APP and Alzheimer disease: Notably, of the 63 AD genetic risk factors, 15 were highly upregulated (i.e., TREM2 and APOE) in AD1-microglia, while only six genes were found to have moderate changes in gene expression in AD2-microglia, suggesting the genetic risk of AD is primarily associated with Aβ plaques pathology (AD1-microglia), but not with phospho-tau pathology (AD2-microglia) (Gerrits et al., 2021).