Based on direct sequencing and MLPA method, we identified 25 nonsynonymous point mutations, 5 large size rearrangements, and 2 CTEPH associated SNPs of 7 PAH-causing genes (BMPR2, ACVRL1, ENG, SMAD9, CAV1, KCNK3, and CBLN2) out of 49 CTEPH patients. The gene discussed is KCNK3; the disease is pulmonary arterial hypertension.