What Your Doctor Isn’t Telling You About Your DNA
The test results were crystal clear, and still the doctors didn’t know what to do. A sick baby whose genome was analyzed at the Children’s Hospital of Philadelphia turned out to possess a genetic mutation that indicated dementia would likely take root around age 40. But that lab result was completely unrelated to the reason the baby’s DNA was being tested, leaving the doctors to debate: Should they share the bad news?
When it comes to scanning DNA or sequencing the genome — reading the entire genetic code — what to do with unanticipated results is one of the thorniest issues confronting the medical community. Many conflicted discussions followed the dementia discovery at the Children’s Hospital of Philadelphia (CHOP) before a decision was reached: the parents would not be told that this fatal memory-sapping disease likely lurks in their child’s future. Given the hopelessness of the situation, with no treatment and no cure, the doctors said forwarding such information along felt pointless. “We came around to the realization that we could not divulge that information,” says Nancy Spinner, who directs the hospital laboratory that tested the infant. “One of the basic principles of medicine is to do no harm.”
Around the same time, Spinner’s lab also tested another child — an unusually short 2-year-old referred for kidney disease — and discovered the toddler had a gene linked to a rare form of colon cancer. In some cases, polyps arising from this kind of cancer have been known to develop as early as age 7. This time, the decision to inform the parents was easier: “We feel good about that one,” says Spinner. “Proper screening can make a huge difference.”
Across the country, a small but growing number of doctors are turning to increasingly sensitive genomic tests to pinpoint the root causes of young patients’ mystifying symptoms. But many still don’t know how to handle results unrelated to the ailments that prompted such sequencing. “If you’re looking in the area of chromosome 17 and BRCA1 [a breast-cancer gene] is nearby, you can’t ignore it,” says Barbara Bowles Biesecker, director of the genetic-counseling program at the National Human Genome Research Institute (NHGRI), which is housed on the campus of the National Institutes of Health. “What are you going to do, put blinders on and not look to the left?”