In this study we aimed at investigating the role of AD known pathogenic alleles and pathways: APOE ε4 allele, APP-Aβ metabolism genes and LOAD most replicated GWAS hits both in terms of genetic variability in a cohort of 96 familial and early-onset SVID patients and differential gene expression during acute and subacute hypoperfusion in the BCCAS mouse model resembling vascular dementia (Fig. 1). Here, APOE is linked to Alzheimer disease.