The degenerative brain disorder Creutzfeldt-Jakob Disease is quite rare, with only one case per million people diagnosed each year. Most cases occur in older adults. Few people had even heard of Creutzfeldt-Jakob disease until the mid-1990s. At that time, there was a great deal of publicity about the so-called mad cow disease (otherwise known as Bovine spongiform encephalopathy) epidemic in the United Kingdom, and publicity and alarm quickly spread to other nations. It was theorized at the time that Creutzfeldt-Jakob disease could be caused by eating the meat of cattle infected with mad cow disease, but that theory has never been proven.

There are two types of Creutzfeldt-Jakob disease: classic and variant. Classic Creutzfeldt-Jakob disease is rapidly progressive and always fatal. The majority of Creutzfeldt-Jakob disease cases (85%) do not occur for any known reason. In rare cases (15%), Creutzfeldt-Jakob disease occurs because of inherited mutations of the prion protein gene. Researchers believe a slow virus is to blame for Creutzfeldt-Jakob disease, but they have never been able to isolate such a virus in humans. The most popular scientific theory is that Creutzfeldt-Jakob disease is caused by a type of protein called a prion.

The variant Creutzfeldt-Jakob disease has been found in young people as well as old, and is believe to be tied to mad cow disease. The majority of these cases have been in the United Kingdom.

Because diagnosis requires samples of brain tissue, Creutzfeldt-Jakob disease is extremely difficult to diagnose. It is possible that estimates of Creutzfeldt-Jakob disease rates in the general population are low, and that sufferers have been misdiagnosed with other diseases that have similar symptoms.

The content in this page is not a substitute for professional medical advice. If you think you have Creutzfeldt-Jakob Disease (CJD), please consult your doctor.