Genetics and Illness: What's Your Fate?
If you have a parent or sibling with heart disease, cancer, or another serious and possibly inherited condition, does that mean you are doomed to the same fate?
Growing volumes of research explain the role that genes--the inherited material that forms your body's blueprint--play in some diseases. Often, your lifestyle and environment--including what you eat and breathe--can combine with disease-prone genes to make a potential disease a reality.
Know your family history
Being aware of your family history tells you about what diseases you may be at special risk for and gives you a chance to delay or control them. Researchers think most cancers, for example, result from “two hits.” You inherit one normal gene from one parent and one cancer gene from your other parent. There are two major types of cancer genes, oncogenes and tumor suppressor genes. You might have one type of cancer gene, but your normal gene protects you from cancer. If lifestyle and environmental factors knock out the normal gene, you may develop cancer.
Improving the odds
Ther are things you can do to help your body's efforts to undo any genetic damage:
That's good advice for anyone. But it's particularly true if you have a family history of certain ailments, such as heart disease, certain cancers, and diabetes. It's even more true if close relatives developed those diseases at a young age.
Follow your doctor's recommendations for health screenings that could determine your risk and detect warning signs or the early stages of a disease.
Researchers believe heart disease has its own as-yet-unidentified genetic component, but it's hard to separate it from other inherited traits. Family histories of high cholesterol, diabetes, or high blood pressure are risk factors for heart disease. You have a significant family history if your father or brother developed heart disease before age 55 or your mother before age 65.
To assess your risk, get your cholesterol and triglycerides checked. Elevated triglycerides are associated with ischemic heart disease and heart attacks. Get your blood pressure checked yearly, or more often if you have high blood pressure. Blood pressure checks detect hypertension. Electrocardiograms and stress tests are checked if you are at higher risk for heart disease or if you are having symptoms.
For a healthier heart, lower your cholesterol, exercise and reduce your fat intake to maintain your ideal weight, seek treatment for hypertension or diabetes, and control your stress. If you smoke, stop.
The rule of thumb for many cancers: The younger your parents or siblings were when they developed the cancer, and the more members of your family who have developed the cancer, the greater your risk.
Colorectal cancer. Familial adenomatous polyposis (FAP), which causes colon polyps by the hundreds, accounts for only a small percentage of colorectal cancers. But FAP almost invariably leads to colorectal cancer by the time a person is in his or her 40s. If you have relatives with FAP, your doctor may recommend screening as early as age 10.
Breast cancer. If either your mother, daughter, or sister has had breast cancer, your risk increases two to three times. And if a woman carries one genetic mutation (in the BRCA1 or BRCA2 genes), her risk can be 60 percent. Nonetheless, only about 5 to 10 percent of breast cancers seem to be caused by currently recognized genetic mutations. If you have a family background, talk to your doctor about early screening.
Prostate cancer. Some investigators believe the majority of men over age 80 have at least microscopic traces of prostate cancer. You need to be particularly on guard, however, if a close relative died of prostate cancer before age 50. If you have a family background, talk to your doctor about early screening.
The American Cancer Society says that a low-fat diet that includes five daily servings of fruit and vegetables, especially tomatoes, may help prevent prostate cancer.
Blood tests can help
It's not too fanciful to envision the day when a simple blood test can probe deeply into your genetic makeup, predicting your future health. With near certainty, you may know the diseases you'll get or face a higher risk of getting.
Already, tests can identify carriers of inherited diseases that require changed genes from both parents, such as sickle-cell anemia and Tay-Sachs disease. Amniocentesis, an analysis of the amniotic fluid surrounding a fetus, can uncover genetic conditions like Down syndrome.
The 15-year effort to map the body's genetic structure continues to pinpoint genes responsible for diseases. With this work, the possibility of identifying people at risk--and perhaps developing gene therapy to eliminate that risk--rises.
For now, the multitude of genetic, lifestyle, and environmental factors believed to cause many of the major diseases do not have available genetic testing. The best things a person can do to prevent or decrease the risk for these genetic diseases remain unchanged:
Get the appropriate diagnostic screening as indicated by the U.S. Preventive Services Task Force or as recommended by your health care provider.
Maintain a healthy weight.
Get regular moderate to vigorous exercise.
Eat 2-1/2 cups of vegetables and 2 cups of fruits each day.
Eat a low-fat diet.
Don’t smoke or use other tobacco products.
Avoid excess alcohol.
Avoid work-related or environmental exposures to known carcinogens by using appropriate protective gear, particularly at work.
Use appropriate sun protection and make sure your children DO NOT GET SUNBURNED.
If you have specific genetic diseases in your family, such as ataxia-telangiectasia, Peutz-Jeghers syndrome, or FAP, talk to a geneticist.
- Clark, Heather, MS, CGC
- newMentor board-certified, academically affiliated clinician