 2006, 126 children with biallelic GJB2 mutations were identified. Of the 30 different mutations identified, 13 (43%) were truncating and 17 (57%) were nontruncating; 62 patients had 2 truncating, 30 had 1 truncating and 1 nontruncating, and 17 had 2 nontruncating mutations. Eighty-four patients (67%) initially had measurable hearing in the mild to severe range in at least 1 of 4 frequencies (500, 1000, 2000, or 4000 Hz). Of these 84 patients with residual hearing, 47 (56%) had some degree of progressive hearing loss. Patients with 2 truncating mutations had significantly worse hearing compared with all other groups. Patients who had 1 or 2 copies of either an M34T or a V37I allele had the mildest hearing loss. CONCLUSIONS Hearing loss owing to GJB2 mutations ranges from mild to profound and is usually congenital. More than 50% of patients will experience some hearing loss progression, generally gradually but occasionally precipitously. Hearing loss severity may be influenced by genetic factors, such as the degree of preserved protein function in nontruncating mutations, whereas hearing loss progression may be dependent on factors other than the connexin 26 protein. Genetic counseling for patients with GJB2 mutations should include the variable audiologic phenotype and the possibility of progression.
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Affiliation(s)
- Margaret A Kenna
- Department of Otolaryngology and Communication Enhancement, Children's Hospital Boston, 300 Longwood Ave, LO-367, Boston, MA 02115, USA.
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Padma G, Ramchander PV, Nandur UV, Padma T. GJB2 and GJB6 gene mutations found in Indian probands with congenital hearing impairment. J Genet 2009; 88:267-72. [DOI: 10.1007/s12041-009-0039-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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da Silva-Costa SM, Coeli FB, Lincoln-de-Carvalho CR, Marques-de-Faria AP, Kurc M, Pereira T, Pomilio MCA, Sartorato EL. Screening for the GJB2 c.-3170 G>A (IVS 1+1 G>A) Mutation in Brazilian Deaf Individuals Using Multiplex Ligation–Dependent Probe Amplification. Genet Test Mol Biomarkers 2009; 13:701-4. [DOI: 10.1089/gtmb.2009.0025] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Sueli Matilde da Silva-Costa
- Laboratório de Genética Molecular Humana, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, Brazil
| | - Fernanda Borchers Coeli
- Laboratório de Genética Molecular Humana, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, Brazil
| | | | | | | | - Tânia Pereira
- Associação Terapêutica de Estimulação Auditiva e Linguagem (ATEAL), Jundiai, Brazil
| | | | - Edi Lúcia Sartorato
- Laboratório de Genética Molecular Humana, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, Brazil
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Cama E, Melchionda S, Palladino T, Carella M, Santarelli R, Genovese E, Benettazzo F, Zelante L, Arslan E. Hearing loss features in GJB2 biallelic mutations and GJB2/GJB6 digenic inheritance in a large Italian cohort. Int J Audiol 2009; 48:12-7. [DOI: 10.1080/14992020802400654] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Prevalence of GJB2 (Connexin-26) and GJB6 (Connexin-30) Mutations in a Cohort of 300 Brazilian Hearing-Impaired Individuals: Implications for Diagnosis and Genetic Counseling. Ear Hear 2009; 30:1-7. [PMID: 19125024 DOI: 10.1097/aud.0b013e31819144ad] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Abstract
Hearing impairment (HI) is the most frequent sensory disorder, with a genetic etiology in >50% of all cases, due to mutations in >44 identified genes. Autosomal recessive inheritance explains the majority, with GJB2 (connexin 26) mutations accounting for 15-50% of paediatric HI. Delayed presentation of HI to 11-60 months in cases of biallelic GJB2 mutations is a concern, necessitating a good audiological follow-up in addition to neonatal hearing screening. Providing a genetic diagnosis in congenital HI has implications for the prognosis, the possible risk of associated medical manifestations, and precise genetic counseling of the family, and should be integrated into the medical examinations done in order to diagnose syndromic features. Large-scale mutation detection methods, such as micro arrays, are promising for wider genetic testing, but few studies on their clinical utility have been published, so far. Limitations of interpretation of genetic test results, combined with significant ethical issues, currently do not justify to institute genetic screening for GJB2 mutations in neonates before a diagnosis of HI is established.
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Lee KY, Choi SY, Bae JW, Kim S, Chung KW, Drayna D, Kim UK, Lee SH. Molecular analysis of the GJB2, GJB6 and SLC26A4 genes in Korean deafness patients. Int J Pediatr Otorhinolaryngol 2008; 72:1301-9. [PMID: 18585793 PMCID: PMC2713596 DOI: 10.1016/j.ijporl.2008.05.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Revised: 05/06/2008] [Accepted: 05/09/2008] [Indexed: 10/21/2022]
Abstract
OBJECTIVES Mutations in the GJB2, GJB6 and SLC26A4 genes are a frequent cause of hearing loss in a number of populations. However, little is known about the genetic causes of hearing loss in the Korean population. METHODS We sequenced the GJB2 and GJB6 genes to examine the role of mutations in these genes in 22 hearing loss patients. We also sequenced the SLC26A4 gene in seven patients with inner ear malformations, including enlarged vestibular aqueduct (EVA) revealed by computer tomography. RESULTS Coding sequence mutations in GJB2 were identified in 13.6% of the patients screened. Two different mutations, 235delC and T86R were found in three unrelated patients. The 235delC was the most prevalent mutation with an allele frequency of 6.9% in our patient group. No mutations, including 342-kb deletion, were found in GJB6 gene. Three different variants of SLC26A4 were identified in the EVA patients, including one novel mutation. Four EVA patients carried two mutant alleles of SLC26A4, and at least one allele in all patients was the H723R mutation, which accounted for 75% of all mutant alleles. CONCLUSIONS Our results suggest that GJB2 and SLC26A4 mutations together make up a major cause of congenital hearing loss in the Korean population. Further studies may be able to identify other common variants that account for a significant fraction of hearing loss in the Korean population.
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Affiliation(s)
- K Y Lee
- Department of Otolaryngology, College of Medicine, Kyungpook National University, Deagu 702-701, Republic of Korea
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Gopalarao D, Kimberling WJ, Jesteadt W, Kelley PM, Beauchaine KL, Cohn ES. Is hearing loss due to mutations in the Connexin 26 gene progressive? Int J Audiol 2008; 47:11-20. [PMID: 18196482 DOI: 10.1080/14992020701602087] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Serial audiograms were analysed for seven subjects, who were homozygous for the 35delG GJB2 mutation. The criterion for determining progression of hearing loss was at least a 1-dB loss in air conduction pure-tone average-3 (ACPTA-3) or ACPTA-4 per year for 2 to 10 years, with a minimum change of 10 dB ACPTA 3 or 4. Bilateral progression of hearing loss was found in 43% (3/7) of the subjects. A meta-analysis of seven studies with non-overlapping data sets and similar ascertainment criteria indicated that 19% of DFNB1 subjects with GJB2 mutations have progressive hearing loss. These data suggest that it may be incorrect to assume that congenital hearing loss due to this mutation is stable. We recommend rigorous audiologic surveillance for individuals with DFNB1.
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Affiliation(s)
- Deepika Gopalarao
- Ali Yavar Jung National Institute for the Hearing Handicapped, New Delhi, India
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Year 2007 position statement: Principles and guidelines for early hearing detection and intervention programs. Pediatrics 2007; 120:898-921. [PMID: 17908777 DOI: 10.1542/peds.2007-2333] [Citation(s) in RCA: 1144] [Impact Index Per Article: 67.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Hernández-Rojas ML, Quiroz-Mercado H, Dalma-Weiszhausz J, Fromow-Guerra J, Amaya-Espinosa A, Solís-Vivanco A, Reyna-Castelán E, Abraham-Marín M, Martínez-Castellanos MA, Aiello LP. Short-term effects of intravitreal bevacizumab for subfoveal choroidal neovascularization in pathologic myopia. Genet Med 2007; 27:707-12. [PMID: 17621179 DOI: 10.1097/gim.0b013e3180a03276] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
PURPOSE To determine short-term effects of intravitreal bevacizumab for subfoveal choroidal neovascularization (CNV) in pathologic myopia. METHODS In this prospective interventional case series, patients were treated with 2.5 mg of intravitreal bevacizumab and followed for 3 months. Best-corrected visual acuity (BCVA), optical coherence tomography (OCT), and fluorescein angiography (FA) were recorded. Indications for retreatment were active leaking CNV shown by FA and presence of subretinal fluid by OCT in combination with visual disturbances. RESULTS Fourteen patients were included, with a mean age of 53.86 +/- 16.26 years (range 29-85). Mean spherical equivalent was -13.87 +/- 3.68 diopters (-7.25 to -20.50). Minimum follow-up was 3 months. There were no adverse events. The mean initial visual acuity was 20/200 improving to 20/100 at 2 weeks, 20/80 at 4 weeks, and 20/60 at 8 and 12 weeks (P=0.007; P=0.001; P=0.005; P=0.001, respectively). Initial foveal thickness improved from 385.43 microm +/- 125.83 microm to 257.64 +/- 76.6 microm and 194.54 +/- 54.35 microm after the first and third month, respectively (P=0.001). CONCLUSIONS Initial treatment results of patients with CNV due to pathologic myopia did not reveal any short-term safety concerns. Intravitreal bevacizumab resulted in a significant decrease in foveal thickness and improvement in visual acuity. These favorable initial results support further larger and long-term studies.
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Affiliation(s)
- Myriam L Hernández-Rojas
- Hospital Luis Sánchez Bulnes, Asociación Para Evitar la Ceguera en México I.A.P., México City, México.
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Apps SA, Rankin WA, Kurmis AP. Connexin 26 mutations in autosomal recessive deafness disorders: a review. Int J Audiol 2007; 46:75-81. [PMID: 17365058 DOI: 10.1080/14992020600582190] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
This review explores the association between GJB2 gene mutations, encoding connexin 26 (Cx26), and nonsyndromic hearing loss. Connexins are proteins that form intracellular membrane channels and regulate ion movement between contiguous fluid spaces. A family of autosomal gene mutations has been identified that lead to abnormal connexin expression within the inner ear that are associated with hearing loss. The exact mechanism by which this link is elicited remains unclear. We aim to highlight the clinically underestimated prevalence of GJB2 gene mutations, to explore the influential role of ethnic diversity in mutation frequency, and to provide a framework for hearing specialists in considering the differential diagnosis of nonsyndromic hearing loss. By linking an observed phenotype associated with abnormal Cx26 expression to the current understanding of the biological and genetic basis underlying it will allow a more accurate clinical description of associated hearing loss, and therefore enable more effective patient management and genetic counselling.
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Affiliation(s)
- Stacey A Apps
- School of Speech Pathology and Audiology, Faculty of Health Sciences, Flinders University, Adelaide, Australia
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Sirmaci A, Akcayoz-Duman D, Tekin M. The c.IVS1+1G>A mutation intheGJB2 gene is prevalent and large deletions involving theGJB6 gene are not present in the Turkish population. J Genet 2006; 85:213-6. [PMID: 17406097 DOI: 10.1007/bf02935334] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Asli Sirmaci
- Division of Pediatric Molecular Genetics, Ankara University School of Medicine, Ankara 06100, Turkey
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Seeman P, Sakmaryová I. High prevalence of the IVS 1 + 1 G to A/GJB2 mutation among Czech hearing impaired patients with monoallelic mutation in the coding region of GJB2. Clin Genet 2006; 69:410-3. [PMID: 16650079 DOI: 10.1111/j.1399-0004.2006.00602.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Biallelic pathogenic GJB2 gene mutations cause pre-lingual genetic hearing loss in up to 50% of individuals with bilateral sensorineural hearing loss worldwide. Sequencing of the entire GJB2 gene-coding region in Czech patients with pre-lingual bilateral hearing loss revealed that 10.3% of Czech patients carry only one monoallelic pathogenic mutation in the coding region of the GJB2 gene, which is significantly more than the population frequency of 3.4%. The 309-kb GJB6 deletion, frequent in Spain and France, is very rare in the Czech population. In order to evaluate the impact of the IVS1 + 1 G to A splice site mutation in the non-coding part of the GJB2 gene among Czech patients, we tested all available patients with pre-lingual hearing loss with only one monoallelic mutation in the coding part of GJB2. By sequencing of the exon 1 region of the GJB2 gene and HphI restriction analysis in 20 Czech patients we identified nine patients carrying IVS1 + 1 G to A. Testing for this mutation explained deafness in 45% of Czech GJB2 monoallelic patients. This mutation represents now 4% of GJB2 pathogenic mutations in Czech patients and is the third most common GJB2 mutation found in our cohort of 242 unrelated Czech patients with prelingual hearing loss. A similar frequency may also be expected in other Central European or Slavic populations.
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Affiliation(s)
- P Seeman
- Department of Child Neurology, DNA Laboratory, Charles University Prague, 2nd School of Medicine, Prague, Czech Republic.
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