SLC9C2 and hydrops fetalis: In addition, using a specific enzyme-linked immunosorbent assay, with total heart samples increased to 80 (HF, n = 70 and CNT, n = 10), we found significant upregulation in the protein levels of NHE11 (FC = 1.614, p = 0.042) and NHE1 (FC = 1.518, p = 0.018) in the HF hearts (Figure 2A).