May 2003

Information

Creutzfeldt-Jakob Disease (CJD): Transmissible Spongiform Encephalopathies (TSEs)

Transmissible spongiform encephalopathies (TSEs), also known as prion diseases, are a group of related but distinct diseases of the nervous system of humans and animals. They cause the central nervous system to degenerate, resulting in the formation of sponge-like holes in the brain. The diseases are always fatal, and there is no known treatment or prevention.

The agent that causes TSEs is believed to be an abnormal form of a protein, known as a prion. Prions are normal cellular proteins that are present in many organs and tissues, including the brain, spinal cord and eyes of healthy humans and animals. The abnormal form of prion causes surrounding proteins to change their shape. The abnormal protein collects in central nervous tissue and by an unknown mechanism causes the nerve cells to die. This results in the characteristic holes in the brain tissue that are seen microscopically after death.

Creutzfeldt-Jakob disease (CJD) is a human TSE that occurs in three classical forms - sporadic, familial and iatrogenic - and a recently discovered variant form.