LINKAGE OF AUTOSOMAL-DOMINANT HEARING-LOSS TO THE SHORT ARM OF CHROMOSOME-1 IN 2 FAMILIES

Background. At least half of the cases of profound deafness of early onset are caused by genetic factors, but few of the genetic defects have been identified. This is particularly true of the most common hereditary forms of deafness, which occur in the absence of any associated syndrome. Methods. We studied a large Indonesian family in which hearing loss was inherited in an autosomal dominant pattern. The hearing loss first affects the high frequencies during the teens or 20s and becomes profound within 10 years. To locate the responsible gene, we performed genetic-linkage analysis, using microsatellite markers distributed over the entire genome. We then performed linkage analyses in an American family and a Dutch family with similar patterns of hereditary hearing loss. Results. In the extended Indonesian family, a gene linked to deafness mapped to chromosome Ip, with a multipoint rod score of more than 7. In the American family, deafness was linked to the same locus on chromosome 1p, with a multipoint rod score of more than 5. In the Dutch family, however, this locus was ruled out. The flanking markers D1S255 and D1S211 defined a region of 6 cM on chromosome 1p that is likely to contain the gene associated with deafness in the first two families. Conclusions. In some families with early-onset autosomal dominant hearing loss, the responsible gene is on chromosome 1p.