It has been estimated that approximately one in 1000 live births suffer from profound deafness, and greater than 50% of this group is genetic etiology. So far more than 300 different genetic conditions responsible for deafness have been reported that among them 70% are non-syndromic and the rest are syndromic. Non-syndromic and syndromic hearing loss may be divided into Autosomal dominant (DFNA), Autosomal recessive (DFNB), X-linked (DFN), and mitochondrial. Approximately 75-80% are autosomal recessive, 10-20% autosomal dominant, 1-5% X-linked, and 0-2% mitochondrial. To date, 51 DFNA loci, 61 DFNB loci, and 7 DFN loci have been described. Non-syndromic hearing loss is divided into two postlingual and perlingual groups. As a general rule, most autosomal dominant non-syndromic hereditary hearing impaired is postlingual, while autosomal recessive non-syndromic hereditary hearing impaired is prelingual.