It is also interesting that ClpP KO mice are viable and are protected from diet-induced obesity and insulin resistance (28, 29), whereas knockout of the ClpX gene in mice results in an embryonic lethal phenotype (2), suggesting that ClpX can play an essential role at a specific stage during the development of embryos without ClpP. The gene discussed is CLPP; the disease is obesity due to melanocortin 4 receptor deficiency.