PRIONS

A new type of disease-causing agent, neither bacterial nor fungal nor viral, containing no genetic material, a prion is a protein that occurs normally in a harmless form in the brain. (The word prion was coined from PRoteinaceous + Infectious + the suffix ON meaning a subatomic particle, like a proton or neutron). By folding into an aberrant shape, the normal prion turns into a rogue agent. It then coopts other normal prions to become rogue prions that slowly destroy brain cells until the ravaged brain resembles a sponge. Prions have been held responsible for a number of degenerative brain diseases including mad cow disease, Creutzfeld-Jacob disease, fatal familial insomnia, kuru (a disease transmitted by cannibalism), an unusual form of hereditary dementia (Gertsmann-Straeussler-Scheinker disease) and some cases of Alzheimer's disease. Dr. Stanley B. Prusiner received the 1997 Nobel Prize in physiology or Medicine for his discovery of prions..