Exercise intolerance with or without myoglobinuria is typical of a number of inherited defects of glycolysis, such as muscle phosphofructokinase deficiency (GSD VII), carnitine palmitoyl transferase II (CPT II) defect, myoadenylate deaminase deficiency, long-chain acyl–coenzyme A (CoA) dehydrogenase (LCAD) and short-chain hydroxyacyl-CoA dehydrogenase (SCHAD) defects. Here, CPT2 is linked to hyperinsulinemic hypoglycemia, familial, 4.