Creutzfeldt-Jakob disease (CJD) is a neurodegenerative process characterized by the accumulation of an abnormally folded protein, called prion protein Sc (“scrapie”).

Symptoms consist of rapidly progressive dementia, accompanied by motor manifestations (muscle twitching, incoordination, tremor, slowness of movement).

Most cases appear spontaneously without a determined cause (sporadic CJD).

Some cases are associated with genetic mutations (genetically determined CJD) or accidental (iatrogenic CJD) or environmental exposures (variant CJD, associated with consumption of cattle affected by mad cow disease).