POMC and obesity due to melanocortin 4 receptor deficiency: The increase in body weight and adiposity by inducible Bbs1 gene ablation in POMC neurons is in line with the effects of constitutive deletion of this gene in these neurons.16 This argues against the idea that BBS-associated obesity is caused by neurodevelopmental defects that arises from prenatal loss of BBS genes.36 It should be noted, however, that the weight gain and adiposity evoked by inducible Bbs1 gene ablation in POMC neurons was less pronounced relative to those evoked by its constitutive deletion.