COL4A1 and hydrops fetalis: In HF patients, the mRNA expression levels of collagen IV (COL4A1 (FC = 1.39, p < 0.01) and COL4A5 (FC = 1.68, p < 0.01) and collagen VIII (COL8A1 (FC = 1.66, p < 0.01)) were higher than those in the control group (Fig. 2C).