title: Codon 129 polymorphism of prion protein gene in is not a risk factor for Alzheimer's disease.
abstract: Interaction of prion protein and amyloid-b oligomers has been demonstrated recently. Homozygosity at prion protein gene (PRNP) codon 129 is associated with higher risk for Creutzfeldt-Jakob disease. This polymorphism has been addressed as a possible risk factor in Alzheimer disease (AD).
  
  
  OBJECTIVE
  To describe the association between codon 129 polymorphisms and AD.
  
  
  METHODS
  We investigated the association of codon 129 polymorphism of PRNP in 99 AD patients and 111 controls, and the association between this polymorphism and cognitive performance. Other polymorphisms of PRNP and additive effect of apolipoprotein E gene (ApoE) were evaluated.
  
  
  RESULTS
  Codon 129 genotype distribution in AD 45.5% methionine (MM), 42.2% methionine valine (MV), 12.1% valine (VV); and 39.6% MM, 50.5% MV, 9.9% VV among controls (p>0.05). There were no differences of cognitive performance concerning codon 129. Stratification according to ApoE genotype did not reveal difference between groups.
  
  
  CONCLUSIONS
  Codon 129 polymorphism is not a risk factor for AD in Brazilian patients.
authors.affiliation: Cognitive and Behavioral Unit, Department of Neurology, School of Medicine, USP, São Paulo SP, Brazil. jsmid@ig.com.br
authors.forename: Jerusa
authors.initials: J
authors.lastname: Smid
authors.forename: Michele Christine
authors.initials: MC
authors.lastname: Landemberger
authors.forename: Valéria Santoro
authors.initials: VS
authors.lastname: Bahia
authors.forename: Vilma Regina
authors.initials: VR
authors.lastname: Martins
authors.forename: Ricardo
authors.initials: R
authors.lastname: Nitrini
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000235:genetics*; D001057:Apolipoproteins E / Q000235:genetics; D001938:Brazil; D016022:Case-Control Studies; D003062:Codon / Q000235:genetics*; D003071:Cognition; D005260:Female; D005787:Gene Frequency; D006801:Humans; D008297:Male; D011110:Polymorphism, Genetic / Q000235:genetics*; D011328:Prions / Q000235:genetics*; D012307:Risk Factors; D012737:Sex Factors
chemical_list: D001057:Apolipoproteins E; D003062:Codon; D011328:Prions