What are prions?

Prions are a type of infectious agent composed solely of protein. They are abnormal, misfolded versions of a normal protein called prion protein (PrP). Unlike other pathogens, prions do not contain nucleic acids (DNA or RNA). They cause a range of neurodegenerative diseases by inducing misfolding of normal prion proteins, leading to the accumulation of abnormal proteins in the brain, which disrupts normal cellular function and leads to brain damage. Diseases caused by prions include Creutzfeldt-Jakob disease, bovine spongiform encephalopathy (mad cow disease), and kuru.