However, in obesity models where fetal size at term is not enhanced or even lower, placental mTOR signalling is reported to be unchanged or reduced and tends to track with reductions in placental size or efficiency (Lager et al., 2014; Ma et al., 2010; Mark et al., 2011; Sferruzzi‐Perri et al., 2013). The gene discussed is MTOR; the disease is obesity due to melanocortin 4 receptor deficiency.