Alzheimer's Disease: An Overview

Causes of Alzheimer's Disease

In the century since it was first identified by Alois Alzheimer, the body of research on Alzheimer's disease and its causes has continued to grow. Continue reading to learn about the cause of this dementia and the changes it produces in the brain.

Causes of Alzheimer's disease

The actual cause of Alzheimer's disease is unknown. Scientists believe that Alzheimer's disease is caused by a combination of genetic, lifestyle, and environmental factors.^[2] Several changes are evident in the brains of persons with Alzheimer's disease. Researchers do not know what the cause of these changes is. The changes involve pieces of a protein, beta-amyloid, that clump inside the brain and interfere with function. These pieces, called plaques and tangles, interfere with communication between brain cells and lead to the death of brain cells.^[2]

A rare form of Alzheimer's disease, called familial Alzheimer's disease, is inherited. Symptoms develop earlier than typical Alzheimer's disease, in some cases as early as age 30.^[1] This form of the disease accounts for about five to ten percent of all Alzheimer's disease cases. It is the result of several mutations located on several different chromosomes. Chromosomes are the cell structures that contain DNA. These mutations cause cells to make abnormal proteins that cause plaques and tangles in the brain. Inheriting these mutations from just one parent nearly always results in early-onset Alzheimer's disease.

This Elder Health Guide was published on August 1, 2009.