OGN and hydrops fetalis: Differential expression analysis between the two branches (OGN+/UCHL1+ →TC1→TC2 and OGN+/UCHL1+→TC1→TC3) revealed that TGFβ and BMP signaling were enriched at the cell fate decision point, indicating the importance of these signaling pathways for regulating HF morphogenesis (Figure S9A, Supporting Information).