The m.8344A>G mutation in the mt-tRNA(Lys) gene, first described in myoclonic epilepsy and ragged red fibers (MERRF), accounts for approximately 80% of mutations in individuals with MERRF syndrome. Although originally described in families with a classical syndrome of myoclonus, ataxia, epilepsy and ragged red fibers in muscle biopsy, the m.8344A>G mutation is increasingly recognised to exhibit...

Human patients with myoclonic epilepsy with ragged-red fibers (MERRF) suffer from regionalized pathology caused by a mutation in the mitochondrial DNA (m.8344A→G). In MERRF-syndrome brain and skeletal muscles are predominantly affected, despite mtDNA being present in any tissue. In the past such tissue-specificity could not be explained by varying mtDNA mutation loads. In search for a region-sp...

Abnormal magnetic resonance spectroscopic (MRS) signals in the basal ganglia may be one of the characteristics in mitochondrial disease. We report MRS study in a family with myoclonic epilepsy with ragged-red fibers (MERRF). Their MRS studies over the basal ganglia revealed decreased N-acetylaspartate/creatine ratio and increased choline/creatine ratio in the four symptomatic members, but norma...

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 associated most common (90% cases) point mutation at position 8344 in mitochondrial lysine transport RNA gene – MTTLys . The diagnostics causes certain difficulties due to insufficient awareness this pathol...

SUMMARY We report 3 patients with myoclonic epilepsy with ragged-red fibers (MERRF) diagnosed by mitochondrial A8344G mutation. Cerebellar ataxia was the first symptom in all patients. Conventional brain MR imaging showed atrophy of the superior cerebellar peduncles and the cerebellum in all patients and brain stem atrophy in 2 patients. In diffusion tensor analysis, fractional anisotropy of th...

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MERRF is typically characterized by myoclonus, generalized seizures and ragged-red fibers in muscular biopsy. We report a family (harbouring the A8344G mutation) with a late onset of the disease and an uncommon clinical manifestation, including episodes of reversible respiratory failure, the presence of ophthalmoplegia, and the absence of seizures and myoclonus in most subjects. We conducted hi...

OBJECTIVE To evaluate the role of chronic cerebral lactic acidosis in mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS). METHODS The authors studied 91 individuals from 34 families with MELAS and the A3243G point mutation and 15 individuals from two families with myoclonus epilepsy and ragged red fibers (MERRF) and the A8344G mutation. Subjects were divided in...