Carrier screening is a type of genetic test that can tell you whether you carry a gene for certain genetic disorders. For some genetic disorders, it takes two genes for a person to have the disorder. These are called recessive disorders. A carrier is a person who has only one gene for the disorder, therefore they do not have any signs or symptoms but can pass the gene on to their children. 

If both parents are carriers of a recessive gene for a disorder, there is a 25% chance that their children with the gene from each parent and have the disorder. There is also a 50% chance that the children will be carriers, just like the parent(s). 

Carrier screening is usually done by testing a blood or saliva sample. It can be done prior to or during pregnancy. Generally, one partner is tested first and if they are not a carrier then no testing needs to be done on the other partner. If the first partner is a carrier, the other partner is tested. Because carrier testing is testing your genes, it only needs to be done once. 

Testing is available for a limited number of diseases and is offered to everyone, although some individuals are at higher risk for certain disorders depending on family history, race or ethnic background. 

• Cystic Fibrosis (CF) - An autosomal recessive disease that affects the lungs and gastrointestinal systems. It results in chronic lung infections that causes breathing problems and can result in poor growth/weight gain as a young child. One out of every 25-60 people will be carriers, depending on ethnicity. Offered to all pregnant women and those considering pregnancy. 

• Spinal Muscular Atrophy (SMA)- Another autosomal recessive disease that leads to wasting/deterioration of muscles and weakness. It can be severe and cause a very shortened lifespan, though there are milder forms. One out of every 40-60 people will be carriers, depending on ethnicity. Offered to all pregnant women and those considering pregnancy. 

• Fragile X - An X-Iinked genetic disorder that results in intellectual disability. The chances of being a carrier are as high as one in 80 if there is a family history of intellectual disability but is much lower for women with no risk factors. Carrier screening is recommended for women with a history of fragile-X syndrome or intellectual disability suggestive of fragile X-syndrome who are pregnant or considering pregnancy. 

• Duchenne Muscular Dystrophy— An X-linked genetic disorder that causes progressive muscle weakness with symptoms usually starting around age 4-6 and generally affects males. DMD can occur as an inherited or sporadic mutation 

If carrier testing is positive, you will be referred to a genetic counselor to discuss your options for the current or future pregnancy.