ActRIIA, activin receptor type IIA; ActRIIA-Fc, activin receptor type IIA–Fc fusion protein; BMP, bone morphogenetic protein; BMPR2, bone morphogenetic protein receptor type 2; EndMT, endothelial-to-mesenchymal transition; ET-1, endothelin-1; NO, nitric oxide; PASMC, pulmonary artery smooth muscle cell; PAH, pulmonary arterial hypertension; TGF-β, transforming growth factor beta. The gene discussed is ACVR2A; the disease is pulmonary arterial hypertension.