APOE and Alzheimer disease: Concerning brain implications, several features have been observed in ApoE4 carriers compared to non-carriers: increased Aβ deposition [169,170], reduced Aβ clearance in the CSF [170,171], grater brain atrophy in subjects affected by AD [172], reduced dendritic spine density in the hippocampus [173], as well as a higher risk of developing cerebral amyloid angiopathy [174], and of progression from mild cognitive impairment to AD [175].