LOCALIZATION OF THE GENE FOR DOMINANT CYSTOID MACULAR DYSTROPHY ON CHROMOSOME 7P

In a family with autosomal dominant cystoid macular dystrophy (DCMD) l inkage was detected with the dinucleotide marker D7S435 on the short a rm of chromosome 7. With markers flanking D7S435, the DCMD locus could be assigned to the interval D7S493-D7S526 at 7p15-p21, which spans ap proximately 20 cM. Three-point linkage yielded a maximal lod score of 9.46 and location score of 43.5 and suggested that DCMD is 5,5 cM prox imal to D7S493. Recently, a retinitis pigmentosa (RP7) locus has been mapped in roughly the same area of chromosome 7. Genetic data of both studies described below, allow a region of overlap between the locatio n of the DCMD and the RP7 gene between D7S435 and D7S526. Both genes b eing one and the same will further substantiate the close relationship between macular degeneration and retinitis pigmentosa.