Our previous studies have reported that Tie2Cre-mediated loss of hypoxia-inducible factor (HIF) prolyl hydroxylase 2 (PHD2, encoded by Egln1) in mice (Egln1Tie2Cre) induced spontaneously progressive severe PAH, which resembles all of the key pathological features of clinical PAH [12]. The gene discussed is EGLN1; the disease is pulmonary arterial hypertension.