Prion diseases such as Creutzfeldt-Jakob disease (CJD) in humans, scrapie in sheep and goats and bovine spongiform encephalopathy (BSE) in cattle are tightly associated with the accumulation of an abnormal form of a host-encoded cellular prion protein (PrP C) in infected tissues [1]. The gene discussed is PRNP; the disease is Creutzfeldt Jacob disease.