Recently, the new proteins of the same family members, fibroblast growth factor-19 (FGF-19) and fibroblast growth factor-21 (FGF-21), with pleiotropic effects on development, organogenesis and metabolism have been proposed to be involved in the pathogenesis of obesity [5]. The gene discussed is FGF19; the disease is obesity due to melanocortin 4 receptor deficiency.