Immunoblots show clear evidence that 117V PrPC is convertible to PrPSc in 117VV Tg31 mice challenged with sporadic CJD inoculum I022 (Figure 3A, lanes 3, 4 and 7) and is present at similar levels in control mice expressing wild type human PrP-129MV challenged with the same prion inoculum (Figure 3A, lane 1). The gene discussed is PRNP; the disease is Creutzfeldt Jacob disease.