A new family of Greek origin maps to the CRD locus for autosomal dominant cone-rod dystrophy on 19q

Retinal photoreceptor dystrophies (RD) are a highly heterogeneous group of genetic disorders of the retina, representing the most frequently inherited form of visual handicap, affecting ~1.5 million people world wide. To date, more than 40 genetic loci have been implicated in RD. One of them, the CORD2 locus, for an autosomal dominant form of cone-rod dystrophy (CRD), maps to chromosome 19q and has previously been reported in a single large family of British origin. We now report a new family with severe early onset CRD, phenotypically very similar to the British family, which also maps to 19q, but is of Greek origin. Haplotype data of the Greek family showed no recombination between and including markers D19S219 and D19S246 and linkage analysis gave a lod score of 2.7 (at θ = 0) with marker D19S412, confirming the data obtained in the British family.