Although OPG has traditionally been implicated in bone remodelling and it has been determined as a biomarker in osteoporosis, the aim of this review is to highlight the association of OPG to other pathologies such as diabetes types 1 and 2, obesity, metabolic syndrome, or hypertension (Figure 3). This evidence concerns the gene TNFRSF11B and obesity due to melanocortin 4 receptor deficiency.