Transmissible spongiform encephalopathies (TSEs) are fatal neurodegenerative disorders characterised by the formation of amyloid aggregates, vacuolation of brain tissue and accumulation in the Central Nervous System (CNS) of a pathological conformer (PrPTSE) of the host-encoded cellular prion protein (PrPC). This evidence concerns the gene PRNP and human prion disease.