Previous studies have reported that plasma endothelin-1 and cyclic guanosine monophosphate (cGMP)/NT-proBNP ratio were related to 6MWD14, and increased serum interleukin (IL)-6/IL-8/IL-10/IL-12 predicted worse survival15 in patients with PAH. The gene discussed is EDN1; the disease is pulmonary arterial hypertension.