Prion diseases are invariably fatal neurodegenerative disorders in humans and animals caused by the conformational transition of the cellular PrP (PrPC) into pathogenic conformers, denoted scrapie prion protein (PrPSc), that are infectious and neurotoxic (Prusiner, 1998; Aguzzi & Polymenidou, 2004; Wadsworth & Collinge, 2011). This evidence concerns the gene PRNP and prion disease.