Cerebrospinal fluid markers in the differentiation of molecular subtypes of sporadic Creutzfeldt-Jakob disease

Background and purpose: Cerebrospinal fluid (CSF) analysis supports the clinical diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD) when applied within an adequate clinical context. A diagnostic potential has been attributed to CSF proteins such as 14-3-3, but also tau protein, phosphorylated tau (181P) (p-tau) protein, amyloid beta(1-42), S100B and neuron-specific enolase (NSE). There has been only limited information available about the contribution of CSF analysis in the differentiation of various molecular sCJD subtypes. Methods: The CSF levels of the aforementioned proteins from 73 sCJD patients with distinct molecular subtypes were determined. Results: Differences in tau values were significant amongst the homozygous patients (MM and VV genotype) compared to the heterozygous group (P = 0.07 and P = 0.02 respectively). Significantly higher CSF tau levels (P = 0.003) and NSE (P = 0.02) but lower p-tau/tau ratio (P = 0.01) were observed in MM1 compared to MM2 patients. The p-tau/tau ratio enabled the differentiation of MV genotype with higher levels in PrPsc type 2 (P = 0.04). Elevation of S100B (P < 0.001) and NSE (P = 0.03) was observed in VV2 compared to VV1 subtype. PRNP codon 129 genotype, PrPsc isotype, disease duration and clinical stage influenced the test sensitivity in all proteins. Conclusions: Cerebrospinal fluid protein levels might be useful in the pre-mortem differentiation of molecular sCJD subtypes when the codon 129 genotype is known.