APOE and early-onset autosomal dominant Alzheimer disease: The E4 variant of apolipoprotein E (APOE), the most prominent genetic risk factor for Alzheimer’s disease (AD) [1, 2] and other forms of dementia [3, 4], dysregulates lipid metabolism in astrocytes [5] and amyloid-beta (Aβ) clearance [6] with increased neuroinflammation [7], which collectively exacerbate cognitive dysfunction.