CNN Medical Correspondent
It sounds like the medical equivalent of a crystal ball: A single test that helps tell you your chances of developing Parkinson’s disease, prostate cancer, diabetes, alcoholism, obesity, Lou Gehrig’s disease, and more than 75 other diseases and conditions . Wow, I thought, I’ve discovered the holy grail of health care.
The genetic analysis is offered by a company called 23andMe – here’s the section that lists all the things they test for. You just spit into a test tube (don’t worry, you won’t miss; they give you a funnel), mail it in, and pay $399 for a genetic analysis of dozens of diseases that ends up on a secure Web site, which you can peruse at your leisure. The site quotes a satisfied customer: “I thought how fascinating if I could know more about my future. I should be aware for myself. For my children. If there’s something that I could prevent for the future…why not learn? Why not help myself?”
I ran into this Web site while researching a story this week on genetic tests being offered online. The question that keeps coming up in my mind is this: What do you get for your $400? Do you find out for sure that you’re destined to get, say, glaucoma? That you’re more likely than most people to get it? Way more likely or just a little more likely?
“I can’t figure out what you get for the $400,” I said to Brian Naughton, the Founding R&D Architect at 23andMe (yes, that really is his title, and the company name comes from the fact that we all have 23 pairs of chromosomes). “For example, if I get your test and it tells me I have the worst possible heart attack genes, what chance do I have of having a heart attack?”
Naughton consulted his notes: If the test shows you have the worst possible genes, you have a 21 percent chance of having a heart attack at some point in your life.
Okay, and the average person? What’s his or her risk of having a heart attack at some point?
18 percent. Oh. So for $400 I get to find out that I have a 21 percent chance of having a heart attack instead of the usual 18 percent? How are these three percentage points helpful to me?
I put that question to Linda Avey, the co-founder of 23andMe. “I don’t think heart attack is really the best category for you to look at,” she said. “There are many genes involved in whether or not you’ll have a heart attack. We’re just testing for one of them.”
Okay, I said to Naughton. Give me your best shot. You test for dozens of diseases. Give me the one that would really make it worth it for me to send you $400. Parkinson’s, he told me. If you have an extremely unusual genetic variation, you have a 59 percent chance of getting Parkinson’s sometime in your life rather than the usual 1-2 percent chance of getting the disease. Wow, a 59 percent risk – that’s high. And if I test positive for this gene, what can I do? “I’d drink more caffeine,” Naughton said. “A study showed that people who drink more caffeine are less likely to get Parkinson’s.”
So I put this question to two neurologists: If a patient came to you who had this “Parkinson’s gene,” would you tell them to start drinking more caffeine? Both said absolutely not. “Caffeine comes with higher risk of hypertension and cardiac arrhythmia,” said Dr. Milind Kothari, vice-chair of the Department of Neurology at the Penn State College of Medicine.
So what’s the bottom line of all this? According to Mark Bouzyk, director of the Center for Medical Genomics, it’s one thing to get a genetic test when you have a specific reason to do so. If your mother and sister have breast cancer and you’re a Jew of Eastern European ancestry, you have a relatively good chance of carrying the bad gene, and knowing if you do or don’t can help you make important health decisions.
But without a specific reason, he says you should be careful when you go fishing into your DNA for information about dozens of diseases. You might end up wasting a lot of money. Or, even worse, you might find you have a high chance of getting a horrible disease – when there’s not much you can do about it.
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