title: Lack of association between mitochondrial DNA G15257A and G15812A variations and multiple sclerosis.
abstract: BACKGROUND
  Multiple sclerosis (MS) is a debilitating disease of the central nervous system for which no definitive therapy has yet been developed. The etiology remains uncertain, but there is evidence of genetic susceptibility to the disease, including contributions from mitochondrial DNA (mtDNA) variations to the pathogenesis of MS. G15257A and G15812A are variations of the mtDNA tRNA(Thr) gene in MS sufferers of different populations. The present study tested the hypothesis of an association of the G15257A and G15812A variations of the mtDNA tRNA(Thr) gene to the susceptibility to MS in an Iranian population.
  
  
  METHODS
  Two hundred subjects included 100 MS patients and 100 unrelated healthy controls. DNA was extracted from blood samples by means of a salting-out method. The mtDNA fragment was amplified by polymerase chain reaction (PCR). Restriction fragment length polymorphism (RFLP) analysis was done by digestion of the PCR products with Acc I and Rsa I restriction endonuclease enzymes for mtDNA G15257A and G15812A variations, respectively. Afterwards, the restriction products were visualized by electrophoresis using 3% Agarose gel and safe DNA gel staining. To confirm the accuracy of genotyping procedure, sequencing of the mtDNA fragments was carried out in randomly selected samples.
  
  
  RESULTS
  The mtDNA G15257A variation was found in one of the 100 patients and one of the 100 controls (P=0.637) (odds ratio [OR]=1, 95% confidence interval [95% CI]=0.0-79.2). The mtDNA G15812A variation was not found in any of the 100 patients or 100 controls (0%) (P=1) (OR=1, 95% CI=0.0-79.2).
  
  
  CONCLUSIONS
  The evidence from the present study is inconsistent with the hypothesis that the G15257A and G15812A variations in the mtDNA tRNA(Thr) gene are associated with susceptibility to MS in the selected population.
authors.affiliation: Neurosciences Research Center, Imam Reza Hospital, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Sasan
authors.initials: S
authors.lastname: Andalib
authors.affiliation: Neurosciences Research Center, Imam Reza Hospital, Tabriz University of Medical Sciences, Tabriz, Iran. Electronic address: talebi511@yahoo.com.
authors.forename: Mahnaz
authors.initials: M
authors.lastname: Talebi
authors.affiliation: Division of Regenerative Medicine, School of Medicine, Faculty of Medical and Human Sciences, The University of Manchester, UK; Department of Medical Genetics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran. Electronic address: esakhinia@yahoo.co.uk.
authors.forename: Ebrahim
authors.initials: E
authors.lastname: Sakhinia
authors.affiliation: Neurosciences Research Center, Imam Reza Hospital, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Farhoudi
authors.affiliation: Department of Public Health Sciences, Karolinska Institute, Stockholm, Sweden; Trauma Epidemiology and Road Traffic Injury Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Homayoun
authors.initials: H
authors.lastname: Sadeghi-Bazargani
authors.affiliation: Department of Neuroscience and Pharmacology, University of Copenhagen, Denmark.
authors.forename: Albert
authors.initials: A
authors.lastname: Gjedde
mesh_terms: D000328:Adult; D004252:DNA Mutational Analysis; D004272:DNA, Mitochondrial / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D008297:Male; D009103:Multiple Sclerosis / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D055815:Young Adult
chemical_list: D004272:DNA, Mitochondrial
keywords: G15257A; G15812A; MS; Mitochondrial DNA; MtDNA variation; Multiple sclerosis; tRNA(Thr) gene