Are There Holes In My Genes?

This year has been tough for my family. First, my uncle was diagnosed with sarcoidosis, an incurable inflammatory disease. Then my sister needed surgery to remove precancerous tissue from her cervix. The hardest blow came this summer, when my cousin--just 28, and always healthier than anyone else in the family--was diagnosed with aggressive breast cancer.

Living on the other side of the world--she's in Australia; I'm in California-- I racked my brains for something, anything, that I could do. I shaved my head and donated the hair to help make a wig. I gave money for cancer research. I pestered friends to donate too. But amid the altruism, there was fear. My cousin's cancer wasn't just about her--it was a little bit about me. I couldn't help wondering: Was I at risk too?

So when I got a call asking if I'd be interested in having my DNA screened by a new company called Navigenics to gauge my genetic risk for a raft of diseases, including breast cancer, I didn't hesitate. Sign me up.

Set to launch in the first quarter of 2008, Navigenics is a pioneer in the nascent industry of ultrapersonalized, genomics-based medicine. The Redwood City, California, company will screen a client's genome for about $2,500, predicting the risk of getting about 20 conditions, such as breast cancer and type 2 diabetes. Its investors, including John Doerr's Kleiner Perkins and Mark Kvamme's Sequoia Capital, have bet millions that consumers will buy it.

While Navigenics bills itself as the first company to offer broad DNA screening for multiple medical conditions, the fledgling sector is already getting crowded. Another startup, the much-hyped 23andMe--cofounded by Anne Wojcicki, wife of Sergey Brin of Google, which has invested $3.9 million--will use the same kind of high-density scanning as Navigenics, though a source close to the secretive company says its applications will be more "fun," allowing you to learn about your genetic characteristics. Other direct-to-consumer genetics shops, such as San Francisco-based DNA Direct, offer more-established tests for individual diseases using technology that takes a deeper, more targeted dive into specific genes.

All of these firms seek to satisfy--some might say exploit--our seemingly insatiable appetite for information about ourselves and our bodies. Navigenics cofounder David Agus, an oncologist at the Cedars-Sinai Outpatient Cancer Center in Los Angeles and an assistant professor at UCLA, sees DNA screening as an agent of clinical democracy: Knowledge is power, so you too can have what's available to doctors and scientists. "Finally," he says, "the technology has come to the point that we can empower individuals."

These firms seek to satisfy--some might say exploit--our insatiable appetite for information about ourselves and our bodies.

But with that power also come myriad questions. Will consumers understand the difference between diagnosis and risk? Will they realize what they can--and can't--do about their genetic proclivities? What about privacy issues? "Are these companies at the cutting edge? Yes," says Reed Pyeritz, a professor of medicine and genetics at the University of Pennsylvania. "But is this also premature? Yes. Is it something that, if these services are set up properly, five years from now will actually be beneficial? Perhaps."

The science works like this: A strand of human DNA has about 3 billion bases. About every 1,000 bases, there's a single nucleotide polymorphism, or SNP (pronounced "snip"). Most SNPs do not themselves cause disease, but Navigenics says it has tapped more than 4,000 scientific papers associating certain SNPs with certain diseases. Those studies are typically retrospective, meaning that researchers took a group of people with a disease, compared their genetics with those of a population without that disease, and found that a particular SNP was associated with having the disease.

Navigenics focused on about 100 of the most definitive papers, building an algorithm that estimates the risk of a healthy person developing a disease if his or her genome has the relevant SNPs. When a client sends in a saliva sample, DNA is extracted and scanned for SNP variations, which are then analyzed to assess disease risk.

Company officials emphasize that the tests can't conclude whether I will get, say, breast or colorectal cancer. They can only estimate my likelihood of developing them over my lifetime. Clients, who receive results via Navigenics's secure Web portal, are prodded with advice on disease prevention and screening. Also included in the test price is consultation by phone with a licensed genetic counselor and a year of updates as the company adds new research on other diseases to its database.