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Creutzfeldt-Jakob Disease

What Is Creutzfeldt-Jakob Disease?

Creutzfeldt-Jakob disease (CJD) is a very rare disorder that causes the brain to break down.

Also called "classic" CJD, it worsens quickly. Most people die within a year of getting it.

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The disease destroys brain cells. Seen through a microscope, it makes the brain look like a sponge.

Classic Creutzfeldt-Jakob disease is not the same as “mad cow disease," which only happens in cattle. It's also not linked to "variant" CJD, which comes from products made from cattle that had mad cow disease.


There are three types of classic CJD. Each has a different cause:

Sporadic: This is the most common type. It's caused by harmful proteins in the body called prions. Prion proteins are a normal part of your body. But sometimes they can fold the wrong way as they form. This “misfolded” prion infects the brain and destroys brain cells. Scientists don’t know why this happens.

Familial: This happens in people who inherit a bad gene from a parent. Only 10% to 15% of CJD cases each year are familial.

Acquired: The rarest form, It happens when someone comes into contact with a medical instrument (like a scalpel), organ (by transplantation), or growth hormone that’s infected with CJD. It makes up less than 1% of classic CJD cases.


The symptoms start and worsen very quickly. People with CJD often have signs of dementia, including:

  • Confusion
  • Trouble walking
  • Jerky muscle movements or twitching
  • Personality changes
  • Trouble with memory and judgment
  • Vision problems

Sometimes people with it have trouble sleeping or become depressed. In later stages of the disease, they often lose the ability to speak or move. They may also get pneumonia or other infections, or slip into a coma.


There is no single test for CJD. Doctors diagnose it from your symptoms. One sign of the disease is how fast it gets worse.

A few tests doctors can use include:

Magnetic resonance imaging (MRI). This brain scan puts together detailed images. Doctors use these images to see changes in the brain over time.

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