ID4 and hydrops fetalis: As an example, the KDDN analysis indicated that upregulated grainyhead like transcription factor 3 (GRHL3) interacted with inhibitor of DNA binding 4 (ID4) and insulin-like growth factor binding protein 6 (IGFBP6) in the HF group, whereas its downregulation in the control group interacted with glycerophosphocholine phosphodiesterase 1 (GPCPD1) and small nucleolar RNA, H/ACA Box 41 (SNORA41).