Importantly, mTOR exists as 1 of 2 complexes and hyper-activity of the mTOR complexes 1 and 2 (mTORC1/2) has been implicated in tumor progression, pathological hypertrophy, diabetes and obesity (Lee et al. 2007; Sharp and Richardson 2011; Zoncu et al. 2011). The gene discussed is MTOR; the disease is obesity due to melanocortin 4 receptor deficiency.