A CEREBELLAR-ATAXIA LOCUS IDENTIFIED BY DNA POOLING TO SEARCH FOR LINKAGE DISEQUILIBRIUM IN AN ISOLATED POPULATION FROM THE CAYMAN-ISLANDS

A non-progressive recessive cerebellar ataxia was identified in a high ly inbred Cayman Island population, Cayman cerebellar ataxia is charac terized by marked pyschomotor retardation, and prominent cerebellar dy sfunction manifested by nystagmus, intention tremor, dysarthric speech , and an ataxic gait, In this study, we identify linkage to chromosome 19p13.3 using pooled DNA samples of affected individuals from an isol ated population as PCR template far a genome wide screen with short ta ndem repeat markers, Our data demonstrate that the DNA pooling approac h to identify disease gene loci is feasible using individuals from iso lated populations in which kindred relationships are highly complex an d exact relationships between all affected individuals are not known. Genetic fine mapping demonstrates that the genetic disease interval is approximately 9 cM, but contained within a small physical region, The existence of multiple individuals that are recombinant with flanking markers indicates that the disease interval can be further narrowed wi th additional markers.