In our wide experience of transmitting multiple sporadic or acquired CJD isolates to 129VV Tg152 mice [19,20,69–72] or the congenic 129VV Tg152c version of this line [65,73], we have never observed the propagation of a disease-related PrP isoform that generates a proteolytic fragment of 8 kDa rather than the typical PrP 27–30 fragment pattern derived from prototypical PrPSc. Here, PRNP is linked to Creutzfeldt Jacob disease.