The “protein only hypothesis” stated by Stanley Prusiner in 1983 proposes that PrPScinteracts with PrPC and generates new infectious molecules by converting the latter’sstructure.3 The fundamentalrole of PrPC as substrate for this conversion has been demonstrated whenPrPC-null mice were bred and proved to be totally resistant to prioninfection.4 In humans, TSE orprion diseases can be transmitted as inherited or acquired forms although sporadicspontaneous onset of the disorder has also been proposed. Here, PRNP is linked to human prion disease.