The extent of tau pathology correlates with symptom severity and the extent of neurodegeneration (Braak et al. 2003); tau knockout or reduction is protective against amyloid toxicity in pre‐clinical models (Gheyara et al. 2014; Ittner et al. 2010; Roberson et al. 2007; Vossel et al. 2010); and mutations in the tau gene, (MAPT) cause frontotemporal dementia (FTD) (Hutton et al. 1998; Poorkaj et al. 1998), confirming a causative link between tau dysfunction and neurodegeneration. The gene discussed is MAPT; the disease is frontotemporal dementia.