Prion diseases are a related group of rare, fatal brain diseases that affect animals and humans. Also known as transmissible spongiform encephalopathies (TSE), they include bovine spongiform encephalopathy ("mad cow" disease) in cattle; Creutzfeldt-Jakob disease in humans; scrapie in sheep; and chronic wasting disease in deer and elk.
Much about TSE diseases remains unknown. The diseases are characterized by certain misshapen protein molecules that appear in brain tissue. Normal forms of these prion protein molecules reside on the surface of many types of cells, including brain cells, but scientists do not understand what normal prion protein does. On the other hand, scientists believe that abnormal prion protein, which clumps together and accumulates in brain tissue, is the likely cause of the brain damage that occurs in TSE diseases. Scientists do not have a good understanding of what causes the normal prion protein to take on the misshapen abnormal form.
NIAID conducts TSE disease research in its Rocky Mountain Laboratories in Hamilton, Montana, and also funds prion disease research in university labs. Two other Institutes at the National Institutes of Health also fund prion disease research—the National Institute of Neurological Disorders and Stroke and the National Institute on Aging.
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Last Updated July 05, 2011
Last Reviewed September 08, 2009