Prion Diseases

Prion diseases are caused by the aberrant form of the physiological prion protein, normally produced from the PRNP gene. Proposed to play roles in long-term memory, among other functions, the disease is itself caused by accumulation of very energetically stable misfolded aggregates of physiological prion protein, called amyloid fibrils. Infectious prion can convert α-helix predominant physiological prion into the β-sheet-rich misfolded form that develops resistance to most classical sterilization techniques. Infectious prion proteins cause disease in grazing cattle and wildlife, among which it spreads by ways like fomites. Humans acquire these through ingestion of or exposure to infected tissue. Modern diagnostic methods to diagnose prion disease have emerged. In vitro and in vivo techniques have developed as well for abrogating infectious prions and alleviating disease symptoms caused by them. The prospect of common neurodegenerative diseases being caused by misfolded protein aggregation, like prions, is a matter of rising interest. This chapter covers the genetic, molecular, and functional nature of prions and also of the diseases caused by them.