Sensorineural hearing loss and the incidence of Cx26 mutations in Austria

A clinical evaluation and Cx26 mutation analysis was performed in 92 consec utive patients with sensorineural hearing loss in order to delineate the sp ectrum of genetically caused hearing loss. Among patients of Austrian origi n, 53% were classified with hereditary hearing loss. Cx26 mutations were fo und in 26% of NSHL patients (40% of familial vs 18% of sporadic cases). The mutation 35delG accounted for 52.8% of all presumed GJB2 disease alleles. The second most frequent mutation was L90P (16.7%) having been reported wit h a prevalence of 0.7-3.5% in other populations. Three novel mutations were found. The novel mutation, R143Q, was associated with dominant high-freque ncy hearing loss. Pseudodominant transmission of NSHL was seen in four fami lies with Cx26 mutations. A mutation 35delG carrier rate of 0.9% was observ ed among 672 controls from West-Austria. Cx26 mutations were found associat ed with mild to profound, and with asymmetric hearing impairment.