Patients in high big endothelin-1 group were significantly older (51.0 ± 12.3 vs. 45.7 ± 13.9 years, P = 0.031) and more likely to have left atrial dilatation (46.0 ± 5.4 vs. 43.5 ± 6.4 mm, P = 0.019), moderate or severe mitral regurgitation (74.6% vs. 70.5%, P = 0.042) and pulmonary hypertension (8.8% vs. 0%, P = 0.036). The gene discussed is EDN1; the disease is pulmonary hypertension.