Prion-protein-related diseases of animals and man

Scrapie, bovine spongiform encephalopathy (BSE), Creutzfeldt–Jakob disease (CJD), and related diseases of mink (transmissible mink encephalopathy), mule deer and elk (chronic wasting disease) are the founder members of a group of diseases called the transmissible degenerative (or spongiform) encephalopathies (TSE). These diseases can be transmitted by prions from affected to healthy animals by inoculation or by feeding diseased tissues. Prions are cellular proteins that can transfer metabolic and pathological phenotypes vertically from parent to progeny or horizontally between cells and animals. TSEs are characterised by the accumulation of the prion form of the mammalian prion protein (PrPC) in the central nervous system or peripheral tissues of animals and humans. Mutations of the human PrP gene are linked to rare, familial forms of disease and prion-protein gene polymorphisms in humans and other species are linked to survival time and disease characteristics in affected individuals. Iatrogenic transmission of CJD in man has occurred, and a variant form of CJD (vCJD) is due to cross-species transmission of BSE from cattle to humans. Atypical forms of scrapie and BSE have been identified during large-scale monitoring for TSEs worldwide. This chapter outlines our current understanding of scrapie, BSE, CJD and other TSEs and highlights recent progress in defining the role in disease of the prion protein, PrP.