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). This evidence concerns the gene PTCH1 and hydrops fetalis.