Neurology · 1986 · 55 citations · 0 references
Life SciencesBiochemistryPhysiologyCellular MetabolismEnzymologyMetabolismCarbohydrate MetabolismEnzyme DeficienciesGlycogen MetabolismMuscle DisordersMuscle PathologyMuscle PhysiologyBlood Lactate MeasurementGlycogen Phosphorylase DeficiencyGlycogen Phosphorylase KinaseGlycogen Storage In Skeletal MuscleMuscle Biopsy HistologyMuscle Enzyme DisordersMuscle Glycogen MetabolismPhosphorylase Kinase Deficiency
A 35-year-old man had severe exercise intolerance and cramps. Venous blood lactate did not rise after ischemic exercise, and electromyographically silent contracture of hand muscles appeared. Histochemistry and electronmicroscopy of a muscle biopsy revealed subsarcolemmal and intermyofibrillar accumulation of glycogen. Biochemical studies showed moderately increased amount of glycogen. Total phosphorylase activity was normal, but the active form "a" was 27% of normal. Phosphorylase kinase activity was 12% of the normal value and was normal in leukocytes and erythrocytes.