Codon 219 Lys allele of PRNP is not found in sporadic Creutzfeldt-Jakob disease.

The polymorphism at codon 219 of the prion protein gene (PRNP) was found in the general Japanese population with 6% allele frequency. Herein, we examined 85 cases of sporadic Creutzfeldt-Jakob disease (CJD) for the codon 219 polymorphism. The codon 219Glu/Lys heterozygous polymorphism was not found in these CJD cases. In addition, we examined 43 patients with dementia of non-CJD origin, and 4 were found to have the codon 219Glu/Lys heterozygous polymorphism with a similar allele frequency as in the general population. Thus, the codon 219Glu/Lys heterozygous polymorphism might be uniquely excluded from sporadic CJD.