Alzheimer's disease is a more serious disease  Mutations in gene No  4 were once considered a cause of Alzheimer's disease
When the mouse brain is infected with HSV-1, the mouse carrying the 4 mutation gene produces 14 times the viral DNA of the normal mouse.
 However, recently some scientists have proposed that the cause of this complex disease may be simple, that is, some microorganisms that can cause brain infections, such as the HSV-1 virus