Good news from genetic screening tests can bring more to its
recipients than relief:it also can bring doubts about the future and, in some cases, guilt. A University of Iowa study reported recently that individuals who received negative results from
genetic screening for Huntington's disease - they did not carry the gene mutation that causes the debilitating
and fatal disorder - usually "were not prepared for the implications
of a 'good news' test outcome."
"They never reported uncomplicated joy," said Janet Williams, PhD, associate
professor of nursing at the University of Iowa and principal investigator for the study.
"The joy and relief were accompanied by concerns" about how family members might receive the
news and how to adjust to a life now free of anxiety about when symptoms of Huntington's disease might
begin to appear. Some even doubted the test results, the study reported.
Published
in the August issue of Research in Nursing and Health, the study involved
a small number of individuals over a relatively short period of time. Even so, Williams said, it identified important
themes with respect to genetic testing. First and foremost, informed consent and one-on-one counseling should be a part
of every testing program.
"Many of the people we talked with were working this out on their own," Williams
said. "Health providers should be aware that this is a group that may benefit from supportive counseling."
Each child of an individual with Huntington's
disease has a 50% chance of inheriting the gene mutation. Thus, Williams said, families with a history of the disease generally
have an intimate understanding of the illness and a sense of shared risk.
When a family learns one of its members has sought genetic testing for the mutation, its
group dynamic may be altered irreversibly. "People who have this test are often departing from family norms,"
Williams said, "and that somewhat isolates these individuals."
Family relationships may be further
upset when an individual's negative test result contradicts the expectation that he or she will develop the disease.
Williams explained that a phenomenon known as preselection often exists within families with a history of Huntington's.
Consciously or unconsciously, family members assign risk to individuals based on
beliefs about who is likely to develop the illness; for example, if in previous generations the oldest child often inherited
the disease, family members may assume that will be true in their case as well.
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When that assumption proves false, Williams said, families face the need to adapt.
"Biological information such as this removes the comfort they may have had in 'knowing' who was going to get
the disease," she said. "There are a number of issues that mean life is not going to be the same within
the family once a person learns they don't have it."
The individual's response to a negative test result is no
less complicated. According to the study, "Adults with normal results had prepared themselves for the worst, and they
expected that they would have the gene mutation."
"I think that's their coping mechanism,"
said Catherine Evers, a coauthor of the study and an advanced practice nurse who is coordinator of the Regional Genetic Consultation
Service based at the University of Iowa Hospitals and Clinics. "When you tell them they don't have it, based on a gene test that's very accurate,
some of them have a hard time believing you," Evers said. "We've had individuals say to us, 'we'd
better do the test again.' "
Study participants had difficulty knowing how to relate to family members who might
have the disease. One individual spoke of encountering a cousin who has Huntington's disease, "who I related to really
easily before, because I figured I was going to be in the same boat, but it was harder for me to feel the same empathy.
I didn't tell him, I could not tell him my test results." Another reported that while some relatives were
supportive, "there's been other people that have been almost jealous. That's the ones that I regret telling."
Ultimately,
the study said, individuals who learn they do not carry the gene for Huntington's disease face the need to redefine their
goals and purpose in life. Six months after learning their test results, participants "began to discard their prior assumptions
and started to consider themselves as healthy individuals who might live a long life."
"It gives them a whole different
perspective on what their potential is," Evers said. "We do see people who change jobs, or go to school
who hadn't gone to school."
Huntington disease affects about 1 in 20,000 people and is caused by a single gene
mutation. Individuals who carry the mutation almost invariably develop the disease unless they die of some other cause prior
to its onset.
Huntington disease is characterized
by a progressive loss of cognitive and physical function and usually begins to manifest itself between the ages of 30 and
50 years. The course of the disease may last anywhere from 10 to 25 years.
Source: Nurse Health. 2000;23:260-269 |
