Glycogen storage disease type V

Glycogen storage disease type V, also known as McArdle's disease, is a glycogen metabolism disorder in which an enzyme known as muscle phosphorylase (myophosphorylase) is deficient. Muscle phosphorylase is necessary to break down glycogen stored in muscles into usable glucose. People with Glycogen storage disease type V can present with rhabdomyolysis, myoglobinuria, exercise intolerance, and muscle weakness.