It has been shown that the angiotensin-converting enzyme (ACE)/Ang II/AT1R axis is upregulated in neurodegenerative diseases, and causes oxidative stress, increased permeability of the blood–brain barrier, neuroinflammation, neurovascular dysfunction [25], and a reduction in cerebral blood flow, contributing to the development of Alzheimer’s disease [26]. The gene discussed is ACE; the disease is neurodegenerative disease.