The vitamin D-dependent mechanisms in disease and the causal relationship between vitamin D status and disease (except vitamin D-deficient rickets/osteomalacia and inherited vitamin D receptor/vitamin D metabolism disorders) have yet to be identified, although an increased risk of some diseases (including obesity) has been linked to vitamin D deficiency and insufficiency [1,2,6,13]. Here, VDR is linked to obesity due to melanocortin 4 receptor deficiency.