Transmissible spongiform encephalopathies (TSEs) are also a group of neurodegenerative diseases caused by misfolding of prion protein (PrP), which include Creutzfeldt-Jakob disease (CJD) in humans, bovine spongiform encephalopathies (BSE) in cattle, chronic wasting disease (CWD) in elk and scrapie in sheep. This evidence concerns the gene PRNP and scrapie.