We subsequently analyzed the relationship between serum TXNRD1 levels and clinical characteristics of IPAH patients, and the results revealed that TXNRD1 levels were negatively correlated with mPAP and PVR (Figures 5D,E) but had no significant correlation with 6MWD and NT-proBNP (Supplementary Figure 2). The gene discussed is NPPB; the disease is idiopathic pulmonary arterial hypertension.