Muscle Pain, Fatigue, and Mitochondriopathies

Muscle pain and fatigue affect nearly half of patients who seek medical care.1 One of the paradoxes of medicine is that patients with these symptoms seldom have a recognizable disorder of muscle that can be identified by objective diagnostic tests such as muscle biopsy, electrophysiology, or imaging.1 The inability to arrive at a specific diagnosis is frustrating to both patients and physicians. In this issue of the Journal, Andreu et al.2 describe five patients with severe limitation of exercise due to muscle fatigability, as well as muscle pain and cramps. These patients were part of a larger group of patients . . .