CPT2 and glycogen storage disease V: In fact, mutations (which in many cases were asymptomatic) for three common myopathic diseases; carnitine palmitoyltransferase II deficiency, McArdle disease and myoadenylate deaminase deficiency (AMPD deficiency), are thought to be the underlying determinants responsible for statin-induced myopathy in up to 10 percent of patients showing adverse effects [5].