Slow catch-up time just understanding what genetic screening can do
Tuesday, April 1, 2008 6:20 AM PDT
By Melissa Healy
Los Angeles Times
Printable version
E-mail this articleWandering the virtual aisles of a genetic-test Web site can be as dazzling and chaotic as shopping at a big-box hardware store on Saturday afternoon. Shelves are bursting with innovative products that promise to reveal a patient’s genetic propensity to conditions as varied as diabetes, alcoholism, post-traumatic stress disorder, Alzheimer’s disease and lung cancer. Fueled by the galloping pace of genomic research, new tests are being stocked daily.
Thinking about shoring up your personal health future? The signs say these are the tools you’ll need.
But don’t count on finding an employee to help you figure out how to use these intriguing new products, what to make of their results or whether you should have them to begin with. This is largely a DIY marketplace, and patients intent on detecting cracks and flaws in their personal genetic foundation and acting to patch them up are finding they’re pretty much on their own.
That’s the finding of a new study by researchers at the Rand Corp. and the Veterans Administration, published as the centerpiece of a special edition of the Journal of the American Medical Association devoted to genomics and genetic testing. After reviewing the findings of 68 studies on genetic testing — its practice, its meaning as understood by health-care professionals and patients, and its effect — the authors concluded that a “wide gap” exists “between what knowledge is available and what health systems need to know” if genetic testing is to improve the nation’s health.
“This is such an exciting time right now,” said Dr. Maren Scheuner, an internal and genetic medicine specialist and lead author of the JAMA article, “Delivery of Genomic Medicine for Common Chronic Adult Diseases.” But, she added, “lots of different things will need to change as we adopt this new information and technology.”
Today, genetic tests can identify and characterize 1,550 genes linked to health outcomes — a more than fifteenfold increase in the past 15 years. As the 20th century came to a close, genetic tests were in wide use to identify carriers of single-gene mutations — patients who, as a result, had a greatly increased likelihood of developing devastating diseases such as sickle-cell anemia or Huntington’s disease. Among the best known and most widely used are those that test for the BRCA1 and BRCA 2 genetic mutations, which raise a woman’s risk of developing breast and/or ovarian cancer to as high as 80 percent.
Tests can also ferret out the genes — including whole suites of genes that interact with each other and the environment — that raise a patient’s risk of developing chronic disorders such as depression, diabetes, osteoporosis, cardiovascular disease and some cancers. But how they interact with each other and the environment, and how powerfully they contribute to a patient’s risk, is poorly understood.
For patients, a finding of increased genetic risk for these chronic conditions could have the positive effect of encouraging lifestyle choices aimed at prevention. But genomic research remains short on specific advice about how to counteract the risk increase from a given genetic mutation.
As a result, a patient deliberating whether to get tested for these gene variations is likely to do so amid huge uncertainty. Researchers and scientists are still working to unlock these mysteries. In studies and surveys assessed by Scheuner and her colleagues, majorities of physicians acknowledged they felt poorly equipped to advise patients on whether to get these tests — or, if they do, how to interpret their meaning. Medical geneticists and genetic counselors — all but 7 percent of whom are clustered in pediatric and obstetric specialties — are scarce and poorly trained in chronic disease and adult medicine. Insurance companies have no means of assessing the therapeutic value of the tests and therefore are disinclined to pay for them.
Patients, although excited by the promise of the new genomic medicine, worry that the results of tests could be used against them by insurance companies, employers and even marital prospects. In studies reviewed by Scheuner, 30 percent to 50 percent of patients surveyed said concerns about privacy and insurance coverage would influence their decision on gene testing.
Researchers acknowledge that there’s substantial uncertainty about the effect genetic tests might have on patients.
But ready or not, the age of genomic medicine is on its way, said cancer and genetic specialist Dr. Patricia Ganz of the University of California, Los Angeles. Scientists are finding significant associations between genes and diseases, and those are quickly finding their way into a thriving market for medical screening.
“We’re going to have people who are willing to pay for genetic tests — we know that because they already pay for full-body CT scans,” Ganz said. “They’ll have this done, and no one will know how to present this information.”
Jennifer, Genetic Counselor wrote on Apr 4, 2008 3:05 PM:
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