Advances in genetic testing are offering women more information than ever before about their genetic makeup and are providing opportunities for empowered decision-making related to a wide range of health issues. In this recurring column, experts provide vital information about how genetic testing suits one’s individual needs, potential risks and benefits, and the role of genetic testing in advancing treatment approaches that target cancer and other diseases.
Top 5 Things to Know about DNA Testing
By Shivani Nazareth, CGC, and Caroline Lieber
A lot has changed over the past few years when it comes to DNA testing. In fact, we can now test for more than 100 diseases prior to pregnancy or predict cancers before they even develop. Researchers are using DNA testing to better target medication responses for a variety of conditions, and as the field progresses you may find yourself wondering whether DNA testing is right for you. Here are some important facts for consideration as you navigate the fast-paced world of genetic testing.
1. Your family history offers clues.
A thorough grasp of your family history can offer clues about the kind of testing that may benefit you. Encourage discussions about health history among your relatives—both male and female—to help determine if health problems such as breast cancer run in the family. If they do, genetic counseling and testing may provide a better understanding of the risks to you and your family members and what to do about them. As you gather clues, notice if there are patterns of cancer, heart disease, or other illnesses that run through the generations. Recognizing inherited patterns of disease can help the entire family. It is important to look at the health history on both sides of the family. For example, when it comes to hereditary breast cancer, your father’s side of the family is equally important. Most women don’t realize that they can inherit the breast cancer gene from their father.
2. You can use results to plan ahead.
There are a number of key times in life when genetic testing can help you plan ahead, such as if you want to have a baby or are concerned about hereditary cancers. In the case of pregnancy screening, a carrier screen performed on a sample of blood or saliva from both you and your partner can provide useful insights prior to conceiving. More than 100 rare but significant genetic diseases can be included in a carrier screen, such as cystic fibrosis, spinal muscular atrophy, Hurler syndrome, and Wilson’s disease. Some of the diseases on carrier screening panels can be improved with such early interventions as nutritional changes at birth or lining up the right medical specialists. With respect to hereditary cancers, understanding your risk ahead of time allows you to take advantage of frequent surveillance or consider risk-reducing medications, lifestyle changes, or even prophylactic surgery.
3. Carriers of genetic diseases are often healthy.
A carrier of a genetic disease is typically a healthy individual. Depending on the type of disease involved, a carrier can remain healthy but pass the disease risk to future generations, as with cystic fibrosis and spinal muscular atrophy. In the case of certain cancers, like hereditary colon cancer, a carrier is more prone to developing a cancer early in life as well as passing on the propensity. Many of us are carriers of rare diseases and do not know until we are tested. This is especially the case with recessive diseases, which can appear to skip generations. For a recessive disease to manifest, both mom and dad must be carriers of the same rare gene. Sometimes people choose not to pursue carrier screening because they have no concerning family history, but it’s important to note that more than 80 percent of children with genetic diseases are born to parents with no prior history in their families.
4. Genetic counselors can help you navigate the results.
Genetic counselors are experts in facilitating decision-making around DNA testing. They understand that each person has his or her own set of values, life goals, and experiences that define what it means to be fully informed and empowered. The decision to have genetic screening involves many factors. It is helpful to talk about the pros and cons with a genetic counselor and determine whether a screening test is right for you. Questions that may arise in a session include why you want the information, what you plan to do with the results, and how to talk to family members about the implications. If you are unable to visit a genetic counselor in person, some laboratories offer free telephone access to board-certified genetic counselors. With good counseling, you will feel empowered to understand your results and make informed health choices that are right for you.
5. It’s surprisingly affordable and often covered by medical insurance.
Just a few years ago, testing for one genetic disease (think cystic fibrosis or sickle cell disease) could cost a few hundred dollars. Advances in DNA technologies have helped reduce the cost of genetic testing so that today, for that same price or less, laboratories are offering DNA tests for large panels of genetic diseases. What’s more, many insurance plans understand the value of genetic testing in preventing the onset of disease and offer coverage for qualifying individuals.
Caroline Lieber is director emeritus of Sarah Lawrence College’s Joan H. Marks Graduate Program in Human Genetics, the country’s first and largest master’s program in genetic counseling. She has 35 years of experience in human genetics, 18 years as a clinical genetic counselor/supervisor, and 15 years in her role as an educator/administrator. She currently serves as a consultant for Counsyl, a fast-growing genomics company.
Shivani Nazareth, CGC, is director of Women’s Health at Counsyl, a DNA testing and genetic-counseling service based in San Francisco. She worked as a clinical genetic counselor for more than 10 years in New York City, most recently at Weill Cornell Medical College. Shivani obtained her graduate degree from the Icahn School of Medicine at Mount Sinai and currently serves on the National Society of Genetic Counselors’ Public Policy Committee.
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