investigation of connexin 26 mutations and three large deletions spanning connexin 30 in 63 iranian families with autosomal recessive non-syndromic hearing loss

objective: hearing loss is the most frequent neurosensory defect in human. mutations in gjb2 and gjb6 are responsible for 50% of autosomal recessive non-syndromic hearing loss (arnshl) cases. here we report on the frequencies of gjb2 and gjb6 mutations and three large deletions spanning the gjb6 gene including del (gjb6-d13s1830), del (gjb6-d13s1854) and a >920 kb deletion in patients affected by arnshl referred to kawsar's human genetics research center. materials and methods: in this study, 94 patients from 63 families with arnshl were investigated. patient's homozygote for 35delg were screened and left out of the study and the remaining samples were analyzed by sequencing of gjb2 and gjb6 genes. also the three large deletions spanning the gjb6 gene were analyzed by real time pcr results: in this study we found gjb2 mutations in 13 families (20.6%) out of 63. the 35delg mutation was the most common mutation in the studied population (61.5%). other gjb2 mutations were dele120, r127h, w24x, and v37i. the heterozygous or negative cases for the gjb2 mutations were screened for mutation in the gjb6 gene by sequencing and no mutation was observed. also, we checked the three large deletions in gjb6, we found no mutations. conclusion: low frequency of mutations in the gjb2 gene implies that other genes may be involved in causing non-syndromic hearing loss in our country.