At a preconception or early prenatal appointment, your doctor may recommend a genetic carrier screening test. A genetic carrier screening is a test that lets you know if you carry a gene for a certain genetic mutation or genetic disorder, and it is most useful for determining your likelihood of having a child with a specific genetic disorder. Carriers do not usually exhibit symptoms of the genetic disease, but are more likely to pass the mutation onto their offspring.
How to Prepare for Genetic Carrier Screening
If you or your partner have a family history of genetic disorders or belong to a particular ethnic group that is at higher risk for a particular genetic disorder, you may want to make an appointment with a genetic counselor to discuss your testing options and future plans if you test positive as a genetic carrier. If you are unsure of your family medical history or ethnic groups to which you belong, you may also want to consider meeting with a genetic counselor to discuss your likelihood of being a carrier of a genetic disorder and coordinate your testing accordingly.
Genetic Carrier Screening Process
There are two kinds of genetic disease inheritance: autosomal recessive and X-linked. When both parents are found to be carriers of a disorder that is passed on through autosomal recessive inheritance, they will have approximately a 25% chance of having a child with that disorder. When only the mother is found to be a carrier of an X-linked disorder, the child has approximately a 50% chance of being born with that X-linked disorder. For both types of disorders, usually the mother will be tested first to see if she is a carrier. If she tests positive, then the father will also undergo testing. If the mother tests negative as a carrier for all recessive and X-linked genetic diseases, then the father will likely not need to undergo testing.
The testing process for genetic disorders is quite simple and can be performed using a simple blood draw from the mother. Results are provided to your doctor within two weeks, and your doctor or genetic counselor will schedule an appointment with you to go over the results.
After Genetic Carrier Screening
A genetic counselor will be able to provide additional insight and guidance about the likelihood that your child will be born with an inherited disease, alternative options to conceive (if necessary), and how to plan for appropriate treatment for a child with an inherited genetic disorder.