Preferred Label : Myoclonic epilepsy, ragged red fibres;
ICD-11 definition : Myoclonic epilepsy associated with ragged red fibers (MERRF) is a rare mitochondrial
disorder. Typical manifestations of the disease are myoclonus, generalized epilepsy,
cerebellar ataxia and ragged red fibers on muscle biopsy. Point mutations in the tRNA
Lys gene of the mithocondrial DNA, mainly A8344G, are responsible for almost 90% of
MERRF cases. Morphological changes seen upon muscle biopsy include a substantive proportion
of ragged red fibers, muscle fibers showing a deficient activity of Cytochrome c oxidase
and the presence of vessels with a strong reaction for succinate dehydrogenase and
Cytochrome c oxidase deficiency.;
ICD-11 synonym : MERRF - [Myoclonic epilepsy - ragged red fibres]; MERRF - [Myoclonic epilepsy - ragged red fibres] syndrome; Myoclonic epilepsy - ragged red fibres; MERRF syndrome; Fukuhara syndrome;
ICD-11 acronym : MERRF;
Origin ID : 1630114989;
Currated CISMeF NLP mapping
Myoclonic epilepsy associated with ragged red fibers (MERRF) is a rare mitochondrial
disorder. Typical manifestations of the disease are myoclonus, generalized epilepsy,
cerebellar ataxia and ragged red fibers on muscle biopsy. Point mutations in the tRNA
Lys gene of the mithocondrial DNA, mainly A8344G, are responsible for almost 90% of
MERRF cases. Morphological changes seen upon muscle biopsy include a substantive proportion
of ragged red fibers, muscle fibers showing a deficient activity of Cytochrome c oxidase
and the presence of vessels with a strong reaction for succinate dehydrogenase and
Cytochrome c oxidase deficiency.
