Prion protein codon 129 polymorphism and risk of Alzheimer disease

The authors investigated the PRNP Met(129)Val polymorphism in 1,393 subjects including 482 patients with Alzheimer disease ( AD) and two independent control groups. In patients, PRNP Met homozygosity conferred increasing risk with decreasing age at onset ( onset: 61 to 70 years, n = 151, p = 0.02, odds ratio [ OR] = 1.72, 95% CI = 1.2 to 2.53; onset: less than or equal to 60 years, n = 138, p = 0.013, OR = 1.92, 95% CI = 1.31 to 2.87), whereas no association was obtained in patients with onset at older than 70 years. The results suggest involvement of the prion protein in the pathogenesis of early-onset AD.