A DNA linkage study of Usher's syndrome excluding much of chromosome 4.

By applying molecular genetic techniques to families in whom inherited forms of hearing impairment are segregating, it will be possible to identify and isolate genes that cause hearing impairment. This will increase our understanding of the biochemical and cytochemical processes associated with hearing, and ultimately could have therapeutic implications. To achieve this goal, DNA linkage studies must be done to localize defective genes to specific chromosome regions. Previous data had suggested that the gene causing Usher's syndrome was located on chromosome 4 in close proximity to the Vitamin D binding protein. A DNA linkage analysis of this chromosome does not confirm the linkage relationship and excludes much of chromosome 4 as the site of the Usher's syndrome gene.