A PROGRESSIVE EARLY-ONSET CATARACT GENE MAPS TO HUMAN-CHROMOSOME 17Q24

Cerulean cataract is an autosomal dominant, early onset, progressive c ataract characterized by blue or white opacifications in the nucleus a nd cortex of the lens. A large four-generation pedigree in which cerul ean cataract segregates was studied for linkage analysis. A genome wid e search was undertaken after the plausible candidate genes were exclu ded and the cerulean cataract phenotype was mapped to chromosome 17q24 . The three markers closest to the disease gene are D17S802 (Z(theta)= 9.46 at (theta)=0.085), D17S836 (Z(theta)=5.26 at (theta)=0.031) and A FMa238yb5 (Z(theta)=7.11 at (theta)=0.032). Multipoint linkage analyse s yielded a maximum lod score of Z(theta)=13.71, placing the cerulean cataract gene between D17S802 and D17S836 at (theta)=0.048 and (theta) =0.013, respectively.