Unraveling Your DNA's Secrets
Do-it-yourself genetic tests promise to reveal your risk of coming down with a disease. But do they really deliver?
Genetics is notoriously confusing, and most people need help interpreting test results. Most primary care doctors never studied genetics in medical school, and there are only about 800 U.S. physicians board-certified in genetics. About 3,000 genetic counselors have master's degrees, but they aren't doctors and thus can't give medical advice.
Annette Taylor, president of Kimball Genetics, is both a geneticist and a certified genetic counselor, and she believes that counseling and interpretation are essential for both patients and doctors. She requires customers to give a healthcare provider's name and faxes them the results. Our celiac disease tester, a 38-year-old male who has irritable bowel syndrome, called the counselors at Kimball because he couldn't decipher the written results. "A DQA 1*05 allele (*0501 or *0505) was detected but neither of the DQB1*02 alleles (*0201 or *0202) was detected," they read in part. The counselor, who said she had a master's in genetic counseling, spent 20 minutes talking with him by phone. He said she explained that the test didn't rule out celiac, which is caused by an autoimmune reaction to gluten in food, but it didn't definitively diagnose celiac, either. A third of the population had this genetic pattern, she said, but only about 1 percent has celiac. She suggested the tester talk with his doctor about a blood test that would detect gluten antibodies. She also suggested, twice, that he buy the test from Kimball, raising the question of whether her focus was on interpreting tests or selling them. "She was just making it convenient for him," says Taylor. "We would never say anything that is not medically indicated."
To gauge how phone counseling compared with face-to-face guidance, U.S. News asked Deborah Nagler of Teaneck, N.J., to call DNA Direct. Nagler had a double mastectomy in 2002 at age 50, after learning she had a BRCA mutation (her sister, mother, and aunt died of breast cancer). The DNA Direct counselor called her at home after she filled out an online form. "I found her to be very empathetic, very knowledgeable, and that there was relative parity with the face-to-face experience I had," says Nagler. "The counseling piece is really, truly critical. It's a personal and emotional upheaval to receive the news."
Nagler worries about her two daughters, both in their 20s. "I could be delivering death sentences to my children, and to my children's children." With more access to genetic testing, more families will face these struggles. The hope is that they will do so armed with real medical insight, not hype.
A BRAVE NEW WORLD
Some genetic tests are already in wide use. Others have yet to fulfill their promise. Tests include:
Carrier screening. Pregnant women can be tested for mutations they can pass on to their children.
Prenatal screening. Tests that pull a fetus's genes from amniotic fluid or chorionic villi can detect disorders.
Newborn screening. All babies are tested right after birth for treatable diseases.
Forensic. DNA can identify criminal suspects or victims, as well as establish paternity.