While the inclusion of blood vessels improves the overall health of the organoids to better model the complexity of the brain environment, we did not detect the presence of CAA, a common vascular pathology in AD where Aβ fibrils are deposited along the cerebral vasculatures [69], using iPSC lines carrying the APOE3/3 or APOE4/4 variants (data not shown). The gene discussed is APOE; the disease is Alzheimer disease.