Font Size

Alzheimer Disease (cont.)

Alzheimer's Disease Causes

We do not know exactly what causes Alzheimer's disease. There is probably not one single cause, but a number of factors that come together in certain people to cause the disease.

  • Most experts believe that Alzheimer's disease is not a normal part of aging.
  • While age is a risk factor for the disease, age alone does not seem to cause it.
  • Family history is another risk factor. The disease does seem to run in some families. However, few cases of Alzheimer's disease are familial. Familial Alzheimer's disease often occurs at a younger age, between ages 30 and 60 years. This is called early-onset familial Alzheimer's disease.

At least 3 different genes have been linked to Alzheimer's disease.

  • The one we know the most about controls production of a protein called apolipoprotein E (apoE), which helps in distribution of cholesterol through the body.
  • Everyone has one of the 3 forms of the apoE gene. While one form seems to protect from AD, another form seems to increase the risk of developing the disease.
  • The other genes-apart from ApoE-are known to be mutated in some people with the disease. These actually cause the disease in a few rare cases.
  • Probably there are other genes that contribute to Alzheimer's disease, but we haven't found them yet.

Much of the research in Alzheimer's disease has focused on why and how some people develop deposits of the abnormal protein in their brains. Once the process is understood, it may be possible to develop treatments that stop or prevent it.

Medically Reviewed by a Doctor on 8/1/2014
Medical Author:
Medical Editor:
Medical Editor:
Medical Editor:

Must Read Articles Related to Alzheimer Disease

Alzheimer's Disease Facts
Alzheimer's Disease FAQs Alzheimer's disease is a fatal brain disorder. Familial and sporadic are the two types of Alzheimer's disease. The three stages include early, intermediate, and...learn more >>
Alzheimer's Disease Symptoms
Alzheimer's Disease Stages: Symptoms and Signs Alzheimer's disease is one of the many causes of dementia. Symptoms of Alzheimer's disease typically progress over a period of years. There are warning signs of...learn more >>
Alzheimer's Disease Support
Alzheimer's Disease Support Alzheimer's disease patients and caregivers are under emotional and physical stress most of the day and night. Information on how to manage the stresses of this...learn more >>

Patient Comments & Reviews

The eMedicineHealth doctors ask about Alzheimer's Disease:

Alzheimer's Disease - Describe Your Experience

Please describe the symptoms you or loved one experienced with Alzheimer's disease.

Alzheimer's Disease - Symptoms

What were the symptoms of your Alzheimer's Disease?

Alzheimer's Disease Stages - Treatment

What was the treatment for you or your loved one's Alzheimer's disease?

Read What Your Physician is Reading on Medscape

Alzheimer Disease »

Alzheimer disease (Alzheimer’s disease, AD), the most common cause of dementia1, isan acquired cognitive and behavioral impairment of sufficient severity that markedly interferes with social and occupational functioning.

Read More on Medscape Reference »

Medical Dictionary