A NEW LOCUS FOR AUTOSOMAL RECESSIVE RETINITIS-PIGMENTOSA (RP19) MAPS TO 1P13-1P21

Autosomal recessive retinitis pigmentosa (arRP) is characterized by co nsiderable allelic and nonallelic heterogeneity. Mutations have been d escribed in the rhodopsin gene (RHO), the genes encoding the alpha and beta subunits of rod phosphodiesterase (PDEA and PDEB), and the gene encoding the alpha subunit of the cGMP-gated channel (CNCG). In additi on, linkage studies in single extended pedigrees have defined two new arRP loci, at 1q and 6p. To identify the disease gene in a Spanish con sanguineous arRP family, a linkage analysis was undertaken. After test ing 102 polymorphic markers, a significant positive lod score (Z(max) = 3.64 at theta = 0) was obtained with marker D1S188 at 1p13-p21, the same region where the Stargardt and fundus flavimaculatus (FFM) loci w ere previously defined. Exhaustive ophthalmologic examination of the p atients clearly distinguished the disease from the Stargardt and FFM p henotypes and revealed an atypical form of arRP with choroidal atrophy as a distinctive feature. (C) 1997 Academic Press.