D2I2.
genetic

McArdle disease

Glycogen storage disease type V, also known as McArdle's disease, is a disorder, one of the metabolic myopathies, more specifically a muscle glycogen storage disease, caused by a of myophosphorylase. Its is reported as one in 100,000, roughly the same as glycogen storage disease type I.

Underlined words are explained — tap any of them.

Symptoms — what it feels like

  • ·Exercise intolerance, inappropriate rapid heart rate response to exercise, exaggerated cardiorespiratory response to exercise, exercise-induced premature muscle and cramping, second wind phenomenon

Causes — why it happens

  • · in PYGM gene coding for myophosphorylase

How it's found

  • · testing (preferred), muscle . Supplemental tests: blood tests, exercise stress test, 12-minute Walk Test, non-ischemic forearm test, EMG

Complications

  • ·Poor physical or mental health due to prolonged delay in , misdiagnosis, or having been given inappropriate exercise advice. Rare include rhabdomyolysis with myoglobinuria requiring hospitalization, transient muscle contracture, and compartment .
Plain-language summary adapted from Wikipedia. Not medical advice.