One of the two bvFTD subgroups, characterized by a low EV tau ratio and high EV TDP-43 levels, overlapped with ALS, whereas the other was characterized by high EV 3R/4R tau ratios but low TDP-43 levels (putative FTLD-TDP and FTLD-tau groups) (Fig. 4a (subcohort 2) and Extended Data Fig. 4 (bvFTD cases only)). Here, MAPT is linked to amyotrophic lateral sclerosis.