线粒体肌病是一种由线粒体的代谢缺陷脱引起的肌病，属于线粒体病。这种疾病也是一种母系遗传病，可根据临床不同症候群再细分为几种疾病。1962年，Luft首次采用改良戈莫理氏染色法（Gömöri trichrome stain，MGT）发现。在活体检查中，线粒体肌病患者的肌肉组织中常带有“破碎红纤维”（ragged red fibers），这些肌纤维内含有轻度累积的糖原和中性脂。此外，破红肌纤维中的琥珀酸脱氢酶活性增强，而细胞色素c氧化酶的活性则会减弱。

Mitochondrial myopathies are types of myopathies associated with mitochondrial disease. On biopsy, the muscle tissue of patients with these diseases usually demonstrate "ragged red" muscle fibers. These ragged-red fibers contain mild accumulations of glycogen and neutral lipids, and may show an increased reactivity for succinate dehydrogenase and a decreased reactivity for cytochrome c oxidase. Inheritance is maternal (non-Mendelian extranuclear). There are several subcategories of mitochondrial myopathies.