Genetic Testing May Lead to Misdiagnoses, Case Study Warns

Amid increasing popularity of genetic testing, new research suggested that the practice may increase the risk that individuals are misdiagnosed with rare diseases, potentially causing serious long-term effects for families.

A case report published in the November 2016 issue of the medical journal Mayo Clinic Proceedings highlights the potential misdiagnosis risks with genetic testing, detailing how after a young boy died suddenly from heart problems, his family underwent genetic testing and were incorrectly led to believe they had a serious heart condition.

The family turned to doctors for answers when their 13 year old son died from heart failure. An autopsy of the body failed to explain the cause of his death. As a result, more than 20 relatives underwent genetic testing for heart conditions that could put them at risk of the same problem.

The genetic testing of the deceased boy identified a genetic mutation (KCNQ1 variant), which doctors interpreted as causing long QT syndrome, a heart rhythm condition. The boy’s brother and other family members were later tested and they were diagnosed with a rare mutation.

As a result of the identified mutation, the boy’s brother had a heart defibrillator surgically implanted to prevent potentially fatal heart rhythms or arrhythmias, such as the one that caused his brother’s death.

Yet, the family decided to get a second opinion at the Mayo Clinic. They were then evaluated again for genetic testing. Researchers collected DNA from the boy and conducted a molecular autopsy. His DNA was isolated and sequenced, then analyzed for genetic variants.

Researchers discovered none of the family members had long QT syndrome after all. Researchers also determined genetic testing of the boy who passed was never done. Instead, the boy died of sudden death from genetically mediated heart muscle disease, due to a different mutation that was present in only him and no other family members.

The findings suggest that genetic testing can, in some cases, cause more harm than good. In this case, a family was seriously misdiagnosed and their son underwent an unnecessary invasive procedure.

The authors of the study are calling for more careful use of genetic testing tools and stricter interpretation of genetic test results. They highlighted that the medical community, and community overall, must have a better grasp on genetic testing before acting on the information received.

“Genetic testing is a powerful tool, but it can also be a dangerous weapon,” wrote the study authors.

When genetic testing is used properly, researchers highlight, the findings can be very helpful.

Genetic Testing Concerns

In this case, researchers say diagnosis of the condition should not have been accepted since none of the family members showed clinical signs of the disease. More so, all family members had electrocardiograms with normal QT intervals, making the diagnosis of the condition highly unlikely.

Researchers also highlight genetic mutations can cause different diseases and conditions in different environments. Overall, genetic mutations have not been evaluated across the board in every environment. Many genetic disease have an environmental component that allows them to express into a condition or disease only under certain conditions.

Recently, researchers warned consumers against genetic testing purchased from the internet citing similar concerns. Those tests often overemphasize the quality and helpfulness of the results, misleading patients and offering incomplete results.

While the newest case was not a genetic test purchased online, the family’s ordeal highlights the need for caution when genetic testing is involved.

Researchers emphasize patients should focus more on lifestyle interventions, like losing weight, exercising, quitting smoking, and not abusing alcohol or prescription drugs.

“Although the technological advances in genetic sequencing have been exponential, our ability to interpret the results has not kept pace,” the researchers warned. “In essence, we must become wiser users of genetic testing and even wiser interpreters of the genetic test results so that the promise of precision medicine can be realized.”