In RAS, the ACE2 converts angiotensin I (ang I) into angiotensin-(1–9) and angiotensin II (ang II) into angiotensin-(1–7) [28,30], where ACE2 plays important roles in the onset and development of myocardial infarction(MI) [29], diabetic cardiovascular complications, systemic and pulmonary hypertension, and COVID-19 pathogenesis [30]. This evidence concerns the gene ACE2 and pulmonary arterial hypertension.