BMPR2 and heritable pulmonary arterial hypertension: Pathogenic variants in the gene encoding the bone morphogenetic protein type 2 receptor (BMPR2), a receptor for the transforming growth factor-beta (TGF-β) superfamily, explain approximately 20–25% of idiopathic PAH (IPAH) cases and 60% of heritable PAH (HPAH) [3,4,5].