For example, mice with a targeted ablation of BAT due to a tissue-specific transgenic expression of diphtheria toxin from the uncoupling protein 1 (UCP1) gene promoter are obese, although it is possible that the obesity of this mouse model is caused by hyperphagia rather than reduced thermogenesis [15]. The gene discussed is UCP1; the disease is obesity due to melanocortin 4 receptor deficiency.