I have previously blogged about some of the complexities of genetic testing for carriers of ApoE4 who are at risk for developing Alzheimer's disease (see: New Gene Testing a Threat to Insurance Companies; How They Might Respond). A recent article in the New York Times addressed this same issue (see: What if You Knew Alzheimer’s Was Coming for You?). Below is an excerpt from it. The article is quite long so follow the link to read the whole thing if you are interested.
Six years ago, at age 49, Julie Gregory paid an online service to sequence her genes, hoping to turn up clues about her poor circulation, blood-sugar swings and general ill health. Instead she learned she had a time bomb hidden in her DNA: two copies of a gene variant, ApoE4, that is strongly linked to Alzheimer’s. Most Americans with this genotype go on to develop late-onset dementia.....In the difficult months after her genetic test, Ms. Gregory “wanted to be with people who were going through the same devastation,” so she sought out other ApoE4 carriers. In 2013, she and a few others started a nonprofit group and created a website (ApoE4.info) where the community could gather. Today the group has more than 2,000 members. They pore over medical journals, reach out to top researchers in the field and share notes about their experiments with diet, exercise and other lifestyle modifications. Many of the members maintain their anonymity for fear of being “outed” as carriers of the gene variant....Jason Karlawish, a professor of medicine and neurology at the University of Pennsylvania, studies how people at high risk of Alzheimer’s disease cope with that knowledge....Many health organizations discourage patients from learning their ApoE genotype. They warn that people may not be able to cope with bad news or will misinterpret the results. But according to Theresa, a member of the ApoE4 community...., it is paternalistic to decide how someone else should feel about the test. “My attitude is that you have to know the facts, analyze them and deal with them,” she said. “The sooner you know your gene status, the sooner you can start doing something about it.”
Here is more information about ApoE4 from the NIH web site (see: Alzheimer's Disease Genetics Fact Sheet):
Researchers have not found a specific gene that directly causes the late-onset form of the disease. However, one genetic risk factor—having one form of the apolipoprotein E (APOE) gene on chromosome 19—does increase a person's risk. APOE comes in several different forms, or alleles:
* APOE ε2 is relatively rare and may provide some protection against the disease. If Alzheimer's disease occurs in a person with this allele, it usually develops later in life than it would in someone with the APOE ε4 gene.
* APOE ε3, the most common allele, is believed to play a neutral role in the disease—neither decreasing nor increasing risk.
* APOE ε4 increases risk for Alzheimer's disease and is also associated with an earlier age of disease onset. A person has zero, one, or two APOE ε4 alleles. Having more APOE ε4 alleles increases the risk of developing Alzheimer's.
Bioethicists have long been discussing the risks involved in sharing genetic information with individuals, particularly data with serious implications for future health. Currently, a number of web sites such as 23andMe and AnecestryDNA will analyze portions of your genome but with a genealogical or genetic trait orientation rather than one related to diagnosing diseases. However, the former company is now authorized to sell some tests for genetic risks to consumers (see: F.D.A. Will Allow 23andMe to Sell Genetic Tests for Disease Risk to Consumers). Genetic studies oriented toward disease predisposition are also increasingly available in hospital settings that potentially could lead to the inadvertent discovery of, say, the presence of ApoE4. Some individuals would prefer to gain knowledge about such genetic information whereas others would be stressed by it. Everyone therefore needs to be cautious when ordering genetic testing when there is the possibility of unveiling unfavorable information.