Several studies in humans have now linked PROX1 expression to the development of hyperlipidemia, obesity, and T2D (Horra et al., 2009; Kim et al., 2013; Kretowski et al., 2015; Adamska-Patruno et al., 2019). This evidence concerns the gene PROX1 and obesity due to melanocortin 4 receptor deficiency.