Most take news of genetic Alzheimer's risk well

By Megan Rauscher

NEW YORK (Reuters Health) - Adult children who have a parent with Alzheimer's disease may want to know if they carry a gene that raises their risk of getting the mind-robbing disease. But can they handle the test result, psychologically? Findings from a study released today hint that most can handle the information.

The e4 version of the apolipoprotein E (APOE) gene is associated with an increased risk of Alzheimer's disease, as well as impaired memory in people without dementia and with progression to Alzheimer's disease in people with mild thinking impairment.

In the REVEAL study, researchers found that disclosing APOE test results to adult children of patients with Alzheimer's disease "did not result in significant short-term psychological risks."

Test-related distress was reduced among those learning they did not carry the Alzheimer's-associated gene and was only modestly and transiently increased in those told they did carry the gene, Dr. Robert C. Green of Boston University School of Medicine and colleagues report in Thursday's issue of The New England Journal of Medicine.

In the study, 162 healthy middle-aged adult children who had a parent with Alzheimer's disease were randomly assigned to receive the results of their APOE genetic test (the disclosure group) or not to receive the results (the nondisclosure group).

People who were informed of their test results, the researchers found, did not have significantly more depression or anxiety than those who were not informed of their test results either immediately after receiving the test results or 1 year later. That was true regardless of whether they were in the subgroup of people found to carry the high-risk APOE e4 gene variant.

"Subjects were not immune to the negative implications of learning that they had an increased risk, but these feelings were not associated with clinically significant psychological distress," Green and colleagues point out.

And for those who were told they did not possess the high-risk gene variant, testing provided a benefit, they report.

"I have worked with families with Alzheimer's disease for quite a while and I thought it might be possible to disclose this information without harming them, but the consensus, sort of, was that this would be commonly met with a great deal of psychological distress," Green told Reuters Health.

"As a first step in exploring the impact of disclosure, I think these results are quite interesting," Green added.

The authors of a commentary caution, however, that it's very likely that the people who agreed to participate in this study were "sufficiently indifferent to the potential test results...and thus are not representative of those who have a strong perceived need to know or need not to know."

Moreover, Drs. Rosalie A. and Robert L. Kane, of University of Minnesota, Minneapolis, pose the question: "Could any societal good or harm result from widespread, on-demand genetic testing for APOE e4?"

"Societal benefit seems unlikely," they contend, "given that it is not possible to prevent Alzheimer's disease, and available treatments have at best a modest effect on disease progression."

"Societal harm from testing remains possible," they add, "given that Alzheimer's disease is widely regarded as being singularly horrific."

SOURCE: The New England Journal of Medicine, July 16, 2009.