There is strong clinicopathologic evidence that tau aggregation correlates with neuronal loss and cognitive decline both in AD (Arriagada et al., 1992; Nelson et al., 2012; Brier et al., 2016) and in tau transgenic animals (Santacruz et al., 2005; Wirths and Bayer, 2010; DeVos et al., 2017). The gene discussed is MAPT; the disease is Alzheimer disease.