MAPT and Alzheimer disease: Aging degus spontaneously develop some neuropathological hallmarks of AD, such as Aβ accumulation, tau hyperphosphorylation, and cognitive impairments when reaching the age of 3–4 years (Inestrosa et al., 2005; Ardiles et al., 2012; Braidy et al., 2012; Deacon et al., 2015; Hurley et al., 2018).