SMAD9 and pulmonary arterial hypertension: Interestingly, in PAH patients with non-SOX17 pathogenic rare variants (n = 29; ACVRL1, ATP13A3, AQP1, EIF2AK4, GDF2, KCNK3, SMAD9 and TBX4) CXCL10 plasma expression did not differ with healthy controls (Z-score = 0.01).