Misdiagnoses: A hidden risk of genetic testing

(CNN)After a 13-year-old boy's heart failed suddenly, his family arrived at Dr. Michael Ackerman's doorstep with questions. He was determined to find them answers.

Since the boy's autopsy report seemingly failed to explain his death, more than 20 of his relatives underwent genetic testing for heart conditions that could put them at increased risk of the same fate. The tests diagnosed the family members, including the boy's brother, as having a potentially deadly genetic heart rhythm condition called long QT syndrome.
    As a result, a heart defibrillator was surgically implanted in the brother's chest to prevent any potentially fatal heart rhythms, or arrhythmias.
    Then the family asked Ackerman for a second opinion about their diagnoses and overall health. Ackerman was skeptical of the previous diagnoses, he said. And after evaluating the family members, he soon concluded that they did not have long QT syndrome after all.

    When genetic testing goes wrong

    "At one level, families like this one go through intense frustration and anger about the missteps that were made. At another level, there is confirmation with their own gut instinct that things were not hanging all together," said Ackerman, a genetic cardiologist and director of the Windland Smith Rice Sudden Death Genomics Laboratory at the Mayo Clinic in Rochester, Minnesota.
    When Ackerman and his colleagues realized that a genetic evaluation of the deceased boy was never performed, they conducted tests and discovered that the boy didn't have long QT syndrome, either.
    "Instead, the boy actually died a sudden death from a genetically mediated heart muscle disease due to a completely different mutation that was present in him and him alone," Ackerman said.
    A negative test result could eliminate the need for unnecessary checkups or screening tests, according to the National Institutes of Health.
    A positive test result could allow patients to take preventive measures in their health care, like actress Angelina Jolie did. She revealed last year that she had her breasts and ovaries removed to prevent cancer.
    Jolie noted in a New York Times op-ed that she lost her mother, aunt and grandmother to cancer. Her mother was diagnosed with ovarian cancer at age 49.

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    However, as the Mayo Clinic paper shows, genetic testing is still complex.
    "Unless you have a family history, I wouldn't be so worried about that," Caplan said of genetic testing.
    "What I would be more worried about is, can I lose weight? Can I exercise? Can I not drink too much? Can I not abuse prescription drugs? Can I wear a helmet when I ride my bike?" he said. "In other words, while we're all fascinated by genes ... it's still the case that the major health care risks, unless you have a family history of something, don't require a genetic test."

    Read more: http://www.cnn.com/2016/10/31/health/genetic-testing-misdiagnosis-risk/index.html