This news release, issued by the American Association of Clinical Chemistry in conjunction with the group’s annual meeting, describes unpublished research results showing that a new biochip assay designed to more easily detect a genetic Alzheimer’s disease (AD) risk factor over traditional DNA tests already available.
Overall, the release ably reports on the findings of the study, which was set up to verify the precision of the biochip test. And it does a creditable job of explaining the role of the gene variant ApoE4 in assessing risk of AD and making the distinction between elevated risk, and disease causation.
It could have been clearer and stronger if it had offered a bit more context for the usefulness of such testing, given there currently is no way to prevent or reverse AD. And it provides no information on the potential costs of the assay or a timetable for its availability. One other concern relates to the lead paragraph which states that the test helps identify “which patients” are at elevated risk of AD, when in fact the blood samples taken from study participants may have included people who were not yet “patients” and — based on their ApoE4 status, at least — are likely never to be.
But the bigger question might be: What is the value of the test to patients or would-be patients? APOE testing has been around for about 20 years and the consensus is that it is a research tool, not a clinical tool.
As the promise of individualized medicine — therapies based on each person’s genotype — grows, so does public interest in rapid, cost-effective means of identifying relevant gene variants. In the case of Alzheimer’s disease and related dementias, public and scientific interest is soaring, owing to growing prevalence of the disorders in an aging population, the high financial and social costs of these disabling diseases, and the understandable fear they sow, especially in those with a positive family history.
Virtually any research news story about advances in diagnosis of AD is bound to find a wide audience, despite the sad fact that little or nothing can be done today to delay, prevent or reverse AD or its symptoms.
The release alludes to lifestyle changes, and in fact there is increasing evidence from both observational and randomized controlled trials that heart healthy lifestyles and higher educational level, for example, are associated with lower dementia risk.
Readers should also keep in mind that APOE4 is influenced by many environmental factors and genes. In addition, APOE4 is not specific to Alzheimer’s. It also increases risk for cardiovascualr disease (and its associated vascular dementia), and other neurodegenerative diseases including multiple sclerosis.
The news release states that the biochip array is “more affordable than the andard DNA test” but it doesn’t provide a cost estimate for either.
The release names several benefits of the new test — accuracy, speed, affordability, ability to run multiple tests from one blood sample — but provides little quantification, and only in terms of its 100 percent accuracy in detecting a protein in the blood associated with increased AD risk.
The release suggests that early testing showing a person carries a genetic risk for AD is a benefit because they can consider medications or lifestyle changes as interventions to stall the disease. However, having a certain genetic profile does not mean a person will develop AD. Nor are there any current medications that effectively prevent or stall AD, or lessen its symptoms.
Although there are likely no direct harms from drawing a blood sample, the release could have noted the potential harm of any screening tests for AD risk factors — such as anxiety, depression, misdiagnosis or over-diagnosis — particularly if screening is conducted on those at potentially very low risk. To its credit, the release includes a quote from one of the investigators who makes it pretty clear that the test is intended for those with probable symptoms and family histories of AD.
Both the release and the study abstract on which it was based offer little information about the characteristics of the participant population whose blood samples were used, or how the participants were recruited and from where. We would also have liked to see it mentioned that the study data have not yet been peer-reviewed or published.
No mongering here.
The release doesn’t say who funded the research or whether there were any financial arrangements, only that “Researchers from Randox Laboratories collaborated with research colleagues at the Medical University of Vienna.”
The release makes it very clear that the new test was being compared with standard DNA testing.
The release should have offered a timetable on availability or next steps in development.
The release claims “This is the first time that we have used this biochip technology to test for an increased risk of Alzheimer’s.”
But a quick online search found that a biochip assay for AD was reported (also by the University of Vienna) in Acta Neuropathologica in 2014.
No problem here.