Disorders of glycogen metabolism of muscle.

This review will briefly outline the major steps of glycogen metabolism in muscle and the role of glycogen as a source of energy in different types of exercise. There are nine specific enzyme defects of glycogen metabolism or glycolysis affecting muscle. Each of the nine glycogenoses will be discussed in terms of typical and variant clinical presentation, genetic transmission, muscle biopsy and biochemical findings. The proposed pathophysiology of the various symptoms and signs will be presented and the many unsolved problems in this area will be discussed.