Regarding previous and current results by the investigators, they hypothesized that combining analysis of different inflammatory biomarkers and BMPR2 mutations, which are currently analyzed in each patient diagnosed with idiopathic or familial PAH, could contribute to establish an earlier diagnosis and consequently better orientate the therapeutic strategy. Moreover, BMPR2 gene mutations are responsible for more than 70% of HPAH and about 20% of IPAH; among human BMPR2 mutation carriers, only 20% will further develop PAH, suggesting that BMPR2 mutation itself is not the unique cause for developing PAH and that a second hit, such as inflammation, would be required and play a triggering role in the development of PAH.