"We can sequence the genome of a fetus. What the hell does it tell us? Much less than most people probably believe. Probabilities are not the same as guarantees," says bioethicist Tom Murphy, a visiting scholar at Yale University, in a quote from the Dec. 24, 2012 issue of Time magazine.
That statement says it all when trying to understand the lead article in this issue of Time, which features a provocative cover asking the question: "Want to Know My Future?" The article is titled "The DNA Dilemma: A Test That Could Change Your Life," and it discusses the evolving technology of genetic testing and the ethical concerns of applying this technology to an understanding of an individual's risk to disease. Already there are specialized medical laboratories offering a complete decoding of an individual's genetic code for close to $1,000. Given the rate of improvement in this technology, it is forecast that in the near term everyone will have their genetic code analyzed for future use in medical assessment.
So what does it mean to have your DNA decoded and have your genetic history at your fingertips? Will it send a message of fear because a person will now know how they will die? Will it cause a person to lose hope because they know what risk to disease they carry in their genes?
The answer to both of these questions is the same: No. As Tom Murphy states so clearly, the decoding of a person's genome doesn't tell them how they will die, but rather how they should live. Yes, this is what we will learn from decoding our genes.
Very few diseases are caused by a single alteration in our genetic code, or what is called a "mutation of the gene." Most of the things we die from -- heart disease, stroke, cancer, diabetes, dementia, and autoimmune diseases -- are a result of many genes working together in response to the lifestyle and environment of a person: diet, nutrient intake, activity patterns, smoking, alcohol consumption, drug use, exposure to chemicals, stress patterns, and radiation. All of these factors are modifiable risk factors for disease.
The important thing we learn from the decoding of our genes is our individual susceptibility. Knowing this can assist a person in learning how to construct a personalized program for their own future health, because both lifestyle and environment are modifiable. Decoding the genes provides information about the risk to various diseases, not the specific disease a person will have to deal with. As implied in the statement by Tom Murphy, the genetic risk to a disease does not become the disease unless other factors translate the risk to the expression of disease.
The future of personalized lifestyle medicine is in understanding the individual's susceptibility to a disease through genetic testing, and then the development of a personalized program for the prevention of the expression of the disease characteristics.
Research over the past decade has shown that genes are very infrequently "hardwired" to produce a disease. Rather, genes contain the information that tells the individual's physiology how it will respond to specific environmental factors that can translate to either health or disease. The Time article focuses on decoding disease through the application of genetic testing, but I think it fails to properly describe the evolving understanding of the gene-environment interaction and how this interaction is being recognized as the origin of the most common diseases. The message should not solely focus on the ethical issues of a person understanding their genetic history. Rather, because of the amazing discoveries of the past decade indicating that most of the diseases we deal with today are potentially preventable, understanding your genetic susceptibility provides an opportunity to implement a lifestyle plan to avoid individual risk factors and live up to your genetic potential.
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