The penetrance of IPAH among individuals with a BMPR2 mutation is only about 20% and is 3 times higher in females than males.[11,12] In this study, we found that a loss-of-function BMPR2 mutation was associated with increased expression of AMHR2, which is phylogenetically close to BMPR2. Here, AMHR2 is linked to idiopathic pulmonary arterial hypertension.