Lorenzoni Paulo José, Scola Rosana Herminia, Kay Cláudia Suemi Kamoi, Silvado Carlos Eduardo S, Werneck Lineu Cesar
Departamento de Neurologia, Hospital de Clínicas, Universidade Federal do Paraná, Curitiba, PR, Brazil.
Arq Neuropsiquiatr. 2014 Oct;72(10):803-11. doi: 10.1590/0004-282x20140124.
Myoclonic epilepsy associated with ragged red fibers (MERRF) is a rare mitochondrial disorder. Diagnostic criteria for MERRF include typical manifestations of the disease: myoclonus, generalized epilepsy, cerebellar ataxia and ragged red fibers (RRF) on muscle biopsy. Clinical features of MERRF are not necessarily uniform in the early stages of the disease, and correlations between clinical manifestations and physiopathology have not been fully elucidated. It is estimated that point mutations in the tRNALys gene of the DNAmt, mainly A8344G, are responsible for almost 90% of MERRF cases. Morphological changes seen upon muscle biopsy in MERRF include a substantive proportion of RRF, muscle fibers showing a deficient activity of cytochrome c oxidase (COX) and the presence of vessels with a strong reaction for succinate dehydrogenase and COX deficiency. In this review, we discuss mainly clinical and laboratory manifestations, brain images, electrophysiological patterns, histology and molecular findings as well as some differential diagnoses and treatments.
肌阵挛性癫痫伴破碎红纤维病（MERRF）是一种罕见的线粒体疾病。MERRF的诊断标准包括该病的典型表现：肌阵挛、全身性癫痫、小脑共济失调以及肌肉活检可见破碎红纤维（RRF）。MERRF的临床特征在疾病早期不一定具有一致性，且临床表现与病理生理学之间的相关性尚未完全阐明。据估计，线粒体DNA（mtDNA）的tRNALys基因中的点突变，主要是A8344G，几乎导致了90%的MERRF病例。MERRF患者肌肉活检时可见的形态学变化包括相当比例的RRF、细胞色素c氧化酶（COX）活性不足的肌纤维以及对琥珀酸脱氢酶有强烈反应的血管和COX缺乏。在这篇综述中，我们主要讨论临床和实验室表现、脑部影像、电生理模式、组织学和分子学发现以及一些鉴别诊断和治疗方法。
