In general, the increased ACE activity and the decreased ACE2 activity in Alzheimer’s disease correlate with the contribution of ACE and ACE2 to the proteolysis of beta-amyloid (Aβ): thus, ACE2 converts the highly amyloidogenic Aβ43 to Aβ42, which is then converted (with the help of ACE) to Aβ40, which is less capable of forming amyloid aggregates in the brain tissue [70, 71]. The gene discussed is ACE2; the disease is Alzheimer disease.