ACE and Alzheimer disease: ACE-2 activity also differed significantly between ACE1 (rs1799752) indel genotypes (P < 0.05), with individuals who were homozygous II for ﻿ACE-1 (previously associated with increased risk for AD [17]) having the lowest ACE-2 activity, although post hoc analysis revealed that this did not reach statistical significance (Fig. 2b).