(CNN) — Summer McKesson struggled to breathe for years. Doctors told her it was because her blood would not stop clotting – and they couldn’t figure out why.

A single clot alone can be lethal; but the recurring and unexplained clots that formed in McKesson’s heart and lungs were a medical mystery.

After multiple surgeries to remove clots and scar tissue, McKesson traveled to the Mayo Clinic, where she sat in a conference room while renowned physicians and specialists worked through her case on a whiteboard.

But even they were baffled.

“To hear that even they had never seen it before,” she told CNN through tears, “I came back (home) just crushed at that point.”

Desperate for answers, McKesson said she turned to 23andMe, hoping the DNA analysis service, which claims to offer insights i

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