C1QTNF1 and pulmonary arterial hypertension: Considering both cohorts, this result suggests NID1 demonstrates the most significant biomarker potential, while the combination of NID1 with C1QTNF1 and CRTAC1 had highest overall performance compared to other combinations in discriminating two subgroups of PAH (AUC = 0.88 and 0.77 in discovery and validation cohorts, respectively; Extended Data Fig. 8).