Recently, a candidate gene approach study demonstrated that the Pro12Ala polymorphism in PPARG was associated with IR in Mexican children and suggested that this relationship was modified by dyslipidaemia.19 Therefore, genetic studies of T2D in adults and epidemiological, as well as non-genetic (such as nutritional and physical activity), studies of IR and T2D in children are numerous, whereas genetic studies specifically aiming to identify novel genes predisposing to IR in children and adolescents are lacking. The gene discussed is PPARG; the disease is type 2 diabetes mellitus.