Alzheimer's Disease

The cause of Alzheimer's disease remains a mystery. However, on-going research has provided clues as to possible underlying causes of the disease. Alzheimer's disease is usually categorized into two types: familial and sporadic onset (National Institute on Aging 2000). Familial Alzheimer's disease, where the cause of the disease is linked to heredity, is most often associated with an early onset of symptoms (under the age of sixty-five). Early onset cases only account for about 5 to 10 percent of the total number of Alzheimer's cases. Defects in three different genes have been linked to familial Alzheimer's disease: chromosomes 21, 14, and 1.

The most prevalent type of Alzheimer's disease is sporadic onset, which is often linked to an onset of symptoms beginning after the age of sixty-five. Indeed, increased age is one of the largest risk factors of developing Alzheimer's. During the aging process, neurons in the brain may die or shrink and lose their ability to maintain functioning. Ongoing research is looking for reasons why these changes in the brain lead to Alzheimer's disease in some people but not others. Other risk factors associated with sporadic onset Alzheimer's disease are head trauma and lesions on the brain.