<strong>Introduction:</strong> Congenital hearing loss is the most common sensory deficit in the world and mutations in <em>GJB2</em> gene are the most common cause of deafness in many populati...<strong>Introduction:</strong> Congenital hearing loss is the most common sensory deficit in the world and mutations in <em>GJB2</em> gene are the most common cause of deafness in many populations. Frequency of <em>GJB2</em> mutations is estimated about 16% in Iran and varies among different provinces with a decreasing trend from north to south. The aim of this study was to investigate the frequency of <em>GJB2</em> mutations in Mazandaran province, north of Iran, among non-syndromic hearing loss patients. <strong>Methods:</strong> 262 patients from 204 families participated in this study. After genomic DNA extraction, <em>GJB2</em> gene analysis was carried out using DNA sequencing of both coding and non-coding regions by ABI 3130XL genetic analyzer. <strong>Results:</strong> 30.15% of all subjects showed mutations in GJB2 gene. Four mutations, including c.35delG (Gly12Valfs*), IVSI-1 + 1G > A, c.95G > A (Arg32His) and c.224 G > A (Arg75Gln) comprises 69.89% of all mutations in this study c.35delG and IVSI-1 were the most common mutations among patients respectively. Codon 75 mutation (c.224G > A. p: Arg75Gln) with autosomal dominant inheritance was seen in 7 cases from 3 families. 22 patients showed only one mutation in <em>GJB2</em> gene and in 126 (48.09%) individuals, parents had a consanguineous marriage. <strong>Discussion:</strong> Frequency of <em>GJB2</em> gene related hearing loss among patients was higher than average (16%) in this province. This study also showed a dominant inheritance pattern of <em>GJB2</em> gene in this area. Consanguineous marriage also showed highly frequent among parents. More investigation needs to clarify cause of hearing loss in those 22 patients with one mutation in <em>GJB2</em> gene, either two gene inheritance or another gene may be responsible for hearing loss.展开更多
文摘<strong>Introduction:</strong> Congenital hearing loss is the most common sensory deficit in the world and mutations in <em>GJB2</em> gene are the most common cause of deafness in many populations. Frequency of <em>GJB2</em> mutations is estimated about 16% in Iran and varies among different provinces with a decreasing trend from north to south. The aim of this study was to investigate the frequency of <em>GJB2</em> mutations in Mazandaran province, north of Iran, among non-syndromic hearing loss patients. <strong>Methods:</strong> 262 patients from 204 families participated in this study. After genomic DNA extraction, <em>GJB2</em> gene analysis was carried out using DNA sequencing of both coding and non-coding regions by ABI 3130XL genetic analyzer. <strong>Results:</strong> 30.15% of all subjects showed mutations in GJB2 gene. Four mutations, including c.35delG (Gly12Valfs*), IVSI-1 + 1G > A, c.95G > A (Arg32His) and c.224 G > A (Arg75Gln) comprises 69.89% of all mutations in this study c.35delG and IVSI-1 were the most common mutations among patients respectively. Codon 75 mutation (c.224G > A. p: Arg75Gln) with autosomal dominant inheritance was seen in 7 cases from 3 families. 22 patients showed only one mutation in <em>GJB2</em> gene and in 126 (48.09%) individuals, parents had a consanguineous marriage. <strong>Discussion:</strong> Frequency of <em>GJB2</em> gene related hearing loss among patients was higher than average (16%) in this province. This study also showed a dominant inheritance pattern of <em>GJB2</em> gene in this area. Consanguineous marriage also showed highly frequent among parents. More investigation needs to clarify cause of hearing loss in those 22 patients with one mutation in <em>GJB2</em> gene, either two gene inheritance or another gene may be responsible for hearing loss.
