Alzheimer’s disease is the most common cause of dementia in humans. In Alzheimer’s
disease, parts of the brain degenerate, destroying cells and reducing the responsiveness ofthe remaining ones to many of the chemicals that transmit signals in the brain. It is
estimated that 4,000,000 people in the United States has Alzheimer’s disease and about
47.2% of 85 year old people and older are thought to have this disease. During autopsy adiseased person that had suffered from Alzheimer’s has abnormal tissues, called senileplaques and neurofibrillary tangles, and abnormal proteins that appear in the brain. Alzheimer’s disease is most associated with forgetfulness in the elderly. The loss of memory is usually gradual. Along with memory, thinking, judgment, and the ability to pay attention and learn are also impaired. Through examination of a doctor, the diagnosis of Alzheimer’s disease is correct 85 % of the time, but only through an autopsy can Alzheimer’s disease be proved through the recognition of abnormal tissues.
One of the largest contributing factors to Alzheimer’s disease is thought to be genetic. The inherited form of this disease has been shown to have mutations in the presenilin protein 1 and 2, and the amyloid precursor protein. These disease-linked mutations result in increased production of the longer form of amyloid-beta. This site will deal with the presenilin 2 gene.