Your family medical history, all organized and updated, will be put to good use if you ever decide to undergo genetic testing. There is a lot of nonsense out there about the do’s and don’t’s and why’s and wherefore’s of genetic testing. There is nothing sinister or subversive about it, nor it is a way to solve all your future medical issues. It’s a tool, a valuable one, should you and your doctor decide to add it to your health care kit.
Such testing can provide very important information for diagnosing and treating illness, and even for preventing illness, but it has its limitations. A negative result does not guarantee that you will never have a specific disorder; a positive result in an otherwise healthy person does not always mean a specific disease is inevitable. There is much art involved in interpreting results – remember, it’s the art of medicine just as much as it’s the science of medicine that our physicians and health care professionals study and practice.
The testing itself involves an examination of your DNA, the instructions for your body’s functions carried in a chemical database. Changes or alterations in your specific genes, as revealed by testing, may cause or predict disease or illness.
- Presymptomatic and predictive testing. Here’s where your family history is really useful. If you have a family history of a genetic condition, genetic testing done before you have any symptoms may show your risk for developing that condition.
- Diagnostic testing. Suppose you have an illness whose symptoms indicate an underlying disease caused by genetic alterations. Testing can reveal if you indeed have the suspected disorder. Such disorders include adult polycystic kidney disease, hemochromatosis (iron overload) and Charcot-Marie-Tooth disease.
- Pharmacogenetics. This type of testing may help sort out which medication and dosage would be most beneficial and effective for you if you are managing a specific disease or health condition.
- Carrier testing. This is the type of testing done before you have children, particularly if you (or your partner) have a family history of a genetic disorder – sickle-cell anemia or cystic fibrosis, for example. This kind of testing may also prove useful if you are part of an ethnic group that has a high risk of a specific genetic disorder. The testing may help you ascertain if your carry a copy of an altered gene, something that may put future children at risk of developing the disease.
- Prenatal testing. There are tests that can detect some abnormalities in the genes of a developing unborn child. Spina bifida and Down syndrome are the two genetic disorders most often screened for by prenatal genetic testing.
- Preimplantation testing. This test, also known as preimplantation genetic diagnosis (PGD), requires that a child be conceived through in vitro fertilization. It is a technique used to lower the chances of having a child with a particular genetic disorder. In vitro fertilization involves removing eggs from the woman and then fertilizing the eggs with donor sperm outside the body to create embryos. These embryos are then screened for abnormalities. Finally, embryos without genetic abnormalities are implanted in the uterus.
- Newborn screening. Here we have the most common type of genetic testing. In fact, in the US, all states require newborns to be tested for certain gene abnormalities that cause specific conditions. This type of testing is of critical importance; if results show a disorder such as hypothyroidism or phenylketonuria (PKU), vital treatment can begin immediately.
- Be sure your family medical history is as accurate and comprehensive as possible.
- Go over your history with your doctor or a genetic counselor.
- Ask questions at that meeting about any concerns or questions you may have about the testing you are undergoing.
- Know your options, depending on the test results, before you proceed.
- Be sure to go over your decision to be tested with your family (they may be affected, too).
- Check with your insurance provider to see what will be covered. And know that some health insurers do not pay for genetic testing.
- The federal Genetic Information Nondiscrimination Act (GINA) helps prevent health insurers and/or employers from discriminating against you based on your test results and most states afford additional protection.