Audiologic Aspects of the Search for DFNA20: A Gene Causing Late-Onset, Progressive, Sensorineural Hearing Loss

Abstract

The purpose of this research was to identify the gene responsible for a novel form of nonsyndromic, late-onset, bilateral, progressive, sensorineural hearing loss in a Michigan family of English descent. This report describes the audiologic aspects of the search. Fifty-eight members of the family served as subjects for the study. Family pedigree information was gathered from family interviews, family records, birth and death registration records and census data. Audiologic evaluation was used to describe the hearing loss (phenotype) and classify family members as affected or unaffected based on hearing status. These data then were used in a linkage analysis, a process in which the inheritance of a trait is compared with the inheritance of genetic markers and statistically significant associations are sought. The team mapped the hearing loss to the long arm of chromosome 17 at band 17q25. The pattern of inheritance is autosomal dominant. The search for the gene is continuing using a candidate gene approach. The hearing loss demonstrated by this mid-Michigan family is a novel form of nonsyndromic, genetic, late-onset, bilateral, progressive, sensorineural hearing loss. The locus of the gene, the 20th for autosomal dominant hearing loss, is at band 17q25 of chromosome 17.