The Genetics of Alzheimer's Disease
Diseases such as cystic fibrosis, muscular dystrophy, and Huntington’s disease are single-gene disorders. If a person inherits the gene that causes one of these disorders, he or she will usually get the disease. Alzheimer’s disease, on the other hand, is not caused by a single gene.
The two basic types of AD are familial and sporadic. Familial AD (FAD) is a rare form of early-onset AD, affecting less than 10 percent of AD patients. The majority of AD cases are sporadic, late-onset, usually developing after age 65. More than one gene mutation can cause AD, and genes on multiple chromosomes are involved.
Late-onset AD has no known cause and shows no obvious inheritance pattern. However, in some families, clusters of cases are seen. Although a specific gene has not been identified as the cause of late-onset AD, genetic factors do appear to play a role in the development of this form of AD. Only one risk factor gene has been identified so far.
It is possible to evaluate your predisposition to develop Alzheimer’s disease and make lifestyle choices that reduce your risk factors. More and more evidence is emerging that proves environmental factors play a significant role in determining if the disease will develop and progress.
Use the internet to do research on genetic conditions and prevention strategies. Some useful sites are: www.alzheimersprevention.org, www.alzheimers.org, www.geneticalliance.org, and www.medlineplus.gov and www.mydna.com .
Learn as much as you can about your family health history, especially about your siblings, parents, and grandparents. Share information with your physician. He or she needs to be aware of your family history in order to help you make medical decisions. Consult a genetic counselor. Genetic counselors provide information and support to families who may be at risk for a variety of inherited conditions. They identify families at risk, analyze inheritance patterns and risks of recurrence and discuss options with the family. Locate a counselor at the National Society of Genetic Counselors at www.nscg.org.
Have a memory screening done on a regular basis, as part of your annual physical. Many memory difficulties are due to correctable conditions, such as vitamin deficiencies or stress. Make healthy lifestyle choices. By using programs like the ARPF’s 4 Pillars of Alzheimer’s PreventionTM it is possible to minimize the risk factors and prevent memory loss.
Preventing Alzheimer’s Disease should be the goal of ALL of us
Dharma S. Khalsa, M.D., is President and Medical Director of the Alzheimer’s Research and Prevention Foundation in Tucson, Arizona. The ARPF is dedicated to fighting Alzheimer’s disease and finding a cure through research and prevention. Dr. Khalsa wrote about Alzheimer’s for HealthCentral.