Codon 129 polymorphism of prion protein gene in is not a risk factor for Alzheimer's disease

Abstract

Interaction of prion protein and amytoid-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 apolipoprotem E gene (ApoE) were evaluated. Results: Codon 129 genotype distribution in AD 45.5% methionine (MM), 42.2% methionine valine (MV), 12.1 % valine (W); and 39.6% MM, 50.5% MV, 9.9% W 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. Conclusion: Codon 129 polymorphism is not a risk factor for AD in Brazilian patients.