We have rechecked the exome data of the 3 patients for 17 genes known to be associated with PAH (BMPR2, EIF2AK4, TBX4, ATP13A3, GDF2, SOX17, AQP1, ACVRL1, SMAD9, ENG, KCNK3, CAV1, SMAD4, SMAD1, KLF2, BMPR1B, and KCNA5). This evidence concerns the gene GDF2 and pulmonary arterial hypertension.