It has been reported that, in SIRT4 knocked-out (KO) mice, the MCD activity was increased and the level of malonyl CoA was decreased in skeletal muscle and white adipose tissue, leading to elevated exercise tolerance, which was considered to have a protective effect on diet-related obesity (Laurent et al., 2013b). The gene discussed is SIRT4; the disease is obesity due to melanocortin 4 receptor deficiency.