Enzyme deficiency in McArdle's syndrome?: (A) Acid maltase, (B) Muscle phosphorylase, (C) Liver debranching enzyme, (D) Branching enzyme
Answer is B. Type name Enzyme Deficiency Clinical Features V Myophosphorylase deficiency, McArdle's syndrome Muscle phosphorylase Poor exercise tolerance Muscle glycogen abnormally high (2.5%-4%) Blood lactate very low after exercise Reference: Harper; 30th edition; Table: 18-2; Page no: 179