title: Mitochondrial complex I gene variant associated with early age at onset in spinocerebellar ataxia type 2.
abstract: BACKGROUND
  A common mitochondrial complex I gene polymorphism (10398G) is reported to be inversely associated with the risk of Parkinson disease. We hypothesized that this variant might have a protective effect on the central nervous system and therefore might delay the onset of symptoms in spinocerebellar ataxia type 2 (SCA2).
  
  
  OBJECTIVE
  To assess the association of the 10398G polymorphism with age at onset in Cuban patients with SCA2.
  
  
  METHODS
  Genetic association study.
  
  
  METHODS
  Holguin, Cuba.
  
  
  METHODS
  Forty-six Cuban patients with SCA2.
  
  
  METHODS
  Presence or absence of the 10398G polymorphism was determined in 46 Cuban patients with SCA2 and early or late onset of symptoms, defined as at least 2 SDs lower than or higher than the mean age at onset for patients with a similarly sized triplet repeat expansion.
  
  
  RESULTS
  The polymorphism was present in 11 of 27 Cuban patients with SCA2 and early onset (41%) vs 2 of 19 with late onset (11%) (Fisher exact test; P = .04).
  
  
  CONCLUSIONS
  Contrary to our prediction of a later onset of SCA2 in patients with the 10398G polymorphism, we find that this variant is associated with an earlier age at onset in Cuban patients with SCA2.
authors.affiliation: Department of Neurology, Beth Israel Deaconess Medical Center, 77 Avenue Louis Pasteur, Room HIM-847, Boston, MA 02115, USA. dsimon1@bidmc.harvard.edu
authors.forename: David K
authors.initials: DK
authors.lastname: Simon
authors.forename: Kangni
authors.initials: K
authors.lastname: Zheng
authors.forename: Luis
authors.initials: L
authors.lastname: Velázquez
authors.forename: Nieves
authors.initials: N
authors.lastname: Santos
authors.forename: Luis
authors.initials: L
authors.lastname: Almaguer
authors.forename: K Pattie
authors.initials: KP
authors.lastname: Figueroa
authors.forename: Stefan-M
authors.initials: SM
authors.lastname: Pulst
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000067528:Ataxins; D001923:Brain Chemistry / Q000235:genetics*; D003462:Cuba; D042622:DNA Repeat Expansion / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics*; D042967:Electron Transport Complex I / Q000235:genetics*; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D009154:Mutation / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000235:genetics; D011110:Polymorphism, Genetic / Q000235:genetics*; D012307:Risk Factors; D020754:Spinocerebellar Ataxias / Q000235:genetics* / Q000378:metabolism* / Q000503:physiopathology; D019680:Trinucleotide Repeat Expansion
chemical_list: D000067528:Ataxins; D004272:DNA, Mitochondrial; D009419:Nerve Tissue Proteins; D042967:Electron Transport Complex I