Previous studies have implicated excessive glucocorticoid action in the development of several phenotypes associated with metabolic syndrome.[3–5] Abnormal glucocorticoid receptor (GR) signalling is associated with insulin and leptin resistance, leading to the development of type 2 diabetes, obesity and cardiovascular disorders.[6, 7] GR activation stimulates hepatic glucose production, antagonises insulin secretion from pancreatic β-cells and insulin-mediated glucose uptake in peripheral tissues,[8–11] and it also promotes lipolysis and fatty acid mobilisation.[12]. The gene discussed is NR3C1; the disease is obesity due to melanocortin 4 receptor deficiency.