The most commonmutation identified is loss of function in BMPR2, which encodes a cellsurface receptor belonging to the transforming growth factor-β (TGFβ)superfamily.1,2 Understanding of the pathogenetic role ofBMPR2 haploinsufficiency has uncovered new potential therapeutictargets in pulmonary arterial hypertension, with multiple clinical trials focusing onthe TGFβ signalling pathway. The gene discussed is TGFB1; the disease is pulmonary arterial hypertension.