The relationship between VitD deficiency and obesity is mediated through several mechanisms, including the decreased bioavailability of VitD3 [15] and increased adipogenesis dependent on the inhibition of peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer binding protein alpha (C/EBPα) modulated by 1,25-hydroxyvitamin D through VDR [44]. The gene discussed is VDR; the disease is obesity due to melanocortin 4 receptor deficiency.