Analysis of Gjb2 (Connexin 26) Mutation in Patients with Congenital Non-Syndromic Sensorineural Hearing Loss

Abstract

Objective: This study was performed to investigate the GJB2 (connexin 26) gene mutations that are the most frequent cause of sensorineural deafness in patients with congenital non-syndromic sensorineural hearing loss in our region. Methods:Sixty patients [35 males (58.3%) and 25 females (41.7%)] between the age of 2-43 years (12.11±9.03) diagnosed with congenital non-syndromic sensorineural hearing loss were included in the study. The control group consisted of 60 individuals with similar demographic features having no hearing problems. 35delG, 167delT, delE120 and 235delC of GJB2 gene mutations and GJB6 gene mutations, and the presence of new mutations were also investigated by analysis of DNA sequences in all individuals.Results: Mutations were identified in 6 (10%) of the 60 patients in the study group. Five of these (8.3% of total) had 35delG and one (1.7%) had a delE120. No mutation was detected in control group individuals. In the study group, a statistically significant correlation was determined between the presence of familial sensorineural hearing loss history and 35delG or delE120 mutation (p=0.011, p=0.034).Conclusion: This is the first study which investigated the GJB2 gene mutation in our region, and our results indicate that 35delG mutation was the most frequent. We believe that our results are noteworthy for the identification of heterozygous or homozygous individuals and the genetic counseling of patients with congenital non-syndromic sensorineural hearing loss and their family.

Screening of the Connexin 26 (35delg) Mutation in Egyptian Patients With Autosomal Recessive Nonsyndromic Deafness and Its Relation to the Patients' Iq

“…More than 100 genes are involved in hearing loss ie, GJB2, GJB3, GJB6…. etc (Frei et al, 2002;Kaskalan et al, 2014;Banjara et al, 2016).…”

“…The Cx26 (35delG) mutation is a deletion of six guanine bases that extend from 30-35 on the GJB2 gene, resulting in a stop codon. This deletion resulted in truncated polypeptide chain consisting of 12 amino acids instead of 226 amino acids (Petersen and Willems, 2006;Serráo de Castro et al, 2013;Kaskalan et al, 2014).…”

“…Cx26 protein plays an important role in the recycling and movement of potassium ions (K+), which have a key role in hearing mechanism as a part of a signal transduction in the inner ear (Cordeiro-Silva et al, 2010). Therefore, the mutation in the Cx26 protein cause autosomal non-syndromic deafness (ANSD) (Masindova et al, 2012;Kaskalan et al, 2014).…”

“…In many populations, the alteration in the connexin 26 is considered the most frequent cause of deafness, as it is responsible for approximately 50% of the Mediterranean region, North American and North and South European patients with H ANSD (Marlin et al, 2001;Kaskalan et al, 2014).…”