MERRF myoclonic epilepsy

MERRF (myoclonic epilepsy with ragged red fibers) Is characterized by weakness on exertion, ataxia, and associated deafness and Is due to mutation of the mitochondrial tRNA gene. 

MERRF (myoclonic epilepsy and ragged-red fiber disease) Progressive myoclonic epilepsy, a mitochondrial myopathy with ragged-red fibers, and a slowly progressive dementia. Onset of symptoms late childhood to adult tRNA v ... 

MERRF (myoclonic epilepsy, ragged red fibers) 521, 525 Metabolic... 

Myoclonic epilepsy with ragged red fibers (MERRF) Mitochondrial tRNAi>,s... 

Mildly deleterious base substitutions 2. Moderately deleterious nucleotide substitutions 3. Severe nucleotide substitutions Familial deafness, Alzheimer s disease, Parkinson s disease Leber s Hereditary Optic Neuropathy (LHON), Myoclonic Epilepsy and Ragged-Red Fiber disease (MERRF) Leigh s Syndrome dystonia... 

Fourteen mtDNA tRNA mutations have been associated with maternally inherited disease. Such mutations are typically associated with severe mitochondrial myopathies, characterized by ragged red skeletal muscle fibers upon Gomori trichrome staining and the accumulation of structurally abnormal mitochondria in muscle. Mutations in tRNAs exemplify the threshold effect whereby (due to replicative segragation) individuals may not exhibit clinical signs until the proportion of mutant mtDNA exceeds 80-90%. Myoclonic epilepsy and ragged red fiber (MERRF) disease, mitochondrial encephalomyo-pathy tactic acidosis (MELAS), as well as maternally inherited myopathy and cardiomyopathy (MMC) are well-characterized mitochondrial diseases. 

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