Study of gjb2 gene mutations, regulating connexin 26(cx26) protein, in patients with congenital non-syndromic hearing loss

Background: Hearing loss is a common sensory disorder, which affects 1 in 1000 live births. Genetic causes are thought to be responsible for more than 50% of the cases with the majority of non-syndromic hearing loss being inherited in an autosomal recessive pattern. The most common form of Autosomal Recessive Non-syndromic Hearing Loss (ARNSHL) is caused by mutations in the gene GJB2 encoding the protein Connexin 26 (Cx26). Cx26 plays a key role in potassium homeostasis, which is essential for sound transduction. Objectives: The aim of this study was to determine the GJB2 gene mutations namely, p.W24X, p.W77X, c.35delG, IVS 1+1G→A and c.235delC in patients with Congenital Non-Syndromic Hearing loss. Methodology: This is a cross-sectional study, in which 50 patients were screened for five mutations in GJB2 gene, by ARMS PCR and/or RFLP. Results: This study revealed high prevalence of p.W24X mutation (8%) and low prevalence of p.W77X (2%). Other mutations associated with Cx26 gene like c.35delG, c.235delC and IVS 1+1G→A were not observed in our patients. Conclusion: We conclude that there is a significant contribution of GJB2 mutations to ARNSHL in this population. Screening for GJB2 mutations particularly, p.W24X and p.W77X should be offered to ARNSHL patients to confirm diagnosis of their congenital deafness, to deliver proper genetic counseling.