No clear cause of Alzheimer's
While it is not clear as to what exactly causes AD, certain risk factors have been identified. Such risk factors include age (65 years old or older), family history of the disease, and genetics. Furthermore, two rather abnormal structures – plaques and tangles – have been associated with the obstruction and death of nerve cells. Plaques are deposits of beta-amyloid proteins, which build up in the spaces among the nerve cells. Tangles are twisted fibers of another type of protein, known as tau, which builds up inside the nerve cells. Most experts believe that build-up of plaques and tangles account for blocking proper communication between the nerve cells. Such blockage can lead to damaging and killing nerve cells, which in turn can cause symptoms of AD.