The discovery of dystrophin as the gene responsible for Duchenne muscular Dystrophy (DMD) has enabled researchers to identify several of the genes linked directly or indirectly to dystrophin and to correlate defects in those genes to many of the different forms of muscular dystrophies (Monaco et al., 1986; Hoffman et al., 1987; Koenig et al., 1987). This evidence concerns the gene DMD and Duchenne muscular dystrophy.