SOX9 and hydrops fetalis: Previous studies in humans and mice also demonstrated that several pathways like WNT/beta-catenin, TGF-beta/BMP, FGF, Hedgehog, NOTCH, and other factors (SOX9, LHX2, DLX3, GATA3, RUNX1, TP63, MSX2, FOXN1, NFATC1, and TBX1) play important roles in HF development8.