What is Creutzfeldt-Jakob disease (CJD)?

Creutzfeldt-Jakob disease (CJD) is a rare, fatal brain disorder. The disease causes problems with cognition (thinking and memory), as well as other symptoms.

There are three types of CJD:

  • Sporadic CJD. In this type, the disease develops in a person for unknown reason(s). Occurring in about 85 percent of cases, this is the most common form of CJD
  • Hereditary CJD. In this type, there is a family history of the disease. Approximately 10 to 15 percent of cases of CJD are hereditary.
  • Acquired CJD. In this type, an infection following a medical procedure or eating the meat of an infected animal leads to CJD. Acquired CJD accounts for less than 1 percent of cases of CJD.

Who gets Creutzfeldt-Jakob disease (CJD)?

Creutzfeldt-Jakob disease (CJD) is typically seen beginning around 60 years of age. Only about 300 to 400 cases of CJD are diagnosed in the United States each year. Worldwide, CJD occurs in about 1 out of every 1 million persons.

What causes Creutzfeldt-Jakob disease (CJD)?

Creutzfeldt-Jakob disease (CJD) is caused by an infectious form of a type of protein called a prion. In CJD, this prion is abnormally shaped compared with the normal prion protein. (Normal prion proteins are found throughout the body, mainly in the nervous system). Scientists believe the abnormal shape of these prion proteins causes them to clump together in the brain, causing nerve cell death and the brain damage that cause the symptoms of CJD.

In sporadic CJD, scientists think an error in the way cells make proteins results in the development of the abnormally shaped prion proteins. Errors in cell development occur more frequently as one grows older, which might explain why the disease is mostly seen in people over 60 years old.

In hereditary CJD, a change (mutation) in the gene that makes the normal prion protein changes it into the infectious form. The abnormally shaped prion protein then continues to reproduce. It should be noted that although this gene can be inherited by children of those who have the disease, not all of the children will develop CJD.

In acquired CJD, the abnormally shaped prion protein is introduced from outside the body—for example, in the meat from an animal that has the disease, or a surgical instrument. When the abnormally shaped prion encounters normal prions, the normal prions change to the abnormal shape. The now abnormally shaped prion protein replicates and spreads.

Researchers are still trying to understand how the abnormally shaped prion proteins damage the brain and what factors make a person more likely to develop CJD.

Because Creutzfeldt-Jakob disease (CJD) is an infectious disease, can it be spread from person to person?

Creutzfeldt-Jakob disease (CJD) is an extremely rare disease that is NOT spread from person to person in the usual way that other infectious illnesses are, such as colds or the flu. There are only rare case reports of individuals who have potentially contracted the disease through blood, organ transplants, or other tissue transplants that were from individuals with unrecognized CJD. The strict criteria for blood, organ and tissue donations include prevention of CJD disease transmission.

What are the symptoms of Creutzfeldt-Jakob disease (CJD)?

Early symptoms of Creutzfeldt-Jakob disease (CJD) may include:

  • Cognitive problems (trouble with memory, thinking, communication, planning and/or judgment)
  • Confusion, disorientation
  • Impaired balance or walking
  • Vision problems
  • Behavior changes, including depression, agitation, mood swings, and anxiety

Later symptoms may include:

  • Severe mental decline
  • Involuntary muscle movements such as muscle jerks in arms and legs (called myoclonus), muscle stiffness, spasms, and tremors
  • Blindness
  • Weakness in arms and legs
  • Coma

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