Genome scans go deep into your DNA

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MY MATERNAL grandmother had Alzheimer's disease. Before she died, she forgot our names, our faces and, eventually, how to speak and think. But my grandfather's heartbreak was the most painful to witness. I remember watching the two of them on the sofa together in the months before she died. My grandfather, a sometimes severe man not overly disposed to expressions of tender emotion, cooed into my grandmother's ear: "My bride, oh my bride. I love you. Do you hear me? I love you." She just stared down blankly, folding napkins.

That scene was burning in my brain last week when I received an e-mail from a company that offers extensive genome scans directly to the public. The e-mail told me that my tube of spit had been analyzed and the results were in. I logged onto my account and began to scan the report for my estimated genetic risk for 17 diseases and conditions.

Breast cancer, colon cancer, Type 2 diabetes: normal. Strangely relieving. Obesity: a little above average (I do not come from thin people).

Heart attack, multiple sclerosis, rheumatoid arthritis, macular degeneration: all a little below average. Even better.

And then there it was, in an orange "warning" box on my Web browser: a significantly higher-than-average lifetime risk for late-onset Alzheimer's disease, the most common type of this devastating disorder. The average risk of late-onset Alzheimer's is about 17%. Mine is 29%, owing to the DNA letters I carry in a gene called APOE, which contains coding instructions for a protein involved in processing cholesterol. It comes in different forms, or alleles -- and in my case, one of the copies I carry confers higher risk.

Before I could process a coherent thought, I burst into tears. Alzheimer's might be decades away for me -- I am not yet 30, and the late-onset disease strikes after 65 -- but that risk allele didn't pop up in my genome out of nowhere. In all likelihood it came from my mother, who just turned 60. My mother -- who already has high cholesterol, a known risk factor for Alzheimer's disease.

I was surprised by my reaction. It wasn't exactly news, was it? Family history alone told me that my mom is at higher risk of Alzheimer's just by being her mother's daughter. And the risk is not excessively high; this is by no means a guarantee that either of us will succumb to the disease.

But something about the plain and simple statement of my own genetic fact seemed shocking and terrifying.

"Genetic information has a special power," says Dr. Robert Green, professor of neurology, genetics and epidemiology at Boston University School of Medicine. "It has a feel of fate about it, a sense of inevitability, that sense that, 'Oh, you are marked.' "

The test I received was from Redwood Shores, Calif.-based Navigenics, the latest company to offer personalized genome scans directly to consumers. Its launch last week follows fast on the heels of the Google-backed start-up 23andMe and Iceland's deCODEme, which both debuted in November.

The companies, which scan the entire genome for telltale DNA variations linked to traits or diseases, are the splashiest manifestation yet of tests the public can buy to learn their genetic risk for a range of conditions including breast cancer, glaucoma, baldness, more.

Cost of knowing

They don't come cheap. Navigenics charges $2,500, plus a $250 yearly fee for scientific updates. The other two charge about $1,000. Navigenics justifies its higher price because it offers unlimited genetic counseling.

But the companies say their services offer something precious: the chance for people to take control of their health and destiny. "The whole goal here is to tell people whether they are at increased risk so they can do something about it," says Dietrich Stephan, Navigenics co-founder (with Dr. David Agus of the Cedars-Sinai Medical Center) and a research director at the Translational Genomics Research Institute in Phoenix.

Some scientists agree the tests could carry special behavior-changing clout -- more than a public service message could ever do. "The public knows what is good for them. They could tell you like robots what it is. But they've become desensitized to it," says Colleen McBride, chief of social and behavioral research at the National Human Genome Research Institute. "One could argue that genetics is like über-personalization . . . it is reasonable to think that it could get their attention."

But many doctors and researchers have voiced concerns over this technology hopping straight from lab bench to Web browser. They say the science of genomic medicine is in its infancy, yielding research-grade information not yet suitable for public consumption. And some raise issues of privacy.

Some researchers say it's unclear whether people will understand the genetic risk data and what they will do with it. Is this just a bit of harmless fun? Will it improve long-term health outcomes? Or will hypochondriacal patients march to their doctors and demand truckloads of unnecessary tests, harming themselves and the healthcare bottom line -- while others incorrectly see their results as destiny and adopt worse lifestyle habits? (What's one more T-bone if you are fated to die of a heart attack anyhow?)

"On the one hand we are excited by technology and its promise, but on the other hand, we want to make sure that the public's health doesn't get hurt," says Dr. Muin Khoury, director of the National Office of Public Health Genomics at the Centers for Disease Control and Prevention in Atlanta.

No matter how grave the concerns, genetic research is speeding ahead. Almost every week these days, genetics researchers are coming up with new DNA variations linked to some disease or another.

Some scientists think the information should be available for people to use.