EVIDENCE FOR GENETIC-HETEROGENEITY IN BESTS VITELLIFORM MACULAR DYSTROPHY

Best's vitelliform macular dystrophy is an early onset, autosomal domi nant macular degeneration. Linkage analysis has previously mapped a di sease locus in this disorder to the pericentromeric region of chromoso me 11. We examined two families, one of German and one of Irish origin , both affected with this disorder. The Irish family (BTMD1) showed st rong evidence for linkage to the previously reported locus on chromoso me 11. Linkage of the disease locus to the same region of chromosome 1 1 has been significantly excluded in the German family (Fam E), thereb y providing evidence of locus heterogeneity in this clinically unique condition.