To further examine potential interactions between aromatase suppression and AD, APP23-ArKO mice have been generated in order to assess the interactions between an increased risk for AD (as in the APP23 mouse model) and a systemic absence of E2 (as occurs in the ArKO model) (McAllister et al., 2010; Li et al., 2013). This evidence concerns the gene CYP19A1 and Alzheimer disease.