Although judging from what I see around Rittenhouse Square and the pages of fashion mags these days, that opinion may once again be in the minority. Gross. Anyway.
Familial jokes about heritable body odor aside, I seem to have done pretty well for myself in the inherited conditions department. (Excepting the body odor. 23andMe doesn’t yet provide analysis for what we call the E Gene, for Uncle Everett, admired far and wide for his eye-wateringly terrible pitstink, but I hereby offer up my genome to the search.) When it comes to Parkinson’s, Crohn’s, Rheumatoid Arthritis, I’m all Typical to Reduced Risk. Huzzah! But there’s one great big insulin-resistant elephant in the genetic room, and that would be...
Type II Diabetes. Dun-dun-dunnnnnn!
If you’ve been here at the Modernity Ward for long, you know that the whole reason I started blogging has to do with my Polycystic Ovary Syndrome. Blah blah no periods, blah blah facial hair, INFERTILITY INFERTILITY, metformin low-carb two kids. Ta-da.
It should have come as no shock to me, with my family history of Type II Diabetes (maternal grandpa, paternal lots of people) and, oh, CONDITION THAT HAS BEEN LINKED TO DIABETES that I carry a genetically increased risk of developing Type II. Still, there was a sinking feeling in my gut when I saw it pop up in forbidding red type. It’s a lot easier to avoid thinking about the possible sequelae of insulin resistance when it’s not blaring from your monitor. I always knew it was a theoretical risk, but diabetes always seemed so far away.
Thankfully the facts are not nearly so horrifying. While on average, 21.9 out of 100 people will develop Type II Diabetes, those with my genotype develop it at a rate of 30.9 out of 100. A significant increase, statistically speaking, but not so enormous as to be a death sentence. More important, the heritability of Type II Diabetes is estimated to be about 26%. Does that mean the other 74% of the equation is within my control? Not really. While 23andMe’s explanation notes that “environmental factors” play a large role in who develops diabetes, they list the following as environmental factors:
“...obesity, gestational diabetes, giving birth to at least one baby weighing nine pounds or more, high blood pressure, abnormal cholesterol levels, physical inactivity, polycystic ovarian syndrome, other clinical conditions associated with insulin resistance, a history of impaired glucose tolerance or impaired fasting glucose, and a history of cardiovascular disease.”
Bolding mine. Those are all things I have done/had/seen on the lab sheet, and while they might play into whether I actually develop diabetes at some point, they’re not exactly independent from diabetes in the first place. I mean, they’re all facets of the same problem, with insulin and inflammation at the center, and maybe some other single factor underlying even that. So it’s not like if can just keep my cholesterol down and, you know, not have another horse baby, I’ll lessen my chances of becoming diabetic. It’s that the appearance of those bolded factors in my own life is telling me that yes indeedy, I am on the Acela to injectable insulin if I don’t watch those carbs. This applies to me. No getting around it.
And as terrifying as that is, it’s awfully useful information to have. Ass-kickingly useful.
What I suspect, and what I’d love to see some data on someday, is whether those “environmental factors” listed above ride right alongside diabetes in the genome. I keep putting “environmental factors” in quotes because the term implies something separate from the diabetes, but I think they’re all just best buddies, diabetes and bad cholesterol and PCOS, and they like to hang out together flirting with the carhops at the drive-in and drag-racing their T-birds and smoking. And I’d like some scientific confirmation on that.
I can't articulate it very well (still), but I find it so strange that you and others of my favorite bloggers are advertising for this company. I get the intrigue with knowing something about your genes, but it also seems so iffy and potentially Brave New World and like something you might in other circumstances be really critical of. Can you write about why you're ok with working for them, or whether you have any qualms?
Posted by: caro | 04/22/2009 at 05:13 PM
I'm very against this whole thing -- it's soooo not ready for prime time. You're super smart, Jo (and you too, Cecily), and very able to understand some of these risk estimates (which, actually, some very smart people can't), but genetic testing for most illnesses is still in its infancy/ experimental phase. The potential for harm seems quite large -- people altering their behavior on what very well could be completely erroneous information. Eating fewer carbs isn't going to hurt anyone, but, say, continuing to smoke because your reading says you're unlikely to get heart disease or cancer would be.
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Information is power, but misinformation is danger, and right now at least some of these interpretations are definitely misinformation.
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As soon as personal genome analysis hit the market, I was fascinated -- I remember reading about it years ago, and thinking how cool it would be to get a gander at my mitochondrial DNA. That was my main reason for signing up as quickly and as enthusiastically as I did for the 23andMe service: the possibility of a look deep into the past, to the best of our ability to interpret the data. The other stuff, well, that came later.
A child of friends was in the hospital recently. His father, a scientist, marveled at the state of treatment at the most respected children's hospital in the country: "There's just so much we don't know." That's a phrase I hear again and again, with respect to the origins of PCOS, the development of Alzheimer's, so many different conditions about which we know a lot more than we did ten years ago but whose geneses remain largely in the dark. There's just so much we don't know.
For me, that's been the appropriate way to approach the question of personal genome analysis. It's a practice still in its infancy, as DoctorMama rightly points out. And in a world where the majority of people don't know how to interpret weather probabilities, the little nibble of information you get about, say, your chances of developing Type II diabetes can be baffling. 23andMe has made geneticists available for us to talk to about these things, which I think would be an absolute necessity for anybody who hasn't had a few statistics classes, but I also think this is the kind of information people need to take to their physicians. Having a slightly lower risk of developing diabetes doesn't mean you won't ever get it -- and having an increased risk doesn't mean that you will. And absolutely no gene will protect you fully from the effects dangerous things like smoking. Or, you know, inhaling asbestos or driving 110 mph without a seatbelt. Just because I'm resistant to norovirus doesn't mean I eat my cereal out of a preschool toilet.
Here's another example. My genes say that I carry a decreased risk of developing OCD -- but I did exactly that after Sophia was born. One genetic marker suggests a decreased risk for asthma, and another suggests an increased risk. Does that mean I break even and have an average risk? Does it even matter? Either way, I have asthma. I carry two markers that suggest I will have babies of typical birth weight (neither lighter nor heavier than average), and I had one 8 pound 3 ounce baby, and one 9 pound 10 ounce baby. Did I have gestational diabetes the second time? I do carry a marker for increased chances of developing GD. But I didn't get tested, so we'll never know.
Clearly, genes are not our destiny entire. We are complex beings composed of an interaction between our genome and our environment, with a little mystery thrown in if you like that sort of thing. Does this mean genetic analysis is useless? Of course not. It means it's a tiny little piece of the picture, a piece that will be more and more useful as we (general we) gather more and more evidence. I want to participate in the research because I think it's useful, I trust my own ability to interpret the evidence (with expert help as needed), and I find it fascinating as heck.
But that's just me.