I hear an awful lot from people (especially those tracking down a sperm or egg donor) who are interested in finding out about their DNA, thinking that their DNA would tell them something about their health. But that’s a bogus supposition.
Even if we take your DNA and if every aspect of your DNA was known, the question is: “would it be possible to predict the diseases in your future? Could that knowledge be used to forestall the otherwise inevitable?“ According to an important article in The New York Times, the answer is: “No.”
While sequencing your entire DNA is proving very useful in understanding diseases and finding treatments, it is not a method that will predict your medical future. You know why? There are other issues involved. It’s not the only variable.
And this new study from twins in five different countries concludes, it is not going to be possible to say that, for example, Type 2 diabetes will occur with absolute certainty unless a person keeps a normal weight, or that colon cancer is a foregone conclusion without frequent screening and a removal of polyps. Conversely, it will not be possible to tell some people that they can ignore all the advice about, for example, preventing a heart attack because they will never get one. According to their DNA they can still get one.
It turns out, even when they find DNA which would indicate a “Whoops! You have a gene for _____,” most people will still be at an average risk for one of more than 20 diseases. Their risk is like the general population, even with the gene. Isn’t that interesting?
There was one positive finding (positive – not in a good way): “…as many as 90 percent of people would learn that they are at high risk of getting at least one disease and the gene sequencing could, in theory at least, identify as many as 75 percent of those who would develop Alzheimer’s.”
The reason for all this is there is behavior, there is environment and there are random events. I have a friend who, sadly, is struggling from lung cancer. Nice, healthy, good environment, good diet, never smoked, not around smokers – yet she has lung cancer. There is a huge issue that comes under the category of “randomness,” i.e. bad luck.
So if you do a whole genetic analysis of yourself, we can look at some things you might want to be more concerned with and maybe make sure you keep your fat level low, your exercise level up, but none of it, in general, determines anything.
“The real benefit of studying your genes is not to predict your future medically, but to understand how diseases occur and how to use that knowledge to develop better therapies.” That’s just the reality. So do not come to me and tell me you want to go back through generations to find out if anybody had a disease because it doesn’t necessarily have a damned thing to do with you.