A Doctor’s Crystal Ball
Genetic testing can reveal your chances of getting a hereditary disease. Do you dare find out your future?

By Victoria Dolby Toews, MPH

How would you like to peer into the future to find out if you might develop a certain disease? It may sound far-fetched, but with the help of genetic testing—an innovative technique that examines your DNA to check for the potential of hundreds of hereditary diseases—that’s exactly what many Americans are doing.

Take Donna Dean, for example, a gutsy Texan who last year, at age 35, decided to get tested to see if she carried the so-called breast cancer genes, named BRCA1 and BRCA2. A woman with one of these two genes has up to an 85 percent chance of developing breast cancer in her lifetime and nearly a 30 percent increased risk of developing ovarian cancer. Dean’s mother and grandmother both died of breast cancer and several of her cousins had either been diagnosed with the disease or tested positive for the genes, which are thought to be responsible for 5 percent to 10 percent of all breast cancer cases. “As I suspected, my DNA did contain one of the breast cancer gene mutations,” says Dean, whose name, along with the other patients mentioned in this story, has been changed to protect her privacy.

Six months ago, Dean took a drastic step to reduce her risk of getting cancer: She underwent surgery to remove her presumably healthy breasts and ovaries before they had a chance to grow cancer cells. During her surgery, doctors made a shocking discovery: Although she had absolutely no symptoms, Dean’s ovaries had already advanced to stage III ovarian cancer. If she hadn’t sought treatment when she did, Dean’s doctor predicts she would have had about six more months to live. “If genetic testing weren’t available I would be dying right about now,” says Dean. “By the time I had any symptoms, it would have been too late for me.”

Why Some Want To Know
Although many people may not take such extreme preventive measures as surgery, genetic testing can spur them to stay informed about ways to decrease their chances of developing a particular disease through frequent screenings and diet and lifestyle changes. Remember that being predisposed to a disease does not mean a person will definitely get the disease; it only increases the chances. And, of course, testing may reveal the good news that a particular disease was not passed down the family tree after all.

“Many women are all too aware of the toll breast and ovarian cancer is taking on their female relatives, watching them die young,” says James C. Coyne, PhD, director of behavioral sciences research at Abramson Cancer Center of the University of Pennsylvania in Philadelphia. “For these women, genetic-susceptibility testing can be a long-awaited tool for understanding and managing their personal risk. For women with such family histories, it can be a relief to discover they don’t carry the altered gene. But even for those who find they do indeed carry the altered gene that causes cancer in their families, they are now armed with that knowledge and can take steps to manage or reduce their risk.”

Genetic testing might even help some women avoid unnecessary surgery. “Before the genetic test was available, my aunt had a prophylactic double mastectomy that removed her disease-free breasts based simply on family history,” says Janet Nutter, a woman from Houston, Texas, who herself tested positive for the breast cancer gene. “She has since been tested for the gene and found out she doesn’t have it. Genetic testing, had it been available when she was younger, would have avoided that unnecessary surgery.”

How Screening Works
The field of genetics has existed since the 1800s, but it has only been since the human genome was mapped in 2000 that genetic testing has rapidly advanced. In fact, the advances have come so fast it doesn’t cost much to decipher your cell structure. Some insurers opt to cover the costs of genetic testing with no direct cost to you. But for many people, it remains an out-of-pocket expense. Costs vary: $200 to check for hemochromatosis (a potentially fatal iron-overload disease); $300 for cystic fibrosis; $400 to $2,000 for one of the breast-cancer gene mutations; and $2,500 for more obscure diseases. It can take as little as a week, or up to several months or more, to get the results of various genetic tests.

Most testing procedures are simple. Many use a sample of your blood; others require a swab from your inner cheek. In some cases, testing your genes is as easy as swishing a special wash in your mouth first thing in the morning and then sending that sample to a lab. An increasing number of tests are available through mail order or in stand-alone genetic laboratories. However, the interpretation of your test results are most meaningful and best understood when ordered and interpreted by a health care professional who knows your full personal and family history.

Genetic counselors fit the bill in this regard. To start, a genetic counselor will analyze your family history and risk for inheriting a given disease to determine if testing is necessary in the first place. (Even though there are more than 900 genetic tests available, it only makes sense to test for a disease that runs in your family.) The counselor will then work with you through the entire testing process both to interpret and help you deal with the results. Counselors will also advise you about the importance of sharing your test results with the rest of your family so that they can use the information to make decisions about their own disease risk and decide whether or not to undergo genetic testing themselves.

“Talking to a genetic counselor was essential for me,” says Sherri Mead from New Orleans, who has an extensive family history of breast cancer. “It is really hard to get positive results for such a serious disease,” she explains, “but genetic counselors help set you up for dealing with the results before they even arrive. They talk about options, statistics, and help put everything into perspective.”

The National Society of Genetic Counselors can help you locate a counselor in your area (see “Genetic Testing Resources").

The Downside Of Testing
Genetic testing is viewed positively when it helps people treat a terrible disease before they ever get sick, but the picture is less rosy if your family has a hereditary disease that is untreatable. It can be emotionally devastating to find out that you have a fatal or untreatable genetic disease, such as Huntington’s disease or Alzheimer’s. Worrying about an illness that may or may not manifest can also affect the rest of your life. This may explain, in part, why in families with a certain genetic disease, only half choose to undergo genetic testing (Archives of Internal Medicine, 2003, vol. 163, no. 5).

Even so, Coyne contends, “Some mental health professionals had it wrong when they predicted that genetic testing was a serious psychological threat.” According to his research on women with the breast cancer gene, on average, women who get tested and find that they have the altered gene are no more at risk for depression and anxiety a few weeks later than women drawn from the general population (American Journal of Medical Genetics, 2003, vol. 116A, no. 3). “Women deal better with this information than many professionals anticipated,” he says.

With genetic testing also comes a certain amount of responsibility. “Because genetic testing has implications for the entire family, it’s important to weigh that into the decision,” says Sue Friedman, executive director of Facing Our Risk of Cancer Empowered (FORCE), a nonprofit organization that helps women who are at high risk for breast and ovarian cancer. “Genetic counseling can help the individual clarify these issues and come to a decision that is right for them.”

Dean, whose ovarian cancer was caught in the nick of time, agrees. “You do have a responsibility to share your results with your family,” she urges. “It can feel very private, but you must share the results. My cousin told me about her positive results, which led me to testing.”

There is also a small concern that test results could be misinterpreted. For example, misinterpreted test results for the cystic fibrosis gene have been reported, leading to undue stress for expectant couples. This is why it is important to work with experienced health care professionals who are very familiar with genetic tests and how to interpret the sometimes-complex results.

Genetic testing could be a Pandora’s box that ends with your health insurance discriminating against you based on your genes. Genetic testing could also be a Pandora’s box that ends with your health insurance discriminating against you based on your genes. Could seeing into the future create a genetic underclass that insurers cover only with sky-high rates or deem too risky to cover at all? Such questions are troubling, leading many states to enact legislation, often referred to as “genetic information nondiscrimination laws,” to protect individuals who seek testing. (See “Genetic Testing Resources” to learn about your state’s laws.) Many people are sidestepping the potential problem by paying for genetic testing out of their own pocket if their state doesn’t have protection laws in place.

Whether you view genetic testing as an empowering medical choice or as an unwelcome look into your physical future, it’s an important tool to consider. Each of us now has the chance to learn more than ever before about our health and the health of our children. But in the end, the choice to tap that knowledge is yours.

Health writer Victoria Dolby Toews, MPH, received her masters of public health from Portland State University, in Oregon.