The plasma CFHR2 level in Mix-PAH patients (83.23 ± 15.96 ng/ml, n = 11; P = 0.006 by ANOVA compared with control group) was significantly lower than that in normal controls (189.1 ± 24.01 ng/ml, n = 16). The gene discussed is CFHR2; the disease is pulmonary arterial hypertension.