KCNA5 and idiopathic pulmonary arterial hypertension: Indeed, mutations in the exon or in the promoter region of KCNA5 gene have been reported to be associated with IPAH and may underline the altered function and expression of voltage-gated K+ channel 1.5 (Kv1.5) observed in pulmonary arteriolar smooth muscle cells (PASMC) from these patients [12], [13].