Cluster of Creutzfeldt-Jakob disease in France associated with the codon 200 mutation (E200K) in the prion protein gene

Between 1992 and 1995, the annual incidence of Creutzfeldt–Jakob disease (CJD) in one of the 96 French departments (adminstrative districts) was found to be about six times higher than the CJD national incidence. Among the 12 definite or probable CJD patients referred during this period within this departement, nine originated from a small confined area (30 × 30 km) and seven patients carried the E200K mutation in their prion protein gene (PRNP). Genealogical data showed that these seven cases, together with three other ones previously referred during the 1970–82 period, probably belonged to different branches of the same family which could be traced to the beginning of the eighteenth century. Interestingly enough, all but two patients presented as sporadic cases before the genealogic and genetic studies. To our knowledge, this study is the first describing in France a focal accumulation of CJD associated with the PRNP E200K mutation.