title: Mitochondrial DNA variant m.15218A > G in Finnish epilepsy patients who have maternal relatives with epilepsy, sensorineural hearing impairment or diabetes mellitus.
abstract: BACKGROUND
  Mitochondrial diseases caused by mutations in mitochondrial DNA (mtDNA) affect tissues with high energy demand. Epilepsy is one of the manifestations of mitochondrial dysfunction when the brain is affected. We have studied here 79 Finnish patients with epilepsy and who have maternal first- or second-degree relatives with epilepsy, sensorineural hearing impairment or diabetes mellitus.
  
  
  METHODS
  The entire mtDNA was studied by using conformation sensitive gel electrophoresis and PCR fragments that differed in mobility were directly sequenced.
  
  
  RESULTS
  We found a common nonsynonymous variant m.15218A > G (p.T158A, MTCYB) that occurs in haplogroup U5a1 to be more frequent in patients with epilepsy. The m.15218A > G variant was present in five patients with epilepsy and in four out of 403 population controls (p = 0.0077). This variant was present in two branches in the phylogenetic network constructed on the basis of mtDNA variation among the patients. Three algorithms predicted that m.15218A > G is damaging in effect.
  
  
  CONCLUSIONS
  We suggest that the m.15218A > G variant is mildly deleterious and that mtDNA involvement should be considered in patients with epilepsy and who have a maternal history of epilepsy, sensorineural hearing impairment or diabetes mellitus.
authors.affiliation: Department of Neurology, Oulu University Hospital, P.O. Box 20, Oulu FI-90029, OYS, Finland.
authors.forename: Heidi K
authors.initials: HK
authors.lastname: Soini
authors.forename: Jukka S
authors.initials: JS
authors.lastname: Moilanen
authors.forename: Tiina
authors.initials: T
authors.lastname: Vilmi-Kerälä
authors.forename: Saara
authors.initials: S
authors.lastname: Finnilä
authors.forename: Kari
authors.initials: K
authors.lastname: Majamaa
mesh_terms: D001483:Base Sequence; D004272:DNA, Mitochondrial / Q000235:genetics*; D003920:Diabetes Mellitus / Q000235:genetics*; D004827:Epilepsy / Q000235:genetics*; D005260:Female; D005387:Finland; D014644:Genetic Variation; D006319:Hearing Loss, Sensorineural / Q000235:genetics*; D006801:Humans; D008297:Male; D008928:Mitochondria / Q000235:genetics*; D028361:Mitochondrial Diseases / Q000235:genetics; D010375:Pedigree; D010802:Phylogeny; D020641:Polymorphism, Single Nucleotide; D017422:Sequence Analysis, DNA
chemical_list: D004272:DNA, Mitochondrial