Pharmacological administration of FGF21 in obese mice improved insulin sensitivity and glycaemic control, reduced dyslipidaemia and promoted energy expenditure and weight loss, whilst treatment of non-human primates with recombinant human FGF21 or an FGF21 mimetic (LY2405319; LY) led to a dramatic and rapid lowering of body weight, glucose, insulin, cholesterol and triglyceride levels3, 4, 6–9. The gene discussed is FGF21; the disease is inherited lipid metabolism disorder.