High plasma EV 3R/4R tau ratios in bvFTD corresponded to more severe clinical and cognitive impairment, as did low ratios in PSP, consistent with 4R tau predominance in PSP (Fig. 1k–n, Supplementary Fig. 5 and Supplementary Tables 4 and 5). The gene discussed is MAPT; the disease is supranuclear palsy, progressive, 1.