[Epidemiology of Creutzfeldt-Jakob disease].

Creutzfeldt-Jakob disease is a rare disease (incidence < 1 case per million inhabitants), reported in all continents. Certain characteristics are constant from one country to another: mean age of onset: 65 years, duration of the disease: about 6 months, sex ratio close to 1 and approximately 10% of familial cases. The geographical sites of this disease identified in Chile, Israel and Czechoslovakia suggest certain genetic and/or environmental risk factors. The principal environmental factor implicated is scrapie in sheep, especially in these regions. Genetic studies have demonstrated the presence of apparently causal mutations of the PrP gene and a high risk of CJD associated with certain normal polymorphisms of this gene (codon 129). Certain grafts (dura mater, cornea) and treatment by extracted growth hormone are responsible for iatrogenic transmission. Multicentre epidemiological studies recruiting a large number of cases are needed to define the risk factors of this disease.