Creutzfeldt-Jakob disease (CJD) is a rare, degenerative and fatal brain disorder caused by an infectious agent known as a “prion.”

In North America, there are about 200 cases of CJD a year, or less than one case per 1 million population. Typically, the disease occurs at about age 60 and 90 percent of patients diagnosed with CJD die within a year.

CJD may occur in three ways:

• Sporadically without apparent cause and no known risk factors. This is the common form of Creutzfeldt-Jakob disease and accounts for about 85 percent of cases.
• Hereditary CJD in which there is a family history or a genetic mutation associated with the disease. About 5 percent to 10 percent of cases in North America are hereditary.
• Transmitted through infection by exposure to brain or nervous system tissue, usually through medical procedures. There is no evidence that Creutzfeldt-Jakob disease is contagious or that it can be spread through casual contact with a patient. Cases acquired through infection are rare.

Creutzfeldt-Jakob disease (CJD) affects many areas of the brain. CJD causes symptoms that occur in many other neurological diseases. In the early stages, symptoms may include failing memory, behavioral changes, lack of coordination and vision problems.

As the disease advances, patients may experience a rapidly progressive dementia and in most cases involuntary and irregular jerking movements called myoclonus. Patients also may appear startled and become rigid. In advanced stages of the disease, patients have difficulties with movement, swallowing and talking.

In the final stage, patients lose all mental and physical function and may lapse into a coma. Many patients die from an infection such as pneumonia.

The average duration of disease — from the onset of symptoms to death — is four to six months. Ninety percent of patients die within a year. Some cases progress very rapidly, lasting only a few weeks before the patient’s death, and others may last two or three years, especially if the disease occurs at an early age.

No generally accepted treatment for CJD currently exists. The disease is invariably fatal and research continues.