The deletion of ABCA1 in AD mouse models significantly decreased, ApoE which was related to Aβ precipitations in the brain.38 A previous study also reported that, in their cultured neuroblastoma cells, 24S-OHC showed a protective effect on beta-amyloid production, whereas 27OHC appeared to have the opposite effect.39 Aβ peptide accumulation in the brain parenchyma and the cerebrovasculature is considered as one of the important hallmarks of AD.40 This evidence concerns the gene APOE and Alzheimer disease.