PRNP and Creutzfeldt Jacob disease: The prion protein (PrP) is essential for the susceptibility to transmissible spongiform encephalopathies (TSE) such as Creutzfeldt-Jacob disease (CJD) in humans, bovine spongiform encephalopathy (BSE) in cattle, scrapie in sheep and goats, and chronic wasting disease (CWD) in deer and elk [1].