FAIM encodes a protein regulator of pituitary adenylate cyclase-activating polypeptide (PACAP) that has an important metabolic role in attenuating hepatic lipid accumulation, obesity-induced insulin resistance (Feng et al. 2024) and lipid metabolism in obese liver (Xiao et al. 2019) to attenuate metabolic disorders by reducing hepatic lipid accumulation (Luo et al. 2022). The gene discussed is FAIM; the disease is obesity due to melanocortin 4 receptor deficiency.