Genetic testing can cause needless worry
NEW YORK — Last year, Katie Burns got a phone call that shows what can happen in medicine when information runs ahead of knowledge.
Burns learned that a genetic test of her fetus had turned up an abnormality. It appeared in a gene that, when it fails to work properly, causes heart defects, mental disability and other problems. But nobody knew whether the specific abnormality detected by the test would cause trouble.
“I was pretty distraught,” says Burns, a photographer in Charlotte, N.C. “I had a baby who was kicking. I could feel him moving inside of me. But at the same time I had this ache in my chest. What was his life going to be for him?”
It took two months to get more reliable information, and Burns says she wasn’t really sure of the answer until after she gave birth in October to a healthy boy.
Her experience is a glimpse into a surprising paradox of modern-day genetics: Scientists have made huge leaps in rapidly decoding people’s DNA, but they sometimes don’t know what their findings mean. They can even get fooled.
Burns’ fetus had what experts call a “variant of uncertain significance,” or a VUS. Many are known: One standard database contains almost 193,000 variants categorized as a VUS, more than twice the number of listed variants known to cause disease.
In each of us, the genetic code is like a text with 3 billion letters. Some of those letters spell words — genes — that carry out specific jobs. If a gene has one or more letters that aren’t the ones found in the generic “spelling” of human DNA, they are called variants.
Some variants lead to disease. But each of us carries many variants, and most are harmless.
So how should a person react to a VUS? Genetic counselors say it should be considered along with the person’s other medical information, but not used as the sole reason for a major decision like breast removal.
Kendra Snyder, of Newton Hamilton, Pennsylvania, recalls being told by her genetic counselor “just to live your normal life” after VUS results this year. She had taken the test because of a heart condition.
“I was a little upset,” she said. “I was hoping I’d have more conclusive answers as to why my heart is like this.”
But upon reflection, she said, she realized she shouldn’t stress over it, because doing so would reduce her quality of life. As for the VUS finding, “it’s there, but I’m not really panicking and thinking much about it.”