Genetic Creutzfeldt-Jakob disease

**Definition:** A disease of the brain, that is associated with a prion. This disease is characterised by neurological deficits, and is fatal. Confirmation is by pathological examination of the brain.

**Long definition:** Creutzfeld-Jakob disease is a transmissible spongiform encephalopathy. Until the 1990s, three forms were recognized: unknown origin sporadic disease; familial cases, associated with a gene mutation; and iatrogenic cases, caused by accidental transmission of the causative agent via contaminated instruments or certain transplants. Most cases were characterized by personality changes and progressive dementia. Death usually occurred within one year. In the 1990s, a variant of CJD was recognized, which was strongly linked to exposure – probably through food – to a disease of cattle, bovine spongiform encephalopathy. Early symptoms include depression or, occasionally, a schizophrenia-like psychosis. As the disease progresses, patients develop more and more neurological signs, including unsteadiness, difficulty walking and involuntary movements.