In some of the FTDP-17 mutations, i.e., tauK257T (95), tauG272V (96), tauΔK280 (97), tauE10+19, and tauE10+29 (98), and in Pick disease most of the tau is 3R isoforms due to the exclusion of axon 10 which codes for the second microtubule binding repeat (R2). Here, MAPT is linked to frontotemporal dementia.