摘要肌阵挛性癫痫伴破碎红纤维（MERRF）-Leigh叠加综合征是一种罕见的线粒体脑肌病。文中报道1例线粒体基因8344A>G（m. 8344A>G）突变相关的MERRF-Leigh叠加综合征，患者15岁起逐渐出现肌阵挛性癫痫、运动不耐受、共济失调、行走困难、大小便障碍、急性呼吸衰竭、视力下降及听力下降。磁共振成像见右侧丘脑、延髓及胸髓异常信号，颈髓萎缩。肌电图提示多发性周围神经损害，感觉运动轴索损害。肌肉病理可见破碎红纤维、破碎蓝纤维、琥珀酸脱氢酶强反应性血管及细胞色素C氧化酶活性降低的肌纤维；基因检测见线粒体基因m.8344A>G突变和m.14484T>C突变。MERRF-Leigh重叠综合征是m.8344A>G的一个重要临床表型，肌阵挛性癫痫数年后出现急性延髓麻痹是其核心症状。

abstractsOverlap myoclonic epilepsy with ragged-red fibers (MERRF)-Leigh syndrome is a rare mitochondrial encephalomyopathy. A case of MERRF-Leigh syndrome associated with mitochondrial DNA 8344A>G (m.8344A>G) mutation was reported in this article. The patient has suffered from the disease since 15-year old with myoclonus, exercise intolerance, ataxia, limb weakness, dysphasia, dyspnea, blurred vision and hearing loss. Magnetic resonance imaging revealed lesions on right thalamus, bilateral medulla and lumbar spinal cord and atrophy of cervical spinal cord. Electromyography showed predominantly axonal damage of both sensory nerve and motor nerve. Histochemical analyses revealed ragged red fibers, ragged blue fibers, succinate dehydrogenase-stronghly reactive vessels and decreased cytochrome oxidase activity. Gene tests demonstrated a high level of m.8344A>G mutation and m. 14484T>C mutation. MERRF-Leigh overlap syndrome with m.8344A>G mutation was rare. Bulbar paralysis following myoclonus is the main clinical symptom.