BMPR2 and pulmonary arterial hypertension: Recent studies highlight GDF2 mutations (BMP9), affecting 6.7% of IPAH cases, leading to reduced BMP9/BMP10 levels and dysfunction in pulmonary endothelial cells [44, 538] Sotatercept, an activin receptor type IIA fusion protein, restores BMPR2/SMAD1/5/8 signaling and counteracts PAH vascular remodeling [539].