Although PH in COPD is incurable, and it is still unclear whether patients with PH in COPD may benefit from therapies targeting these dysfunctional pathways (NO, prostacyclin, and endothelin-1), research has been evaluating the effect of using targeted therapies approved for PAH in patients with PH due to COPD, with heterogeneous results. The gene discussed is EDN1; the disease is chronic obstructive pulmonary disease.