A novel point mutation in the mitochondrial tRNA((Trp)) gene produces late-onset encephalomyopathy, plus additional features

BACKGROUND: Mitochondrial diseases due to mitochondrial tRNA genes mutations are usually multisystem disorders with infantile or adult onset. OBJECTIVE: To identify the molecular defect underlying a mitochondrial encephalomyopathy. METHODS/PATIENTS: Case report of a 51year-old woman presenting with late-onset myoclonic epilepsy plus additional features. Proband's mother presented hypothyroidism and diabetes. RESULTS: Muscle biopsy showed mitochondrial changes. Respiratory chain activities were reduced. The novel G5538A mutation was identified in different tissues DNAs from the proband and from her mother. CONCLUSION: We were able to identify a novel mtDNA tRNA((Trp)) gene pathogenic mutation.