HIF1A and obesity due to melanocortin 4 receptor deficiency: HIF-1α may have a dual role in the development of obesity-related disorders, because of its different functions in WAT and BAT cells; Zhang et al. reported that increased HIF-1α induces thermogenesis in BATs by increasing both VEGF-dependent angiogenesis and mitochondria biogenesis; on the other hand, increased HIF-1α increases fibrosis and inflammation in WATs [98].