MUTATIONS IN THE RETINAL GUANYLATE-CYCLASE (RETGC-1) GENE IN DOMINANTCONE-ROD DYSTROPHY

The dominant cone-rod dystrophy gene CORD6 has previously been mapped to within an 8 cM interval on chromosome 17p12-p13. The retinal-specif ic guanylate cyclase gene (RETGC-1), which maps to within this genetic interval and previously was implicated in Leber's congenital amaurosi s, was screened for mutations within this family and in a panel of sma ll families and individuals with various cone and cone-rod dystrophy p henotypes. A missense mutation (E837D) was identified in affected memb ers of the CORD6 family, as well as a second missense mutation (R838C) in three other families with dominant cone-rod dystrophy. RETGC-1 is only the fourth gene to be implicated in cone-rod dystrophy and this i s the first report of dominant mutations in this gene.