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New risk-scoring method for deadly diseases crunches millions of potential gene variants

August 16, 2018

“I think I carry the gene for ___.”

This colloquial explanation for myriad traits and behaviors belies the fact that many conditions are believed to arise not from single genetic variations but combinations of thousands or millions.

That’s the crux of “polygenic risk scoring,” the subject of new research that accounts for the genetic complexity of common disease risks. As the New York Times reported:

Scientists have created a powerful new tool to calculate a person’s inherited risks for heart disease, breast cancer and three other serious conditions.

By surveying changes in DNA at 6.6 million places in the human genome, investigators at the Broad Institute and Harvard University were able to identify many more people at risk than do the usual genetic tests, which take into account very few genes.

Of 100 heart attack patients, for example, the standard methods will identify two who have a single genetic mutation that place them at increased risk. But the new tool will find 20 of them, the scientists reported on Monday in the journal Nature Genetics.

Common conditions analyzed

Researchers looked at coronary artery disease, atrial fibrillation, type 2 diabetes, inflammatory bowel disease, and breast cancer, according to a Broad Institute news release:

For each disease, they applied a computational algorithm to combine information from all of the variants — most of which individually have an extremely small impact on risk — into a single number, or polygenic risk score. This number could be used to predict a person’s chances of getting these diseases based on his or her genome.

This new information, previously invisible to clinicians and patients, could help doctors and patients make better decisions on interventions.

Scoring could improve care

“We’ve known for a long time that there are people out there at high risk for disease based just on their overall genetic variation,” said senior author Dr. Sekar Kathiresan, who led a team at the Broad Institute of MIT and Harvard, Massachusetts General Hospital and Harvard Medical School. “Now, we’re able to measure that risk using genomic data in a meaningful way. From a public health perspective, we need to identify these higher-risk segments of the population so we can provide appropriate care.”

Researchers validated their algorithms against data from 400,000 individuals in the UK Biobank. According to the Times, they also validated the method on populations of East Asians, South Asians, African Americans and Hispanics.

Researchers found that those who had a high risk score for a heart attack were four times more likely to have had a heart attack than other patients, according to the Times. “Unless I do this genetic testing, there is no way I could pick those people out,” first author Dr. Amit V. Khera told the newspaper.

The use of biobanks and patient data to enable and validate this exciting new approach affirms the value of philanthropic patients sharing their biospecimens, and biorepositories making those samples available for study beyond their walls. Specimen sharing is at the center of our company vision and is the impetus behind the iSpecimen Marketplace.

Sharing is more important than ever. The more we learn, it seems, the more we need to know.

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