PRNP and scrapie: PrPSc (scrapie prion protein), is the misfolded isoform of PrPC and is the main cause for a group of fatal neurodegenerative disorders known as prion diseases or transmissible spongiform encephalopathies, including Creutzfeldt–Jakob disease, Gerstmann–Sträussler–Scheinker syndrome, fatal familial insomnia and kuru in humans, scrapie in sheep, bovine spongiform encephalopathy in cattle and chronic wasting disease in deer and elk [2].