When should MERRF (myoclonus epilepsy associated with ragged-red fibers) be the diagnosis?

Arquivos de Neuro-Psiquiatria

Paulo José Lorenzoni¹  Rosana Herminia Scola¹  Cláudia Suemi Kamoi Kay¹  Carlos Eduardo S. Silvado¹  Lineu Cesar Werneck¹ 

关键词: MERRF;    mitochondrial;    epilepsy;    myoclonus;    myopathy;    MERRF;    mitocondria;    epilepsia;    mioclonia;    miopatia;   

DOI  :  10.1590/0004-282X20140124

来源: SciELO

【 摘 要 】

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.

【 授权许可】

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