Genetic heterogeneity in Miyoshi-type distal muscular dystrophy.

Miyoshi-type distal muscular dystrophy (MMD) is an autosomal recessively inherited progressive disorder. The putative locus of MMD is linked to the limb-girdle muscular dystrophy 2B locus on chromosome 2p12-14. In this study three of four MMD pedigrees show non-linkage to the region spanned by D2S134-D2S358-D2S145 on chromosome 2p, indicating genetic heterogeneity. A genome wide screen was performed to identify loci linked to MMD. In two non-chromosome 2-linked families, a 23 cM region on chromosome 10 segregated with MMD.