A novel locus DFNA23 for prelingual autosomal dominant hearing loss maps to 14q in a Swiss German kindred. A.A. Salam1, F.M. Häfner2, T. Linder2, A. Baumer3, D. Balmer3, T. Spillmann2, A. Schinzel3, S.M. Leal1. 1) Laboratory of Statistical Genetics, The Rockefeller University, New York, NY; 2) Department of Otohinlaryngology and Head and Neck Surgery, University Hospital of Zurich, Zurich, Switzerland; 3) Institute of Medical Genetics, University of Zurich, Zurich, Switzerland.
A novel locus for non-syndromic hearing loss has been identified in a Swiss German kindred with autosomal dominant bilateral sensorineural hearing loss. A total of 25 members of this family over three generations were ascertained for study. Eleven of the family members were considered affected, 13 family members unaffected and one family member was excluded from analysis due to uncertain affection status. No evidence for acquired risk factors predisposing to hearing loss was observed for any of the affected individuals. The history and records of the patients suggested a prelingual onset (at birth or in the first years of life). The majority of the affected family members did not display progression of hearing loss during a follow up period which varied between 6 and 32 years. In only two cases the hearing loss showed progression. Audiometry displayed a bilateral and symmetrical hearing loss. In 6 cases there existed a conductive component (which produced an air-bone-gap between 10 dB and 40 dB). All audiograms showed sloping curves with normal hearing ability to mild hearing loss in low frequencies, normal to profound hearing loss in mid frequencies and moderate to profound hearing loss in high frequencies.
A genome scan was carried out in this family and a maximum multipoint los score of 3.9 was obtained. The locus which segregates in this family maps to 14q and does not overlap with DFNA9. Additional work is being carried out to further refine the genetic region for this novel locus.
This work was supported by the NHLBI Mammalian genotyping service, NIH-NIDCD grant DC03594 and the American Hearing Research Foundation. .