Analysis of catalase and glutathione peroxidase enzyme genes in pediatric cochlear implant patients

Hearing loss is one of the commonest congenital abnormalities. Genetic factors account for 60% of congenital hearing loss. It is reported that usually single gene mutation results with profound hearing loss. Free radicals are electron carriers which have high reaction capacity. They may cause damage to cell structures and DNA. The system that prevents formation of free radicals and supplies detoxification is called antioxidants. The aim of this study was to search codon 200 T/C polymorphism on glutathione peroxidase 1 (GPX1) gene and A/T change on promoter region of catalase gene (CAT) in cochlear implant patients with congenital profound hearing loss. Sixty- five cochlear implant patients with congenital hearing loss and 100 age and gender matched healthy volunteers were evaluated between 2011 and 2013. In codon 200 on GPX 1 gene no statistically significant difference was found in CC and CT genotypes (CC/p=0.0978 and CT/p=0.4825). However, there was a statistically significant difference in TT genotype(p=0.0421). In CAT promoter region genotypes there was no statistically significant difference between patients and control groups (AA/p=0.4130, TA/p=0.1649, TT/p=0.0805). As a conclusion, TT genotype on GPX 1 codon 200 may have relation with congenital profound sensorineural hearing loss. Key Words: Free radicals, Antioxidants, Polymorphism, Genotype.