McArdle disease is an autosomal recessive metabolic disorder characterized by onset of exercise intolerance and muscle cramps in childhood or adolescence. Transient myoglobinuria may occur after exercise, due to rhabdomyolysis. Severe myoglobinuria may lead to acute renal failure. Patients may report muscle weakness, myalgia, and lack of endurance since childhood or adolescence. Later in adult life, there is persistent and progressive muscle weakness and atrophy with fatty replacement. McArdle disease is a relatively benign disorder, except for possible renal failure as a complication of myoglobinuria.
Confirmation of a clinical diagnosis, Carrier testing in unaffected family members