Relevance of Connexin 26 (GJB2) Gene Mutations With Congenital Nonsyndromic Sensorineural Hearing Loss in Lraqi Deafness Patients.

Abstract Objective: This study aimed to detect the frequency of the three most common mutations of GJB2 in nonsyndromic sensorineural deafness for Iraqi population.Method: The current case-control study was conducted from January 2018 to November 2019 at ENT Departments from middle Euphrates region of Iraq. The study was included 95 deaf patients group (55 males and 40 females) their age range between 11-40 years old and 21.5 ± 6.3 year (mean ± SD). and 110 healthy control group, their ages range between 10-40 years old and 20.1 ± 5.9 year (mean ± SD), these two groups were matched in age and gender. In order to detect c.35delG, 235delC and 167delT mutations in GJB2 gene, we were employed the polymerase chain reaction – restriction fragment length polymorphism (PCR-RFLP) technique.Results: From 95 deaf patients with non syndromic hearing loss (NSHL), were participated in this study. The c.35delG was the main frequent mutation encountered with GJB2 gene, of the 95 patients, 38(40%) were heterozygous and the others 57(60%) were homozygous genotypes. The second degree mutation in GJB2 gene was c.235delC mutation. Which from the 95 deaf patients, 35 (36.8%) were carried out homozygous, 5 (5.3%) were carried out heterozygous and 55(57.9) of the study individuals were appeared wild genotypes. None of the 95 deaf patients were showed the c.167delT mutation, while Connexin 26 studied mutations were not detected in healthy control group.Conclusion: Our data conclude that the GJB2 c.35delG and c.235delC gene mutations were the main cause of congenital hearing loss in Iraqi deaf population.