Connexin 26 and 30 mutations in paediatric patients with congenital, non-syndromic hearing loss treated with cochlear implantation in Mediterranean Turkey

2012 ◽  
Vol 127 (1) ◽  
pp. 33-37 ◽  
Author(s):  
Ö Tarkan ◽  
P Sari ◽  
O Demirhan ◽  
M Kiroğlu ◽  
Ü Tuncer ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Cochlear Implantation ◽  
Autosomal Recessive ◽  
Connexin 26 ◽  
Enzyme Linked Immunosorbent Assay ◽  
Paediatric Patients ◽  
Study Population ◽  
Connexin 30 ◽  
Syndromic Hearing Loss ◽  
35Delg Mutation

AbstractObjective:Mutations in the genes for connexin 26 (GJB2) and connexin 30 (GJB6) play an important role in autosomal recessive, non-syndromic hearing loss. This study aimed to detect the 35delG and 167delT mutations of theGJB2gene and the del(GJB6-D13S1830) mutation of theGJB6gene in paediatric patients diagnosed with congenital, non-syndromic hearing loss and treated with cochlear implantation in Mediterranean Turkey.Materials and method:We included 94 children diagnosed with congenital, non-syndromic hearing loss and treated with cochlear implantation. Blood samples were collected, DNA extracted and an enzyme-linked immunosorbent assay performed to enable molecular diagnosis of mutations.Results:Of the 94 children analysed, the 35delG mutation was detected in 12 (12.7 per cent): 10 (83.3 per cent) were homozygous and 2 (16.7 per cent) heterozygous mutant. The 167delT and del(GJB6-D13S1830) mutations were not detected.Conclusion:The GJB2-35delG mutation is a major cause of congenital, non-syndromic hearing loss in this study population.

scholarly journals High prevalence of theW24X mutation in the gene encoding connexin-26 (GJB2) in Spanish Romani (gypsies) with autosomal recessive non-syndromic hearing loss

2005 ◽  
Vol 137A (3) ◽  
pp. 255-258 ◽  
Author(s):  
Araceli Álvarez ◽  
Ignacio del Castillo ◽  
Manuela Villamar ◽  
Luis A. Aguirre ◽  
Anna González-Neira ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Autosomal Recessive ◽  
Connexin 26 ◽  
Gene Encoding ◽  
High Prevalence ◽  
Syndromic Hearing Loss

Hearing loss associated with 35delG mutation in Connexin-26 (GJB2) gene: audiogram analysis

2004 ◽  
Vol 118 (1) ◽  
pp. 8-11 ◽  
Author(s):  
Fabrizio Salvinelli ◽  
Manuele Casale ◽  
Luca D’Ascanio ◽  
Luca Firrisi ◽  
Fabio Greco ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Autosomal Recessive ◽  
Pure Tone Audiometry ◽  
Gjb2 Gene ◽  
Connexin 26 ◽  
Common Mutation ◽  
Congenital Hearing Loss ◽  
35Delg Mutation ◽  
The Relationship

35delG is the most common mutation in the Connexin-26 gene, representing a major cause of autosomal recessive hearing loss. The aim of this study was to evaluate the relationship between the audiological phenotype and the 35delG mutation in 64 Sicilians with non-syndromic deafness. Pure-tone audiometry and a screening for 35delG mutation were performed. Audiograms were evaluated according to the classification of Liu and Xu. Thirteen homozygotes and nine heterozygotes for the investigated mutation were found. Symmetrical hearing loss was significantly (p=0.008) more common in homozygous subjects than in those without the Connexin-26 mutation. Profound-severe hypoacusia was found in 92.3 per cent of 35delG homozygous, 22.3 per cent of heterozygous and 58.7 per cent of 35delG absent patients. Residual shape audiograms were more frequent in homozygotes. A molecular analysis for the 35delG mutation should be performed in cases of symmetric, severe-profound congenital hearing loss, as a genetic cause is probable in such cases.

Auditory Outcome after Cochlear Implantation in Children with DFNB7/11 Caused by Pathogenic Variants in TMC1 Gene

2020 ◽  
pp. 1-7
Author(s):  
Samanta Gallo ◽  
Patrizia Trevisi ◽  
Chiara Rigon ◽  
Ezio Caserta ◽  
Dario Seif Ali ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Functional Outcome ◽  
Cochlear Implantation ◽  
Autosomal Recessive ◽  
Pediatric Patients ◽  
Panel Testing ◽  
Pathogenic Variants ◽  
Excellent Functional Outcome ◽  
Speech Performance ◽  
Syndromic Hearing Loss

<b><i>Introduction:</i></b> Non-syndromic hereditary hearing loss is characterized by extreme genetic heterogeneity. So far, more than 100 pathogenic or likely pathogenic variants in <i>TMC1</i> gene have been reported in patients with autosomal recessive hearing loss (HL) DFNB7/11. The prevailing auditory phenotype of individuals with DFNB7/11 is congenital, profound, bilateral HL, but the functional outcome after cochlear implantation (CI) described in the literature is variable. The objective of this work is to evaluate the auditory outcome after CI in pediatric patients with DFNB7/11, born to non-consanguineous parents. <b><i>Methods:</i></b> A retrospective analysis of genetic and audiological data of DFNB7/11 patients followed up in a single Italian otolaryngology clinic was performed. Cases with biallelic pathogenic variants in <i>TMC1</i> were selected from the cohort of children with non-syndromic hearing loss who had undergone CI and had been molecularly characterized by multigene panel testing. All patients underwent extensive audiological assessment, and the auditory outcome after CI was evaluated. <b><i>Results:</i></b> DFNB7/11 was diagnosed in a total of 3 patients from 2 non-consanguineous families; a novel disease-causing variant in <i>TMC1</i> was detected [c.962G&#x3e;A p.(Trp321*)]. All the affected children showed the typical DFNB7/11 phenotype characterized by prelingual, severe-to-profound HL. The patients showed an excellent functional outcome after CI; speech perception, nonverbal cognition, and speech performance were comparable to those of patients with DFNB1 deafness. <b><i>Discussion/Conclusion:</i></b> Our results do not support the variable auditory outcome reported in the literature, which may be affected by several social and environmental factors and by the genetic background.

scholarly journals Prevalence of congenital non syndromic hearing loss among offspring of consanguineous marriage: a pilot study

2020 ◽  
Vol 6 (5) ◽  
pp. 874
Author(s):  
Gangadhar K. S. ◽  
Geetha Bhaktha ◽  
Manjula B. ◽  
Nageshwari P.
Keyword(s):  
Hearing Loss ◽  
Consanguineous Marriage ◽  
Gene Encoding ◽  
Single Nucleotide ◽  
Junction Protein ◽  
Study Population ◽  
Syndromic Hearing Loss ◽  
Gap Junction Protein ◽  
Polymerase Chain ◽  
Recessive Defect

<p class="abstract"><strong>Background:</strong> Mutations in the gene encoding the gap-junction protein connexin-26, is understood to be the most important cause of non-syndromic hearing loss (NSHL). An attempt to identify the single nucleotide polymorphism (SNP) for W24X mutation was done.  Consanguineous marriage was seen among the NSHL subjects.</p><p class="abstract"><strong>Methods:</strong> SNP was identified using restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR).  Forty-five subjects were screened for congenital hearing loss. Twenty subjects matched the inclusion criteria and were included in the study.</p><p class="abstract"><strong>Results:</strong> 5 out of 20 subjects were found to have mutation i.e., 25%. Though consanguinity is known to cause autosomal recessive defect, the same could not be depicted in this study.</p><p class="abstract"><strong>Conclusions:</strong> 25% of the study population had a mutation in their gene and the rest though had consanguineous marriage had not been affected genotypically.</p>

Decreased disulphide/thiol ratio in patients with autosomal recessive non-syndromic hearing loss

2018 ◽  
Vol 112 ◽  
pp. 188-192
Author(s):  
Burhan Balta ◽  
Ramazan Gundogdu ◽  
Murat Erdogan ◽  
Murat Alisik ◽  
Aslihan Kiraz ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Autosomal Recessive ◽  
Syndromic Hearing Loss

An update of common autosomal recessive non-syndromic hearing loss genes in Iranian population

2017 ◽  
Vol 97 ◽  
pp. 113-126 ◽  
Author(s):  
Tohid Ghasemnejad ◽  
Mahmoud Shekari Khaniani ◽  
Fatemeh Zarei ◽  
Mina Farbodnia ◽  
Sima Mansoori Derakhshan
Keyword(s):  
Hearing Loss ◽  
Autosomal Recessive ◽  
Iranian Population ◽  
Syndromic Hearing Loss

Whole Exome Sequencing of Six Chinese Families With Hereditary Non-Syndromic Hearing Loss: A Genetic Etiology Study

2020 ◽  
Author(s):  
Pengfei Liang ◽  
Fengping Chen ◽  
Shujuan Wang ◽  
Qiong Li ◽  
Wei Li ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Sanger Sequencing ◽  
Large Scale ◽  
Autosomal Recessive ◽  
Autosomal Recessive Inheritance ◽  
Chinese Families ◽  
Whole Exome ◽  
Syndromic Hearing Loss

Abstract Background: Hereditary non-syndromic hearing loss (NSHL) has a high genetic heterogeneity with >152 genes identified as associated molecular causes. The present study aimed to detect the possible damaging variants of the deaf probands from six unrelated Chinese families.Methods: After excluding the mutations in the most common genes, GJB2 and SLC26A4, 12 probands with prelingual deafness and autosomal recessive inheritance were evaluated by whole-exome sequencing (WES). All the candidate variants were verified by Sanger sequencing in all patients and their parents.Results: Biallelic mutations were identified in all deaf patients. Among these six families, 10 potentially causative mutations, including 3 reported and 7 novel mutations, in 3 different deafness-associated autosomal recessive (DFNB) genes (MYO15A, COL11A2, and CDH23) were identified. The mutations in MYO15A were frequent with 7/10 candidate variants. Sanger sequencing confirmed that these mutations segregated with the hearing loss of each family.Conclusions: Next-generation sequencing (NGS) approach becomes more cost-effective and efficient when analyzing large-scale genes compared to the conventional polymerase chain reaction-based Sanger sequencing, which is often used to screen common deafness-related genes. The current findings further extend the mutation spectrum of hearing loss in the Chinese population, which has a positive significance for genetic counseling.

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