title: Late onset of stroke-like episode associated with a 3256C-->T point mutation of mitochondrial DNA.
abstract: Mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) are usually associated with the common 3243A-->G mutation of mtDNA. Onset of stroke-like episodes usually occurs before age 30. We report a patient with late onset MELAS harboring a rare 3256C-->T mutation in the tRNA(Leu(UUR)) gene of mtDNA. The patient presented with a stroke-like episode at age 36. MRI showed a stroke-like lesion in the right parietooccipital brain region. Proton MR spectroscopy showed elevated lactate concentrations in the lesion (8.4 mmol/l), and in the mid-occipital region (2.3-3.2 mmol/l) that appeared normal on MRI. Further tests revealed evidence of a severe oxidative defect of muscle metabolism as well.
authors.affiliation: The Copenhagen Muscle Research Center, National University Hospital, Rigshospitalet, Copenhagen, Denmark. dysgaard@rh.dk
authors.forename: Tina Dysgaard
authors.initials: TD
authors.lastname: Jeppesen
authors.forename: Marianne
authors.initials: M
authors.lastname: Schwartz
authors.forename: Klaus
authors.initials: K
authors.lastname: Hansen
authors.forename: Else R
authors.initials: ER
authors.lastname: Danielsen
authors.forename: Flemming
authors.initials: F
authors.lastname: Wibrand
authors.forename: John
authors.initials: J
authors.lastname: Vissing
mesh_terms: D000328:Adult; D017668:Age of Onset; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology*; D004272:DNA, Mitochondrial / Q000235:genetics*; D017079:Exercise Tolerance / Q000235:genetics; D005260:Female; D006801:Humans; D019344:Lactic Acid / Q000378:metabolism; D017241:MELAS Syndrome / Q000000981:diagnostic imaging / Q000235:genetics* / Q000378:metabolism*; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D018482:Muscle, Skeletal / Q000378:metabolism / Q000503:physiopathology; D010085:Oxidative Phosphorylation; D017354:Point Mutation / Q000235:genetics*; D012343:RNA, Transfer / Q000235:genetics; D011877:Radionuclide Imaging
chemical_list: D004272:DNA, Mitochondrial; D019344:Lactic Acid; D012343:RNA, Transfer