ASK DR. BAUGHAN                                                          February 6, 1997

GENETIC TESTING FOR ALZHEIMER’S DISEASE

“How does one get tested for the Apolipoprotein E4 gene?  For some people it is vital to know if they have the Alzheimer’s susceptibility gene.”

We would all at times like to predict the future, particularly regarding our health.  The advent of genetic testing suggests we are on the verge of doing just that by unlocking the secrets of our chromosomes.  The Human Genome Project is unwinding the double helix of our DNA and identifying new genes at the rate of one a day.  There are an estimated hundreds of thousands of genes, though, so the project has a ways to go.  But with each report of a new gene identified that affects a certain disease, anticipation mounts.  The Apolipoprotein E4 gene has been identified and linked strongly to Alzheimer’s disease.  Is this a breakthrough to be embraced?  Like much of modern science this new discovery creates many  questions regarding how to use the information with wisdom, compassion and effectiveness.

In the November 22/29, 1996 issue of the Journal of the American Medical Association there is a consensus statement by the American College of Medical Genetics and the American Society of Human Genetics Working Group on ApoE and Alzheimer’s Disease.  They state, “There is general consensus that APOE4  is strongly associated with Alzheimer’s Disease (AD) and that when present may represent an important risk factor for the disease.  However, at the present time it is NOT recommended for use in routine clinical diagnosis nor should it be used for predictive testing.”  Have information and not use it?  Why would they say such a thing?  Consider the following:

1.       Up to 65% of individuals with Alzheimer’s Disease have the APOE4 gene.  But that means 35% or more of those with AD will not have the gene.  So a negative test does not give complete reassurance that you will not have AD.

2.       Twenty-four to 31% of people without AD may have a positive test for the APOE4 gene.  So a positive test does not absolutely mean you will have AD.

3.       The test cannot tell when you would develop AD, at age 55? 75? 95? If at all.

4.       With no effective preventive treatment, there is no therapeutic reason for screening for the gene.

5.       Health insurance companies may not want to offer health insurance to people with the APOE4 gene to minimize their risk.  Employers may not want to hire people with the gene.

At present the places doing the test are participating in further research to see how this information might be more useful.  For further information or for those willing to participate in the effort to learn more about this disease, some helpful contacts include:  The Foundation for Blood Research in Portland, ME (207-883-4131), the Alzheimer’s Association (800-272-3900), the University of Pennsylvania Medical Center (J. Kant 215-662-6550), and the University of Washington School of Medicine (G. Schellenberg 206-543-2340).

The concept of genetic testing is tantalizing, but the present reality is still quite limited.