Candidate genes prediction in pakistani families with hearing impairment by using bioinformatic approach

Abstract

Multiple factors such as genetic and environmental, are involved in causing hearing impairment (HI). Severe or profound hearing loss affects approximately one in 1000 children worldwide and half of these cases are due to genetic factors. In case of hereditary nonsyndromic HI, approximately 75-80% of cases are involved in autosomal recessive inheritance and 15% of cases involve autosomal dominant inheritance. HI represents extreme genetic heterogeneity. In nonsyndromic deafness, 135 loci have been mapped till now including 77 autosomal recessive genes of which only 29 corresponding nuclear genes have been cloned. This study was designed to apply bioinformatic approach for reducing large number of candidate genes responsible for deafness to a handy number for their mutation analysis. Databases of expressed mouse inner ear genes and the expressed human cochlear genes were used to cross-reference all genes present in particular locus predicting candidate genes for phenotypes of nonsyndromic hereditary HI. These candidate genes are a source of starting point for mutation analysis along with genetic linkage to refine the loci. After characterization, it was observed that KIAA119 and EDN3 are candidate genes for deafness. In present study, there were total 14 loci and two genes KIAA119 and EDN3 were identified as candidate genes in locus 48 and locus 65 respectively. If mutation analysis of the two characterized genes is done, it will not be a comparatively time taking and labor-intensive process as these genes are only two in number.