CD33 and Alzheimer disease: Previous works characterizing the genetics of Siglecs suggest that an AD‐protective allele in CD33 improves the microglial response during neurodegeneration (Naj et al, 2011; Griciuc et al, 2013; Bradshaw et al, 2013; Chan et al, 2015; Siddiqui et al, 2017; Griciuc et al, 2019).