PRNP and scrapie: Reduction in susceptibility to RML scrapie prions was reported in tg(PrPΔ32–93)/Prnp0/0 and tg(PrPΔ23–88)/Prnp0/0 mice, which express mouse (mo) PrP lacking residues 32–93 or 23–88 on the Prnp0/0 background, respectively [9], [10].