PRNP and Alzheimer disease: The cellular prion protein has been shown to act as a functional high affinity receptor for Aβ42[29]–[31] Strittmatter and colleagues report that association of PrPC with Aβ42 mediates downstream Aβ42-impairement of hippocampal long term potentiation and that AD transgenic mice lacking PrPC accumulate Aβ42 but have normal survival and test normal for learning and memory [29], [31].