Intriguingly, it was recently shown that FGF21 expression is increased in skeletal muscle of muscle-specific Akt1 transgenic mice which exhibit protection from high-fat diet (HFD)-induced obesity and insulin resistance, indicating the beneficial effects of FGF21 as a myokine in metabolic disorders [2]. The gene discussed is FGF21; the disease is obesity due to melanocortin 4 receptor deficiency.