Molecular subtype-specific clinical diagnosis of prion diseases.

Sporadic Creutzfeldt-Jakob disease (sCJD) is a rare transmissible disease caused by accumulation of pathological prion protein (PrP(sc)) in the CNS. According to the codon 129 polymorphism (methionine or valine) and the prion protein type 1 or 2, a classification into distinct subtypes was established. Further analysis of these subtypes detected atypical clinical forms with longer disease duration or younger age at onset. The CJD subtype influences sensitivity of the technical investigations such as 14-3-3 in CSF, periodic sharp wave complexes in the EEG or hyperintense basal ganglia in MRI. A further characterization of these subtypes is important for reliable diagnosis and identification of rare disease variants. The aim is to establish specific patterns of test results and clinical findings. These improvements in diagnostics may be the reason for the apparent increase in sCJD incidence in Germany from 0.9 in 1994 to 1.6 in a million in 2005. Despite careful surveillance, no patient with variant CJD has been detected to date in Germany. Here we present the data of the CJD surveillance of the last 13 years. Additionally, the improvements in diagnostics and differential diagnosis are discussed.