KCNA5 and pulmonary arterial hypertension: Inhibited gene transcription and/or decreased stability of KV1.5 mRNA has been implicated in the reduction of functional KV current in pulmonary artery smooth muscle cells (PASMCs) from patients with primary pulmonary hypertension (PPH).148,149 PPH is a relatively rare disease characterized by increased pulmonary vascular resistance and arterial pressure that can ultimately lead to right heart failure.