Three patients had NT-proBNP values > 3,000 pg/ml; these patients had the most severe pulmonary hypertension at RHC (mPAP, 58.3 ± 6.0 mm Hg; mean right atrial pressure (mRAP) 13.7 ± 3.5 mm Hg; peripheral vascular resistance (PVR), 11.0 ± 0.9 Wood units). The gene discussed is NPPB; the disease is pulmonary arterial hypertension.