Taxonomic models (including 24 genera) and functional models (including 25 Gene Ontology [GO] features and 33 Kyoto Encyclopedia of Genes and Genomes ortholog [KO] features) each demonstrated superior prognostic value compared to a clinical-only model (which included age, gender, body mass index [BMI], and Apolipoprotein E [ApoE] genotype), highlighting the importance of incorporating gut microbiome data to predict AD conversion. The gene discussed is APOE; the disease is Alzheimer disease.