BMPR2 and pulmonary arterial hypertension: Heritable pulmonary arterial hypertension (HPAH) is a group of diseases characterized by persistent increase of pulmonary vascular resistance and progressive right heart failure caused by genetic factors, which includes clinically sporadic idiopathic PAH with germline mutations and clinical familial cases with or without identified germline mutations.[1] The bone morphogenetic protein receptor 2 (BMPR2) gene mutation is an important pathogenic factor of HPAH.[2,3] It exists in around 70% to 80% of families with PAH and 10% to 20% of IPAH cases.[4]