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). This evidence concerns the gene APP and Alzheimer disease.