I Googled my DNA…I am 23% more likely to have a heart attack

Offered the chance to be among the early testers, I agreed, but not without reservations. What if I learned I was likely to die young? Or that I might have passed on a rogue gene to my daughter? And more pragmatically, what if an insurance company or an employer used such information against me in the future?

But three weeks later, I was already somewhat addicted to the daily communion with my genes. (Recurring note to self: was this addiction genetic?)

For example, my hands hurt the other day. So naturally, I checked my DNA. Was this the first sign that I had inherited the arthritis that gnarled my paternal grandmother’s hard-working fingers? Logging onto my account at 23andMe, the start-up company that is now my genetic custodian, I typed my search into the “Genome Explorer” and hit return. I was, in essence, Googling my own DNA.

At times, surfing my genome induced the same shock of recognition that comes when accidentally catching a glimpse of oneself in the mirror.

I had refused to drink milk growing up. Now, it turns out my DNA is devoid of the mutation that eases the digestion of milk after infancy, which became common in Europeans after the domestication of cows.

But it could also make me question my presumptions about myself. Apparently I lack the predisposition for good verbal memory, although I had always prided myself on my ability to recall quotations. Should I be recording more of my interviews? No, I decided; I remember what people say. DNA is not definitive.

I have the snippet of DNA that gives me the ability to taste a compound that makes many vegetables taste bitter. I differ from people who are blind to bitter taste by a single spelling change in our four-letter genetic alphabet: somewhere on human chromosome 7, I have a G where they have a C.

It is one of roughly 10 million tiny differences, known as single nucleotide polymorphisms, or SNPs scattered across the 23 pairs of human chromosomes from which 23andMe takes its name. The company generated a list of my genotypes, based on which versions of every SNP I have on my collection of chromosome pairs. For instance, I tragically lack the predisposition to eat fatty foods and not gain weight. But people who, like me, are GG at the SNP known to geneticists as rs3751812 are 6.3 pounds lighter, on average, than the AA’s. Thanks, rs3751812!

And although there is great controversy about the role that genes play in shaping intelligence, it was hard to resist looking up the SNPs that have been linked to IQ. Three went in my favour, three against.

I was not always so comfortable in my own genome. Before I spit into the vial, I called several major insurance companies to see if I was hurting my chances of getting coverage. They said no, but that is now, when almost no one has such information about their genetic make-up.

Some health care providers argue that the public is unprepared for such information and that it is irresponsible to provide it without an expert to help put it in context. And at times, as I worked up the courage to check on my risks of breast cancer and Alzheimer’s, I could see their point.

I had decided not to submit my daughter’s DNA for testing because I didn’t want to regard anything about her as predestined. If she wants to run the 100-metre dash, who cares if she lacks the sprinting gene? And did I really want to know what genes she got from which parent and grandparent?

I, however, am not age 3. Whatever was lurking in my genes had been there my entire life. Not looking would be like rejecting some fundamental part of myself.

Compelled to know, I breezed through the warning screens on the site. There would be no definitive information, I read, and new discoveries might reverse whatever I was told. Even if I learned that my risk for developing a disease was high, there might well be nothing to do about it, and, besides, I should not regard this as a medical diagnosis. “If, after considering these points, you still wish to view your results,” the screen read, “click here.” I clicked.

In the bar charts that showed good genes in green and bad ones in red, I found a perverse sense of accomplishment. My risk of breast cancer was no higher than average, as was my chance of developing Alzheimer’s. I was 23 per cent less likely to get Type 2 diabetes than most people. And my chance of being paralysed by multiple sclerosis, almost nil.

And then I opened my “Gene Journal” for heart disease to find that I was 23 per cent more likely than average to have a heart attack. “Healthy lifestyle choices play a major role in preventing the blockages that lead to heart attacks,” it informed me.

I soon found that I might well be sight impaired. According to the five SNPs for macular degeneration I fed into the “Genome Explorer,” I was nearly 100 times more likely to develop the disease than someone with the most favourable A-C-G-T combination.

And unlike the standard eat-right-and-exercise advice for heart health, there was not much I could do about it. Still, I found the knowledge of my potential future strangely comforting. At least my prospects for nimble fingers in old age were looking brighter. I didn’t have the bad form of that arthritis SNP.

Maybe I was just typing too much.