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Carrier Blood Test for Genetic Screening



Just about everyone carries a gene for at least one genetic disorder — even if it’s never shown up in your family history. If you have a mutation in just one set of genes, you’re what’s known as a “carrier”: you’re carrying the genes for a genetic disorder but have no signs of the disease. Most carrier screening is for recessive disorders. It takes two genes to pass on these mutations. Our carrier blood test will determine what, if any, mutations you and your partner may be carriers for. This will determine if it’s possible for you to pass on any of these diseases to your child. If both you and your partner are carriers, further testing and evaluation are necessary to ensure you don’t pass this disease to your future child.

Rarely, a condition (like Huntington’s disease) can be caused by a mutation in just one set of DNA. But in most cases — including cystic fibrosis and sickle cell anemia — it takes a mutation in both sets of DNA, one from the egg and one from the sperm, for a child to actually be affected by a genetic disease.

If both parents are carriers of a recessive gene for a disorder, there is a 25% (1-in-4) chance that their child will get the gene from each parent and will have the disorder. There is a 50% (1-in-2) chance that the child will be a carrier of the disorder—just like the carrier parents.

Typically, we will test one partner first (usually the one with a uterus). If test results show that the first partner is not a carrier, then no additional testing is needed. If test results show that the first partner is a carrier, the other partner is tested.

Parental genetic screening

There are two components of genetic testing: 1) parental screening and 2) embryo testing. Parental screening is when a genetic evaluation is done on future parents to determine if there is a known or suspected risk of passing on a genetic disease to offspring. Embryo testing can be done during IVF to specifically evaluate whether an embryo has specific genetic risk(s). Screening pre-pregnancy offers the advantage of identifying patients at risk of having children with a genetic disease. Patients at risk of having children with specific genetic disease can be educated about reproductive options including interventions such as preimplantation genetic testing of embryos. 

The American College of Obstetricians and Gynecology (ACOG) and the American Society for Reproductive Medicine (ASRM) recommend: A thorough genetic screening including: a family history of known genetic disorders, birth defects, mental disorders and breast, ovarian, uterine and colon cancer. Genetic carrier screening: a blood or saliva test that allows patients to find out if they are carriers of genes that could cause disease in offspring. Genetic counseling for patient(s) diagnosed as genetic disease carriers. The goal of which is to educate and review reproductive options. 

What genetic carrier screening is performed at Mate?

Mate offers expanded carrier screening that is pan-ethnic. Expanded means the number of genes tested are much larger than the original genetic screening tests. Carrier screening means that the tests are designed not to look for diseases in a patient undergoing testing, but to look for diseases that a patient is at increased risk of passing on to their child. Pan-ethnic means testing is inclusive, regardless of patient ethnicity. 

Who should be screened?

Screening is optional but highly recommended as it allows patients to be fully informed and educated about their risks. Many patients think that if they do not have a personal or family history of  genetic disease that their children will not have an increased genetic risk. Some patients however are silent carriers of a genetic mutation. Silent means they exhibit no symptoms. Silent genetic mutations may or may not cause disease in their children depending on how that gene works. One way children may inherit a genetic disease is if both the egg and the sperm harbor the same genetic mutation (This is called autosomal recessive inheritance). Another way children may inherit a genetic disease is if the X chromosome from the egg harbors a genetic mutation and the embryo receives a Y chromosome from the sperm (This is called X-linked inheritance).