Angiotensin-converting enzyme inhibitors (ACEIs), suppressing the activity of angiotensin-converting enzyme (ACE) that is responsible for the conversion of angiotensin I to angiotensin II, have been the first-line drugs for improving hypertension [4,5]; however, ACEIs have side effects such as an irritating dry cough, angioedema, and abnormal renal function, which seriously affect the quality of life and health of patients [6,7,8]. The gene discussed is ACE; the disease is angioedema.