ACER2 and obesity due to melanocortin 4 receptor deficiency: Further, it is found that UMP administration restores sphingolipid homeostasis and can reduce obesity in mice by reversing obesity‐induced inhibition of adipocyte hypoxia inducible factor 2a (Hif2α) and its target gene alkaline ceramidase 2 (Acer2), so as to promote ceramide catabolism and alleviate its accumulation within cells.