WNT4 and hydrops fetalis: We further analyzed the network of KEGG pathways related to HF development in Stage A and identified 20 genes, including TGFβ2, WNT10A, PTCH1, BMP2, ACVR1B, WNT5A, WNT16, LAMA5, WNT10A, and WNT4, that may be involved in HF development (Fig. 5d).