Interestingly, in addition to direct nucleic acid binding (reviewed above), PrP binds tightly to Aβ, PrP and Aβ are codeposited in both AD and TSE brain, and PrP modulates the generation and fibrillization of Aβ (see reference [149] for review), reinforcing the idea that both PrP and Aβ are components of the innate immune system. Here, PRNP is linked to Alzheimer disease.