what is a prion

A prion is a type of protein that can trigger normal proteins in the brain to fold abnormally, leading to a group of rare, progressive neurodegenerative disorders known as prion diseases or transmissible spongiform encephalopathies (TSEs) . These diseases affect both humans and animals and are usually fatal. Prions are able to induce abnormal folding of specific normal cellular proteins called prion proteins, which are found most abundantly in the brain. The abnormal folding of the prion proteins leads to brain damage and the characteristic signs and symptoms of the disease. Prion diseases include Creutzfeldt-Jakob Disease (CJD), Variant Creutzfeldt-Jakob Disease (vCJD), Gerstmann-Straussler-Scheinker Syndrome, Fatal Familial Insomnia, Kuru, Bovine Spongiform Encephalopathy (BSE), Chronic Wasting Disease (CWD), Scrapie, and others. Prions are transmissible, untreatable, and their cause is highly unusual: the hosts normal prion protein can malfunction and assemble into structured aggregates called prions that cause infectious brain disease. Prions form abnormal aggregates of proteins called amyloids, which accumulate in infected tissue and are associated with tissue damage and cell death. The term "prion" was coined in 1982 by Stanley B. Prusiner to distinguish the infectious agent that causes these diseases from other more typical infectious agents.