Overview Creutzfeldt-Jakob Disease is a rapidly progressive degenerative disease of the nervous system that can be transmitted by blood or tissues between human beings. Epidemiology It is estimated that 50-100 cases occur each year in the UK, with an equal sex ratio and onset typically occurring between the ages of 40 and 60. Aetiology The disease is caused by the accumulation of an abnormal prion protein in the brain, which is encoded on chromosome 20. Those with the E4 allele of apolipoprotein are at a higher risk of developing the disease, and the familial form, known as Gerstmann-Straussler-Scheinker, accounts for 10% of patients and principally affects the cerebellum. It is also autosomal dominant. Clinical Features Clinical features of the disease can include personality changes, seizures, intellectual deterioration, and neurological deficits such as cerebellar ataxia, spasticity, extrapyramidal signs, and myoclonus sensitivity to noise or touch. In new-variant CJD (nvCJD), initi