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Predictive Genetic Testing for Huntington's Disease: A Journey With a Genetic Counselor as Your Guide

06/18/2015 10:17 am ET | Updated Jun 18, 2016

In 1993, a remarkable scientific discovery was made -- the genetic mutation that causes Huntington's disease (HD) was identified. This breakthrough allowed for predictive genetic testing of individuals at-risk of the disease, like Marianna Palka in the film The Lion's Mouth Opens. Predictive testing involves a simple blood test to detect whether or not a person has the genetic mutation associated with HD. It is available to adults 18 years or older who have an affected family member but do not yet have symptoms of the disease. All individuals considering predictive testing should meet with a genetic counselor.

The role of genetic counseling
As a genetic counselor specializing in predictive genetic testing for HD, it is important that individuals at-risk of the disease understand the role we play in the testing process. Genetic counselors empower individuals with information and emotional support to help them understand their family health history and evaluate genetic testing options. We provide people at-risk for HD with the guidance and knowledge they need in order to make informed decisions about testing. The decision to have predictive genetic testing for HD is extremely complex. Genetic counselors can help talk through all the factors to consider. While genetic testing should always be accompanied by genetic counseling, genetic counseling can occur in the absence of testing. This means that someone may decide not to proceed with predictive testing after meeting with a genetic counselor.

How the predictive testing process works
Individuals seeking predictive testing will often attend two genetic counseling sessions at minimum. The genetic counseling and testing process occurs over the course of many weeks to allow the patient sufficient time to assess whether or not he or she would like to proceed with receiving the test results. Patients are encouraged to bring a support person, such as a significant other or a friend, to all genetic counseling sessions.

During the genetic counseling appointments many topics are discussed, including the potential benefits and harms of testing, the person's motivations for testing, expectations about the test result, the impact either a mutation-positive or negative result might have on their life, and strategies for dealing with the test result. A neurological exam is also performed to assess whether or not the person is displaying early symptoms of the disease.

A genetic counselor will also help identify other issues to consider such as the impact testing may have on a person's relationship with their significant other, children, and extended family members, their career, and their finances and insurance. For example, results from predictive testing could make it difficult to purchase life, disability or long-term care insurance.

To test or not to test?
The decision about whether to have predictive genetic testing for HD is extremely personal. Not surprisingly, it is very common for family members to have different opinions on testing. When considering predictive testing it is important to take time to make an informed choice that is right for you.

People in favor of testing often cite their motivations to be an increased ability to plan for the future and make informed reproductive decisions, the relief of uncertainty and worry, the desire to learn their children's risk status, the ability to participate in research and clinical trials, and simply for the sake of wanting to know.

Others choose not to have testing due to concerns over the possibility of a negative emotional reaction, fear of receiving a mutation-positive result, genetic discrimination such as the inability to obtain long-term care insurance, the lack of a cure for the disease, the preference of living with hope that they will not develop the disease, and simply the desire not to know.

Often people who have not had the experience of living in a family affected by HD underestimate the impact of predictive testing and assume that all persons who are at-risk will have the test. This decision is particularly difficult when you have seen generations of your family die of the disease and have cared for affected loved ones. The complexity of this decision is likely why not everyone who is at-risk pursues testing.

Reactions to the results
Most individuals generally experience a positive impact on their psychological well-being regardless of their predictive test result.

Individuals who receive a mutation-positive result may initially experience feelings of depression, anger, fear, or despair. Many people struggle with not knowing when exactly they will first exhibit symptoms of the disease and may start to "symptom watch" and wonder if occasional clumsiness or forgetfulness is a sign of disease. With time and support, most people come to accept their result.

People who receive a mutation-negative result may initially experience feelings of joy and relief. Some may struggle with "survivor's guilt" since they escaped the disease but other family members did not. These people may also feel an increased responsibility to care for affected family members. It is important to acknowledge that individuals who receive a negative result may also benefit from additional support following testing.

If you would like more information on predictive genetic testing for HD, find a genetic counselor in your area by using the National Society of Genetic Counselors' "Find a Genetic Counselor" tool.

This op-ed is a part of a Huntington's Disease Awareness Month collection and in collaboration with The Lion's Mouth Opens, which premiered on HBO this June 1st and is available on HBO Go and HBO Now.