Dr. MJ Bazos MD, Patient Handout
Genetic Testing: What You Should Know
What are genes and how are they related to disease?
Genes are long molecules called DNA that are present in every cell in your body. DNA controls growth and helps you stay healthy. If your DNA is abnormal or damaged, it may not work properly, which may lead to disease. Some genetic abnormalities, or “gene mutations,” may run in families. Some just happen by chance. Sometimes one mutation can cause a person to have a disease, but most diseases are caused by a combination of genetic and environmental factors.
What is genetic testing?
Genetic testing may help to show if you’ve inherited a tendency to get certain diseases. A sample of blood or skin is usually needed for genetic testing. Genetic testing for mutations is gradually becoming available.
What does a positive test result mean?
A positive test result means that you have the mutation you’ve been tested for. If you have a positive test result, it means you may be more likely to get a particular disease than most people, but it doesn’t mean you will definitely get the disease.
What does a negative test result mean?
A negative test result means that you don’t have that particular mutation. This may mean that the disease doesn’t run in your family, or it may mean that some other gene mutation causes the disease. A negative result doesn’t mean you won’t get the disease. It only means that you’re not more likely to get the disease than other people are.
Who should be tested?
By looking at your family history, your doctor can tell if you’re likely to have a gene mutation that may contribute to disease. A disease might run in your family if a blood relative developed the disease at a young age, if several family members have the disease or if the condition is rare. People from certain ethnic groups may also be more likely to get certain diseases. If one of your family members already has the disease, that person should be tested first. This helps show which genes, if any, are associated with the disease.
How do I decide if I should get tested?
If you think you may be at high risk for an inherited disease, talk to your family doctor. Your doctor will ask you questions about your health and the health of your blood relatives. This information will help your doctor find out what your risks might be. The information your doctor gives you about your risks can help you decide whether you want to be tested.
There are two important questions you should think about before you go through genetic testing:
  1. What can I gain by being tested?
Here are some reasons you might want genetic testing:
  1. Are there any negative effects of testing?
Here are some reasons you might not want to know that you may be at risk for a certain disease:
The National Society of Genetic Counselors : www.nsgc.org
The National Cancer Institute: www.nci.nih.gov