Endothelial-specific knockout of SOX17 or enhancer region knockout, in mice exposed to hypoxia or SUGEN5416/hypoxia exaggerates the development of pulmonary hypertension, as demonstrated by increased pulmonary arteriolar muscularization and endothelial cell proliferation, along with right ventricular hypertrophy and raised right ventricular systolic pressure3,5,6. The gene discussed is SOX17; the disease is pulmonary arterial hypertension.