Previously, several genes have been identified as potentially associated with different features of the metabolic syndrome, such as transcription factor 7-like 2 (TCFL2), fat mass and obesity gene (FTO), adenylate cyclase type 5 (ADCY5), fatty acid desaturase 1 (FADS1), GLI-similar 3 (GLIS3), insulin-like growth factor 1 (IGF1) and peroxisome proliferator-activated receptor-gamma (PPARγ) [7,8,9]. The gene discussed is IGF1; the disease is obesity due to melanocortin 4 receptor deficiency.