MAPT and Alzheimer disease: Perhaps the lack of neuritic core plaques plays a role in the absence of tau pathology in the cerebellum in DS (present findings; Mann and Jones, 1990; Cole et al., 1993; Li et al., 1994; Davidson et al., 2018) and AD (Aikawa et al., 1985; Azzarelli et al., 1985; Joachim et al., 1989; Mann and Jones, 1990; Li et al., 1994; Mann et al., 1996; Zhu et al., 2019).