Figure 1.

Partial pedigree of the family with MD. Affected individuals are shaded in black, and obligate carriers are in gray. Haplotypes are given at tested markers in the 11q22–11q23 region. Boxed haplotypes cosegregate with the disease/carrier status. DRD2^a denotes the polymorphic repeat marker located within intron 2 of the DRD2 gene (39); DRD2^b indicates the known, silent polymorphism in exon 3 (1, polymorphism present; 2, polymorphism not present) of the DRD2 gene (28) that cosegregates with the G → A sequence change in exon 3 in affected individuals (denoted DRD2^c; +, the normal sequence of G; −, altered sequence A).