A Silicon Valley gene-testing start-up is responding to criticism that the tests could spur bad health-care choices by teaming up for a broad study of how the results affect behavior.
Navigenics charges customers $2,500 to analyze their DNA to assess their risk of developing more than 20 diseases. Several public health officials have said the science on which the tests by Navigenics and other companies are based is too new to be used for making serious medical decisions.
Critics fear that some consumers will use positive results to seek treatments they might not need or suffer unnecessary emotional distress. Negative results, critics say, could inspire others to be less cautious than they should be about lifestyle choices or preventative care.
On Thursday, the Redwood Shores-based company announced it was joining with the Scripps Translational Science Institute in San Diego in hopes of showing those fears are unfounded.
"We have so much knowledge now that we didn't have just a couple of years ago that it's about time we started finding out what kind of impact this knowledge has," said the institute's director, Dr. Eric Topol, who is leading the study.
Researchers plan to gauge whether personal genetic testing encourages people to improve their diets, exercise, quit smoking and work with their doctors to prevent future health problems.
Navigenics will offer to analyze the DNA of up to 10,000 Scripps Health hospital chain employees, family members and friends. The study will track changes in their behaviors over the next 20 years.
Over the course of the study, participants will be surveyed on the lifestyle changes and health decisions they make after receiving the test results.
Scripps hopes to report its first findings in April or May, about three months after participants receive their DNA test results, Topol said.
Navigenics has found anecdotally that its customers are working with their doctors to head off diseases for which their genes show a risk, said Dr. Vance Vanier, the company's chief medical officer.
"We've had those individual experiences, but there has never been a study before of this scale and this systematic a fashion to prove that point," Vanier said.
Boosters of direct-to-consumer genetic testing believe the technology is helping to usher in the era of so-called personalized medicine. Backers promise the field will ultimately deliver highly customized risk assessments, diagnoses and treatments based on an individual's genetic code.
Recent advances in cheaper, faster gene-sequencing gear have led to an avalanche of studies tying DNA variations among individuals to specific diseases. But the biology of how those variations actually lead to developing those diseases is still often poorly understood.
Other study sponsors include Microsoft, which offers Web-based software for storing personal health information, and gene-detection equipment maker Affymetrix Inc.
Navigenics has secured more than $25 million in start-up funding from several backers, including Silicon Valley venture capital firm Kleiner Perkins Caufield & Byers, the founding investor of biotech giant Genentech Inc. in the 1970s.