In contrast to these studies, our present report demonstrates that upon HFD feeding for 10 weeks, the mPer2Brdm1 mice do not reveal any difference in body weight gain as compared to WT control mice, suggesting that the Per2 gene mutation does not have an impact on growth development and predisposition to obesity. The gene discussed is PER2; the disease is obesity due to melanocortin 4 receptor deficiency.