To Test or Not To Test-UCDMC

To test or not to test?
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Since the discovery of the gene for HD in 1993, this question has loomed before thousands of people who are themselves at risk, or have friends or relatives at risk for Huntington's Disease.

There are no easy answers. Indeed, says Barbara Briscoe, a genetic counselor who runs the HD support group at UC Davis, there is no single answer. While the test is simple enough in technical terms, the issue of whether or not to undergo testing is fraught with complications.

The occurrence of HD correlated with

the presence of a mutation - in the form of repeated units of a triplet nucleotide sequence CAG - in a specific gene present in the upper portion of the

short arm of chromosome number 4.

"The average person has fewer than 29 CAG repetitions while individuals with HD consistently have upwards of 40 repeats in this gene," explained Briscoe. "The presence of 40 or more CAG repeats is a positive diagnosis - individuals will develop symptoms at some point in their life, if they live long enough."

But the test provides no more than a confirmation or negation of risk. There are no preventive measures against the disease. Furthermore, a positive diagnosis does not predict even exactly when the disease will strike or how severe it will be. In light of these considerations, many people decide against taking the test.

"Until there is a treatment or cure, I am firmly against predictive genetic testing," declared Judy Roberson. Judy's husband has the disease and their four children are therefore at risk for HD. "Once symptoms begin, I think it is a valid tool to confirm the diagnosis. But a positive diagnosis early in life may expose people to genetic discrimination and other problems.

"If you get tested and it goes in your medical record or on your insurance forms, you can risk being discriminated against for life, health and disability insurance and certain types of jobs,

even though you show no symptoms

of the disease," she said. "Also, it is important to be able to handle the knowledge that you have the genetic mutation. I recently learned of a 21-year old in Oregon who committed suicide two days after testing positive. I just don't think having this information too soon is helpul."

But not everyone agrees with this viewpoint.

Laurie Retzlaff cared for her mother for more than 15 years before her mother

died from HD. Retzlaff couldn't bear the uncertainty of not knowing whether she carried the gene too.

"I went through a lot of heartache and trouble for many years, as my mother's condition gradually deteriorated," she said. "I had been told that there was a fifty-fifty chance of inheriting the gene, and I wanted to know if I had it, so I could mentally prepare myself for the symptoms."

The possibility that she might be at risk also impinged upon her quality of life,
Retzlaff added. "Before I got tested, I would do a lot of symptom-seeking. Every time I dropped a plate or some-thing, I would think that I was developing the disease."

While Retzlaff was fortunate to find out that she tested negative, not all results

are unequivocal.

"The diagnosis of people with 29 to 39 CAG repeats in the HD gene is a gray area," Briscoe warned. "We cannot be sure if these people will develop the disease or not."

But regardless of their ultimate decision counseling plays an important and prominent part in the testing protocol - both before and after the actual genetic test.

"Any person who considers taking the test goes through extensive counseling,"

she explained. "We want to make sure that they are able to cope with results,

no matter what they are. Before they make a decision, we try to identify their

motives and expectations in taking the test. We try to explore the ramifications of the results at a deeply personal level."

"One of the biggest questions they asked me during the counseling session was

how the results would change my life. It really made me think hard about why I was taking the test," said Retzlaff, who continues to attend support group meetings despite having tested negative. "I want to be able to help someone else so that they don't have to go through what I did with my mother."

Added Briscoe, "As a counselor, it not my place to tell people what they should decide. I can only tell them about their options and counsel them on how best to cope with their decision and the outcome. Ultimately, it is a very personal decision."

April, 1997

Source: UCDMC Article