[Human prion diseases: the Hungarian experience]

Sporadic Creutzfeldt-Jakob disease is the most frequent human prion disease. Genetic forms are associated with mutations in the human prion protein gene (PRNP) and thought to comprise 5-15% of cases. Acquired forms include iatrogenic and variant Creutzfeldt-Jakob disease. The latter is associated with the bovine spongiform encephalopathy. We recently reported the high incidence of genetic Creutzfeldt-Jakob disease in Hungary.

In the present study we summarize the results of a widened investigation comprising Creutzfeldt-Jakob disease cases collected in the National Institute of Psychiatry and Neurology, Hungary in the last 12 years. We examined the disease forms and their geographical distribution.

Our study involved 155 patients. The four major results are as follows: 1. In Hungary we detected only sporadic and genetic forms of human prion disease, while iatrogenic and variant Creutzfeldt-Jakob disease were not observed. 2. The proportion of genetic prion disease (E200K mutation), similarly to Slovakia, is higher than reported worldwide. Our observations indicate that at least every third case is genetic Creutzfeldt-Jakob disease. The mean incidence of genetic Creutzfeldt-Jakob disease (0.42/million) is unusually high. Especially the year 2006 was striking when the incidence of genetic Creutzfeldt-Jakob disease was 1.4/million. 3. More than half of genetic Creutzfeldt-Jakob disease cases lack a positive family history. 4. Some counties and the eastern part of Hungary shows elevated incidence of human prion disease.

Differences in the geographical distribution may be related to migration and historical relationship with the Slovakian population. Based on the increased incidence of E200K mutation, genetic testing of the PRNP is recommended in all cases with atypical neuropsychiatric disorder or suspicion of prion disease.