SIM1 and obesity due to melanocortin 4 receptor deficiency: Interestingly, Sim1-Cre::γ2flox/flox mice were previously shown to have reduced body weight20, which is in contrast to the obesity phenotype in mice with inducible γ2 deletion by AAV-Cre-GFP shown in this study, suggesting strong compensatory effects from development in Sim1-Cre::γ2flox/flox mice.