PRNP and Alzheimer disease: To contribute knowledge on these issues, we thoroughly characterized the AD/PART pathology spectrum in a series of 450 cases with definite CJD, analyzed the effect the CJD molecular subtype, the M/V polymorphism at codon 129 of PRNP, and the presence of PRNP mutations on the co-occurring neurodegenerative pathology, and evaluated the effect of APOE genotype on both CJD and AD/PART pathologies.