Although many genetic variants have been repeatedly associated with obesity, such as those located within FTO or MC4R genes (Frayling et al., 2007; Loos et al., 2008; Rouskas et al., 2012), their ability to stratify obesity remains insufficient, as compared to traditional risk factors or familial resemblance (Loos and Janssens, 2017). Here, MC4R is linked to obesity due to melanocortin 4 receptor deficiency.