MAPT and Pick disease: 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).