Study of three common mitochondrial mutations in Arab patients with nonsyndromic hearing loss in Khuzestan province, I.R.Iran

Hearing Impairment (HI) is the most prevalent neurosensory disorder occurs in 1/1000 newborn. The majority of hearing deficiencies are of genetic origin. About %0-2 of the genetic HI cases are due to mutations in mitochondrial genes. In the present study we investigated the frequency of 3 mtDNA A1555G, A3243G and A7445G mutation of 62 patients with nonsyndromic hearing loss in Khuzestan province. In this descriptive study, we investigated the presence of three mitochondrial mutations; A1555G, A3243G and A7445G in 62 Arab subjects with autosomal recessive non syndromic hearing loss in Khuzestan province. DNA was extracted using standard phenol –chloroform method. The screening of the mitochondrial gene mutations was performed by PCR-RFLP procedure.The possible mutations were confirmed by direct sequencing. None of the investigated mutations; A1555G, A3243G and A7445G were detected in this study. However PCR-RFLP revealed two mutations; G3316A, A7445C in 2 deaf subjects studied. This study is shown that mtDNA mutations consist of G3316A and A7445C are responsible for few of ARNSHL in sample studied and none of the A1555G, A3243G and A7445G mutations are responsible for ARNSHL in this population. The data presented here will improve the genetic counseling of hearing impaired patients in Khuzestan province