Complex mechanisms involving a dysregulation of nitric oxide, endothelin-1 production and the intervention of multiple cell types like pulmonary artery smooth muscle cells (PASMCs), pulmonary artery endothelial cells (PAEs) and fibroblasts constitute the hallmarks of pulmonary arterial hypertension (PAH), although they are involved to a lesser or greater degree in all cases of PH (Humbert et al., 2019). The gene discussed is EDN1; the disease is pulmonary arterial hypertension.