In 2008, Rai et al. found that Wnt7a was absent in ECs with cluster lesions in patients with severe PAH.267 In 2009, Laumanns et al. found that Wnt/PCP pathway mediators in IPAH were significantly upregulated in the pulmonary resistance vessel endodermis.268 The expression of Wnts varies across different etiologies of PAH, influencing the activation or inhibition of the Wnt signaling pathway. The gene discussed is WNT7A; the disease is pulmonary arterial hypertension.