Hand holding an image of a DNA strand
Genetic testing can reveal changes (or mutations) in your genes that may cause illness or disease, including over 2,000 rare and common conditions.

Genetic Testing: Prenatal, Diagnostics, Carrier and More

Genetic testing can reveal changes (or mutations) in your genes that may cause illness or disease, including over 2,000 rare and common conditions. It can provide valuable information for diagnosing, treating and preventing illnesses, but it is limited.

You may get a positive result for a particular disease, but there is also a good chance you will not ever develop that disease. The opposite is also true – your genetic test may not indicate a particular condition, but that is not a guarantee.

Also, there is the appeal of home genetic tests, which you may learn something about your future health risks with a test that is easy and affordable. However, it is often not identical to clinical genetic testing with a physician or a genetic counselor.

Genetic testing should involve a discussion with your doctor, a medical geneticist or a genetic counselor about your results, what they indicate and what you can do with them.

Genome Sequencing

In some cases, genomic testing is advised when a genetic cause is still suspected yet genetic testing has been inconclusive. Your genome is made up of the DNA in all of your genes. Genomic testing can help identify genetic variants that relate to your health.

Why Have Genetic Testing?

Genetic testing helps to determine the risk of developing certain diseases and can also provide a guide toward appropriate medical treatment. You can find different types of genetic testing below.

1. Diagnostic Testing

It identifies a genetic condition or disease that a person currently has or may develop in the future. For example, the results may help in treating and managing a disorder like asthma or bipolar disorder.

2. Presymptomatic and Predictive Testing

This test identifies genetic variations of a disease if you have a family history of a genetic condition. For instance, you can learn, if you have a genetic risk for a certain type of colon cancer. This new-found information may help you make decisions about making lifestyle changes to help prevent that disease.

3. Carrier Testing

This test lets you know if you carry a genetic change that could cause a disease. Carriers can pass along the genetic variation to their children, yet never develop it themselves.

4. Pharmacogenetics

If you have a certain disease, genetic testing can help determine what medication and dosage will be most effective for you.

5. Prenatal Testing

This is offered during pregnancy to help identify fetuses that have certain diseases.

6. Newborn Screening

Used to test babies one or two days after birth, it helps find out if they have certain conditions known to cause problems with health and development.

7. Preimplantation Testing

This is done in conjunction with in vitro fertilization to determine if embryos for implantation carry genes that could cause disease.

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What Does Genetic Testing Involve?

  • Cheek swab.
  • Blood sample.
  • Pricking a baby's heel for blood sample.
  • Amniocentesis to collect a small amount of amniotic fluid.
  • Chorionic villus sampling of a tissue sample from the placenta.

What Are the Risks?

Prenatal testing, such as amniocentesis or chorionic villus sampling, has a small risk of pregnancy loss.

It can have emotional, social and financial risks as well. Discuss all risks and benefits of genetic testing with your doctor, a medical geneticist or a genetic counselor before you have a genetic test. Also, before you have a genetic test, check with your insurance provider to see what will be covered.

In the U.S., the federal Genetic Information Nondiscrimination Act of 2008 (GINA) helps prevent health insurers or employers from discriminating against you based on test results. Under GINA, employers cannot discriminate based on genetic risk.

However, this act does not cover insurance companies, including life, long-term care or disability insurance. Most states offer additional protection.

No matter what the results of your genetic testing, talk with your doctor, medical geneticist or genetic counselor about questions or concerns you may have. This will help you understand what the results mean for you and your family.