The increase in pericyte coverage is also found in the lungs of patients with idiopathic PAH (iPAH) and heritable PAH (hPAH) patients with a low proportion of α-SMA+/SM22+ pericytes in contrast to pericytes from control lungs, which are negative for these two SMC markers [54]. The gene discussed is ACTA1; the disease is pulmonary arterial hypertension.