These findings may suggest that the observed overrepresentation of Faecalibacterium in AD groups could be due to its confounding correlation with APOE4. Given the known role of APOE4 in conferring maladaptive inflammatory and oxidative stress via mitochondrial damage, it is possible that the gene may provide a confounding variable responsible for the occasional correlation between Faecalibacterium and AD; however, mechanistic insights are necessary to draw further conclusions[113,114]. The gene discussed is APOE; the disease is Alzheimer disease.