1 Department of Neurology (S.T., M.P., P.S.), Karolinska University Hospital, Stockholm, Sweden; Department of Clinical Neuroscience (S.T., M.P., P.S.), Karolinska Institutet, Stockholm, Sweden; Department of Psychiatry (L.W.), North West District in Stockholm, Sweden; Department of Molecular Medicine and Surgery (H.T.), Center for Molecular Medicine, Karolinska Institutet; Department of Clinical Genetics (H.T.), Karolinska University Laboratory, Karolinska University Hospital; Colin Smith (C.S.), National CJD Research & Surveillance Unit, Edinburgh, United Kingdom; and Department of Pathology (I.N.), Karolinska University Hospital, Stockholm, Sweden.