Pathological tau propagates through neuroanatomically connected circuits in AD and mouse models (Clavaguera et al., 2013; De Calignon et al., 2012; DeVos et al., 2018; Liu et al., 2012; Vogel et al., 2020; Wegmann et al., 2015), potentially via synapses (Calafate et al., 2015; Dujardin et al., 2014; Pickett et al., 2017). The gene discussed is MAPT; the disease is Alzheimer disease.