We queried gene expression for twelve known PAH risk genes (ACVRL1, BMPR2, CAV1, EIF2AK4, ENG, KCNK3, KDR, NOTCH1, SMAD4, SMAD9, SOX17, TBX4) and the two new candidate risk genes (FBLN2, PDGFD). This evidence concerns the gene ACVRL1 and pulmonary arterial hypertension.