These studies reported that the CD9+ macrophages have high amounts of intracellular lipid in lysosome‐like structures, express genes related to lysosomal‐dependent lipid metabolism (Hill et al., 2018) and represent the majority of total adipose tissue macrophages in obesity (Jaitin et al., 2019). The gene discussed is CD9; the disease is obesity due to melanocortin 4 receptor deficiency.