Germline mutations in the bone morphogenetic protein receptor type 2 (BMPR2) gene, a member of the transforming growth factor β superfamily, are found in the majority of individuals (≥ 75%) with PAH and a positive family history of the disease; in addition, BMPR2 mutations are found in 10-25% of cases of sporadic PAH [4-7]. Here, BMPR2 is linked to pulmonary arterial hypertension.