Alzhemer's disease is characterized by deposition of proteins in the brain.The depositions forms the Plaques and Tangles.

Plaques – deposits of the protein beta-amyloid that accumulate in the spaces between nerve cells.

Tangles – deposits of the protein tau that accumulate inside of nerve cells.

Genetic Factors

The gene apolipoprotein E (ApoE) has been identified that linked to late-onset Alzheimer's disease. However, only a small percentage of people carry the form of ApoE that increases the risk of late-onset Alzheimer's. Other genes or combinations of genes may be involved.

Environmental Factors

Researchers have investigated various environmental factors that may play a role in Alzheimer' s disease or that trigger the disease process in people who have a genetic susceptibility. Some studies have suggested Alzheimer's development is due to serious head injuries in early adulthood. Lower educational level, which may decrease mental activity and neuron stimulation, has also been investigated.