DMD and limb-girdle muscular dystrophy: For instance, Duchenne muscular dystrophy (DMD) is caused by mutations within the dystrophin gene, limb-girdle muscular dystrophies (LGMD), which are genetically heterogeneous, can be also caused by genetic alterations of sarcoglycans, and congenital muscular dystrophy type 1A (MDC1A) is due to mutations in the extracellular matrix protein laminin-211.