When Jen graduates from college in 2009, her parents’ gift to her is a scan of her genome. (Jen was hoping for a car.) Her results reveal no increased risk for developing Alzheimer’s disease, but an above average risk for breast cancer. Her physician suggests that she start mammograms before the recommended age of 40. After Jen marries, her doctor suggests that she and her husband have a fuller reading of their genomes so they can benefit from the most thorough prenatal analysis. For about a thousand dollars each, they do so. They discover that they are carriers for a rare lethal genetic condition, raising serious worries about starting a family. After genetic counseling, they decide to go ahead anyway, and Jen gives birth to a healthy baby boy.

When Jen is 42, doctors detect a lump in her left breast during a routine mammogram. A biopsy determines that she has stage one breast cancer. Her genetic analysis shows that the risk of recurrence is very low. She is successfully treated with the drug tamoxifen instead of undergoing chemotherapy.

Jen’s story is now close to being possible. The landmark sequencing of the human genome in 2003 has brought enormous scientific opportunities and a tidal wave of progress. In fact, you now can have your whole genome sequenced, albeit at the relatively prohibitive cost of $350,000.¹ But that’s far cheaper than the price tag for the original genome sequence, estimated at $300 million—and costs continue to plummet. In October 2008, a new company announced that it would sequence individual genomes for $5,000 by the second quarter of 2009.² Some companies are vying for the $10 million X Prize, which will be given for the first effort that succeeds in reading 100 genomes in 10 days for less than $10,000 each.

Yet developing the technology for sequencing genomes is the easy part. Far harder is accurately interpreting the meaning of the three billion base pairs of DNA in each genome and translating that information into medical interventions. To try to figure out if genes or individual base pairs of DNA are linked to complex diseases such as asthma, cancer, heart disease, schizophrenia, and type 2 diabetes, researchers perform “genome-wide association studies.” These studies examine hundreds of thousands of places across the genome and look for genetic differences between people with diseases and similar people who are healthy.

Hundreds of such associations between genetic markers and diseases have been identified, more than 130 in 2008 alone.³ These genetic discoveries are helping researchers to better understand the biological pathways of disease and to find new targets for drug development. But we have a long way to go before we can use most findings to make major changes in medical practice for ordinary people like Jen.

The problem is that the scientific evidence is still limited. Associations between genetic markers and disease that show up in one group of people may not appear in a different population. In addition, the increased or decreased risks associated with these genetic factors are usually modest—too small to be of use in making medical decisions—and many of the genetic factors have yet to be identified. One study of old, healthy people is finding these so-called wellderly people all have “bad” genes. Yet since they don’t seem to get the diseases associated with those genes, perhaps they also have still-undiscovered genes that decrease the risk of disease. We don’t yet understand how these factors combine to affect disease, nor do we fully understand the enormous contribution of environment.

These limitations mean that Jen could be falsely reassured about her reduced risk for Alzheimer’s disease, or about the chances that her cancer won’t recur. It may be that she has other genetic risk factors that have not yet been identified or that environmental exposures in her life have added to her risks of disease.

Yet, despite these uncertainties, companies are already selling genetic information to the public. Like Jen, we can go online and order a test that will scan our genome and offer us information about ourselves and our future. One such company promises an analysis of your genetic predisposition to a variety of common health conditions and help in determining what steps you can take to prevent, detect, or diagnose them. But unlike drugs, genetic tests are largely unregulated. Companies can make these claims about the benefits without having to substantiate their claims. In fact, many experts are skeptical about the benefits of this very early application of genomic information, doubting that results have any clinical utility.⁴

Is this opportunism or consumer empowerment? And more important, what are the implications for the future of genomic medicine? The worry is that early tests that offer scant information may sour peoples’ opinion of genetics.

To guard against a backlash, and to ensure that the tremendous promise of personalized genomic medicine is realized, we should consider at least four major policy steps. First, we must regulate genetic tests.⁵ Second, we should develop guidelines for the use of genetic information by doctors and other health care professionals, based on rigorous scientific evidence. Third, we need to perform careful economic analyses to determine if reimbursement for genetic tests are justified. And fourth, we have to pass laws that keep up with the progress of science and medicine. One example is the federal Genetic Information Non-Discrimination Act (GINA), passed in 2008 after 13 years of effort. GINA protects Americans from discrimination by employers or insurers based on their genetic information.

We also need to use genetic tests wisely, ensuring that we analyze their utility as they are being introduced into medical practice. Right now, the most promising application is pharmacogenetics—using genetic information to guide drug prescribing. One genetic test approved by the Food and Drug Administration, for instance, spots differences in how quickly patients metabolize warfarin, an anticoagulant prescribed after heart attacks. The drug is widely used, but it’s difficult to get the right dose—and the wrong dose can significantly increase risks of bleeding. Knowing the speed of metabolism helps pinpoint the right dose. The FDA recently changed the labeling on warfarin and several other drugs, encouraging doctors to undertake pharmacogenetic testing before prescribing them.⁶

The tremendous promise of personalized genomic medicine will almost certainly be realized during the 21st century. The path, however, will be smoother if we make the right policy decisions along the way.

¹ Price listed by Knome, current as of October 29, 2008.
² Complete Genomics.
³ L. A. Hindorff, H. A. Junks, and T. A. Manolio, “A catalog of published genome-wide association studies”, accessed October 30, 2008.
⁴ See David J. Hunter, Muin J. Khoury, and Jeffrey M. Drazen, “Letting the genome out of the bottle—will we get our wish?” New England Journal of Medicine, 2008, Volume 358, Number 2, pp. 105–7.
⁵ See U.S. System of Oversight of Genetic Testing: A Response to the Charge of the Secretary of Health and Human Services, US Department of Health and Human Services, 2007.
⁶ See “FDA approves updated warfarin (coumadin) prescribing information,” US Food and Drug Administration, 2007.

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