Contrary to our expectation, in a large series of well-characterized human post-mortem brains, we found that NEP, IDE, ACE, and ECE-1 activities and ECE-2 levels were all higher in AD than in age-matched controls (Miners et al., 2008c, 2009, 2010b; Palmer et al., 2009, 2010) and rose progressively with disease severity, as indicated by Braak tangle stage. The gene discussed is ACE; the disease is Alzheimer disease.