Refined localization and two additional linked families for the DFNA10 locus for nonsyndromic hearing impairment

DFNA10 originally was mapped to the long arm of chromosome 6 in a large Ame rican family segregating for autosomal dominant progressive nonsyndromic he aring impairment. By extending this American family, we have reduced the or iginal DFNA10 candidate region from 13 cM to 3.7 cM. We also report a Belgi an family with autosomal dominant nonsyndromic hearing impairment linked to DFNA10 and a Norwegian family with the same condition in which linkage is suggestive, although maximum lod scores are only 2.5. The hearing phenotype in all three DFNA10 families is similar, with losses beginning in the midd le frequencies and involving the low and high frequencies later in life.