Thus, in addition to regulating cholesterol/lipid homeostasis in the CNS, ApoE modulates multiple mechanistic pathways that collectively affect neurogenesis, glucose metabolism, synaptic function, cognition, mitochondrial function, neuronal atrophy, neuroinflammation, tau phosphorylation, and metabolism and aggregation of Aβ, which are of relevance for AD. The gene discussed is APOE; the disease is Alzheimer disease.