The conversion of the cellular prion protein PrPC to a misfoldedβ-rich conformer called PrPSc underlies a group ofneurodegenerative diseases known as transmissible spongiform encephalopathies (TSEs).PrPSc is self-propagating, i.e, capable of inducing the conversion ofnaïve PrPC molecules to the misfolded conformation1 and the accumulation of sufficient levels of PrPSc resultsin the formation of oligomers and higher-order fibrillar aggregates. The gene discussed is PRNP; the disease is human prion disease.