GJB2 Mutations Screening in Autosomal Recessive Non-Syndrome Deaf Patients of Khouzestan Province

Hereditary Hearing loss (HHL) affects one in 1000-2000 newborns and more than 50% of these cases, the loss has a genetic basis. About 70% of HHL is non-syndromic with autosomal recessive forms accounting for ~85% of the genetic load. To date, more than 100 locus estimated for this kind of deafness. Different genes have been reported to be involved, but mutations in the connexin 26 gene (Cx26) have been established as the basis of autosomal recessive non-syndromic hearing loss. The aim of this project is to study the prevalence of connexin 26 mutations. In this study from the population that referred to welfare center of Khoozestan province for genetic counseling, 50 individual have been selected and getting 5-10 ml blood then after DNA extraction we analyzed quality of DNA by spectrophotometry. Mutation screening began by using Amplification Refractory Mutation System (ARMS) – Polymerase Chain Reaction (PCR) for detection of 35delG and then we analyzed all samples excluding 35delG homozygote by Denaturation High Polymorphic liquid Chromatography (DHPLC) and Direct Sequencing. We screened 100 chromosomes (50 patients) for GJB2 mutations. Thirteen (13%) carry GJB2 mutations including 35delG, R184P, R32H, R127H, 300del2 (AT). Among them, 35delG has the highest frequency (61%). Polymorphism V153I was found in three chromosomes and also polymorphism V52V was found in family. According to our results, other loci and genes may be the major responsible for non-syndromic deafness in this population.