scholarly journals GJB2 and GJB6 genes mutations in children with non-syndromic hearing loss

2017 ◽  
Vol 25 (1) ◽  
pp. 37-46 ◽  
Author(s):  
Călin Lazăr ◽  
Radu Popp ◽  
Camelia Al-Khzouz ◽  
Gheorghe Mihuț ◽  
Paula Grigorescu-Sido
Keyword(s):  
Hearing Loss ◽  
Gjb2 Gene ◽  
Pcr Analysis ◽  
Profound Hearing Loss ◽  
Prevalence Data ◽  
Sample Group ◽  
First Case ◽  
Syndromic Hearing Loss ◽  
The Moment ◽  
Moderate Hearing Loss

Abstract Introduction. At the moment there is not enough data in Romania about the incidence of the main genetic mutations which can cause hearing loss. Objective. The current research aims to determine on a representative sample the prevalence of two mutations of genes GJB2 -c.35delG and p.W24X- and two mutations of genes GJB6 -del(GJB6-D13S1830), del(GJB6-D13S1854) respectively - in patients with congenital nonsyndromic sensorineural hearing loss (CNSHL). Methods: The sample group included 179 children with CNSHL. The evaluation consist in: a.Clinical, laboratory and imagistic examination; b.ENT exam and audiological evaluation. c.Two methods (semi-nested PCR technique followed by RFLP, validated with ARMS-PCR analysis) for detection of c.35delG and pW24X mutations; d.PCR-multiplex technique for detecting del(GJB6-D13S1830) and del (GJB6-D13S1854). Results: The audiological diagnosis was: profound hearing loss in 116 patients (64.8%), severe hearing loss in 29 children (16.2%) and moderate hearing loss in 34 patients (representing 19% of the trial patients). The prevalence for the three mutations was: 27.3 % for c.35delG, 3.6 % for p.W24X and 0.28% for del(GJB6-D13S1830). The detection of the three mutations (two on GJB2 gene and one on GJB 6 gene) has allowed to establish the genetic cause for deafness in 45 patients, representing 25.14% of the sample group. Our study is reporting the first case in Romania with a mutation of gene GJB6. Mutation del(GJB6-D13S1854) lacked in all 179 patients. Conclusion: The prevalence data obtained in the current research are comparable to data communicated by studies from other European countries.

scholarly journals Whole-Genome Sequencing Improves the Diagnosis of DFNB1 Monoallelic Patients

Genes ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1267
Author(s):  
Anaïs Le Nabec ◽  
Mégane Collobert ◽  
Cédric Le Maréchal ◽  
Rémi Marianowski ◽  
Claude Férec ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Gjb2 Gene ◽  
Whole Genome ◽  
Genetic Origin ◽  
Functional Assays ◽  
Syndromic Hearing Loss ◽  
Sensory Defect

Hearing loss is the most common sensory defect, due in most cases to a genetic origin. Variants in the GJB2 gene are responsible for up to 30% of non-syndromic hearing loss. Today, several deafness genotypes remain incomplete, confronting us with a diagnostic deadlock. In this study, whole-genome sequencing (WGS) was performed on 10 DFNB1 patients with incomplete genotypes. New variations on GJB2 were identified for four patients. Functional assays were realized to explore the function of one of them in the GJB2 promoter and confirm its impact on GJB2 expression. Thus, in this study WGS resolved patient genotypes, thus unlocking diagnosis. WGS afforded progress and bridged some gaps in our research.

scholarly journals Mutations in the connexin26/GJB2 gene are the most common event in non-syndromic hearing loss among the German population

2001 ◽  
Vol 17 (6) ◽  
pp. 521-522 ◽  
Author(s):  
Heinz Gabriel ◽  
Petra Kupsch ◽  
J�rgen Sudendey ◽  
Elke Winterhager ◽  
Klaus Jahnke ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Gjb2 Gene ◽  
German Population ◽  
Common Event ◽  
Syndromic Hearing Loss

scholarly journals Spectrum and Frequency of the GJB2 Gene Mutations Among Latvian Patients with Prelingual Nonsyndromic Hearing Loss

2009 ◽  
Vol 63 (4-5) ◽  
pp. 198-203
Author(s):  
Olga Šterna ◽  
Natālija Proņina ◽  
Ieva Grīnfelde ◽  
Sandra Kušķe ◽  
Astrīda Krūmiņa ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Gene Mutations ◽  
Gjb2 Gene ◽  
Connexin 26 ◽  
Compound Heterozygous ◽  
Nonsyndromic Hearing Loss ◽  
Profound Hearing Loss ◽  
Common Cause ◽  
Gjb2 Mutation ◽  
35Delg Mutation

Spectrum and Frequency of the GJB2 Gene Mutations Among Latvian Patients with Prelingual Nonsyndromic Hearing Loss Mutations in the GJB2 gene (connexin 26) are the most common cause of congenital nonsyndromic severe-to-profound hearing loss. Sixty-five hearing impaired probands from Latvia were tested for mutations in the GJB2 gene to determine the percentage of hearing loss attributed to connexin 26 and the types of mutations in this population. A total of 62% of patients tested had GJB2 mutations. Four different mutations in the GJB2 gene were identified in Latvian patients with nonsyndromic sensorineural hearing loss: 35delG, 311-324del14, 235delC and M34T. The most prevalent mutation is 35delG (47% of all probands were homozygous and 8% compound heterozygous). Our findings support the conclusion that the 35delG mutation is the most prevalent GJB2 mutation and that it is the common cause of hereditary nonsyndromic hearing loss in populations of European descent.

Association of GJB2 gene mutation with cochlear implant performance in genetic non-syndromic hearing loss

2011 ◽  
Vol 75 (12) ◽  
pp. 1572-1575 ◽  
Author(s):  
Recep Karamert ◽  
Yildirim A. Bayazit ◽  
Senay Altinyay ◽  
Akın Yılmaz ◽  
Adnan Menevse ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Cochlear Implant ◽  
Gene Mutation ◽  
Gjb2 Gene ◽  
Syndromic Hearing Loss

scholarly journals Investigating GJB2 Mutation in 31 Individuals With Non-syndromic Hearing Loss

2021 ◽  
Vol 24 (1) ◽  
pp. 50-61
Author(s):  
Pedram Pouryari Biyachal ◽  
◽  
Najmeh Ranji ◽  
Ali Nazemi ◽  
◽  
...  
Keyword(s):  
Hearing Loss ◽  
Cross Sectional Study ◽  
Gjb2 Gene ◽  
Common Mutation ◽  
Cross Sectional ◽  
Gjb2 Mutation ◽  
Syndromic Hearing Loss ◽  
Pcr Method ◽  
Gilan Province ◽  
35Delg Mutation

Background and Aim: Non-syndromic hearing loss is a genetically heterogeneous disorder. Mutation in the GJB2 gene is a major cause of non-syndromic hearing loss in numerous countries. This study aimed to evaluate GJB2 mutations in 31 individuals with non-syndromic hearing loss Methods & Materials: In this descriptive cross-sectional study, the required blood samples were collected from 31 individuals with non-syndromic hearing loss in Rasht and Bandar Anzali Cities, Gilan Province, Iran. After DNA isolation, the GJB2 gene was amplified by the PCR method and underwent sequencing. Ethical Considerations:This study was approved by the Ethics Committee of the Islamic Azad University, Mashhad Branch (Code: IR.IAU.MSHD.REC.1398.027). Results: In this study, 3 mutations were determined in 18 individuals with hearing loss. Accordingly, 35delG mutation had the highest frequency (48.38%) in individuals with hearing loss as homozygote (n=14) and heterozygote (n=2). A patient with heterozygosity in V153I mutation and a patient with compound heterozygosity in 35delG/G200R mutation was determined. Conclusion: It appears that 35delG mutation is a common mutation in the GJB2 gene in individuals with non-syndromic hearing loss in Guilan Province.

scholarly journals Identification of Main Genetic Causes Responsible for Non-Syndromic Hearing Loss in a Peruvian Population

Genes ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 581 ◽  
Author(s):  
Figueroa-Ildefonso ◽  
Bademci ◽  
Rajabli ◽  
Cornejo-Olivas ◽  
Villanueva ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Genetic Factors ◽  
Stop Codon ◽  
Premature Stop Codon ◽  
Gjb2 Gene ◽  
Pathogenic Variants ◽  
Novel Variants ◽  
Syndromic Hearing Loss ◽  
Different Populations ◽  
Global Population

: Hearing loss (HL) is a common sensory disorder affecting over 5% of the global population. The etiology underlying HL includes congenital and acquired causes; genetic factors are the main cause in over 50% of congenital cases. Pathogenic variants in the GJB2 gene are a major cause of congenital non-syndromic hearing loss (NSHL), while their distribution is highly heterogeneous in different populations. To the best of our knowledge, there is no data regarding the genetic etiologies of HL in Peru. In this study, we screened 133 Peruvian families with NSHL living in Lima. We sequenced both exons of the GJB2 gene for all probands. Seven probands with familial NSHL that remained negative for GJB2 variants underwent whole genome sequencing (WGS). We identified biallelic pathogenic variants in GJB2 in 43 probands; seven were heterozygous for only one allele. The c.427C>T variant was the most common pathogenic variant followed by the c.35delG variant. WGS revealed three novel variants in MYO15A in two probands, one of them was predicted to affect splicing and the others produce a premature stop codon. The Peruvian population showed a complex profile for genetic variants in the GJB2 gene, this particular profile might be a consequence of the admixture history in Peru.

Considerations for Pediatric Cochlear Implant Recipients With Unilateral or Asymmetric Hearing Loss: Assessment, Device Fitting, and Habilitation

2017 ◽  
Vol 26 (2) ◽  
pp. 91-98 ◽  
Author(s):  
Laura Greaver ◽  
Hannah Eskridge ◽  
Holly F. B. Teagle
Keyword(s):  
Hearing Loss ◽  
Cochlear Implant ◽  
Cochlear Implantation ◽  
Clinical Report ◽  
Loss Assessment ◽  
Profound Hearing Loss ◽  
Single Sided Deafness ◽  
Asymmetric Hearing Loss ◽  
Case Basis ◽  
Moderate Hearing Loss

Purpose The purpose of this clinical report is to present case studies of children who are nontraditional candidates for cochlear implantation because they have significant residual hearing in 1 ear and to describe outcomes and considerations for their audiological management and habilitation. Method Case information is presented for 5 children with profound hearing loss in 1 ear and normal or mild-to-moderate hearing loss in the opposite ear and who have undergone unilateral cochlear implantation. Pre- and postoperative assessments were performed per typical clinic routines with modifications described. Postimplant habilitation was customized for each recipient using a combination of traditional methods, newer technologies, and commercial materials. Results The 5 children included in this report are consistent users of their cochlear implants and demonstrate speech recognition in the implanted ear when isolated from the better hearing ear. Conclusions Candidacy criteria for cochlear implantation are evolving. Children with single-sided deafness or asymmetric hearing loss who have traditionally not been considered candidates for cochlear implantation should be evaluated on a case-by-case basis. Audiological management of these recipients is not vastly different compared with children who are traditional cochlear implant recipients. Assessment and habilitation techniques must be modified to isolate the implanted ear to obtain accurate results and to provide meaningful therapeutic intervention.

scholarly journals Exome sequencing analysis reveals homozygous GJB2 gene mutation in a Mexican family with profound hearing loss

2017 ◽  
Vol 80 (2) ◽  
pp. 77-80
Author(s):  
M. Martínez-Saucedo ◽  
M.R. Rivera-Vega ◽  
L.M. Gonzalez-Huerta ◽  
H. Urueta-Cuéllar ◽  
S.A. Cuevas-Covarrubias
Keyword(s):  
Hearing Loss ◽  
Exome Sequencing ◽  
Gene Mutation ◽  
Gjb2 Gene ◽  
Sequencing Analysis ◽  
Profound Hearing Loss ◽  
Mexican Family

scholarly journals GJB2: Frequency of the Less Common Variants in a Sample of the Portuguese Population

2021 ◽  
Vol 34 (13) ◽  
Author(s):  
Cláudia Sousa Reis ◽  
Ana Cristina Santos ◽  
Henrique Barros ◽  
Susana Fernandes ◽  
Carla Pinto Moura
Keyword(s):  
Hearing Loss ◽  
Caucasian Population ◽  
Hearing Impaired ◽  
Gjb2 Gene ◽  
Common Variants ◽  
Patient Assessment ◽  
Portuguese Population ◽  
Moderate Hearing Loss ◽  
Selection Of

Introduction: Sequence variants in the GJB2 gene account for up to 50% of cases of non-syndromic sensorineural hearing loss in the Caucasian population. In this study, we report the frequency of the less common variants of the GJB2 gene in a Portuguese sample and compare these frequencies with those of a group of hearing-impaired patients.Material and Methods: In order to select the less common GJB2 variants, 147 hearing-impaired patients followed in Centro Hospitalar Universitário de São João were evaluated. Afterwards, the presence of those variants was tested in 360 individuals from Generation 21.Results: The patient assessment enabled the selection of 11 GJB2 variants. Of those, 10 were investigated in Generation 21 participants, with only four being detected, in heterozygosity: p.Phe83Leu, p.Arg127His, p.Val153Ile and p.Asn206Ser, with the allelic frequencies (95% confidence interval) of 0.14% (0.01% - 0.87%), 0.28% (0.01% - 1.08%), 0.97% (0.43% - 2.04%) and 0.14% (0.01% - 0.88%), respectively. Two variants, p.Val37Ile and p.Val95Met, were more frequent in the patients’ group with statistical significance.Discussion: Our results allow for the p.Arg127His and p.Val153Ile variants to comply with polymorphism criteria and support the pathogenicity of p.Val37Ile and p.Val95Met variants. Moreover, two cases of moderate hearing loss were explained by the p.Val37Ile/p. Asn206Ser genotype, substantiating both the pathogenicity of such variants and the hypothesis that compound heterozygosity with p.Ans206Ser is associated with mild-moderate genotypes.Conclusion: Understanding the role of the variants is essential in order to provide genetic counselling to patients and their families. We explored a set of uncommon GJB2 variants that comprised 12% of the hearing-impaired patients in this study, supporting the relevance of their description.

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