In heritable PAH and idiopathic PAH, the critical breakthrough over the past decades is that bone morphogenetic protein (BMP) signaling reduction is caused by pathogenic mutations of BMP receptor 2 (BMPR2), and triggers proliferation and anti-apoptosis of pulmonary artery smooth muscle cells; however, CHD-PAH showed the lowest level of BMPR2 mutation but commonly suppressed BMP cascade in lungs (27). The gene discussed is BMPR2; the disease is pulmonary arterial hypertension.