User:Yanubha/ALZHEIMER DISEASE

Alzheimer Disease Alzheimer's disease is named after Dr. Alois Alzheimer, a German doctor. In 1906, Dr. Alzheimer noticed changes in the brain tissue of a woman who had died of an unusual mental illness. He found abnormal clumps and tangled bundles of fibers.

The clumps are now called amyloid plaques and the tangles are called neurofibrillary tangles. Today, these plaques and tangles in the brain are considered signs of Alzheimer's disease.Scientists also have found other brain changes in people with Alzheimer's disease. There is a loss of nerve cells and pathways in areas of the brain that are vital to memory and other mental abilities. There also are lower levels of some of the chemicals in the brain that carry complex messages back and forth between nerve cells.Alzheimer's disease may disrupt normal thinking and memory by blocking these messages between nerve cells.

The disease usually begins after age 65 and risk goes up with age. While younger people also may get Alzheimer's disease, it is much less common. About 5 percent of men and women ages 65 to 74 have Alzheimer's disease, and nearly half of those age 85 and older may have the disease. It is important to note, however, that Alzheimer's disease is not a normal part of aging. ---

Causes and Risk Factors Scientists do not yet fully understand what causes Alzheimer's disease. There probably is not one single cause, but several factors that affect each person differently. Age is the most important known risk factor for Alzheimer's disease. The number of people with the disease doubles every 5 years beyond age 65.

Family history is another risk factor. Scientists believe that genetics may play a role in the causes of Alzheimer's disease. For example, early-onset familial Alzheimer's disease, a rare form of Alzheimer's disease that occurs between the ages of 30 and 60, is inherited.

The more common form of Alzheimer's disease is known as late-onset. It occurs later in life, and no obvious family pattern is seen in most cases. One risk factor for this type of Alzheimer's disease is a gene that makes one form of a protein called apolipoprotein E, or apoE.

Everyone has apoE, which helps carry cholesterol in the blood. Only about 15 percent of people have the form that increases the risk of Alzheimer's. It is likely that other genes may also increase the risk of Alzheimer's or protect against it, but they remain to be discovered.

WORK IN PROGRESS................................