Recent gene sequencing studies4, 5, 6 have revealed rare mutations in several genes, including BMPR2, genes encoding potassium channels, and most recently the transcription factor SOX17. Rare genetic variation is associated with both the risk of developing pulmonary arterial hypertension and survival, and it is found in up to 25% of patients with pulmonary arterial hypertension. Here, SOX17 is linked to pulmonary arterial hypertension.