There is evidence for induction of Nox‐4 expression within the medial layer of remodeled pulmonary arteries, in patients with iPAH, reflecting a critical role for Nox‐4 in TGF‐β1‐mediated VSMC hyperplasia and hypertrophy (Mittal et al. 2007). The gene discussed is NOX4; the disease is idiopathic pulmonary arterial hypertension.