PRNP and prion disease: The transmission of sCJD (from 23 sCJD cases) to mice that overexpress the methionine and/or valine 129 variants of human PrPC allowed the identification of two dominant sCJD strains, named M1CJD and V2CJD, which were preferentially associated with MM/MV1 and MV/VV2 prion disease cases, respectively.