Clinical studies and genetic linkage analysis in 64 members of a family with autosomal dominant congenital cataracts demonstrated intrafamilial variable expressivity and asymmetry between the two eyes. On the basis of 26 polymorphic phenotypic gene markers, linkage was excluded with the Duffy blood group (located on chromosome 1), haptoglobin (chromosome 16), and others. These data supported genetic heterogeneity of congenital cataracts as previous linkage assignments have included the pulverulent or Coppock cataract to chromosome 1 with Duffy and a posterior polar cataract to chromosome 16 with haptoglobin.