Genetic epidemiology of Creutzfeldt-Jakob disease in Europe

The prion protein gene was studied in patients with definite or probable Cr eutzfeldt-Jakob disease (CJD) registered by national CJD units of 6 Europea n countries. The role of genetic factors in CJD was also investigated by co mparing the frequencies of a family history of dementia and Parkinson's dis ease in CJD cases and matched controls. Codon 129 genotype was examined in 337 CJD cases of whom 73.2 p. 100 were homozygous for methionine, 10.9 p. 1 00 were homozygous for valine and 15.7 p. 100 were heterozygous. The genoty pe frequencies were not statistically different across countries. Future di fferences, if any, would constitute a meaningful signal for the surveillanc e of CJD in Europe. A prion protein gene mutation was found in 14.5 p. 100 of CJD cases, only 40 p. 100 of them had a known family history of CJD. The case-control study showed that positive family histories of dementia and P arkinson's disease were both associated with CJD. Although recall bias is t he most likely explanation for this finding, the hypothesis that neurodegen erative diseases might share unknown genetic risk factors can also be consi dered.