Carrier screening checks if a person is a "carrier" for a genetic disease. This is often done as part of prenatal testing. Carrier screening also is done when a child is diagnosed with a condition to confirm that both parents are also carriers. Someone who carries a genetic change, or mutation, has one copy of the gene that works normally and one copy of the gene that does not function properly that make up their pair. The functional copy of the gene can usually do the job for the pair. Most of the time carriers are healthy which is how a recessive genetic change can be passed down through generations without anyone knowing about it.
If you decide to have carrier screening, a healthcare professional will order genetic testing to see if you are a carrier for one or more genetic diseases.
Understanding Carrier Screening Results
If you carry a genetic mutation, it does not mean that your children definitely are at risk for having a genetic disease. Both parents must be carriers of the same genetic mutation to pass on a recessive disease.
Two carriers for a particular disease have a chance their children will be born with the same condition. This chance is 1 in 4 (or 25%) each time you get pregnant. A recessive disease can be inherited, or passed down, in two ways:
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autosomal recessive way
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X-linked recessive way
Check out the Main Inheritance Patterns page for more information on how this works.
Why Should I Think about Carrier Screening?
You may want to think about carrier screening if:
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You have a family history of a specific disease. Doctors may need to do genetic testing on a relative who shows signs of the disease first. If doctors find a specific gene change in your relative who has the condition, they can look for that gene change in you.
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You have signs of a genetic condition.
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You are worried about passing on a genetic problem common to your ethnic group. Why does your ethnic group matter? Some diseases, like sickle cell disease and Tay-Sachs disease , are more common in certain ethnic groups.(Maybe here we could have a link to a page that goes over conditions that are common in certain ethnic groups? The marriage card has all of that information.)
Where Can I Be Screened?
If you are pregnant or thinking about becoming pregnant and want to learn more:
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Ask your primary care provider, or
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Talk to you obstetrician/gynecologist
Most carrier screening is based on your ethnicity and family health history. Your provider can help you figure out which carrier screening to consider. Your insurance may cover the costs of the tests. It is important to check with your plan first.
A genetic counselor can talk to you about personal and social concerns before and after screening.
