May 10, 2010

Patient’s Whole Genome Reveals Disease and Medication Risks

Photo of hands holding a medicine vial and a DNA label Jane Ades, NHGRI.

Scientists have evaluated the entire genome of a 40-year-old man to determine his risk for dozens of diseases and his likely response to several common drugs. The study provides a glimpse of how whole-genome sequencing might one day be used in the clinic.

Recent advances in technology now allow scientists to sequence the entire human genome much more quickly and at a lower cost than ever before. Earlier this year, 2 separate research teams showed how whole-genome sequencing among family members can help to diagnose disease at the molecular level (Read the story in NIH Research Matters). If genome analysis shows an increased risk for certain conditions, patients could take steps to reduce their risk—by changing behaviors, such as eating a healthier diet or exercising more, or by taking certain medications.

In the new study, a research team led by Dr. Euan A. Ashley of Stanford University analyzed the genome of a single person with a family history of vascular disease and early sudden death. They compared it to several databases of disease-related gene variants to identify genes and mutations with known links to disease. The researchers also looked at pharmacogenomics databases for genetic evidence of unusual drug responses. As part of the analysis, the scientists factored in the patient's medical and family history as well as other statistical disease risks. The research was supported in part by NIH’s National Institute of General Medical Sciences (NIGMS) and other NIH components.

In the May 1, 2010, issue of The Lancet, the team reported that whole-genome sequencing yielded useful and clinically relevant information about their patient. The researchers pinpointed gene variants associated with several diseases in the man’s family, including osteoarthritis, vascular disease and early sudden death. They also uncovered variants linked to conditions not known to be in his family, such as iron overload and thyroid and parathyroid diseases.

In addition, some gene variants predicted the patient's likely responses to certain heart medications. That information would be especially helpful because he's at risk for cardiovascular disorders.

"This opens the door to targeted environmental interventions based on a patient's genomics," says paper co-author Dr. Atul Butte of Stanford.

"When combined with other sources of information, genomics has the power to predict the diseases a person is most likely to develop and how he or she might respond to certain medicines," says NIGMS Director Dr. Jeremy Berg. "This work provides a glimpse of how genomics can play a role in personalizing the medical care of individual patients."

Although the study provides evidence that whole-genome sequencing can yield clinically useful information for individuals, many challenges remain. These include understanding the effects of the environment, which are difficult to quantify and often change throughout a person's life. Practically, genome-informed medical care will require an integrated team that includes medical and genetics professionals along with ethicists. Many ethical and policy questions need to be addressed before this kind of analysis becomes widespread.

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