Research indicates a link between CD33 overexpression in microglia and reduced beta-amyloid (Aβ) clearance, with APPSwe/PS1rE9 mouse studies showing that CD33 knockout decreases Aβ42 levels and plaque burden.2 This suggests that CD33 overexpression hinders microglial Aβ clearance in Alzheimer’s disease. This evidence concerns the gene CD33 and early-onset autosomal dominant Alzheimer disease.