A COMPANION paper in this issue¹ reports on the apparent iatrogenic transmission of Creutzfeldt—Jakob disease to a young adult who had been a recipient of human pituitary growth hormone. This report describes the medical history of another such patient, a young man from Buffalo, and presents data on the clinical, pathological, and laboratory confirmation of Creutzfeldt—Jakob disease by isolation and identification of scrapie-associated fibrils with immunoelectron microscopy using rabbit antibodies to scrapie-associated fibrils, and by identification of the scrapie-associated fibril protein PrP_27–30 with Western immunoblots using fresh-frozen brain taken at autopsy of the patient. Attempts to isolate scrapie-associated fibrils . . .