HNF1B and gestational diabetes: Although classical MHC class II molecules HLA-DR3 and DR4 were not found to be related to GDM [20], recent studies have found genetic evidence from PPARG, KCNJ11, TCF2/HNF1B, and WFS1 or HNF4A that is related to dysfunctional pancreatic b-cell secretion and GDM, suggesting new possibilities for the study of GDM [21, 22].