Heightened incidence of sporadic Creutzfeldt-Jakob disease is associated with a shift in clinicopathological profiles.

Incidences of human transmissible spongiform encephalopathies are monitored by national registries in the majority of countries in Western Europe. During the past 13 years incidences for Creutzfeldt-Jakob disease (CJD) in Switzerland fluctuated between 0.4 and 2.63 cases/10(6) inhabitants. We have compared clinicpathological patient profiles including geographic and gender distribution, age at disease onset, duration of disease, clinical symptoms, and recognized or hypothetical risk factors for CJD, genetic risk factors, biochemical and histopathological data for two cohorts of Swiss sporadic CJD patients from years of regular sporadic CJD incidence (1996-2000, mean incidence 1.3 cases/10(6) inhabitants, n = 47) to Swiss sporadic CJD patients from years of elevated sporadic CJD incidence (2001-2004, mean incidence 2.3 cases/10(6) inhabitants, n = 73). Sporadic CJD patients from the cohort with elevated sporadic CJD incidence presented with a higher frequency of rare sporadic CJD subtypes. Patients of these subtypes were significantly older and showed a skewed male/female ratio when compared to published patients of identical sporadic CJD-types or to patients from the 1996-2000 cohort and indicates that improved detection of rare sporadic CJD subtypes may have contributed to increased incidence.