Ribbon-like filaments with wide regions of 25.2 (±6.7) nm diameter and narrow regions of 7 nm diameter were twisted with 236.5 (±21.2) nm periodicity in the case of FTDP-17T with intron 10 mutation +16, which increases the expression of 4R tau, indicating the diversity of tau filament structures within 4R tauopathy. This evidence concerns the gene MAPT and tauopathy.