In addition, although both of GNAS and IGF2 gene are associated with obesity [29,30] and hypertension [31-34], currently there is no evidence if GDM modifies epigenetic imprints of GNAS and IGF2 of fetus, or, GNAS and IGF2 are possibly involved in the induction of high risk of GDM-related metabolic diseases in adulthood. The gene discussed is GNAS; the disease is obesity due to melanocortin 4 receptor deficiency.