Epidemiological genetics and meta-analysis of a polymorphism at codon 129 of the PRNP gene in Alzheimer's disease in Brazil.

The polymorphism at codon 129 of the prion protein gene (PRNP) is a major risk factor for Creutzfeldt-Jakob disease (CJD). Several authors reported neuropathological and clinical overlapping between CJD and Alzheimer's disease (AD), with a few association studies generating conflicting results. To investigate the distribution of this polymorphism in AD, we selected 58 patients with probable AD and 73 controls from a Brazilian population. There was no association between the PRNP polymorphism at codon 129 and AD. Our meta-analysis (performed using Alzgene; http://www.alzgene.org) along with previous studies conducted in Brazil demonstrated a negative association.