*A bodhi of medical knowledge, incite, and experiences from a future physician.

Saturday, May 15, 2010

What's Wrong With This Picture?

For now, unlike originally announced last week, this product will not yet be available at your neighborhood Walgreen's...but it is only a matter of time, believe me. The proposed product: a home genetic test...check that, a home saliva test (self dubbed: "health risk assessment kit") which you can send to a California company for a DNA analysis. And their promise? A risk report for a plethora of medical issues - all within the confines of your home. Great, right? Wrong. I have spent 3 years in med school and 4 more years studying genetics/developmental biology for my B.S. degree, and I have not even the first clue what gene data they are using to tell you your risk for: (off their own website mind you): Asthma, Atrial fibrillation, Coronary artery disease, Diabetes - Type 1 & 2, Glaucoma, Hypertension, Melanoma, Myocardial infarction, Obesity, Osteoarthritis, Peripheral arterial disease, and a number of cancers too.

You see, as much as scientists have discovered when it comes to genes and disease, they are not even close to understanding how your DNA dictates your propensity for certain illnesses. For example, there is the concept of epigenetics stating that many or our bodies cells 'override' the DNA code contained within their nucleus, sometimes temporarily and sometimes permanently, to produce gene products in response to the local extracellular environment. Genetic tests will only tell you what the sequence of your DNA compared with the so-called "normal" or in other words, how the majority of the population's DNA sequence reads. These gene tests do not take into account a whole balderdash worth of medical genetics concepts: paramutation, bookmarking, imprinting, gene silencing, X chromosome inactivation, position effect, reprogramming, transvection, carcinogenesis, teratogenic effects, histone modifications, and heterochromatin changes. All this means that one's cells can change frequently by a whole number of mechanisms and all those changes might not be reflected in the actual DNA sequence.

Not only are there a whole slew of post-DNA production changes, most mutations seen in a DNA sequences do not directly correlate 1:1 to disease states. Some you've heard of do...like with cystic fibrosis (CFTR gene), however most don't, like with obesity (or any of the other above diseases). So next time you are at your doctor's, and they hesitate to recommend genetics testing bought at your local Walgreen's....now you know why. Spend your $200 on quit smoking classes or a personal trainer at least that will help extend your life.

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