In a recent whole-genome sequencing (WGS) study by Graf et al. comprising 1048 PAH cases and 6385 controls, the authors first removed samples with deleterious mutations that were previously described as “PAH genes”, including BMPR2, ACVRL1, ENG, KCNK3, SMAD9, and TBX4 to further increase the statistical power of the analysis. The gene discussed is SMAD9; the disease is pulmonary arterial hypertension.