Broadening the phenotype of m.5703G>A mutation in mitochondrial tRNAAsn gene from mitochondrial myopathy to myoclonic epilepsy with ragged red fibers syndrome

To the Editor:Mutations in mitochondrial DNA(mtDNA)cause mitochondrial diseases with multisystem involvement and variable clinical phenotypes.Myoclonic epilepsy with ragged red fiber(MERRF)syndrome is characterized by myoclonus,generalized epilepsy,cerebellar ataxia,and mitochondrial myopathy with ragged red fibers(RRFs).Other features include hearing impairment,psychiatric disorders,and dysarthria.