PRNP and Alzheimer disease: PrPC has been found to undergo a pH-dependent conformational change in the range of pH 4.4–6.0, with a loss of α-helical content and a gain of β-structure.21 PrPSC also acts as a template for the structural conversion of PrPC as well as huntingtin proteins, subsequently forming aggregates.22 Moreover, unlike AD, it is believed that in Prion’s disease, the conformational infection and aggregation can take place both extracellularly and intracellularly.23