IDENTIFICATION OF A NEW LOCUS FOR AUTOSOMAL-DOMINANT NON-SYNDROMIC HEARING IMPAIRMENT (DFNA7) IN A LARGE NORWEGIAN FAMILY

Hereditary hearing impairment affects about 1 in 1000 newborns. In mos t cases hearing loss is non-syndromic with no other clinical features, while in other families deafness is associated with abnormalities. An alysis of large non-syndromic and syndromic deafness have been used to identify genes or gene locations that cause hearing impairment. The p resent report describes a large Norwegian family with autosomal domina nt nonsyndromic, progressive high tone hearing loss with linkage to 1q 21-q23. A maximum LOD score of 7.65 (theta = 0.00) was obtained with t he microsatellite marker D1S196. Analysis of recombinant individuals m aps the deafness gene (DFNA7) to a 22 cM region between D1S104 and D1S 466. The region contains several attractive candidate genes. This repo rt supports the idea of extensive genetic heterogeneity in hereditary hearing impairment and represents the first localization of a deafness gene in a Norwegian family.