PRNP and prion disease: Prion diseases are fatal neurodegenerative disorders which are often characterized by a cerebral accumulation of a protease-resistant, misfolded isoform of the prion protein, PrPSc (scrapie PrP), which derives from the glycosylphosphadidyl inositol (GPI)-anchored cellular isoform PrPC (cellular PrP) [1]–[3].