Since the discovery of KCNK3 mutations in PAH patients, we have found that KCNK3 expression is reduced in lung and pulmonary arteries from iPAH and hPAH patients and that the KCNK3 function is reduced in hPASMCs from iPAH patients. This evidence concerns the gene KCNK3 and idiopathic pulmonary arterial hypertension.