Study of families of nonsyndromic hearing impairment segregating with mutations in Cx26 gene

Autosomal recessive nonsyndromic hearing impairment (ARNSHI) is the most common form with profound hereditary hearing impairment linked to DFNB1 locus (connexin26 gene) at 13q12. Mutations in connexin26 (Cx26) gene are known to be frequently associated with ARNSHI. Here, we report results on 13 families with NSHI screened for entire coding region of Cx26 using ARMS-PCR, restriction digestion analysis, SSCP and sequencing. Cx26 mutations were found in seven of the 13 families with inheritance of W24X (G to A at 71bp) in six and R127H (G to A at 380bp) in one of them. The observations imply that the G to A transition at position 71 in exon2 of Cx26 gene could play a major role in the phenotypic expression of recessive hearing impairment while R127H could be an associated polymorphism in Indian population.