Furthermore, the enzymes that dephosphorylate S1P, sphingosine-1-phosphate phosphatase 1 and 2 (SGPP1: −1.49 ± 0.24, p = 0.044; SGPP2: −2.83 ± 0.28, p = 0.002), and S1P receptor 3 (S1PR3: −1.78 ± 0.28, p = 0.003) were all downregulated in HF patients (Figure 1). This evidence concerns the gene S1PR3 and hydrops fetalis.