Myoclonic epilepsy and ragged red fibers

Myoclonic epilepsy with ragged red fibers (MERRF) is a multisystem mitochondrial syndrome characterized by progressive myoclonus and seizures. Other features associated with MERRF include cerebellar ataxia, myopathy, cardiac arrhythmia, sensorineural hearing loss, optic atrophy, and dementia. MERRF occurs due to genetic mutations in the mitochondrial DNA (mtDNA) with A8344G mutation in the tRNA (Lys) gene being the most common and present in more than three-fourth of the patients. The pathognomonic red-ragged muscle fibers are seen on muscle biopsy. In 1980, Fukuhara et al. gave the first detailed clinical description of MERRF; hence this condition is also known as Fukuhara syndrome. MERRF is a rare disorder and is included in the National Organization for Rare Disorders (NORD).