A NEW LOCUS FOR DOMINANT ZONULAR PULVERULENT CATARACT, ON CHROMOSOME-13

Inherited cataract is a clinically and genetically heterogeneous disea se that most often presents as a congenital autosomal dominant trait. Here we report the linkage of a new locus for dominant ''zonular pulve rulent'' cataract (CZP) to chromosome 13. To map the CZP locus we perf ormed molecular-genetic linkage analysis using microsatellite markers in a five-generation English pedigree. After exclusion of eight known loci and several candidate genes for autosomal dominant cataract, we o btained significantly positive LOD scores (Z) for markers D13S175 (max imum Z [Z(max)] = 4.06; maximum recombination frequency [theta(max)] = 0) and D13S1236 (Z(max) = 5.75, theta(max) = 0). Multipoint analysis gave Z(max) = 6.62 (theta(max) = 0) at marker D13S175. Haplotype data indicated that CZP probably lies in the centromeric region of chromoso me 13, provocatively close to the gene for lens connexin4G.