As with other TSEs, including scrapie of sheep, bovine spongiform encephalopathy (BSE), and human variant and sporadic Creutzfeldt-Jakob disease (CJD), CWD is characterized by central nervous system pathology mediated by an abnormally folded isoform of the normal cellular prion protein (PrPres when referring to the misfolded variant or PrPSc when referring to the infectious isoform specifically, and PrPC, respectively). This evidence concerns the gene PRNP and scrapie.