title: The common MELAS mutation A3243G in mitochondrial DNA among young patients with an occipital brain infarct.
abstract: The syndrome of mitochondrial encephalomyopathy, lactic acidosis, and strokelike episodes (MELAS) may present with symptoms that resemble a stroke. The strokelike episodes most commonly involve the posterior part of the cerebrum. We identified retrospectively 38 patients with an occipital stroke between ages 18 to 45 years during a 19-year period in a hospital serving as the only neurologic center for a specific population. The common MELAS mutation at the base pair 3243 (A3243G) of the mitochondrial DNA (mtDNA) was analyzed in blood samples. We found four patients (10%) with a clinical or molecular diagnosis of a mitochondrial disorder. Two of the patients carried the A3243G mutation, suggesting frequencies of 6% among patients younger than 45 years of age and 14% among patients younger than 30 years for this mutation. Furthermore, we identified two patients with a clinically definite mitochondrial disorder, and sequencing of the 22 transfer RNA genes revealed the mtDNA mutation A12308G in one patient. Clinical evaluation revealed that occipital stroke was part of a more complex syndrome in these four patients. These population-based findings demonstrate that the A3243G mutation in the mtDNA, and mitochondrial disorders are not uncommon among young patients with occipital stroke.
authors.affiliation: Department of Neurology, University of Oulu, Finland.
authors.forename: K
authors.initials: K
authors.lastname: Majamaa
authors.forename: J
authors.initials: J
authors.lastname: Turkka
authors.forename: M
authors.initials: M
authors.lastname: Kärppä
authors.forename: S
authors.initials: S
authors.lastname: Winqvist
authors.forename: I E
authors.initials: IE
authors.lastname: Hassinen
mesh_terms: D000293:Adolescent; D000328:Adult; D002544:Cerebral Infarction / Q000209:etiology / Q000235:genetics* / Q000401:mortality; D015331:Cohort Studies; D004252:DNA Mutational Analysis; D004272:DNA, Mitochondrial / Q000235:genetics*; D005192:Family Health; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017241:MELAS Syndrome / Q000150:complications / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009778:Occipital Lobe / Q000473:pathology*; D017354:Point Mutation; D012189:Retrospective Studies
chemical_list: D004272:DNA, Mitochondrial