"I think a broad-spread application of personalized genetic testing would create havoc and would likely lead to more harm than good," he says. "It will make people anxious, and it would probably push doctors to more aggressive interventions simply because of lack of information and a feeling they had to do something."
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The Washington, D.C.-based Genetics and Public Policy Center is also pushing for the Food and Drug Administration to regulate consumer genetic testing.
The center's director Kathy Hudson says that though these three genome-scanning companies appear scientifically stringent and transparent in their messages, there are no laws to prevent businesses from over-selling results or providing inappropriate tests, as some have done.
Ultimately, it will take extensive research on people receiving genome scans to reveal whether they offer real, long-term health benefits or evidence of harm. Will learning that a propensity to heart attacks lurks in your DNA finally give that extra push to cut back on the T-bones, take the stairs and finally stop smoking? Will knowing that you are loaded with cancer risk alleles hurry you to early screening?
One such study began last year. Headed by McBride and Lawrence Brody at the National Human Genome Research Institute, it will offer subjects the opportunity to be tested for eight conditions, including skin, colon and lung cancer; heart disease; and Type 2 diabetes.
The team will follow subjects from their earliest interviews all the way to their doctors' offices, kitchens and gyms to try and determine who seeks testing and why, if they understand their results and what they do with them.
Navigenics announced Tuesday that it will be partnering with scientists at the Mayo Clinic to study how its customers use the results. Customers like me.
So what am I going to do? I don't quite know yet.
Had I seen an increased risk of breast cancer you can bet I'd be feeling myself up every other Tuesday and pushing for an early start to mammogram screening.
My lifetime estimated risk for obesity is 36%, just above the population average of 32% -- a higher risk because I carry two copies of the "fat gene" FTO, discovered last April. Obesity is a risk factor for several diseases -- cancers, heart disease -- so I'll work hard to keep my weight within a healthy range, and will probably have to keep working all my life.
Does this genetic information give me the motivation to ride my bike to work and not eat that last cookie? Sure. But did I already have that motivation? In spades.
I've told my parents about the Alzheimer's results, and I am pushing my mother to talk with her doctor about taking statins to bring down her high cholesterol.
She half-laughs me off because she is already doing lots of the "right" things. She has low blood pressure; takes multivitamins and folic acid supplements; eats healthfully, including lots of fish and olive oil; keeps her mind and body active with knitting, a busy social life and regular exercise.
So maybe I should sit back and chill. Maybe the statins would hurt her in the long-run. But when scary orange boxes glare at you from your computer screen, it's hard. You just want to do something.
That is the potential power of these tests. Whether that power urges us toward healthy change, paranoid medical flailing or nothing at all, is still an open question. But as private genome scanning companies drive the science of genomic medicine forward, we'll find out soon enough.