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Creutzfeldt-Jakob disease (CJD) is an extremely rare form of dementia that affects just one in every million people across the world. In CJD symptoms get worse very quickly, with 90% of patients dying within a year of their diagnosis. Read on to learn more about this extraordinary type of dementia.

Cattle in a farm putting their heads through bars to feed.

CJD hit the headlines in the mid-1990s after people in the UK and Europe began contracting it as a result of eating products from cows infected with bovine spongiform encephalopathy (BSE), commonly known as ‘mad cow disease’. Almost 30 years on, our understanding of the various forms of CJD is still fairly limited, in part due to the extreme rarity of the condition.

Like more common types of dementia, CJD attacks the brain causing confusion, memory impairment, disorientation, depression, agitation, and problems with thinking skills like planning and judgement. It also affects movement, triggering involuntary jerky movements, muscle stiffness, twitches, and difficulty walking. CJD also impacts vision, resulting in double vision and hallucinations.

These symptoms are caused by an abnormality in prion protein. Prion protein is a mysterious protein present on the surface of cells throughout the body, especially through the nervous system. In prion diseases like CJD, prion protein folds into an abnormal 3D shape and triggers this change in its neighbours. This misfolded shape is harmful and causes the symptoms of CJD – but scientists don’t yet understand how it does this.

Diagnosing CJD is difficult as there is no specific test for it, but the rapid progression of symptoms suggests to clinicians that a patient has CJD. Some tools can help with diagnosis, including brain scans like MRIs and EEGs, plus procedures like lumbar punctures where a sample of spinal fluid is taken to test for certain proteins.

There are three main subtypes of CJD, the main one being sporadic CJD, which affects 85% of people with CJD. This form develops randomly with no known cause and usually affects people aged 60-65. The second most common type is familial CJD, which causes roughly 10-15% of CJD cases. As the name suggests, people with this form inherit one of the 50 known changes in the gene that codes for prion protein. People with familial CJD are usually younger than those with sporadic CJD, but often survive longer after diagnosis.

The final subtype is acquired CJD, the category which variant CJD – the form linked with BSE – falls into. Acquired CJD is contracted from exposure to prion protein from an external source, such as through eating infected produce or receiving medical procedures where human cells are taken from cadavers (dead bodies used in medicine). Cases of acquired CJD have fallen dramatically due to greater awareness of the condition and improved animal feeding and medical sterilisation protocol.

Unfortunately, there is no treatment able to slow or stop the progression of CJD. Existing therapies are limited to treating symptoms with strong painkillers and muscle relaxants to make patients more comfortable.

The CJD Foundation and CJD Support Network provide emotional and practical support for people affected by any type of CJD. Meanwhile, the University of Edinburgh houses the National CJD Research & Surveillance Unit, which provides a full diagnostic service of CJD and monitors the current prevalence of the condition. The CJD Foundation has just awarded grants of up to $100,000 to research projects aiming to find treatments for CJD, bringing fresh hope to people affected by the condition.