Carrier Screening

Genetic Carrier Screening

We each carry two copies of every gene. A carrier is someone who has a mutation in one copy of a gene, while the other copy functions normally. Because the healthy copy compensates, carriers typically do not show symptoms. When a person has mutations in both copies of a gene, the condition may become active—this is known as autosomal recessive inheritance.

Most people are unaware they are carriers because being a carrier does not cause illness. However, if both parents are carriers of the same genetic condition, each pregnancy has a:

• 25% (1 in 4) chance of having an affected child

• 50% (1 in 2) chance of having a child who is also a carrier

• 25% (1 in 4) chance of having a child who is neither a carrier nor affected

Carrier screening is a test that identifies whether one or both parents carry a genetic mutation that may be passed to a child. Screening recommendations may be based on family history, ethnic background, or personal preference. Carrier screening is most commonly performed using a blood sample, although some tests are available using saliva. If one partner is found to be a carrier, testing of the other partner is recommended. While carrier screening can significantly reduce the chance of an undetected genetic condition, no test can eliminate the risk entirely.

At CFFM, we offer a full range of carrier screening options. Testing is available for individual conditions as well as expanded panels that include disorders such as cystic fibrosis, sickle cell disease, thalassemia, Tay-Sachs disease, fragile X syndrome, and spinal muscular atrophy.

For patients who prefer broader testing, we also offer cell-free DNA–based carrier screening, which can evaluate risk for up to 90 different recessive conditions. To learn more about carrier screening options, please visit www.mytestingoptions.com.

Ideally, carrier screening is performed before pregnancy, allowing time to understand risks and discuss reproductive options with a genetic counselor. If screening is done during pregnancy and both partners are found to be carriers of the same condition, diagnostic testing—such as chorionic villus sampling (CVS) or amniocentesis—can determine whether the fetus is affected.