APOE is the strongest genetic risk factor for sporadic Alzheimer’s disease (AD), influencing both proteinopathies and cerebrovascular integrity. While the ε4 allele is well studied, the role of ε2—particularly in relation to blood-brain barrier (BBB) permeability—remains underexplored. To investigate the association between APOE genotype, BBB permeability, and AD pathology in a large cohort of biomarker-confirmed AD patients. We analyzed data from 895 patients with a CSF-based diagnosis of AD. A...