a novel de novo dominant mutation in gjb2 gene associated with a sporadic case of nonsyndromic sensorineural hearing loss.

mutations in the gjb2 gene are the most common known cause of hereditary congenital hearing loss. rapid genomic dna extraction (rgde) method was used for genomic dna extraction. after amplification of coding region of cx26 gene with specific primers, expected pcr products with 724bp length were subjected to direct sequencing in both directions. we describe here a novel heterozygous -t to -c transition at codon 202 (tgc→cgc) of the gjb2 gene in a patient, 40-year-old iranian woman, which replaces a cysteine with an arginine residue (c202r). the dominant mutation c202r associated with non-syndromic sensorineural hearing loss. this mutation has not previously been described in affected or control samples from other populations investigated for gjb2 mutations, indicating that it is a rare substitution. this dominant mutation was recorded in ncbi genbank with accession number kf 638275.