Myoclonic epilepsy with ragged red fibers in childhood

Myoclonic epilepsy with ragged  red fibers (MERRF) is a maternally inherited disease characterized by myoclonic epilepsy, cerebellar ataxia and progressive muscle weakness. Development of the disease is associated with the most common  (90% of cases)  point mutation at position 8344 in the mitochondrial lysine transport RNA gene – MTTLys. The disease diagnostics causes  certain difficulties due to the insufficient awareness of this pathology and polymorphism of clinical manifestations. The article presents a brief review of the literature data on current views on the disease pathogenesis, diagnostic methods and opportunities for drug treatment, and describes a clinical observation of a 7-year-old child with MERRF syndrome caused by a point  mutation  at position 8344  in the MTTLys gene.  The girl was under dynamic  supervision  at the neuropsychiatric department.  A comprehensive clinical, laboratory and instrumental examination was carried out that also included molecular genetic testing. The progredient progression and multiple symptoms of the disease, slightly increased lactate acidosis in the absence of typical neuroimaging and electromyographic changes are of interest in the observation, thereby confirming they might not necessarily be observed in MERRF. Intrafamily clinical diversity was noted in the absence of signs of the disease in paired mother.  A highly informative  method of MERRF diagnostics is provided by molecular genetic testing. Establishing a genetic diagnosis underlies a need for conducting medical and genetic counseling for family planning to prevent the re-birth of other sick siblings inheriting this pathology.