Alzheimer's disease, also known as irreversible dementia, is a neurodegenerative disease that slowly progresses over the years and eventually leads to the death of the person. Its symptoms include cognitive decline, forgetfulness, inability to recognize family members or carry out normal activities, depression, mood swings, lack of coordinated muscle movement. In the later stages, inactivity combined with loss of appetite and a weak immune state make the disease fatal. . It was previously believed to be an age-related decline in brain function, but Dr. Alois Alzheimer's 1906 report showed that it was much more than just an age-related disorder. He observed the presence of plaques and tangles and also the disappearance of many nerve cells from the brain tissues he had studied1. These were believed to be the cause of Alzheimer's disease. There are two types of Alzheimer's disease: familial Alzheimer's disease (FAD), which is a rare, inherited form of Alzheimer's disease, and the more common, sporadic form of Alzheimer's disease. FAD affects a person at an early age, but the sporadic form generally appears at age 65 or older. Summary: Changes that occur in the brain of an Alzheimer's patient: 1) Plaque formation: The plaques observed by Dr. Alzheimer are actually made up of beta-amyloid, Aβ protein for short which derives from the precursor of the amyloid protein (APP). Although Aβ and APP are present in healthy nerve cells, in the Alzheimer's brain they accumulate in enormous quantities due to overproduction of Aβ or failure of clearance mechanisms2. The blood vessels that collect and remove A-beta also proliferate and become leaky and therefore cannot function properly3. But the real danger is not the individual A-beta molecules... at the center of the paper... the element of risk. It also causes the formation of plaques and tangles and interrupts mitochondrial function and some synaptic mechanisms involved in communication between nerve cells14. So the alternative could be to find more protective genes like ApoE2 and always maintain a healthy lifestyle.2) Other genetic variants that act as risk factors-i) People with FAD tend to have a mutation in one of the three genes, namely APP gene and two presenilin genes (PSEN-1 and PSEN-2). So it is highly likely that people who inherit these defective genes will contract the disease at an early age (30 or 40 years)12. ii) A recently identified gene, GAB2, promotes the development of tangles15. iii) Four recently identified genes, CLU, PICALM, CR1 and BIN1 also act as risk factors, probably hindering the elimination of excess Aβ protein, thus leading to its accumulation17.