Study of Cx26 gene mutations in patients with non-syndromic sensorineural hearing loss

Non-syndromic sensorineural hearing loss (NSHL) is the most common sensory disorder worldwide and more than 100 genetic loci have been identified in NSHL so far. Mutations in the CX26 (GJB2) gene at the DFNB1 locus on chromosome 13q12 are associated with autosomal recessive non-syndromic hearing loss in a variety of populations. The purpose of this study was to investigate the CX26 gene mutations in patients with NSHL. In this descriptive laboratory study, 50 patients with NSHL were selected from the welfare organization of Marand city, Iran. Blood samples (5 ml) were collected from the patients and genomic DNA was extracted using the rapid genomic DNA extraction method. After amplification of the CX26 gene coding region using the polymerase chain reaction method, direct sequencing of amplified fragments was performed. In this study, six different mutations including 35delG, R184P, R216K, 363delC, C202R and V84M were identified in 10 out of 50 cases with NSHL. Therefore, mutations in the CX26 gene were found in 20% of the patients. Among these mutations, the 35delG was the most common mutation found in 5 out of 50 cases with 6% allelic frequency. According to the results of this study, other genes may be involved in hearing loss in the study population and further studies are needed to identify these genes. Therefore, mutation screening of individuals with hearing loss referred to genetic counseling centers before marriage and pregnancy is recommended.