Alloprevotella has been shown to produce various short-chain fatty acid metabolites (Huang et al., 2023; Zhao et al., 2021) and the short-chain fatty acids produced can increase energy expenditure, reduce weight, and decrease liver TG accumulation by activating the PPAR signaling pathway, thereby regulating lipid metabolism and improving obesity (Ai et al., 2022). The gene discussed is PPARA; the disease is obesity due to melanocortin 4 receptor deficiency.