- conversion of a α-helical protein termed prion protein (PrP^c) to a β-pleated form (PrP^sc), which is transmissible via CNS-related tissue (iatrogenic CJD) or food contaminated by BSE-infected animal products.- resistant to autoclaving- results in spongiforme encephalopathy, dementia, ataxia, death

Creuzfeldt-Jakob disease: rapidly progressive dementia, myoclonias, triphasic EEG waves

Bovine spongiform encephalopathy (BSE) - "mad cow disease"

Kuru - acquired disease in tribal populations practicing human cannibalism