Several French teams including clinicians and researchers have created a group within the European network for the study of Creutzfeldt-Jakob disease and other human spongiform encephalopathies. The main objectives are to monitor the incidence of the disease and to search for possible risk factors with a case-control study. The diagnosis is based on neuropathological studies or the identification of an abnormal protein prion in cerebral fragments. The sequence of the gene encoding for the prion protein has was studied from blood or cerebral samples. The early results indicate that the incidence, mortality and clinical presentation remain relatively constant compared with earlier studies. Studying the expression of the 129 codon of the prion protein gene has led to the verification that homozygous methionine/methionine forms predominate in sporadic forms.