A novel locus (DFNA23) for prelingual autosomal dominant nonsyndromic heaving loss maps to 14q21-q22 in a Swiss German kindred

DFNA23, a novel locus for autosomal dominant nonsyndromic hearing loss, was identified in a Swiss German kindred. DNA samples were obtained from 22 fa mily members in three generations: 10 with hearing impairment caused by the DFNA23 locus, 8 unaffected offspring, and 4 spouses of hearing-impaired pe digree members. In this kindred, the hearing-impaired family members have p relingual bilateral symmetrical hearing loss. All audiograms from hearing-i mpaired individuals displayed sloping curves, with hearing ability ranging from normal hearing to mild hearing loss in low frequencies, normal hearing to profound hearing loss in mid frequencies, and moderate to profound hear ing loss in high frequencies. A conductive component existed for 50% of the hearing-impaired family members. The majority of the hearing-impaired fami ly members did not display progression of hearing loss. The DFNA23 locus ma ps to 14q21-q22. Linkage analysis was carried out under a fully penetrant a utosomal dominant mode of inheritance with no phenocopies. A maximum multip oint LOD score of 5.1 occurred at Marker D14S290. The 3.0-LOD unit support interval is 9.4 cM and ranged from marker D14S380 to marker D14S104G.