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Ask Stanford Med: Genetics chair answers your questions on genomics and personalized medicine

Ask Stanford Med: Genetics chair answers your questions on genomics and personalized medicine

Thank you for submitting your questions on genomics, personalized medicine and our recent “omics” study. I hope my responses help you better understand the significance of our findings, how DNA sequencing may benefit patients and the health-care system and what challenges still need to be overcome for genetic testing to be useful in a clinical setting.

@TracySherman asks: How do you hope your study will help advance personalized medicine?

In the study, we demonstrated for the first time that sequencing the genome of a healthy person can provide valuable information that can help them improve their well being. My genome predicted a disease risk and by watching out for traits (such as high blood glucose levels) associated with that disease I caught my disease (diabetes) early.

The findings also demonstrated the power of frequent monitoring. Because I had been closely following my glucose levels and other molecules in my blood, I was able to identify the onset of diabetes very early. Our study could be a paradigm for heath care in general (i.e. genome sequencing to predict risk, coupled with close monitoring for symptoms of potential diseases) and emphasizes a shift from the way medicine is currently practiced. Today, treatments or therapies are prescribed after physical symptoms arise, which is often too late. We need to predict which diseases patients have an increased risk of developing and either prevent or diagnose them early when they are more manageable.

Lastly, I believe that “omics” profiling, in which we measure thousands of molecules at once from one person, could be a model for the future. Right now we identify diseases very poorly, typically by measuring only a few components in our blood. By following many more molecules (40,000, in my case), health-care providers could more-clearly see changes in common biological pathways. For example, this approach made it easy to see that I acquired diabetes during a viral infection. We hope that in the future we can routinely follow very a large number of molecules in a person and see how they change from healthy to altered states. Then we can more precisely see what is wrong with the person, particularly at an early stage, and use therapies that directly target the altered or disease state.

@miss_tmo asks: How can we expand access to genetic services so more people are able to benefit from personalized medicine?

Right now nearly all of this activity is in the research phase because scientists are still learning the power of genome sequencing – what can and cannot be learned from a person’s genome. As more people realize benefits from genome sequencing there will be more demand for its use.

One way genetic testing is likely to unfold is in the effort to understand certain diseases. Take the example of cancer, a genetic disease in which not only can your DNA increase your risk, but genetic alterations are also accrued during cancer formation. Genome sequencing is already significantly impacting the study of cancer, as well as helping to identify effective treatments. Likewise, for patients with unsolved genetic diseases, genome sequencing can, in some cases, be useful in zeroing in on the underlying cause of the disease. In these circumstances, genome sequencing will become the standard of care for patients.

For healthy people the pace will move slowly. This is because the benefits are less obvious. In addition, some physicians and other experts are worried that genome sequencing could cause patients additional stress and anxiety or even result in false information. More research should help reveal the benefits of genome sequencing in healthy people and how to deliver this information as part of routine health care.

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