DEFINITION

• Prion diseases are rare and invariably fatal neurodegenerative disorders caused by transmissible misfolded prion proteins.
  • The "prion protein" that causes all known mammalian prion diseases is a misfolded form of protease-resistant protein (PRP).
  • The endogenous, properly folded form is PRP^c (for Common or Cellular), whereas the misfolded protein is PRP^sc (for SCrapie).

• Collectively these are known as transmissible spongiform encephalopathies.
  • They primarily affect the central nervous system of humans and other mammals.
  • Discussed here are Creutzfeldt-Jakob disease, variant Creutzfeldt-Jakob disease, kuru, Gerstmann-Sträussler-Scheinker syndrome, fatal familial insomnia.
• The condition may be hereditary, idiopathic, or acquired through exposure to affected tissues or contaminated surgical instruments.

• Cognitive impairment due to prion disease is classified under the neurocognitive disorders (NCDs) section of the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5)[1].