In previous studies, several polymorphisms were identified in intronic and upstream regions of human PRNP. The single nucleotide polymorphism (SNP) at position -101 (PRNP 12533) within the regulatory region of PRNP was associated with sporadic CJD in the British population [38], but not in samples derived from Dutch and German populations [20,39]. Here, PRNP is linked to sporadic Creutzfeldt-Jakob disease.