What is carrier screening?
For those who aren’t already familiar with the process, here’s the full carrier testing definition: performed on a completely voluntary basis, carrier screening identifies the presence of recessive genes that may cause your baby to be more susceptible to certain diseases.
If you and your partner are attempting to conceive but remain concerned about a family history of chronic conditions, ask your doctor if this test is right for you. That way, you’ll be better equipped to make decisions based on your chances of passing on a genetic disorder.
Carrier screenings involve collecting a small sample of your tissue. This step is usually as quick and painless as doing a cheek swab. In some cases, a blood or saliva sample is also taken.
What are recessive diseases?
Genes always come in pairs. For each pair, the offspring receives one copy from the mother and one copy from the father. It’s possible for a child to develop a recessive disease if they happen to inherit two copies of an abnormal gene. Note that the inheritance of just one copy of an abnormal gene typically will not result in a genetic disorder.
It’s possible for a child to develop a recessive disease if they happen to inherit two copies of an abnormal gene.
Of all the recessive diseases discovered so far, cystic fibrosis is one of the most well-known. Those diagnosed with this condition experience difficulty breathing and often battle persistent lung infections. Sickle cell anemia is also caused by the combination of two recessive genes and causes chronic anemia, recurring infections, and several other symptoms.
Who is a carrier?
Carriers of recessive diseases only have one copy of the abnormal gene that can potentially be passed on to their biological children.
What happens if your baby receives just one copy of an abnormal gene (either from you or your partner)? If this happens, chances are they won’t display any symptoms of the genetic disorder, and in the rare event that they do, their symptoms would be very mild.
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Carriers of recessive diseases only have one copy of the abnormal gene that can potentially be passed on to their biological children.
Keep in mind, though, if your children inherit one copy of the abnormal gene, they in turn become carriers themselves.
What are the chances of carrying a genetic disease?
While it’s difficult to accurately predict your risk for carrying a genetic disease, contributing factors include ethnicity and family history.
Tay-Sachs disease, for example, occurs more frequently in individuals with Cajun, French Canadian, or Eastern/Central European Jewish heritage. Sickle cell disorders, on the other hand, have a higher incidence rate among African Americans.
While it’s difficult to accurately predict your risk for carrying a genetic disease, contributing factors include ethnicity and family history.
Family history plays a significant role as well. If your parents or grandparents suffered from a genetic disease, it may be wise to consider carrier screening.
What if both partners are carriers of the same genetic condition?
If you and your partner opt to undergo carrier testing, you may find out you’re both carriers of the same abnormal gene. However, it’s not an absolute certainty your child will develop the disorder, or that they will be severely affected by it.
When both parents carry the same recessive gene, your child has a:
- 25 percent chance of inheriting two copies of the abnormal gene, increasing their risk for developing the disease
- 25 percent chance of inheriting two normal, healthy genes
- 50 percent chance of inheriting one copy of the abnormal gene, thereby becoming a carrier themselves
The signs and symptoms associated with chronic conditions vary greatly from one individual to the next, so it’s hard to predict the exact impact it will have on your child if they inherit a pair of abnormal genes.
When to get prenatal testing
Carrier screenings can be performed before or after you become pregnant. Getting screened before you are pregnant gives you a wider variety of options and more time to contemplate next steps. But there’s certainly nothing wrong with doing it afterwards, either.
If you learn through carrier testing before getting pregnant that you and your partner are both carriers, you have a few options. Some couples decide to use donor eggs or sperm and in vitro fertilization. If you decide to do this, it’s possible to test the embryos for specific genetic disorders prior to implantation.
Carrier screenings can be performed before or after you become pregnant. Getting screened before you are pregnant gives you a wider variety of options and more time to contemplate next steps.
Some couples choose not to pursue pregnancy at all. And other couples opt to undergo carrier screening during the first trimester or at a later time in the pregnancy. By this point, however, your options will be somewhat limited.
How to order carrier testing
If you’re interested in ordering carrier testing, consult your doctor. They’ll provide detailed information on the test and how it works.
They may even recommend targeted carrier screening based on your family history or ethnic background. Furthermore, expanded carrier screening is capable of identifying over 100 different types of genetic disorders.
With a better understanding of the carrier testing definition, you and your partner will be able to make informed decisions about your family’s future.
References
History of updates
Current version (20 July 2020)
Published (20 September 2019)
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