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DNA Carrier Testing for Huntington Disease

Genetic testing is an excellent way to determine whether or not an individual is at risk for developing a particular disease. It becomes particularly important when the disease for which a person is tested has the potential to significantly impact a person's functioning and health. One such disease is Huntington's disease, the screening for which is available.

  1. Why the Test Is Done

    • Huntington's disease is a disease of the nervous system. It is considered very serious because the impact on the nervous system can result in loss of mental and motor function, as well as changes in personality. There currently is no cure. People who undergo the genetic test for Huntington's disease typically do so to find out what kind of future is ahead of them and to make arrangements for care if necessary.

    How the Test Is Done

    • The test for Huntington's disease consists of several pre-test evaluations, a blood draw and post-test disclosure and counseling. In the first sessions, the doctor evaluates the patient for symptoms and provides psychological counseling. The blood test is then done at a lab. This is followed by the doctor providing the test results, which can take up to a month to get back. If the test is positive, then more sessions may be scheduled to discuss treatment options and to lessen any negative psychological impact of the diagnosis.

    What the Doctor Looks For

    • Molecules of DNA are made up of four separate types of bases. On the fourth chromosome, a particular set of three of the four bases (cytosine, adenine and guanine) repeats. When the test for Huntington's disease is done, the doctor or laboratory technician determines whether or not the sequence occurs more than 35 times. If the sequence occurs between 36 and 39 times, then the test is inconclusive, while the test is considered positive if 40 or more repetitions are found.

    Cost

    • The average cost for Huntington's disease testing is between $1,500 and $2,000. This cost includes the cost of the primary and post-testing evaluations and counseling. $220 of the total is spent toward the actual DNA analysis, so the majority of the price involves the office visitations rather than laboratory costs.

    Considerations

    • Although the test for Huntington's disease can determine whether or not someone is a carrier for the condition, the test is insufficient at predicting whether or not symptoms will occur or when they will manifest. Additionally, although the test can be done during pregnancy to determine whether not a child is a carrier, to do so is a bit controversial because, as with other genetic tests, a positive test result may result in the termination of the pregnancy. This is why the evaluation and counseling sessions are taken so seriously.

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