PFKFB1 and hydrops fetalis: 6-Phosphofructo-2-kinase/fructose-2,6-biphosphatase 1 (Pfkfb1), the gene encoding 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 1 (PFK2), which indirectly regulates glycolysis by activating PFK1 through fructose 2,6-bisphosphate, was downregulated in both the CH (Figure S3A) and HF phases.