ACOX1 and obesity due to melanocortin 4 receptor deficiency: ACOX1 is an enzyme primarily responsible for the oxidation of very-long-chain fatty acids in the peroxisome, and recent animal and human data supports its role in obesity, lipid metabolism, and insulin resistance.51 A liver-specific knockout of ACOX1 has been reported to promote resistance to diet-induced obesity, inflammation, and insulin resistance, further reinforcing its metabolic significance.51 Additionally, common genetic variants in ACOX1 have been associated with SBP52 and lipid levels,53 aligning with our findings.