Rhabdomyolysis is the rapid breakdown of damaged skeletal muscle. In some cases, there may be a genetic cause.

Muscle cramps are common, but cramps in a young man with large calves and elevated creatine kinase levels may indicate Becker muscular dystrophy.

Muscular dystrophy should be considered as a diagnosis in children presenting with progressive muscle weakness, delayed motor and/or speech milestones, isolated deranged liver enzymes on blood test and/or global developmental delay.

A male fetus will have a one-in-two chance of developing Duchenne muscular dystrophy or Becker muscular dystrophy if their mother is a carrier for the condition.