Familial CJDs (fCJD) are caused by mutations in the prion gene (PRNP) and represent in average 10% of all cases, whereas less than 1% of CJDs are infectious, highlighting new variant CJD, which is most likely associated with the consumption of cattle affected with bovine spongiform encephalopathy [5], [6]. Here, PRNP is linked to Creutzfeldt Jacob disease.