As recently reviewed by Olschewski et al. 21, the contribution of alterations at ion channels to pulmonary hypertension is progressively emerging because they are supposed to play a pivotal role in both the triggering and the development of the disease, as demonstrated by the function of KCNA5 and KCNK3 in regulation of pulmonary vascular tone. This evidence concerns the gene KCNA5 and pulmonary arterial hypertension.