ACE and Alzheimer disease: However, Genome Wide Association Studies (GWAS) indicate ACE as risk factor for AD (Meng et al., 2006; Marioni et al., 2019; Xin et al., 2021) and GWAS data on ACE polymorphisms show a correlation between low ACE activity and increased AD severity (Meng et al., 2006; Marioni et al., 2019).