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What is CJD?

Creutzfeldt-Jakob disease (CJD) is a rare and fatal neurodegenerative disorder that affects the brain and nervous system. Head to our Share Your Story page to read about the lived experience of people with a personal connection to CJD.

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What is CJD?

CJD is one of a group of diseases called prion diseases, it affects 1 – 2 people per million of the population per year. The lifetime risk of CJD is around 1 in 5,000.

There are four types of CJD:

Sporadic CJD (or classical CJD)

is the most common form, accounting for around 85 per cent of cases. The cause is unknown. It mainly affects the over 50s and has a rapid onset. The course of the disease is usually measured in months.

Genetic CJD (sometimes known as familial CJD)

is an inherited form of the disease, with a younger onset and a longer time course than sporadic CJD.

Iatrogenic CJD

occurs through contamination with infected tissue via medical procedures, for example, the use of human growth hormone, blood transfusion, or surgical instruments. 

Variant CJD

is caused by exposure to bovine spongiform encephalopathy, or BSE, and typically affects younger people. It has a relatively long time course – an average of 14 months from onset of symptoms to death. There is a combination of psychiatric, neurological, and physical symptoms.

Symptoms of CJD

The precise symptoms and clinical time course of CJD vary according to the type of disease. Details for the particular types can be found in our separate Fact Sheets.

Symptoms reflect brain dysfunction and certain features are common in all types: memory problems, confusion, clumsiness, unsteadiness, and jerky movements with progressive disability leading to loss of awareness, loss of mobility, loss of speech, incontinence, and the need for full nursing care.