Congenital deafness occurs in approximately one in 1000 live births and 50% of these cases are hereditary. Non-syndromic autosomal recessive deafness (NSARD) accounts for more than 70% of cases of hereditary deafness. In the field of non-syndromic hearing loss, at least 21 genes associated with autosomal recessive inheritance have been identified and characterized. One of these genes named GJB2 encodes for a gap junction protein connexin-26 (Cx26) which is important for intracellular communication and homeostasis in many tissues, including the inner ear. Mutations in this gene represent the most common cause of sporadic and autosomal recessive non-syndromic sensorineural hearing loss. Some of these mutations have been detected at a relatively high frequency in patients with NSARD in many populations.

In this study, 95 patients with profound loss and 67 healthy controls were evaluated. After genomic DNA extraction from whole blood, two GJB2 gene mutations, 35delG and del120E, were screened using standard PCR-RFLP method.

Of 95 patients, 63 (66.3%) were sporadic and 32 (33.7%) were familial cases. Among patients, the 35delG mutation rate was detected higher than del120E mutation, 8.4% and 2.1% respectively. For the 35delG mutation, 3 (37.5%) heterozygote and 5 (62.5%) homozygote patients were found. On the other hand, del120E mutation was found in 2 (2.1%) patients who were homozygous for the mutation. In the control group, 35delG mutation was the only mutation detected in 2 of 67 patients who were heterozygous for the mutation (mutation frequency of 1.4%).