Genetic Linkage Analysis of DFNB2 Locus with Autosomal Recessive Hearing Loss in Families Negative for GJB2 Mutations in Khuzestan Province

Hearing loss is a common sensory impairment in humans which half of its causes are genetic reasons. Genetic hearing loss can be divided into the two types of syndromic and non-syndromic, which 80% of non-syndromic cases is Autosomal Recessive Non-Syndromic Hearing Loss. The aim of the present research is to determine the contribution of DFNB2 locus (MYO7A gene) in causing an autosomal recessive hearing loss in the one group of the deaf families of Khuzestan province.
This study was conducted on 26 families with autosomal recessive hearing loss (with 4 patients) and negative for GJB2 mutations in Khuzestan province. 22 families suffered from ARNSHL and 4 families suffered from Usher syndrome. Linkage analysis was performed by using STR (Short Tandem Repeat) markers related to DFNB2 locus. Each family’s genotype was determined by PCR-PAGE method. Furthermore, haplotypes drawing and LOD score calculations were performed.
From 26 families with hearing loss participating in this research, following genetic linkage analysis and haplotypes drawing, two families (7.7% of the families) showed linkage to DFNB2 locus. One family (4.5%) suffered from ARNSHL and another family suffered from Usher syndrome.
The results of the present research show that the contribution of DFNB2 locus in causing hearing loss in the population of Khuzestan province was similar to other studies conducted in Iran and this locus with other important loci should be considered to check in the hearing loss panel.