Researching of GJB2 gene mutations in patients with congenital hearing loss

Hearing loss is one of the most common sense defects, leading to serious disruptions in developing of comminication, expression, perception and social life of person. Hearing loss affects about 1 in 1000 newborns and a genetic basis is assumedin at least 50% of the cases. Enviromental effects are responsbility for other 50 percent. Mutations in GJB2 gene have been seen at 70% of the cases with hearing loss which are non-syndromic and autosomal recessive. Two different family living in Kozan disrict of Adana city and having hearing loss, were included to our case study report. As well individuals with hearing loss, their brothers and parents, not having hearing loss, were involved as control to understand better the effects of mutations and polymorphisms when they are discovered. The first family involve 5 patient and 2 control and second family involve 4 patient and 5 control. 16 individuals were researched. DNAs were isolated from blood donors by salt precipitation method and all regions of GJB2 gene were amplified. All mutations and polymorphisms were found by determining all nucleotid sequence. Results of our study showed that some of mutations and polymorphisms found affect to the severity of hearing loss as direct, some affect occurrence of illness as indirect. Keywords: GJB2, hearing loss, mutations, PCR, polymorphism