PRNP and variant Creutzfeldt-Jakob disease: We and others have reported previously that PrP 129M homozygosity is required for the experimental recapitulation of abundant florid plaque formation from BSE and vCJD prion infection (Crozet et al., 2001; Asante et al., 2002; Wadsworth et al., 2004; Bishop et al., 2006).