What are the causes for Alzheimer's Disease FAQs?

What exactly causes Alzheimer's disease is not known in most cases. Most often, a number of factors, rather than a single cause, come together in certain people to cause the disease. Two forms of Alzheimer's disease have been recognized.
  • In familial Alzheimer's disease, a person's genes directly cause the disease. This form of disease is very rare; only a few hundred families worldwide include individuals with the genes that cause this form of Alzheimer's disease. However, individuals who inherit these genes will almost certainly develop the disease, usually when younger than 65 years and sometimes as young as 30 years. At least three different genes have been found to be related early-onset or familial Alzheimer's disease.
  • In sporadic Alzheimer's disease, the more common form of the disease, genes do not cause the disease; however, certain genetic mutations have been shown to increase an individual's risk of developing the condition. Cases of sporadic Alzheimer's disease occur in a less predictable manner than familial Alzheimer's disease, and usually not as many members in the same family acquire it compared to families with familial Alzheimer's disease.

    Source: http://www.emedicinehealth.com