Human prion diseases and bovine spongiform encephalopathy (BSE).

Prion diseases are transmissible neurodegenerative disorders which affect a range of mammalian species. In humans they can be inherited and sporadic as well as acquired by exposure to human prions. Prions appear to be composed principally of a conformational isomer of host-encoded prion protein and propagate by recruitment of cellular prion protein. Recent evidence argues that prion protein can also encode disease phenotypes by differences in its conformation and glycosylation. Such molecular analysis of prion strains suggests that new variant Creutzfeldt-Jakob disease is caused by BSE exposure. The novel biology of prion propagation may not be unique to these rare degenerative brain diseases.