We confirmed the feasibility of using plasma EV tau ratio as a diagnostic marker for different tauopathies by ROC analysis (sEV 3R/4R tau ratio: PSP versus HC (AUC 1.00, CI [0.960–1.000]), PSP versus ALS (AUC 0.99, CI [0.962–1.000]), PSP versus ALS–FTD (AUC 0.98, CI [0.960–1.000]) and PSP versus bvFTD (AUC 1.00, CI [0.969–1.000]); bvFTD versus HC (AUC 0.95, CI [0.905–0.985]) and bvFTD versus ALS (AUC 0.90, CI [0.845–0.948])) (Extended Data Fig. 5a–g and Supplementary Table 14 (sEV), and Supplementary Fig. 16b–h and Supplementary Table 14 (mEV)). The gene discussed is MAPT; the disease is frontotemporal dementia.