APOE and Alzheimer disease: Although the association between the APOE ε4 and occurrence of AD is strong (Genin et al., 2011, Winblad et al., 2016), the APOE gene is also implicated in many complex processes in the central nervous system, for example, neurogenesis and plasticity, (Mahley and Rall, 2000) and linked to other neurological disorders, such as neurovascular dysfunction (Greenberg et al., 1996, Premkumar et al., 1996).