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McArdle Disease (GSD5)

Andrew Wakelin

Andrew Wakelin

Your GSD5 Coordinator

McArdle disease is an ultra-rare disorder of energy supply which can cause exhaustion, cramping and muscle pain in everyday activities. If activity is continued whilst in pain, muscle damage ensues with the risk of muscle breakdown (rhabdomyolysis), which can lead to acute kidney failure or compartment syndrome.

Symptoms are usually apparent before age 10 but many people do not manage to obtain a diagnosis until their thirties or even later. In middle or old age some people with McArdle disease experience fixed muscle weakness, possibly from cumulative muscle damage.

With diagnosis, correct advice on management can be followed and further problems can be avoided.  Those with McArdle disease should take regular aerobic exercise such as walking, and limit anaerobic activities such as lifting heavy weights to no more than 6 seconds at a time.

Other names Myophosphorylase deficiency, muscle phosphorylase deficiency, GSD type V
Affected Skeletal muscle
Inheritance Autosomal recessive
Incidence Approx. 1 in 100,000
UK diagnosed About 350  (UK diagnosed explained)
Symptoms Muscle pain and fatigue on everyday activity and exercise. Fixed contractures with rhabdomyolysis.
Secondary symptoms Raised urate level. Possible muscle wasting. Risk of acute renal failure.
Treatment No specific treatment. Maintain healthy diet, control weight, take regular gentle aerobic exercise.
Outlook Good with gentle aerobic exercise and only very brief anaerobic activity.

How can we help?


Diagnosis & Follow up

Summary, Getting diagnosed, Newly diagnosed, McArdle’s Clinic, Self management


Information & Support

Support, Coordinator, Publications, Social media, Links


Activity & Exercise

Exercise, Key concepts, Walking course, Children & Parents, Walk over Wales

Research & Development

Research agenda, ASGD-UK research, Joining a trial

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