High diagnostic performance of plasma and cerebrospinal fluid beta‐synuclein for sporadic Creutzfeldt–Jakob disease

Beta‐synuclein is a promising cerebrospinal fluid and blood biomarker of synaptic damage. Here we analysed its accuracy in the discrimination between sporadic Creutzfeldt–Jakob disease (n = 150) and non‐prion rapidly progressive dementias (n = 106). In cerebrospinal fluid, beta‐synuclein performed better than protein 14‐3‐3 (AUC 0.95 vs. 0.89) and, to a lesser extent, than total tau (AUC 0.92). Further, the diagnostic value of plasma beta‐synuclein (AUC 0.91) outperformed that of plasma tau (AUC 0.79) and neurofilament light chain protein (AUC 0.65) and was comparable to that of cerebrospinal fluid biomarkers. Beta‐synuclein might represent the first highly accurate blood biomarker for the diagnosis of sporadic Creutzfeldt–Jakob disease.