title: Failure to confirm influence of methyltetrahydrofolate reductase (MTHFR) polymorphisms on age at onset of Huntington disease.
abstract: BACKGROUND
  Huntington disease (HD) is a fully penetrant, autosomal dominantly inherited disorder associated with abnormal expansions of a stretch of perfect CAG repeats in the 5' part of the IT15 gene. The number of repeat units is highly predictive for the age at onset (AO) of the disorder. But AO is only modestly correlated with repeat length when intermediate HD expansions are considered. Recently, suggestive association has been reported between a single nucleotide polymorphism (SNP; rs1801131, also known as A1298C) in the methyltetrahydrofolate reductase (MTHFR) gene and AO of HD. 5,10-MTHFR is a key enzyme in the folate metabolism, diverting metabolites toward methylation reactions or nucleotide synthesis. Using part of a previously established study cohort plus additional patients and appropriate statistical methods, we reinvestigated two polymorphisms in the MTHFR gene, C677T and A1298C, as well as their association with AO in 167 HD patients.
  
  
  RESULTS
  There was no statistically significant impact on AO for HD patients, neither of MTHFR SNPs nor of the combinations thereof.
  
  
  CONCLUSIONS
  Contrary to previously described evidence the A1298C polymorphism in the MTHFR gene does not appear to modulate AO of HD patients.
authors.affiliation: Department of Human Genetics, Ruhr-University, 44780 Bochum, Germany. wiebke.hansen@rub.de
authors.forename: Wiebke
authors.initials: W
authors.lastname: Hansen
authors.forename: Carsten
authors.initials: C
authors.lastname: Saft
authors.forename: Jürgen
authors.initials: J
authors.lastname: Andrich
authors.forename: Thomas
authors.initials: T
authors.lastname: Müller
authors.forename: Stefan
authors.initials: S
authors.lastname: Wieczorek
authors.forename: Jörg T
authors.initials: JT
authors.lastname: Epplen
authors.forename: Larissa
authors.initials: L
authors.lastname: Arning
mesh_terms: D017668:Age of Onset; D005838:Genotype; D006801:Humans; D006816:Huntington Disease / Q000201:enzymology* / Q000453:epidemiology / Q000235:genetics*; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics*; D011110:Polymorphism, Genetic / Q000235:genetics*
chemical_list: D042965:Methylenetetrahydrofolate Reductase (NADPH2)