A rare genetic disorder characterized by muscle stiffness and painful cramps that increase during exertion and afterwards. The cause is a deficiency of an enzyme in muscle cells that stimulates breakdown of the carbohydrate glycogen into the simple sugar glucose. The result is a build-up of glycogen and low levels of glucose in the muscles. Damage to the muscles occurs, causing myoglobinuria (muscle-cell pigment in the urine), which may lead to kidney failure. There is no treatment, but symptoms may be relieved by eating glucose or fructose before exercise.
McArdle’s disease |
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