Patients can cope with learning their Alzheimer's risks
■ Genetic testing results can alarm patients, but distress levels are not clinically significant, a new study says.
By Kevin B. O’Reilly — Posted Aug. 7, 2009
- WITH THIS STORY:
- » Related content
Alzheimer's disease is unpreventable and largely untreatable. Though genetic testing can tell patients if they have an elevated risk of developing the condition, the expert consensus has been that disclosing such information would distress patients while giving them no medical benefit.
That consensus may be wrong, according to a study in the July 16 New England Journal of Medicine (link).
More than 160 patients whose parents had Alzheimer's disease were offered genotyping results for apolipoprotein E, or APOE, which is associated with increased susceptibility to the disease. There was no significant difference in pre- and post-test disclosure measures of anxiety, depression or distress up to one year, the study found.
The authors said the data "support the psychological safety of disclosing data regarding genetic-counseling protocols to screened adult children of patients with Alzheimer's disease who request such information."
The findings could change medical professionals' minds about whether patients can handle these potentially life-changing test results, said Angela M. Trepanier, immediate past president of the National Society of Genetic Counselors. She was not involved in the study.
"The study takes this test off the taboo list and makes it something to consider offering," said Trepanier, an assistant professor in the Center for Molecular Medicine and Genetics at Wayne State University School of Medicine in Michigan. "This opens the door."
A woman who is a first-degree relative of someone with Alzheimer's has a 30% chance of developing the disease by 85, versus 10% for the general population, the study said. If the APOE gene is present, that risk rises to 52%.
While there are no medical benefits to knowing the increased risk, there are personal benefits, such as the ability to plan, Trepanier said. "It is called personal utility, and the question is how do you measure the personal utility versus other medical benefits in that benefit-risk ratio?"
Trepanier said she was not surprised that patients, so long as they understand the meaning of what the test says about their risk profile, are able to handle the news gracefully.
"People are more resilient than we give them credit for being."
The study's authors excluded patients with preexisting symptoms of anxiety and depression to avoid biasing results. But it is precisely those kinds of patients who might react badly to test results, Trepanier said.
"Having a conversation is the first step in trying to assess whether genetic testing might be beneficial."