The downstream prion-like protein (doppel or Dpl) shares significant biochemical and structural homology with the cellular prion protein, PrP(C), which is considered as a responsible protein for the transmissible spongiform encephalopathies (TSEs) or prion diseases. Recently, polymorphisms in open reading frame (ORF) of the prion-like protein gene (PRND) have been analysed in relation to the occurrence of prion diseases and other neurodegenerative disorders. We examined the role of a single-nucleotide polymorphism (SNP) at 3' untranslated region (UTR) +28 of PRND. We analysed this polymorphism in 110 Korean patients with sporadic Creutzfeldt-Jakob disease (CJD) and 102 healthy control subjects. Significant differences in genotype (P=0.005) and allele (P=0.032) frequencies at 3' UTR +28 were observed between sporadic CJD and normal controls. This result suggests that the PRND polymorphism at 3' UTR +28 might be associated with the occurrence of sporadic CJD.