PRNP and Creutzfeldt Jacob disease: “Classical” prions are infectious conformers of the prion protein (PrP) which cause transmissible spongiform encephalopathies, such as scrapie in sheep, chronic wasting disease in cervids, bovine spongiform encephalopathy (BSE) in cattle, or Creutzfeldt–Jakob disease (CJD) in humans [13, 26, 40].