Genes are the foundation of our physiology. They contain the code that determines what we look like and how our bodies function. Scientists now believe all disease is the result of mutations that occur within our genes. This knowledge has spurred the rapid development of genetic testing.
Currently, there are genetic tests for 1,400 diseases and many more are in the research pipeline. While the test itself is usually quite simple (a small amount of blood is drawn or a bit of tissue is swabbed from inside your cheek), understanding what the results are actually telling you can be difficult.
As a matter of fact, scientists themselves are not always sure how to interpret genetic test results. Still, in certain circumstances, genetic testing can help you make informed decisions about your health and it may even save your life.
Here’s what you can learn from a genetic test
You can pick up telltale clues from testing your genetic makeup; among them:
If you have symptoms of a certain disease, a genetic test can verify your diagnosis. If you’re suspected of suffering from an illness with an identified gene mutation, genetic testing can confirm you have that alteration in your genes.
For instance, Charcot-Marie-Tooth disease causes muscle weakness in a person’s arms and legs. Doctors know the disease is caused by a mutation in the genes that are responsible for how our nerves work. They also know the alteration that causes Charcot-Marie-Tooth disease is inherited, passed from blood relative to blood relative.
Genetic testing can tell you if you have a high risk for developing a disease. If your family has a high incidence of a certain disease — even if you don’t have symptoms of that disease — a genetic test can tell you if you have the genetic mutation for that disease.
This type of predictive or presymptomatic testing is done for many diseases including breast cancer, Graves disease (an autoimmune disease that results in an overactive thyroid), and Huntington’s disease (a progressive disease that destroys nerve cells).
You can find out whether or not you carry a genetic mutation for a disease that you can pass on to your children. If there’s a certain disease that runs in your family, you can give that illness to your children, even if you don’t have the condition. Sickle-cell anemia (a red blood cell disorder) and Tay-Sachs (a fatal nervous system disease) are two examples.
Genetic tests can provide insight into the health of your unborn child. If you’re pregnant, your doctor may recommend prenatal testing for your unborn baby. This form of genetic testing can determine if your child has already developed a certain condition, such as down syndrome or spina bifida (an abnormality that causes spinal cord and backbone defects). Prenatal testing can also tell you if your baby carries the mutation for inherited diseases, such as sickle-cell anemia and Tay-Sachs.
You can learn if your newborn has certain genetic mutations that need be treated before they develop into disease. All states require that newborns be tested for at least 21 different mutations. Left unattended, these gene defects can cause a wide-range of health difficulties, including heart problems, infections, hearting loss, and mental retardation.
Genetic tests can indicate how well a certain drug will work in your body. Everyone is different and scientists are discovering that a person’s particular genetic makeup can play a role in how a person responds to a certain drug. For instance, the genetic test results of patients suffering from chronic myelogenous leukemia can tell doctors whether or not they’ll respond to a drug called imatinib.
Here’s what a genetic test can’t do
A genetic test isn’t a crystal ball. The results can tell you if you have the propensity to develop a certain disorder but, in most cases, that’s where the insight ends. If you decide to undergo genetic testing, be aware of these limitations:
A genetic test can’t tell you whether or not you’ll actually develop a disease, even if you have the mutation.
A genetic test can’t tell you how slowly or quickly a disease will progress if you do begin to have symptoms.
A genetic test can’t predict the severity of your symptoms.
Proceed with caution if you’re considering taking one of the many genetic tests that are being marketed directly to consumers via mail order. The quality and accuracy of these tests can vary widely. Be sure to talk with your doctor before undergoing any type of genetic testing.