Conversely, a recent study demonstrated that during chronic exposure to hypoxia, mice lacking myeloid-specific HIF-1α exhibited a significant decrease in right ventricular systolic pressure (RVSP), suggesting the contribution of myeloid-specific HIF-1α in the progression of pulmonary vascular remodeling and pulmonary hypertension.350 These studies delineated the distinct pathogenic roles and mechanisms of HIF1α and HIF2α in HAPH pathogenesis, providing novel therapeutic approaches for the treatment of this condition. The gene discussed is EPAS1; the disease is pulmonary arterial hypertension.