This is a large group of genetic diseases featuring muscle weakness and wasting (muscular dystrophy). Most are inherited in an autosomal recessive manner (both parents must have the defective gene for a child to inherit it), but some are autosomal dominant (only one parent needs to carry the bad gene to affect the child). For some of these conditions, the defective gene has been discovered, but for others, the gene is not yet known.
Typically, onset of pelvic muscle weakness (difficulty standing from a sitting position without using arms, difficulty climbing stairs) starts in childhood to young adulthood. Later there is the onset of shoulder weakness with progression to significant loss of mobility or wheelchair dependence over the next 20-30 years.
An important risk factor is having a family member with muscular dystrophy.
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