PRNP and prion disease: There are multiple strains of prion agent that exhibit unique prion disease phenotypes (e.g. incubation period, location of PrPSc deposition, PRNP genotype of susceptible animals, conformational stability, electrophoretic mobility, reactivity to N-terminal antibodies after proteinase-K digestion) that may be encoded in the tertiary and/or quaternary structure of the misfolded protein [2].