1
|
Jahn KN, Morse-Fortier C, Griffin AM, Faller D, Cohen MS, Kenna MA, Doney E, Arenberg JG. Programming Levels and Speech Perception in Pediatric Cochlear Implant Recipients With Enlarged Vestibular Aqueduct or GJB2 Mutation. Otol Neurotol 2023; 44:e273-e280. [PMID: 37167444 PMCID: PMC10176457 DOI: 10.1097/mao.0000000000003879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
OBJECTIVE To determine the relationship between hearing loss etiology, cochlear implant (CI) programming levels, and speech perception performance in a large clinical cohort of pediatric CI recipients. STUDY DESIGN Retrospective chart review. SETTING Tertiary care hospitals. PATIENTS A total of 136 pediatric CI recipients (218 ears) were included in this study. All patients had diagnoses of either enlarged vestibular aqueduct (EVA) or GJB2 (Connexin-26) mutation confirmed via radiographic data and/or genetic reports. All patients received audiologic care at either Boston Children's Hospital or Massachusetts Eye and Ear in Boston, MA, between the years 1999 and 2020. MAIN OUTCOME MEASURES Electrode impedances and programming levels for each active electrode and speech perception scores were evaluated as a function of etiology (EVA or GJB2 mutation). RESULTS Children with EVA had significantly higher impedances and programming levels (thresholds and upper stimulation levels) than the children with GJB2 mutation. Speech perception scores did not differ as a function of etiology in this sample; rather, they were positively correlated with duration of CI experience (time since implantation). CONCLUSIONS Differences in electrode impedances and CI programming levels suggest that the electrode-neuron interface varies systematically as a function of hearing loss etiology in pediatric CI recipients with EVA and those with GJB2 mutation. Time with the CI was a better predictor of speech perception scores than etiology, suggesting that children can adapt to CI stimulation with experience.
Collapse
Affiliation(s)
- Kelly N Jahn
- Department of Speech, Language, and Hearing, University of Texas at Dallas, Richardson, Texas
| | | | | | - David Faller
- Department of Otolaryngology and Communication Enhancement, Boston Children's Hospital
| | - Michael S Cohen
- Department of Otolaryngology-Head and Neck Surgery, Harvard Medical School, Boston, Massachusetts
| | | | | | | |
Collapse
|
2
|
Jahn KN, Bergan MD, Arenberg JG. Auditory Detection Thresholds and Cochlear Resistivity Differ Between Pediatric Cochlear Implant Listeners With Enlarged Vestibular Aqueduct and Those With Connexin-26 Mutations. Am J Audiol 2020; 29:23-34. [PMID: 31934787 DOI: 10.1044/2019_aja-19-00054] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Purpose The goal of this study was to evaluate differences in the electrode-neuron interface as a function of hearing loss etiology in pediatric cochlear implant (CI) listeners with enlarged vestibular aqueduct (EVA) syndrome and in those with autosomal recessive connexin-26 mutations (DFNB1). Method Fifteen implanted ears (9 participants, 5 ears with EVA, 10 ears with DFNB1) were assessed. Single-channel auditory detection thresholds were measured using broad and spatially focused electrode configurations (steered quadrupolar; focusing coefficients = 0 and 0.9). Cochlear resistivity estimates were obtained via electrode impedances and electrical field imaging. Between-group differences were evaluated using linear mixed-effects models. Results Children with EVA had significantly higher auditory detection thresholds than children with DFNB1, irrespective of electrode configuration. Between-group differences in thresholds were more pronounced on apical electrodes than on basal electrodes. In the apex, electrode impedances and electrical field imaging values were higher for children with EVA than for those with DFNB1. Conclusions The electrode-neuron interface differs between pediatric CI listeners with DFNB1 and those with EVA. It is possible that optimal clinical interventions may depend, in part, on hearing loss etiology. Future investigations with large samples should investigate individualized CI programming strategies for listeners with EVA and DFNB1.
Collapse
Affiliation(s)
- Kelly N. Jahn
- Department of Otolaryngology–Head and Neck Surgery, Harvard Medical School, Boston, MA
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear Infirmary, Boston
| | - Molly D. Bergan
- Department of Speech and Hearing Sciences, University of Washington, Seattle
| | - Julie G. Arenberg
- Department of Otolaryngology–Head and Neck Surgery, Harvard Medical School, Boston, MA
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear Infirmary, Boston
| |
Collapse
|
3
|
Abstract
The incidence of hearing impairment (HI) is higher in low- and middle-income countries when compared to high-income countries. There is therefore a necessity to estimate the burden of this condition in developing world. The aim of our study was to use a systematic approach to provide summarized data on the prevalence, etiologies, clinical patterns and genetics of HI in Cameroon. We searched PubMed, Scopus, African Journals Online, AFROLIB and African Index Medicus to identify relevant studies on HI in Cameroon, published from inception to 31 October, 2019, with no language restrictions. Reference lists of included studies were also scrutinized, and data were summarized narratively. This study is registered with PROSPERO, number CRD42019142788. We screened 333 records, of which 17 studies were finally included in the review. The prevalence of HI in Cameroon ranges from 0.9% to 3.6% in population-based studies and increases with age. Environmental factors contribute to 52.6% to 62.2% of HI cases, with meningitis, impacted wax and age-related disorder being the most common ones. Hereditary HI comprises 0.8% to 14.8% of all cases. In 32.6% to 37% of HI cases, the origin remains unknown. Non-syndromic hearing impairment (NSHI) is the most frequent clinical entity and accounts for 86.1% to 92.5% of cases of HI of genetic origin. Waardenburg and Usher syndromes account for 50% to 57.14% and 8.9% to 42.9% of genetic syndromic cases, respectively. No pathogenic mutation was described in GJB6 gene, and the prevalence of pathogenic mutations in GJB2 gene ranged from 0% to 0.5%. The prevalence of pathogenic mutations in other known NSHI genes was <10% in Cameroonian probands. Environmental factors are the leading etiology of HI in Cameroon, and mutations in most important HI genes are infrequent in Cameroon. Whole genome sequencing therefore appears as the most effective way to identify variants associated with HI in Cameroon and sub-Saharan Africa in general.
Collapse
|
4
|
Wonkam Tingang E, Noubiap JJ, F. Fokouo JV, Oluwole OG, Nguefack S, Chimusa ER, Wonkam A. Hearing Impairment Overview in Africa: the Case of Cameroon. Genes (Basel) 2020; 11:genes11020233. [PMID: 32098311 PMCID: PMC7073999 DOI: 10.3390/genes11020233] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Revised: 02/15/2020] [Accepted: 02/19/2020] [Indexed: 01/27/2023] Open
Abstract
The incidence of hearing impairment (HI) is higher in low- and middle-income countries when compared to high-income countries. There is therefore a necessity to estimate the burden of this condition in developing world. The aim of our study was to use a systematic approach to provide summarized data on the prevalence, etiologies, clinical patterns and genetics of HI in Cameroon. We searched PubMed, Scopus, African Journals Online, AFROLIB and African Index Medicus to identify relevant studies on HI in Cameroon, published from inception to 31 October, 2019, with no language restrictions. Reference lists of included studies were also scrutinized, and data were summarized narratively. This study is registered with PROSPERO, number CRD42019142788. We screened 333 records, of which 17 studies were finally included in the review. The prevalence of HI in Cameroon ranges from 0.9% to 3.6% in population-based studies and increases with age. Environmental factors contribute to 52.6% to 62.2% of HI cases, with meningitis, impacted wax and age-related disorder being the most common ones. Hereditary HI comprises 0.8% to 14.8% of all cases. In 32.6% to 37% of HI cases, the origin remains unknown. Non-syndromic hearing impairment (NSHI) is the most frequent clinical entity and accounts for 86.1% to 92.5% of cases of HI of genetic origin. Waardenburg and Usher syndromes account for 50% to 57.14% and 8.9% to 42.9% of genetic syndromic cases, respectively. No pathogenic mutation was described in GJB6 gene, and the prevalence of pathogenic mutations in GJB2 gene ranged from 0% to 0.5%. The prevalence of pathogenic mutations in other known NSHI genes was <10% in Cameroonian probands. Environmental factors are the leading etiology of HI in Cameroon, and mutations in most important HI genes are infrequent in Cameroon. Whole genome sequencing therefore appears as the most effective way to identify variants associated with HI in Cameroon and sub-Saharan Africa in general.
Collapse
Affiliation(s)
- Edmond Wonkam Tingang
- Division of Human Genetics, Department of Pathology, University of Cape Town, Cape Town 7925, South Africa; (E.W.T.); (O.G.O.); (E.R.C.)
| | - Jean Jacques Noubiap
- Centre for Heart Rhythm Disorders, South Australian Health and Medical Research Institute (SAHMRI), University of Adelaide and Royal Adelaide Hospital, Adelaide 5000, Australia;
| | | | - Oluwafemi Gabriel Oluwole
- Division of Human Genetics, Department of Pathology, University of Cape Town, Cape Town 7925, South Africa; (E.W.T.); (O.G.O.); (E.R.C.)
| | - Séraphin Nguefack
- Department of Paediatrics, Faculty of Medicine and Biomedical Sciences, University of Yaoundé I, Yaoundé 1364, Cameroon;
- Paediatrics unit, Gynaeco-Obstetric and Paediatric Hospital, Yaoundé 4362, Cameroon
| | - Emile R. Chimusa
- Division of Human Genetics, Department of Pathology, University of Cape Town, Cape Town 7925, South Africa; (E.W.T.); (O.G.O.); (E.R.C.)
| | - Ambroise Wonkam
- Division of Human Genetics, Department of Pathology, University of Cape Town, Cape Town 7925, South Africa; (E.W.T.); (O.G.O.); (E.R.C.)
- Department of Medicine, University of Cape Town, Cape Town 7925, South Africa
- Correspondence: ; Tel.: +27-21-4066-307
| |
Collapse
|
5
|
GJB2 and GJB6 Mutations in Hereditary Recessive Non-Syndromic Hearing Impairment in Cameroon. Genes (Basel) 2019; 10:genes10110844. [PMID: 31731535 PMCID: PMC6895965 DOI: 10.3390/genes10110844] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 10/07/2019] [Accepted: 10/23/2019] [Indexed: 02/06/2023] Open
Abstract
This study aimed to investigate GJB2 (connexin 26) and GJB6 (connexin 30) mutations associated with familial non-syndromic childhood hearing impairment (HI) in Cameroon. We selected only families segregating HI, with at least two affected individuals and with strong evidence of non-environmental causes. DNA was extracted from peripheral blood, and the entire coding region of GJB2 was interrogated using Sanger sequencing. Multiplex PCR and Sanger sequencing were used to analyze the prevalence of the GJB6-D3S1830 deletion. A total of 93 patients, belonging to 41 families, were included in the analysis. Hearing impairment was sensorineural in 51 out of 54 (94.4%) patients. Pedigree analysis suggested autosomal recessive inheritance in 85.4% (35/41) of families. Hearing impairment was inherited in an autosomal dominant and mitochondrial mode in 12.2% (5/41) and 2.4% (1/41) of families, respectively. Most HI participants were non-syndromic (92.5%; 86/93). Four patients from two families presented with type 2 Waardenburg syndrome, and three cases of type 2 Usher syndrome were identified in one family. No GJB2 mutations were found in any of the 29 families with non-syndromic HI. Additionally, the GJB6-D3S1830 deletion was not identified in any of the HI patients. This study confirms that mutations in the GJB2 gene and the del(GJB6-D13S1830) mutation do not contribute to familial HI in Cameroon.
Collapse
|
6
|
Han JJ, Nguyen PD, Oh DY, Han JH, Kim AR, Kim MY, Park HR, Tran LH, Dung NH, Koo JW, Lee JH, Oh SH, Anh Vu H, Choi BY. Elucidation of the unique mutation spectrum of severe hearing loss in a Vietnamese pediatric population. Sci Rep 2019; 9:1604. [PMID: 30733538 PMCID: PMC6367484 DOI: 10.1038/s41598-018-38245-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 12/17/2018] [Indexed: 11/09/2022] Open
Abstract
The mutational spectrum of deafness in Indochina Peninsula, including Vietnam, remains mostly undetermined. This significantly hampers the progress toward establishing an effective genetic screening method and early customized rehabilitation modalities for hearing loss. In this study, we evaluated the genetic profile of severe-to-profound hearing loss in a Vietnamese pediatric population using a hierarchical genetic analysis protocol that screened 11 known deafness-causing variants, followed by massively parallel sequencing targeting 129 deafness-associated genes. Eighty-seven children with isolated severe-to-profound non-syndromic hearing loss without family history were included. The overall molecular diagnostic yield was estimated to be 31.7%. The mutational spectrum for severe-to-profound non-syndromic hearing loss in our Vietnamese population was unique: The most prevalent variants resided in the MYO15A gene (7.2%), followed by GJB2 (6.9%), MYO7A (5.5%), SLC26A4 (4.6%), TMC1 (1.8%), ESPN (1.8%), POU3F4 (1.8%), MYH14 (1.8%), EYA1 (1.8%), and MR-RNR1 (1.1%). The unique spectrum of causative genes in the Vietnamese deaf population was similar to that in the southern Chinese deaf population. It is our hope that the mutation spectrum provided here could aid in establishing an efficient protocol for genetic analysis of severe-to-profound hearing loss and a customized screening kit for the Vietnamese population.
Collapse
Affiliation(s)
- Jae Joon Han
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Pham Dinh Nguyen
- Department of Otorhinolaryngology, Children's Hospital 1, Ho Chi Minh City, Vietnam
| | - Doo-Yi Oh
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Jin Hee Han
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Ah-Reum Kim
- Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea
| | - Min Young Kim
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Hye-Rim Park
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Lam Huyen Tran
- Department of Otorhinolaryngology, University of Medicine and Pharmacy at Ho Chi Minh City, Ho Chi Minh City, Vietnam
| | - Nguyen Huu Dung
- Department of Otorhinolaryngology, University of Medicine and Pharmacy at Ho Chi Minh City, Ho Chi Minh City, Vietnam
| | - Ja-Won Koo
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Jun Ho Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Hospital, Seoul, Korea
| | - Seung Ha Oh
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Hospital, Seoul, Korea
| | - Hoang Anh Vu
- Center for Molecular Biomedicine, University of Medicine and Pharmacy at Ho Chi Minh City, Ho Chi Minh City, Vietnam.
| | - Byung Yoon Choi
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Bundang Hospital, Seongnam, Korea.
| |
Collapse
|
7
|
del Castillo FJ, del Castillo I. DFNB1 Non-syndromic Hearing Impairment: Diversity of Mutations and Associated Phenotypes. Front Mol Neurosci 2017; 10:428. [PMID: 29311818 PMCID: PMC5743749 DOI: 10.3389/fnmol.2017.00428] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 12/07/2017] [Indexed: 02/02/2023] Open
Abstract
The inner ear is a very complex sensory organ whose development and function depend on finely balanced interactions among diverse cell types. The many different kinds of inner ear supporting cells play the essential roles of providing physical and physiological support to sensory hair cells and of maintaining cochlear homeostasis. Appropriately enough, the gene most commonly mutated among subjects with hereditary hearing impairment (HI), GJB2, encodes the connexin-26 (Cx26) gap-junction channel protein that underlies both intercellular communication among supporting cells and homeostasis of the cochlear fluids, endolymph and perilymph. GJB2 lies at the DFNB1 locus on 13q12. The specific kind of HI associated with this locus is caused by recessively-inherited mutations that inactivate the two alleles of the GJB2 gene, either in homozygous or compound heterozygous states. We describe the many diverse classes of genetic alterations that result in DFNB1 HI, such as large deletions that either destroy the GJB2 gene or remove a regulatory element essential for GJB2 expression, point mutations that interfere with promoter function or splicing, and small insertions or deletions and nucleotide substitutions that target the GJB2 coding sequence. We focus on how these alterations disrupt GJB2 and Cx26 functions and on their different effects on cochlear development and physiology. We finally discuss the diversity of clinical features of DFNB1 HI as regards severity, age of onset, inner ear malformations and vestibular dysfunction, highlighting the areas where future research should be concentrated.
Collapse
Affiliation(s)
- Francisco J. del Castillo
- Servicio de Genética, Hospital Universitario Ramón y Cajal, IRYCIS, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Ignacio del Castillo
- Servicio de Genética, Hospital Universitario Ramón y Cajal, IRYCIS, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| |
Collapse
|
8
|
Stinckens C, Kremer H, van Wijk E, Hoefsloot LH, Huygen PLM, Standaert L, Fryns JP, Cremers CWRJ. Longitudinal Phenotypic Analysis in Patients with Connexin 26 (GJB2) (DFNB1) and Connexin 30 (GJB6) Mutations. Ann Otol Rhinol Laryngol 2016; 113:587-93. [PMID: 15274422 DOI: 10.1177/000348940411300714] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In 15 Belgian subjects with prelingual sensorineural hearing impairment, the connexin 26 (GJB2) gene and the connexin 30 (GJB6) gene were analyzed for the presence of the 35delG mutation and the △( GJB6-D13S1830) deletion first described by del Castillo et al in 2002. Seven patients were found to be homozygous for the 35delG mutation; 7 were combined heterozygotes for the 35delG mutation and the GJB6 deletion. In 11 subjects, phenotype and genotype were correlated. Significant, transient progression, in the range of 1.7 to 2.7 dB/y, was only found in 2 patients in the first part of the second decade of life. Hearing impairment was otherwise stable, with mean thresholds of 75, 90, and 100 dB at 0.125, 0.25, and 0.5 kHz, respectively, and 100 dB or higher at 1 to 4 kHz. There was no significant difference in hearing impairment between the patients with the homozygous 35delG mutation in GJB2 and those who are heterozygous for both the 35delG mutation and the deletion encompassing part of GJB6.
Collapse
Affiliation(s)
- Christel Stinckens
- Department of Otorhinolaryngology, University Hospitals Leuven, Leuven, Belgium
| | | | | | | | | | | | | | | |
Collapse
|
9
|
Mikstiene V, Jakaitiene A, Byckova J, Gradauskiene E, Preiksaitiene E, Burnyte B, Tumiene B, Matuleviciene A, Ambrozaityte L, Uktveryte I, Domarkiene I, Rancelis T, Cimbalistiene L, Lesinskas E, Kucinskas V, Utkus A. The high frequency of GJB2 gene mutation c.313_326del14 suggests its possible origin in ancestors of Lithuanian population. BMC Genet 2016; 17:45. [PMID: 26896187 PMCID: PMC4761217 DOI: 10.1186/s12863-016-0354-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 02/15/2016] [Indexed: 12/30/2022] Open
Abstract
Background Congenital hearing loss (CHL) is diagnosed in 1 – 2 newborns in 1000, genetic factors contribute to two thirds of CHL cases in industrialised countries. Mutations of the GJB2 gene located in the DFNB1 locus (13q11-12) are a major cause of CHL worldwide. The aim of this cross-sectional study was to assess the contribution of the DFNB1 locus containing the GJB2 and GJB6 genes in the development of early onset hearing loss in the affected group of participants, to determine the population-specific mutational profile and DFNB1-related HL burden in Lithuanian population. Methods Clinical data were obtained from a collection of 158 affected participants (146 unrelated probands) with early onset non-syndromic HL. GJB2 and GJB6 gene sequencing and GJB6 gene deletion testing were performed. The data of GJB2 and GJB6 gene sequencing in 98 participants in group of self-reported healthy Lithuanian inhabitants were analysed. Statistic summary, homogeneity tests, and logistic regression analysis were used for the assessment of genotype-phenotype correlation. Results Our findings show 57.5 % of affected participants with two pathogenic GJB2 gene mutations identified. The most prevalent GJB2 mutations were c.35delG, p. (Gly12Valfs*2) (rs80338939) and c.313_326del14, p. (Lys105Glyfs*5) (rs111033253) with allele frequencies 64.7 % and 28.3 % respectively. GJB6 gene mutations were not identified in the affected group of participants. The statistical analysis revealed significant differences between GJB2(−) and GJB2(+) groups in disease severity (p = 0.001), and family history (p = 0.01). The probability of identification of GJB2 mutations in patients with various HL characteristics was estimated. The carrier rate of GJB2 gene mutations – 7.1 % (~1 in 14) was identified in the group of healthy participants and a high frequency of GJB2-related hearing loss was estimated in our population. Discussion The results show a very high proportion of GJB2-positive individuals in the research group affected with sensorineural HL. The allele frequency of c.35delG mutation (64.7 %) is consistent with many previously published studies in groups of affected individuals of Caucasian populations. The high frequency of the c.313_326del14 (28.3 % of pathogenic alleles) mutation in affected group of participants was an unexpected finding in our study suggesting not only a high frequency of carriers of this mutation in our population but also its possible origin in Lithuanian ancestors. The high frequency of carriers of the c.313_326del14 mutation in the entire Lithuanian population is supported by it being identified twice in the ethnic Lithuanian group of healthy participants (a frequency 2.0 % of carriers in the study group). Conclusion Analysis of the allele frequency of GJB2 gene mutations revealed a high proportion of c. 313_326del14 (rs111033253) mutations in the GJB2-positive group suggesting its possible origin in Lithuanian forebears. The high frequency of carriers of GJB2 gene mutations in the group of healthy participants corresponds to the substantial frequency of GJB2-associated HL in Lithuania. The observations of the study indicate the significant contribution of GJB2 gene mutations to the pathogenesis of the disorder in the Lithuanian population and will contribute to introducing principles to predict the characteristics of the disease in patients. Electronic supplementary material The online version of this article (doi:10.1186/s12863-016-0354-9) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Violeta Mikstiene
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
| | - Audrone Jakaitiene
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
| | - Jekaterina Byckova
- Centre of Ear, Nose and Throat Diseases, Vilnius University Hospital Santariskiu clinics, Vilnius, Lithuania.
| | - Egle Gradauskiene
- Centre of Ear, Nose and Throat Diseases, Vilnius University Hospital Santariskiu clinics, Vilnius, Lithuania.
| | - Egle Preiksaitiene
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
| | - Birute Burnyte
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
| | - Birute Tumiene
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
| | - Ausra Matuleviciene
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
| | - Laima Ambrozaityte
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
| | - Ingrida Uktveryte
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
| | - Ingrida Domarkiene
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
| | - Tautvydas Rancelis
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
| | - Loreta Cimbalistiene
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
| | - Eugenijus Lesinskas
- Centre of Ear, Nose and Throat Diseases, Vilnius University Hospital Santariskiu clinics, Vilnius, Lithuania.
| | - Vaidutis Kucinskas
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
| | - Algirdas Utkus
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
| |
Collapse
|
10
|
Loeza-Becerra F, Rivera-Vega MDR, Martínez-Saucedo M, Gonzalez-Huerta LM, Urueta-Cuellar H, Berrruecos-Villalobos P, Cuevas-Covarrubias S. Particular distribution of the GJB2/GJB6 gene mutations in Mexican population with hearing impairment. Int J Pediatr Otorhinolaryngol 2014; 78:1057-60. [PMID: 24774219 DOI: 10.1016/j.ijporl.2014.04.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 03/30/2014] [Accepted: 04/01/2014] [Indexed: 10/25/2022]
Abstract
BACKGROUND Hereditary sensorineural hearing loss (SNHL) is a genetically heterogeneous disorder worldwide. Mutations in the GJB2 gene are a frequent cause of hereditary SNHL. There is a prevalence of certain mutations in various populations which suggests that specific mutations may be influenced by ethnic background. OBJECTIVE To analyze the prevalence of GJB2, GJB6 mutations in several geographic areas of Mexico in patients with hereditary SNHL. MATERIALS AND METHODS One hundred and forty Mexican unrelated propositi with prelingual SNHL were included in the study. All patients had three previous generations born in Mexico and belonged to no specific ethnic group. Analyses of the GJB2 and GJB6 genes and mt.1555A<G were performed in all subjects. RESULTS Twenty-three homozygous mutations, 57 heterozygous mutations, 1 double heterozygous (GJB2/GJB6) and 59 wild-type genotypes in the GJB2 gene were observed. Three patients had the homozygous c.del35 mutation whereas 26 patients were heterozygous for this gene defect. Only one patient with the GJB6 gene deletion was present (it includes the double heterozygous GJB2/GJB6). The mt.1555A>G mutation was not detected. CONCLUSION We found a great variety of mutations depending on the analyzed region in patients with SNHL; 57.86% of patients had affection in one or two alleles in GJB2 or GJB6 genes whereas 42.14% were wild-type. In some cases, allele distribution depended on region. Molecular studies of more genes involved in hereditary non-syndromic SNHL are required to completely confirm the molecular basis of hearing loss in Mexican population.
Collapse
Affiliation(s)
- Francisco Loeza-Becerra
- Servicio de Genética, Hospital General de México, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico
| | - María del Refugio Rivera-Vega
- Servicio de Genética, Hospital General de México, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico
| | - Mirna Martínez-Saucedo
- Servicio de Genética, Hospital General de México, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico
| | - Luz María Gonzalez-Huerta
- Servicio de Genética, Hospital General de México, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico
| | - Héctor Urueta-Cuellar
- Servicio de Genética, Hospital General de México, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico
| | - Pedro Berrruecos-Villalobos
- Servicio de Audiología, Hospital General de México, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico
| | - Sergio Cuevas-Covarrubias
- Servicio de Genética, Hospital General de México, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico.
| |
Collapse
|
11
|
Dahl HHM, Ching TYC, Hutchison W, Hou S, Seeto M, Sjahalam-King J. Etiology and audiological outcomes at 3 years for 364 children in Australia. PLoS One 2013; 8:e59624. [PMID: 23555729 PMCID: PMC3610796 DOI: 10.1371/journal.pone.0059624] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Accepted: 02/15/2013] [Indexed: 01/29/2023] Open
Abstract
Hearing loss is an etiologically heterogeneous trait with differences in the age of onset, severity and site of lesion. It is caused by a combination of genetic and/or environmental factors. A longitudinal study to examine the efficacy of early intervention for improving child outcomes is ongoing in Australia. To determine the cause of hearing loss in these children we undertook molecular testing of perinatal “Guthrie” blood spots of children whose hearing loss was either detected via newborn hearing screening or detected later in infancy. We analyzed the GJB2 and SLC26A4 genes for the presence of mutations, screened for the mitochondrial DNA (mtDNA) A1555G mutation, and screened for congenital CMV infection in DNA isolated from dried newborn blood spots. Results were obtained from 364 children. We established etiology for 60% of children. One or two known GJB2 mutations were present in 82 children. Twenty-four children had one or two known SLC26A4 mutations. GJB2 or SLC26A4 changes with unknown consequences on hearing were found in 32 children. The A1555G mutation was found in one child, and CMV infection was detected in 28 children. Auditory neuropathy spectrum disorder was confirmed in 26 children whose DNA evaluations were negative. A secondary objective was to investigate the relationship between etiology and audiological outcomes over the first 3 years of life. Regression analysis was used to investigate the relationship between hearing levels and etiology. Data analysis does not support the existence of differential effects of etiology on degree of hearing loss or on progressiveness of hearing loss.
Collapse
Affiliation(s)
- Hans-Henrik M. Dahl
- Murdoch Childrens Research Institute, Royal Children’s Hospital, Melbourne, Australia
- Department of Pediatrics, University of Melbourne, Melbourne, Australia
| | - Teresa Y. C. Ching
- National Acoustic Laboratories, Sydney, Australia
- HEARing Cooperative Research Centre, Melbourne, Australia
- * E-mail:
| | - Wendy Hutchison
- Murdoch Childrens Research Institute, Royal Children’s Hospital, Melbourne, Australia
| | - Sanna Hou
- National Acoustic Laboratories, Sydney, Australia
- HEARing Cooperative Research Centre, Melbourne, Australia
| | - Mark Seeto
- National Acoustic Laboratories, Sydney, Australia
- HEARing Cooperative Research Centre, Melbourne, Australia
| | - Jessica Sjahalam-King
- National Acoustic Laboratories, Sydney, Australia
- HEARing Cooperative Research Centre, Melbourne, Australia
| |
Collapse
|
12
|
Bukhari I, Mujtaba G, Naz S. Contribution of GJB2 mutations to hearing loss in the Hazara Division of Pakistan. Biochem Genet 2013; 51:524-9. [PMID: 23504403 DOI: 10.1007/s10528-013-9583-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Accepted: 11/15/2012] [Indexed: 10/27/2022]
Abstract
Mutations of GJB2, which encodes connexin 26, are the most common cause of hereditary hearing loss in many human populations. This study was initiated to determine the prevalence of GJB2 mutations in individuals with hearing loss from the Hazara Division in Pakistan. We recruited 70 participants with nonsyndromic deafness segregating as an apparently recessive trait and directly sequenced the GJB2 coding region from their DNA. The homozygous mutations c.71 G → A (p.W24X), c.104 T → G (p.I35S), and c.35delG (p.G12VfsX1) were identified as the cause of hearing loss in three participants (4.28%); in populations from other areas of Pakistan, frequencies of 6-7% have been observed. The mutations c.104 T → G and c.35delG were identified in Pakistan for the first time. These results confirm the low prevalence of GJB2 mutations in Hazara and suggest that mutations in other genes may play a significant role in the etiology of deafness in this population.
Collapse
Affiliation(s)
- Ihtisham Bukhari
- School of Biological Sciences, University of the Punjab, Quaid-i-Azam Campus, Lahore 54590, Pakistan
| | | | | |
Collapse
|
13
|
Heman-Ackah SE, Roland JT, Haynes DS, Waltzman SB. Pediatric cochlear implantation: candidacy evaluation, medical and surgical considerations, and expanding criteria. Otolaryngol Clin North Am 2012; 45:41-67. [PMID: 22115681 DOI: 10.1016/j.otc.2011.08.016] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Since the first cochlear implant approved by the US Food and Drug Administration in the early 1980s, great advances have occurred in cochlear implant technology. With these advances, patient selection, preoperative evaluation, and rehabilitation consideration continue to evolve. This article describes the current practice in pediatric candidacy evaluation, reviews the medical and surgical considerations in pediatric cochlear implantation, and explores the expanding criteria for cochlear implantation within the pediatric population.
Collapse
Affiliation(s)
- Selena E Heman-Ackah
- Department of Otolaryngology, New York University Cochlear Implant Center, New York University School of Medicine, 660 First Avenue, 7th Floor, New York, NY 10016, USA
| | | | | | | |
Collapse
|
14
|
Hayashi C, Funayama M, Li Y, Kamiya K, Kawano A, Suzuki M, Hattori N, Ikeda K. Prevalence of GJB2 causing recessive profound non-syndromic deafness in Japanese children. Int J Pediatr Otorhinolaryngol 2011; 75:211-4. [PMID: 21112098 DOI: 10.1016/j.ijporl.2010.11.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Revised: 10/18/2010] [Accepted: 11/02/2010] [Indexed: 10/18/2022]
Abstract
OBJECTIVE GJB2 (gap junction protein, beta 2, 26kDa: connexin 26) is a gap junction protein gene that has been implicated in many cases of autosomal recessive non-syndromic deafness. Point and deletion mutations in GJB2 are the most frequent cause of non-syndromic deafness across racial groups. To clarify the relation between profound non-syndromic deafness and GJB2 mutation in Japanese children, we performed genetic testing for GJB2. METHODS We conducted mutation screening employing PCR and direct sequencing for GJB2 in 126 children who had undergone cochlear implantation with congenital deafness. RESULTS We detected 10 mutations, including two unreported mutations (p.R32S and p.P225L) in GJB2. We identified the highest-frequency mutation (c.235delC: 44.8%) and other nonsense or truncating mutations, as in previous studies. However, in our research, p.R143W, which is one of the missense mutations, may also show an important correlation with severe deafness. CONCLUSION Our results suggest that the frequencies of mutations in GJB2 and GJB6 deletions differ among cohorts. Thus, our report is an important study of GJB2 in Japanese children with profound non-syndromic deafness.
Collapse
Affiliation(s)
- Chieri Hayashi
- Department of Otorhinolaryngology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan.
| | | | | | | | | | | | | | | |
Collapse
|
15
|
Etiology and one-year follow-up results of hearing loss identified by screening of newborn hearing in Japan. Otolaryngol Head Neck Surg 2010; 143:97-100. [DOI: 10.1016/j.otohns.2010.02.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Revised: 01/30/2010] [Accepted: 02/03/2010] [Indexed: 11/18/2022]
Abstract
Objective: To evaluate the incidence of newborn hearing loss in a Japanese population and to elucidate etiological factors and one-year prognosis. Study Design: Screening of newborn hearing. Setting: Children's tertiary referral center. Subjects and Methods: Between 1999 and 2008, 101,912 newborn infants were screened, with 693 infants (0.68%) referred. Etiology investigation included CT, detection of cytomegalovirus (CMV) DNA, and connexin 26 mutation. Results: Abnormal results (auditory brainstem response [ABR] threshold ≥ 35 normal hearing level [dB nHL] in either side) were observed in 312 infants (0.31%), and 133 subjects (0.13%) with ABR thresholds ≥ 50 dB nHL on both sides were classified into the habilitation group. In this group, inner ear/internal auditory meatus anomalies were detected in 20 of 121 subjects (17%) tested, middle/external ear anomalies in 14 of 121 subjects (12%), CMV DNA in 13 of 77 subjects (17%), and connexin 26 mutation in 28 of 89 subjects (31%). In 68 subjects undergoing all three investigations (CT, CMV, and connexin 26), 41 (60%) had positive results in at least one test. With inclusion of otitis media with effusion and perinatal problems, this rate amounted to 78% (53 subjects). Of the 97 infants in the habilitation group successfully followed up to one year, 36 (37%) showed a threshold change of 20 dB or more in either ear: 11 (11%) progression and 25 (26%) improvement, and 15 infants (15%) were reclassified into a less severe classification. Conclusion: Considering that 26 percent of infants with bilateral moderate to severe hearing loss showed improvement in one year, habilitation protocols, especially very early cochlear implantation within one year of birth, should be reconsidered.
Collapse
|
16
|
Mahdieh N, Rabbani B. Statistical study of 35delG mutation of GJB2 gene: a meta-analysis of carrier frequency. Int J Audiol 2010; 48:363-70. [PMID: 19925344 DOI: 10.1080/14992020802607449] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
GJB2 mutations are major causes of autosomal recessive nonsyndromic hearing loss (ARNSHL) in many populations. However, a few mutations have an ethnic-specific background. We performed a review by means of a meta-analysis to evaluate the influence of the 35delG on ARNSHL. A PubMed, InterScience, British Library Direct, and Sciencedirect search using keywords '35delG', 'GJB2' and 'Connexin 26' associated with 'carrier frequency' was carried out to include all papers from February 1998 to February 2008. 35delG carrier frequencies in 23187 random controls were analysed and categorized, corresponding with geographical boundaries, from all over the world. Mean carrier frequencies of 35delG mutation were found to be 1.89, 1.52, 0.64, 1, and 0.64 for European, American, Asian, Ocean, and African populations, respectively. We found that the average 35delG carrier frequency is highest in southern Europe and lowest in eastern Asia. The south-to-north European gradient in the carrier frequency of 35delG was confirmed and also a west-to-east Asian gradient is suggested. This study highlights the importance of establishing prevalence, based on the local population for screening and diagnostic programs of live births.
Collapse
Affiliation(s)
- Nejat Mahdieh
- Genetics Department, School of Medicine, Tarbiat Modares University, Tehran, Iran.
| | | |
Collapse
|
17
|
Screening for gap junction protein beta-2 gene mutations in Malays with autosomal recessive, non-syndromic hearing loss, using denaturing high performance liquid chromatography. The Journal of Laryngology & Otology 2008; 122:1284-8. [PMID: 18353197 DOI: 10.1017/s0022215108002041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVE To determine the frequency and type of gap junction protein beta-2 gene mutations in Malay patients with autosomal recessive, non-syndromic hearing loss. METHODS A total of 33 Malay patients with autosomal recessive, non-syndromic hearing loss were screened for mutations in the Cx26 coding region. Deoxyribonucleic acid was extracted from buccal swab samples and subjected to polymerase chain reaction. Slow-reannealing was performed, followed by screening using denaturing high performance liquid chromatography. RESULTS Eight of the samples (24.2 per cent) showed heterozygous peaks, and further sequencing of these samples revealed four patients (50.0 per cent) with the W24X mutation, two (25.0 per cent) with the V37I mutation and another two (25.0 per cent) with the G4D mutation. CONCLUSIONS Analysis of buccal swab samples by denaturing high performance liquid chromatography is noninvasive and suitable for rapid and reliable screening of gap junction protein beta-2 gene mutations in patients with autosomal recessive, non-syndromic hearing loss. Malay patients with autosomal recessive, non-syndromic hearing loss have different kinds of gap junction protein beta-2 gene mutations which are rarely found in other populations.
Collapse
|
18
|
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.
Collapse
Affiliation(s)
- Stacey A Apps
- School of Speech Pathology and Audiology, Faculty of Health Sciences, Flinders University, Adelaide, Australia
| | | | | |
Collapse
|
19
|
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.
Collapse
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.
| |
Collapse
|
20
|
Dahl HHM, Tobin SE, Poulakis Z, Rickards FW, Xu X, Gillam L, Williams J, Saunders K, Cone-Wesson B, Wake M. The contribution of GJB2 mutations to slight or mild hearing loss in Australian elementary school children. J Med Genet 2006; 43:850-5. [PMID: 16840571 PMCID: PMC2563186 DOI: 10.1136/jmg.2006.042051] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2006] [Revised: 06/01/2006] [Accepted: 06/14/2006] [Indexed: 12/15/2022]
Abstract
BACKGROUND There is a lack of information on prevalence, cause and consequences of slight/mild bilateral sensorineural hearing loss (SNHL) in children. We report the first systematic genetic analysis of the GJB2 gene in a population-derived sample of children with slight/mild bilateral SNHL. METHODS Hearing tests were conducted in 6240 Australian elementary school children in Grades 1 and 5. 55 children (0.88%) were found to have a slight/mild sensorineural hearing loss. 48 children with slight/mild sensorineural hearing loss and a matched group of 90 children with normal hearing participated in a genetic study investigating mutations in the GJB2 gene, coding for connexin 26, and the presence of the del(GJB6-D13S1830) and del(GJB6-D13S1854) deletions in the GJB6 gene, coding for connexin 30. RESULTS Four of 48 children with slight/mild sensorineural hearing loss were homozygous for the GJB2 V37I change. The four children with homozygous V37I mutations were all of Asian background and analysis of SNPs in or near the GJB2 gene suggests that the V37I mutation arose from a single mutational event in the Asian population. DISCUSSION Based on the prevalence of carriers of this change we conclude that V37I can be a causative mutation that is often associated with slight/mild sensorineural hearing loss. No other children in the slight/mild hearing loss group had a hearing loss related to a GJB2 mutation. One child with normal hearing was homozygous for the R127H change and we conclude that this change does not cause hearing loss. Two children of Asian background were carriers of the V37I mutation. Our data indicate that slight/mild sensorineural hearing loss due to the GJB2 V37I mutation is common in people of Asian background.
Collapse
Affiliation(s)
- H-H M Dahl
- Genetic Hearing Research, Murdoch Childrens Research Institute & Department of Paediatrics (Melbourne University), Royal Children's Hospital, Melbourne, Victoria, Australia.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Siemering K, Manji SSM, Hutchison WM, Du Sart D, Phelan D, Dahl HHM. Detection of mutations in genes associated with hearing loss using a microarray-based approach. J Mol Diagn 2006; 8:483-9; quiz 528. [PMID: 16931589 PMCID: PMC1867613 DOI: 10.2353/jmoldx.2006.050147] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Knowing the etiology of hearing loss in a person has implications for counseling and management of the condition. More than 50% of cases of early onset, nonsyndromic sensorineural hearing loss are attributable to genetic factors. However, deafness is a genetically heterogeneous condition and it is therefore currently not economically and practically feasible to screen for mutations in all known deafness genes. We have developed a microarray-based hybridization biochip assay for the detection of known mutations. The current version of the hearing loss biochip detects nine common mutations in the connexin 26 gene, four mutations in the pendrin gene, one mutation in the usherin gene, and one mutation in mitochondrial DNA. The biochip was validated using DNA from 250 people with apparent nonsyndromic, moderate to profound sensorineural hearing loss. The hearing loss biochip detected with 100% accuracy the mutations it was designed for. No false-positives or false-negative results were seen. The biochip can easily be expanded to test for additional mutations in genes associated with hearing impairment or other genetic conditions.
Collapse
Affiliation(s)
- Kirby Siemering
- Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Victoria 3052, Australia
| | | | | | | | | | | |
Collapse
|
22
|
Cheng X, Li L, Brashears S, Morlet T, Ng SS, Berlin C, Hood L, Keats B. Connexin 26 variants and auditory neuropathy/dys-synchrony among children in schools for the deaf. Am J Med Genet A 2006; 139:13-8. [PMID: 16222667 DOI: 10.1002/ajmg.a.30929] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Genetic and auditory studies of 731 children with severe-to-profound hearing loss in US schools for the deaf and 46 additional children receiving clinical services for hearing loss ranging from moderate to profound demonstrated that mutations in the connexin 26 (GJB2) and connexin 30 (GJB6) genes explain at least 12% of those with nonsyndromic sensorineural deafness. Otoacoustic emissions (OAEs) testing to detect functional outer hair cells indicated that 76 of the children had emissions and therefore may have (as yet unconfirmed) auditory neuropathy/dys-synchrony (AN/AD). Five of these children with OAEs were GJB2 homozygotes or compound heterozygotes with the genotypes 35delG/35delG, W77X/W77X, 35delG/360delGAG, 35delG/V95M, and V84M/M34T. In particular, unilateral AN/AD was confirmed in a child with moderate hearing loss and the 35delG/V95M genotype. Detecting OAEs in individuals with GJB2 mutations suggests that lack of functional gap junctions as a result of GJB2 mutations does not necessarily destroy all outer hair cell function.
Collapse
Affiliation(s)
- Xing Cheng
- Department of Genetics, Kresge Hearing Research Laboratory, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, USA
| | | | | | | | | | | | | | | |
Collapse
|
23
|
Propst EJ, Stockley TL, Gordon KA, Harrison RV, Papsin BC. Ethnicity and mutations in GJB2 (connexin 26) and GJB6 (connexin 30) in a multi-cultural Canadian paediatric Cochlear Implant Program. Int J Pediatr Otorhinolaryngol 2006; 70:435-44. [PMID: 16125251 DOI: 10.1016/j.ijporl.2005.07.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2005] [Accepted: 07/20/2005] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To determine the relationship between ethnicity and mutations in the GJB2 and GJB6 genes in multi-cultural patients enrolled in a Canadian paediatric Cochlear Implant Program. METHODS Blood was analyzed from 65 paediatric cochlear implant users by direct sequencing of the coding region and intron/exon boundaries of the GBJ2 gene. Individuals heterozygous for one mutation in GJB2 or in whom mutations in GJB2 were not detected were analyzed for the common 342 kb deletion mutation D13S1830 in the GJB6 gene. Information regarding ethnicity of patients' families was obtained from patient records and/or interview. RESULTS GJB2 mutations were found in 36.9% of paediatric cochlear implant users tested. Nine different GJB2 mutations were identified among individuals from 14 different countries of origin. Seventy-eight percent of all identified pathogenic GJB2 mutations were 35delG. Biallelic GJB2 mutations were found in 16 cochlear implant users (66.7% of GJB2 mutations). Three novel GJB2 sequence changes were identified: (1) a missense mutation T107C (L36P) in an individual of African decent; (2) a missense mutation G475T (D159Y) in an individual of Caribbean decent; (3) a regulatory region change 1-34C to T in an individual of African decent. GJB6-D13S1830 mutations were not found in any of the patients tested. Individuals of African, Caribbean and East Indian decent had different GJB2 mutations than the remainder of individuals tested. Patients of Asian, Italian, Spanish, Polish and Armenian decent were not found to carry mutations in GJB2 or the common GJB6-D13S1830 mutation. CONCLUSIONS This study represents the largest number of biallelic GJB2 mutations isolated in a group of paediatric cochlear implant users to date. Numerous and diverse GJB2 mutations were found in this multi-cultural group of children. Even though GJB2 mutations have been widely reported in the literature, this discussion represents the first report of GJB2 mutations in a multi-ethnic population (Canadian), as compared with previous studies that investigated fairly homogeneous populations. The diversity of GJB2 mutations identified reinforces the importance of testing for changes in GJB2 by direct sequencing of the entire coding region rather than testing only for common mutations.
Collapse
Affiliation(s)
- Evan Jon Propst
- Cochlear Implant Program, Department of Otolaryngology, The Hospital for Sick Children, Toronto, Ont., Canada M5G 1X8.
| | | | | | | | | |
Collapse
|
24
|
Yoong S, Spencer N. Audit of local performance compared with standards recommended by the national guidelines for aetiologic investigation of permanent childhood hearing impairment. Child Care Health Dev 2005; 31:649-57. [PMID: 16207222 DOI: 10.1111/j.1365-2214.2005.00558.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND National guidelines for aetiologic investigation of childhood deafness were developed as the Newborn Hearing Screening Program (NHSP) was being implemented in the United Kingdom. This guidance document was expected to be incorporated into the operational procedure of the NHSP. METHOD This criterion-based audit compared local care set against developed guidelines that can be used to assess the appropriateness of specific investigations, services and outcomes. Data on children diagnosed to have sensorineural deafness from March 2002-2004 were extracted from an established computerized database for analysis. RESULTS Forty-seven children were included; 17 have bilateral severe to profound hearing loss, 25 have bilateral mild to moderate loss and 5 with unilateral loss. A high proportion of Pakistani children were from consanguineous marriages with a family history of deafness. Total 29.8% of children were diagnosed through newborn screening and 70.2% detected through hearing surveillance programmes. For children with bilateral severe to profound deafness, 53.0% accepted, 5.9% declined and 41.2% were not offered imaging of their inner ears. A total of 47.1% accepted and 52.9% declined electrocardiograph (ECG) evaluation. Total 70.6% accepted and 29.4% declined connexin mutations testing. Parental requests were required for those with lesser degree of hearing loss. Total 24% accepted, 28% declined and 48% were not offered connexin testing. None were offered ECG and imaging. Testing for congenital infections was inappropriate for children over 1 year old. Ten subjects accepted and five declined this investigation. In the total group, 63.8% accepted, 17.0% declined and 19.1% were not offered referral to the ophthalmic service. Total 46.8% accepted, 44.7% declined and 8.5% were not offered referral to genetics service. Investigations resulted in two connexin-positive children with moderate loss. CONCLUSION Our study identified key areas where guidelines were not followed. These were related to lack of funding and parental choice. This sample has a higher connexin 'hit' rate for lesser degree deafness.
Collapse
Affiliation(s)
- S Yoong
- St Luke's Hospital, Little Horton Lane, Bradford Teaching Hospitals Foundation NHS Trust, Bradford, UK.
| | | |
Collapse
|
25
|
Skinner JR, Chong B, Fawkner M, Webster DR, Hegde M. Use of the newborn screening card to define cause of death in a 12-year-old diagnosed with epilepsy. J Paediatr Child Health 2004; 40:651-3. [PMID: 15469540 DOI: 10.1111/j.1440-1754.2004.00498.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Post-mortem investigation of sudden death in young people frequently reveals no overt cause for the death. Full investigation is hampered if tissue or blood is not retained for DNA analysis. We report a post mortem molecular diagnosis of long QT syndrome in a 12-year-old boy diagnosed with epilepsy who died suddenly playing sport. The DNA was extracted from an archived blood spot on his newborn screening ('Guthrie') card, which had been taken from him at 6 days of age. A missense mutation was detected in exon 5 of the KCNQ1 gene; R243C (835C > T), associated with long QT type 1. The same mutation was found in the mother (who now takes effective preventative therapy), but not in the sib who has now been reassured that she is not at risk of sudden death.
Collapse
Affiliation(s)
- J R Skinner
- Department of Paediatric Cardiology, Starship Hospital, Auckland, New Zealand.
| | | | | | | | | |
Collapse
|
26
|
Shi GZ, Gong LX, Xu XH, Nie WY, Lin Q, Qi YS. GJB2 gene mutations in newborns with non-syndromic hearing impairment in Northern China. Hear Res 2004; 197:19-23. [PMID: 15504600 DOI: 10.1016/j.heares.2004.06.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2004] [Accepted: 06/29/2004] [Indexed: 11/18/2022]
Abstract
Mutations in GJB2 account for the majority of recessive forms of prelingual hearing loss. However, in most previous studies it was not possible to distinguish between congenital (present at birth) and non-congenital prelingual hearing loss. In the present study, the frequency of GJB2 alleles in 20 newborns with bilateral severe-to-profound non-syndromic hearing impairment (NSHI) who were found at birth through newborn hearing screening and clinical examination is reported. PCR was used to amplify the coding region of GJB2 gene followed by sequencing analyses. Fifty volunteers with normal hearing were included as controls. Results showed that three cases were 235delC/235delC homozygotes; one was 235delC/605ins46 compound heterozygotes, 605ins46 mutation was a novel mutation reported in the Chinese population; another was 235delC/299-300delAT compound heterozygotes. 25% (5/20) of the deafness in newborns studied was caused by GJB2 gene mutations. The frequency of 235delC allele carrier in patients and in control group was 22.5% and 1%, respectively. One case was identified as being a 235delC heterozygote without other mutations detected. Besides, multiple polymorphisms such as V27I, V37I, E114G, T123N were also detected. In conclusion, GJB2 analysis is an important test that identifies a major cause of newborns with bilateral severe-to-profound NSHI screened by universal newborn hearing screening in Northern China. The most common pathologic mutation of GJB2 in studied cases was 235delC. Molecular analysis and genetic counseling will be extremely important for congenital deafness present at birth.
Collapse
Affiliation(s)
- Gui-zhi Shi
- Department of Forensic Medicine, Medical College of Shantou University, 22 Xinling Road, Shantou 515031, Guangdong, People's Republic of China.
| | | | | | | | | | | |
Collapse
|
27
|
Wattanasirichaigoon D, Limwongse C, Jariengprasert C, Yenchitsomanus PT, Tocharoenthanaphol C, Thongnoppakhun W, Thawil C, Charoenpipop D, Pho-iam T, Thongpradit S, Duggal P. High prevalence of V37I genetic variant in the connexin-26 (GJB2) gene among non-syndromic hearing-impaired and control Thai individuals. Clin Genet 2004; 66:452-60. [PMID: 15479191 DOI: 10.1111/j.1399-0004.2004.00325.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hearing loss is highly prevalent with a worldwide incidence of 1-2 per 1000 newborns. Several previous studies have demonstrated that mutations of connexin 26 (Cx26 or GJB2) are responsible for most cases of the recessive non-syndromic sensorineural hearing loss (NSSHL). Certain mutations have been described frequently among various populations, which include 35delG, 167delT, and 235delC. Recently, a missense mutation, V37I, was reported as a pathogenic change in East Asian affected individuals. To identify genetic variants associated with NSSHL in Thai population, we performed mutation analysis of Cx26 in 166 unrelated probands with NSSHL and 205 controls. We identified seven novel genetic variants in Cx26. We also identified a high prevalence of the V37I mutation among both affected probands (11.1%) and control subjects (8.5%), which suggests that the pathologic role of V37I may be modified by other genes. Our data support previous studies that show heterogeneity in the frequencies and types of mutations in Cx26 within populations and among ethnicities and that before clinical significance and causality can be attributed to a genetic variant, functional characterization is necessary.
Collapse
Affiliation(s)
- D Wattanasirichaigoon
- Department of Pediatrics, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Erbe CB, Harris KC, Runge-Samuelson CL, Flanary VA, Wackym PA. Connexin 26 and connexin 30 mutations in children with nonsyndromic hearing loss. Laryngoscope 2004; 114:607-11. [PMID: 15064611 DOI: 10.1097/00005537-200404000-00003] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES/HYPOTHESIS Mutations in the connexin 26 (Cx26) or gap junction beta 2 gene are the leading cause of hereditary nonsyndromic sensorineural hearing loss in Caucasians. The Cx26 coding region of 68 children with nonsyndromic sensorineural hearing loss was sequenced to determine the frequency and type of Cx26 mutations in this population. Screening was also performed for a common connexin 30 (Cx30) or gap junction beta 6 mutation (del [GJB6-D13S1830]). Children also underwent audiological testing to determine whether any correlation exists between Cx26 mutations and severity of hearing loss. STUDY DESIGN In all, 68 children with nonsyndromic sensorineural hearing loss were screened for Cx26 and Cx30 mutations by polymerase chain reaction and direct sequencing. METHODS Genomic DNA was amplified by polymerase chain reaction using primers that flank the entire Cx26 coding region. Screening for the 342-kb Cx30 deletion was performed using primers that amplified the breakpoint junction of the deletion. The amplicons were then sequenced in both directions and analyzed for mutations. Audiometric testing, including pure-tone audiometry and auditory evoked brainstem response, was also performed to determine the degree of hearing loss. RESULTS Twenty-seven of 68 children tested had mutations in Cx26 with 35delG being the most prevalent. Ten additional Cx26 mutations were detected including a novel compound heterozygote. Two children were heterozygous for the Cx30 del (GJB6-D13S1830) mutation. CONCLUSION Cx26 and Cx30 mutations were present in 41.2% of children tested in the study population. Audiometric data supported previous studies demonstrating a greater degree of hearing loss in subjects who are homozygous for the 35delG mutation.
Collapse
Affiliation(s)
- Christy B Erbe
- Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, U.S.A
| | | | | | | | | |
Collapse
|
29
|
Wu BL, Lindeman N, Lip V, Adams A, Amato RS, Cox G, Irons M, Kenna M, Korf B, Raisen J, Platt O. Effectiveness of sequencing connexin 26 (GJB2) in cases of familial or sporadic childhood deafness referred for molecular diagnostic testing. Genet Med 2002; 4:279-88. [PMID: 12172394 DOI: 10.1097/00125817-200207000-00006] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
PURPOSE Hearing loss is a common congenital disorder that is frequently associated with mutations in the GJB2 gene encoding the connexin 26 protein (Cx26). We sought to evaluate the effectiveness of direct DNA sequencing for detection of Cx26 mutations as a clinical diagnostic test. METHODS We designed a clinical assay using a three-step polymerase chain reaction (PCR)-based DNA sequencing strategy to detect all possible mutations in the open reading frame and flanking sequences of Cx26. The results of the first 324 cases of childhood deafness referred for diagnostic testing were analyzed. RESULTS A total of 127 of the 324 (39.2%) cases had at least one mutant Cx26 allele (36.1% of sporadic cases, 70% of familial cases). Of these 127 case, 57 (44.8%) were homozygotes or compound heterozygotes. Thirty-four different mutations were identified, including 10 novel mutations, 6 of which (T8M, K15T, R32L, M93I, N206S, and 511-512insAACG) may be pathogenic. We also provide new evidence on the pathogenicity or nonpathogenicity of 12 previously reported mutations, and clarify the confusing nomenclature of the 313-326del14 mutation. CONCLUSION A simple and rigorous method for efficient PCR-based sequence analysis of Cx26 is a sensitive clinical assay for evaluating deaf children. Its widespread use is likely to identify additional pathogenic mutations and lead to a better understanding of the clinical significance of previously identified mutations.
Collapse
Affiliation(s)
- Bai-Lin Wu
- Department of Laboratory Medicine, Children's Hospital, Boston, Massachusetts 02115, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Kenneson A, Van Naarden Braun K, Boyle C. GJB2 (connexin 26) variants and nonsyndromic sensorineural hearing loss: a HuGE review. Genet Med 2002; 4:258-74. [PMID: 12172392 DOI: 10.1097/00125817-200207000-00004] [Citation(s) in RCA: 282] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Despite the enormous heterogeneity of genetic hearing loss, variants in one locus, Gap Junction Beta 2 or GJB2 (connexin 26), account for up to 50% of cases of nonsyndromic sensorineural hearing loss in some populations. This article reviews genetic epidemiology studies of the alleles of GJB2, prevalence rates, genotype-phenotype relations, contribution to the incidence of hearing loss, and other issues related to the clinical validity of genetic testing for GJB2. This review focuses primarily on three alleles: 167 Delta T, 35 Delta G, and 235 Delta C. These alleles are recessive for nonsyndromic prelingual sensorineural hearing loss, and the evidence suggests complete penetrance but variable expressivity.
Collapse
Affiliation(s)
- Aileen Kenneson
- National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia 30341-3724, USA
| | | | | |
Collapse
|
31
|
|