The microbiome of AD participants had reduced richness, with both ACE and Chao1 significantly decreased in the AD group compared to the Control group (t-test; ACE: DF = 48, t = 3.05, p = 0.004; Chao1: DF = 48, t = 2.98, p = 0.004) (Supplementary Fig. S2). The gene discussed is ACE; the disease is Alzheimer disease.