Iatrogenic transmission of Creutzfeldt-Jakob disease (CJD) after treatment of stunted growth in children with cadaveric growth hormone, transmission of bovine spongiform encephalopathy (BSE) from cattle to humans in the form of variant CJD (vCJD) through consumption of BSE-tainted meat products, and transmission of vCJD among humans via blood transfusions have clearly demonstrated that prions can invade the central nervous system (CNS) after peripheral challenge in humans (24, –, 26). Here, GH1 is linked to variant Creutzfeldt-Jakob disease.