The mRNA levels of octamer-binding transcription factor 4 (Oct 4) pseudogene Oct-4-psG1 and Oct-4-psG5 are significantly down-regulated in pulmonary arterial smooth muscle cells (PASMC) in patients with idiopathic pulmonary arterial hypertension (IPAH), indicating that Oct-4-psG1 and Oct-4-psG5 are involved in IPAH [51]. Here, POU5F1 is linked to idiopathic pulmonary arterial hypertension.