The U.S. National Prion Disease Pathology Surveillance Center at Case Western Reserve University in Cleveland, OH, said in a news release Wednesday that the new type of fatal dementia has been discovered in 16 Americans since 2002, 10 of whom have already died of the condition.
Cases of CJD, which can be called a human form of mad cow disease or bovine spongiform encephalopathy (BSE), were first described in the Annals of Neurology in 2006 and are discussed in an article in the June 20 issue of the journal and in a July 9 article in New Scientist.
The disease resembles CJD as its sufferers gradually lose their ability to think, speak and move, but it has features that make it distinct from known forms of CJD. The common factor was that patients came from families with a history of dementia, suggesting a genetic cause.
As in other spongiform encephalopathies, such as CJD and BSE, the brain tissue of victims is full of tiny holes. The accumulation of prions, misfolded versions of a brain protein called PrP seems to cause damage to the brain. In the case of CJD, prions are not broken down by enzymes, but in the new disease, they are. The patients lose the ability to think, speak and move.
However the patients of the new fast-advancing form of fatal dementia did not carry the gene traditionally associated with CJD cases. Researchers are still investigating how the disease originates, or under what conditions it might spread. It is still not clear how many people have the condition.
Between 50 and 100 new cases of so-called sporadic CJD are diagnosed in the U.K. every year. About 30 cases of classic CJD turn up in Canada per year.
CJD can spread to humans by consumption of brain material of an animal with mad cow disease or through exposure to medical instruments that have been improperly sterilized.
