MAPT and neurodegenerative disease: Aging is a major risk factor for neurodegeneration (Wyss-Coray, 2016; Hou et al., 2019), and aging-related brain pathologies such as DNA damage (Lu et al., 2004), synaptic loss (Morrison and Baxter, 2012), and accumulation of tau aggregates (Harrison et al., 2019) are often exacerbated in neurodegenerative diseases.