Epidemiologic approach to Huntington's disease in northern Italy (Ferrara area).

As part of a multidisciplinary study program, an epidemiological descriptive survey was carried out in the province of Ferrara, northern Italy. The temporal trend of Huntington chorea (HC) in the last century (1871-1987) was determined in the study area, and the patients and subjects at risk were identified with the aim of creating genetic advisory councils offering preventive interventions to eliminate the disease. The final study population consisted of 10 unrelated families with HC and 47 HC cases who lived in the province of Ferrara in the survey period. The estimate of the prevalence rate varied over the time period considered between 3.09 and 0.36 cases per 100,000 inhabitants. The temporal trend was characterized by increasing and decreasing phases, reflecting the incidence (varying between 0.20 and 0.00 annual cases per 100,000 inhabitants) and mortality (varying between 0.21 and 0.00 annual deaths per 100,000 inhabitants) rates. This trend shows that the frequency of HC in the study area was not stable. It was characterized by a cyclic course with a period of about 50 years. In the recent decades of the study, the incidence and the prevalence rates showed a relative increase. Thus, HC persists in the Ferrara population despite a greater public awareness and the recent lower birth rate. A new peak of prevalence is likely in the near future.