Partial deficiency of phosphoglycerate mutase with diabetic polyneuropathy: the first Japanese patient.

We report here findings in a 51-year-old Japanese man with non-insulin-dependent diabetes mellitus who complained of exercise-induced cramps. Muscle biopsy showed scattered regenerating fibers, small angular fibers and increased PAS positive particles. Electron microscopic examination revealed an abnormal accumulation of glycogen particles in subsarcolenmmal areas and between myofibrils while chemical studies showed an increased glycogen concentration and decreased phosphoglycerate mutase (PGAM), 46.9% of the normal mean value. Thus, partial PGAM deficiency, insulin resistance and mild diabetic sensory-motor polyneuropathy can induce severe cramps.