Skip to content

    Genetics

    Font Size
    A
    A
    A

    Carrier Identification

    Every person carries two copies of most genes (one copy from the mother and one from the father). A carrier is a person who has a change in one copy of a gene. The carrier does not have the genetic disease related to the abnormal gene. A carrier can pass this abnormal gene to a child. Carrier identification is a type of genetic testing that can determine whether people who have a family history of a specific disease, or who are in a group that has a greater chance of having a disease, are likely to pass that disease to their children. Information from this type of testing can guide a couple's decision about having children.

    For many genetic disorders, carrier testing can help determine how likely it is that a child will have the disease:

    Recommended Related to Pregnancy

    Top Pregnancy Health Stories of 2007: Readers' Choice

    How to handle embarrassing pregnancy symptoms? Can you exercise -- and what should you eat -- while pregnant? And how do you get that pregnancyskin glow? You'll find those topics on this list of the 10 most viewed pregnancy health stories on WebMD for 2007. 6 Embarrassing Pregnancy Symptoms Pregnancy Symptoms: What They Never Told You Foods to Avoid When You're Pregnant Pregnancy: Healthy Eating for Two Toxins and Pregnancy ...

    Read the Top Pregnancy Health Stories of 2007: Readers' Choice article > >

    • If both parents carry the abnormal gene, there is a 1-in-4 (25%) chance that their child will have the disease and a 2-in-4 (50%) chance that their child will be a carrier of the disease (but will not have it). There is also a 1-in-4 (25%) chance that the child will not get the abnormal gene and so will not have the disease nor be a carrier.
    • If only one parent carries the abnormal gene, the child has a 1-in-2 (50%) chance of being a carrier but almost no chance that he or she will have the disease.

    Examples of screening tests to identify carriers for specific genetic disorders include:

    • Cystic fibrosis carrier screening. This test identifies the most common changes (mutations) in the cystic fibrosis transmembrane regulator (CFTR) gene. Many couples planning to become pregnant have this type of screening to determine whether either or both of them carry a defective CFTR gene.
    • Tay-Sachs test. This test is used to identify Tay-Sachs carriers. People of Ashkenazi Jewish or French-Canadian descent or those who have a family history of Tay-Sachs disease may choose to be tested to see if they are a Tay-Sachs carrier.
    1

    WebMD Medical Reference from Healthwise

    Last Updated: March 12, 2014
    This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.
    Next Article:

    Hot Topics

    WebMD Video: Now Playing

    Click here to wach video: Dirty Truth About Hand Washing

    Which sex is the worst about washing up? Why is it so important? We’ve got the dirty truth on how and when to wash your hands.

    Click here to watch video: Dirty Truth About Hand Washing

    Popular Slideshows & Tools on WebMD

    disciplining a boy
    Types, symptoms, causes.
    fruit drinks
    Eat these to think better.
    embarrassed woman
    Do you feel guilty after eating?
    diabetes supply kit
    Pack and prepare.
    Balding man in mirror
    Treatments & solutions.
    birth control pills
    Which kind is right for you?
    Remember your finger
    Are you getting more forgetful?
    acupuncture needle on shoulder
    10 tips to look and feel good.
    Close up of eye
    12 reasons you're distracted.
    woman biting a big ice cube
    Habits that wreck your teeth.
    apple slices with peanut butter
    What goes best with workouts?
    Pink badge on woman chest to support breat cancer
    Myths and facts.

    Women's Health Newsletter

    Find out what women really need.