The origins of these TSEs remain debated but at least some of them (H-type and L-type BSEs, Nor98) probably arise sporadically [10], [11], such as most cases of Creutzfeldt-Jakob disease (CJD) in humans [12], although particular sequences of the prnp gene (A136H154Q171 and A136F141R154Q171 genotypes) have a major predisposing influence in the case of No98 [13]. Here, PRNP is linked to Creutzfeldt Jacob disease.