PRNP and variant Creutzfeldt-Jakob disease: While therefore it is possible that some naturally occurring human prion strains could transmit more efficiently for example to wild type mice rather than to mice transgenic for a particular human PrP polymorph (as is the case for vCJD for example [37]), it is logical to test for transmissibility of GSS A117V using transgenic mice expressing only human PrP 117V.