The structure of the ordered part of tau filaments formed in several tauopathies has recently been determined using Cryo‐EM.[17, 18] Furthermore, very sensitive tau seeding assays have been developed to detect the number of seed competent tau aggregates in postmortem brain samples and CSF.[19, 20, 21] However, despite their importance, the small, soluble tau aggregates that form during the aggregation process are more challenging to study, since they are highly heterogeneous in size, shape, and phosphorylation state.[22]. The gene discussed is MAPT; the disease is tauopathy.