The genetic understanding of the muscular dystrophies has advanced considerably in the
last two decades. Over 25 different individual genes are now known to produce muscular
dystrophy, and many different “private” mutations have been described for each individual
muscular dystrophy gene. For the more common forms of muscular dystrophy, phenotypic
variability can be explained by precise mutations. However, for many genetic mutations, the
presence of the identical mutation is associated with marked phenotypic range that affects …