What is Predictive Testing?

This section is intended to help the individual considering testing for HD reflect on some of the issues involved in testing and in dealing with the test results.

Family, friends and professional support people may also find this material useful in supporting those considering testing.

In 1983, genetic markers closely linked to the Huntington disease (HD) gene were identified. This discovery, together with the identification of additional genetic markers, led to the development of predictive testing programs for HD. Problems with this approach included some inaccuracy as it was not possible to test directly for the presence or absence of the genetic defect underlying HD.

In March, 1993, the gene causing Huntington disease was identified. This means that individuals at risk for HD can now be directly tested to “predict” who will develop this disease. The same test may be used to confirm the presence of the gene that causes HD in individuals already exhibiting clinical symptoms of the disease, especially when the family history is sketchy or unknown.

The decision about whether or not to have testing for HD is a very complex and personal one. Each individual in a family with HD will feel differently about testing.

For some, this test will provide much desired information about their future. Others will choose not to undergo testing. There are no right or wrong choices. It is important, however, that the person who is thinking about being tested make an informed choice.