Numerous mutations in the MAPT gene, which encodes the protein Tau, have been identified in FTD.78,79 Tau is a microtubule binding protein that supports axonal transport and contributes to stability of microtubules.80,81 Six isoforms of tau are produced with differential inclusion of two N-terminal domains (termed 0N, 1N or 2N) and addition of three or four microtubule binding domains (3R or 4R). Here, MAPT is linked to frontotemporal dementia.