July 5, 2017

Whole-genome sequencing is finally here—but is it actually helpful?

Daily Briefing

    Whole-genome sequencing can reveal DNA mutations linked to rare diseases, but few individuals benefit clinically from the sequencing information, which makes the clinical value of such a test unclear, according to a study published in Annals of Internal Medicine.

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    The study was the first to rigorously examine the value of whole-genome sequencing on asymptomatic primary care patients, according to Reuters.

    Study details

    For the study, researchers from Brigham and Women's Hospital, Harvard Medical School, and Baylor College of Medicine examined the value of whole genome sequencing among a group of 100 asymptomatic primary care patients and physicians. The researchers randomly assigned half of the patients to receive whole genome sequencing and a family history assessment, while the other half of patients only received a family history assessment. Patients then met with their physicians to discuss the reports.

    Findings

    Of the patients who had their genomes sequenced, the researchers identified 11 who carried a DNA variant linked with a rare disease. Of those 11 patients, only two showed signs of an underlying condition. None of the patients who carried a DNA variant benefited from receiving their "molecular diagnosis" in the short term, the researchers said.

    The researchers also found that neither the patients nor the primary care providers were overwhelmed or overreacted to the information, which is a common concern among experts in the field, according to "Shots."

    However, the researchers found patients who had their genomes sequenced underwent more medical tests, which resulted in higher medical costs. According to the study, patients who had their genomes sequenced on average spent $350 more on health care expenses in the six months after they received their DNA results than those who only received their family history assessments. Though because of the small sample size, the finding was not statistically significant, according to "Wonkblog."

    Ultimately, the researchers said more studies are needed to determine whether the clinical actions prompted by the tests are valuable.

    Discussion

    Jason Vassy, the study's lead author who works for Brigham and Women's Hospital, said the researchers "were surprised" by the high incidence of DNA variants linked to disease, but they "were surprised even more" by the number of individuals with "disease-causing mutations" who had the disease. Vassy said sequencing genomes for healthy asymptomatic individuals will provide patients new information, but only some of that information will help improve a patient's health.

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    Teri Manolio, who works for the National Human Genome Research Institute in an editorial accompanying the study wrote that the "lack of evidence of utility will be one of the hardest (obstacles) to overcome" for genome sequencing to become a routine part of medical practice.

    Other experts were more skeptical of the findings. James Evans, a geneticist at the University of North Carolina, said, "This study shows that [genomic sequencing's] routine provision, in that context, is vastly premature and likely lead to more mischief than benefit."

    Mark Rothstein—director of the University of Louisville's Institute for Bioethics, Health Policy, and Law—said another concern is whether individuals who have their genomes sequenced will face discrimination. He said, "That information is accessible by third parties who can require access to it" for "applying for life insurance or disability insurance or long-term care or other things" (Begley, STAT News, 6/26; Steenhuysen, Reuters, 6/26; Johnson, "Wonkblog," Washington Post; Stein, "Shots," NPR, 6/26).

    The journey to personalized medicine

    From risk assessment to shared decision-making to self-management, learn the nine steps your organization can take on the path toward personalized medicine.

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