PPARG and obesity due to melanocortin 4 receptor deficiency: To further elucidate the genetic mechanisms underlying GDM, we selected several gene polymorphisms previously associated with T2DM: rs1421085 (fat mass and obesity associated;FTO), rs1137100 and rs1137101 (leptin receptor;LEPR), rs1801282 (peroxisome proliferator-activated receptor gamma;PPARg), and rs7901695 (transcription factor 7-like 2;TCF7L2) and investigated their association with GDM.