The majority of subjects had severe symptoms, indicated by the frequent need of intensive care unit (43%), high N-terminal prohormone brain natriuretic peptide levels [NT-proBNP; median, 4765 (1539.7-11782.2) pg/mL], and presence of either atrial fibrillation, severe mitral regurgitation, or significant pulmonary hypertension in approximately one-third of cases. The gene discussed is NPPB; the disease is pulmonary arterial hypertension.