Similarly, in the pathway analysis, it was found that 17 of the above genes (ACVR1B, BMP4, DKK1, EGFR, FGF10, FGF7, FZD3, FZD6, GLI1, INHBA, NOTCH1, RBPJ, SFRP4, SMO, TGFβ2, TNF, and WNT10A) were enriched in the TGF-β signaling pathway, Wnt signaling pathway, Notch signaling pathway, Hippo signaling pathway, MAPK signaling pathway, VEGF signaling pathway and Hedgehog signaling pathway, and these pathways are known to be related to skin or HF development (Fig. 4b). This evidence concerns the gene BMP4 and hydrops fetalis.