Investigations into the impact of FTDP-17 (frontotemporal dementia and Parkinsonism linked to chromosome 17) mutations on the Fyn-tau interaction provide evidence that the abnormal interaction of tau-Fyn results in the neurodegenerative process (Figure 1B; Lee et al., 2004; Bhaskar et al., 2005; Ittner et al., 2011). Here, MAPT is linked to semantic dementia.