Genetic investigation in congenital hearing loss

This study is planned to investigate any genetic mutation on the genes encoding Cx26 and C30 proteins which are frequently responsible of the nonsendromic congenital hearing loss.Patients having extreme sensorineural hearing loss identified at Çukurova University Faculty of Medicine ENT department and trained at Halil Avcı Hearing disabled training center were selected.The parents of 37 patients ( %56.9) were close relatives; and 27 patients ( %41.5) have relatives having similar disabilities in their families.To identify the mutations, genotyping is done by ELİSA method using PRONTO® Connexin reagents in Çukurova University Faculty of Medicine Department of Medical Biology and Genetics.Genotyping results show that 11 patients out of 65 (%16.9) have 35delG mutation which is the most frequently found mutation on Cx26 gene. Among these 11 mutations, 9 (%13,8) were homozygote mutations and 2 (%3,07) were heterozygote mutations.In this study we did not find any evidence for mutations at 167delT seen on Cx26 gene and del(GJB6-D13S1830) seen on Cx30 gene.Our results show that in congenital nonsendromic deafness, the most frequently mutation is the 35delG mutation which is seen on Cx26 gene. This study shows the mutation ratio in the Çukurova region. With this findings, it will be possible to consult the families having hearing anomalies about the risk of deafness by testing, evaluating their genetic encoding and getting more successful results by confirming patients with hearing loss earlier.Keywords: Congenital deafness, connexin 26, 35delG