Recently we showed that reduced mitochondrial protein synthesis caused by haploinsufficiency of PTCD1 led to increased weight gain in haploinsufficient mice (Ptcd1+/-) on a NCD from 15 weeks of age compared to their wild type littermates (Ptcd1+/+), causing adult onset obesity by 30 weeks of age [20]. Here, PTCD1 is linked to obesity due to melanocortin 4 receptor deficiency.