GSD5 – MCARDLE DISEASE
Also known as muscle phosphorylase (or myophosphorylase) deficiency, McArdle disease was the first discovered metabolic myopathy.
Estimated cases diagnosed worldwide: 4,000 to 5,000.
Muscle pain and fatigue on everyday activity and exercise. Fixed contracture with rhabdomyolysis. Raised baseline CK.
Raised urate level, possible muscle wasting.
No specific treatment. Maintain healthy diet, control weight, take gentle aerobic exercise.
Good with gentle aerobic exercise and only very brief anaerobic or isometric activity.
First described in a paper by Dr. Brian McArdle in 1951, McArdle disease is a rare metabolic disorder which causes muscle fatigue, cramping, and pain in everyday activities and exercise. If activity is prolonged despite these warnings, then muscle damage ensues, with the risk of muscle breakdown (rhabdomyolysis) and possible kidney failure.
MANY HAVE DELAYED DIAGNOSIS
Symptoms are usually apparent during the first decade of life, but many people do not manage to obtain a diagnosis until the third or fourth decade. Later in life some people with McArdle disease experience fixed muscle weakness, possibly from cumulative muscle damage or from muscle wasting due to avoidance of activity. IamGSD is working to reduce the average age of diagnosis to below the age of 10.
REGULAR ACTIVITY & EXERCISE
It is important for those with McArdle disease to regularly engage in aerobic exercise such as walking. At least 150 minutes per week is advised. It is just as important to avoid more than very brief isometric (static) and anaerobic activities such as lifting heavy weights or sprinting.
ADAPT AND BOOST AEROBIC FITNESS
It is a major advantage to be diagnosed early and to be given the correct advice. Learning to adapt activities, maintaining aerobic fitness, and keeping weight under control can have a very significant beneficial impact on long-term outcomes.
Four minutes on personal experiences of joining a walking course.