In addition, our demonstration of previously unreported type 5 PrPSc in brain samples of vCJD-challenged knock-in Ki-Hu129V/V mice (30) establishes that the evolution of type 5 PrPSc associated with the transmission of vCJD prions to the Val129 genotype is not an artifact of PrP overexpression. The gene discussed is PRNP; the disease is variant Creutzfeldt-Jakob disease.