Notably, the APOE4 gene variant has been found to increase the risk of AD by disrupting cholesterol homeostasis in oligodendrocytes and affecting myelin formation (Blanchard et al., 2022), and APOE4 carriers may exhibit an accelerated breakdown of the blood-brain barrier before the onset of cognitive impairment (Montagne et al., 2020). Here, APOE is linked to Alzheimer disease.