ADCYAP1 and obesity due to melanocortin 4 receptor deficiency: 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).