In 3R/4R tauopathies, the tau filament folds are very similar to those found in AD (Fitzpatrick et al., 2017) and CTE (Falcon et al., 2019), although the filament folds in Pick's disease (Falcon et al., 2018) and CBD (Zhang et al., 2020a) differ from those observed in 3/4R tauopathies and the tau filament core in Pick's disease is distinct from that in CBD. The gene discussed is MAPT; the disease is Alzheimer disease.