Linkage analyses in tibial muscular dystrophy

Tibial muscular dystrophy (TMD) is a recently described muscular disease first discovered in a highly consanguineous family in Finland. The pedigree also included patients whose symptoms resembled another phenotype, classical limb-girdle muscular dystrophy. Extensive linkage analysis was carried out in this complex pedigree using 157 highly polymorphic DNA markers. Because of the presence of two phenotypes, several inheritance models were used in linkage analysis studies to allow for the possibility of intrafamilial heterogeneity. The results summarize information from over 10,000 genotypings and exclude several known loci for muscular dystrophies. The findings suggest that TMD may be caused by a mutation in a previously unknown locus for muscular dystrophy.