PDC and pulmonary hypertension: Although the phenotypes caused by PHD KO cannot be necessarily attributed to HIF activity, since PHDs may also have additional substrates or partners [108], pulmonary hypertension has been long known to be linked to HIF activation, since exposure to chronic hypoxia can indeed cause pulmonary arterial smooth muscle cell proliferation, migration and hypertrophy leading to pulmonary vascular remodeling and eventually pulmonary hypertension [109].