BMPR2 and pulmonary arterial hypertension: Much of our understanding of the pathogenesis of PAH is shaped by the seminal human genetic studies which revealed that mutations in BMPR2, a gene encoding bone morphogenetic protein receptor type 2, account for ~80% of patients with hereditary PAH and ~20% of sporadic cases (Southgate et al., 2020; Ruopp and Cockrill, 2022).