A case of overlap myoclonic epilepsy with ragged-red fibers-Leigh syndrome associated with mitochondrial DNA 8344A>G mutation / 中华神经科杂志

ABSTRACT

Overlap 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.