Describe prions and their function, give example of prion disease

Prions are certain proteins naturally occuring in organisms that have assumed wrong conformation during folding. This misfolded structure is highly infectious - if it comes into contact with healthy version of itself, it will change it's conformation too. Prion diseases are therefore rapidly progressive and target central nervous system, making holes in the structure. Prions can occure sporadically or be transmited genetically or by coming into contact with contaminated tissue, e.g. eating contaminated tissue or by transplation, most notably cornea transplation. Prions cause for example Creuzfeld-Jakob Disease - the most widely-spread human prion disease, Kuru disease which was observed on New Guinea and caused by consumation of brains of deceased people, Bovine Spongiform Encephalopathia also known as the 'mad cow disease' or Scrapie