The aims of the LGMD Study group are: 1) Determine how many dystrophin positive patients could be found to have a specific gene defect after excluding known disorders including: congenital muscular dystrophies, congenital myopathies, congenital myasthenia gravis, inflammatory myopathies, fascioscapulohumeral muscular dystrophy, defects in glycolysis and lipid storage, 2) determine genotype-phenotype correlations for specific gene defects, 3) determine the natural history of LGMD in relation to specific gene defects, 4) establish a pool of well characterized patients for potential enrollment in gene therapy clinical trials.