HIF1A and hydrops fetalis: The ROC curves revealed that all four hub genes exhibited strong discriminatory power between HF and normal control samples, with HIF1A showing the highest AUC of 0.80, followed by GABPA (AUC = 0.78), SOX6 (AUC = 0.76), and CCND1 (AUC = 0.69) (Fig. 4B).