DNA Testing Can Unlock the Path to Precision Medicine & Personal Wellness

President Obama made waves last year when he used some of his State of the Union address to call for $215 million to be devoted to developing what the White House is calling “precision medicine,” medical care that leverages advances in genomics to deliver extremely personalized and thereby more effective—and cost effective—medical care.

At the hospital level, sequencing of genes such as in the case of a cancer patient’s tumor—basketball legend Kareem Abdul-Jabbar being one of the most famous examples—can help doctors select the most effective drug to fight it. But hospitals are not the sole source of genetic screening these days. A growing number of consumers are taking their health care into their own hands and using direct-to-consumer screening services such as Genetic Direction and 23andMe, which use saliva samples to identify and analyze dozens of traits embedded in the 23 pairs of chromosomes that make up your human DNA.

By pulling back the curtain on your molecular make up, you can gain insights on how your body works and how your diet, exercise, environment, lifestyle habits and behaviors, and medications you take directly impact how you look, feel and function.

“We know genetics plays a role in certain diseases and conditions such as high blood pressure and high blood glucose,” says genetic epidemiologist Mark Sarzynski, PhD, Director of Genomics Research at Genetic Direction. “Traditionally, if you have these inclinations, maybe you’d change your diet, begin to exercise, and/or take a pill. All of those interact with your genes. We’ve always known that influence was there. Now the science behind how genes interact with all these factors is really starting to emerge.”

The results, when paired with appropriate advice, can have a significant impact on your health and well being. In one study conducted by investigators from Stanford Prevention Research Center, scientists found that a group of dieters who were provided with a diet appropriate for their genotype lost more than twice as much weight as their peers following a generic diet not tailored to their specific DNA. Among those following the lowest carb and the lowest fat diets, the results were even more remarkable. The men and women following those diets who were genetically inclined to have success with that type of macronutrient intake enjoyed a weight reduction of nearly 7 percent compared to only a 1.4 percent loss among those following those diets without being a genetic match for them.

Personalizing Your Lifestyle
Most of us already have a fairly decent grasp of our basic inheritable traits. We know, for instance, if we sunburn easily or are likely to develop male pattern baldness. Other traits, however, are more elusive or may be tendencies you didn’t realize were genetically influenced. Take exercise for example. “Everyone who gets off the couch and starts exercising has some benefit,” says Sarzynski. “But research has shown us that there’s a lot of variation in how much. So we look at gene variations and we see there’s a large genetic component of up to 50 percent that influences weight loss and fitness responses to exercise.” By analyzing a person’s personal genome, scientists may be able to tell who will be responsive to various types of training and what types of training will be most beneficial for their personal genotype.

The same can be done for myriad health, wellness, diet, and lifestyle factors, ranging from how likely you are to crave sugar to your risk for cognitive decline. It’s essential to recognize, however, that the presence of certain genotypes does not mean any given outcome is certain. Possessing a genotype that gives you an increased or decreased potential for a certain health trait does not mean you will ever, in fact, express that trait. Behavioral, environmental and other factors all play an important role in gene expression.

It’s also a relatively new field of study that is developing and evolving every day, says licensed genetic counselor Amy Sturm, associate professor of human genetics at The Ohio State University Wexner Medical Center. “In some cases there still isn’t enough genetic data to draw absolutely conclusive results,” she says. For instance, a team of Harvard researchers recently discovered that genetic variants once thought to cause hypertrophic cardiomyopathy, a genetic heart condition that can cause sudden death in young athletes, are in fact benign. Newly available genomic datasets showed the researchers that these variants were found mainly in people of African descent, and at relatively high frequencies. Because of how common the variants are in individuals of African ancestry, they are known to be likely benign. That means African Americans were receiving a disproportionately high number of false positives for having a risk of the potentially lethal condition.

The researchers further concluded that if more people of African ancestry had been sequenced and included in the original studies and databases, they would have had a more accurate picture of the real risk for that particular variant. But the data simply wasn’t available until now. Because many of the databases are population based, more of those types of discoveries may be made as the databases grow and become more diverse.

It’s also extremely important to take it all in context says Sturm. “I had one client who had a ‘typical’ risk for heart disease according to his DTC genetic testing report,” says Sturm. “Problem was that he was a former smoker with high blood pressure who also had a full three generation pedigree of early onset heart disease, so he was actually at high risk!” Sturm counseled him about this as well as on his other potential risks, flagging real concerns, assuaging others and directing him to the heath care professionals he needed to consult to stay healthy and avoid disease.

“Genomic screening can be a useful tool, but it’s just part of the picture,” says Sturm. “You have to put it in context of your whole self—your age, family history, medical conditions, and current habits and behaviors. Used that way it can open the door to making meaningful behavior and lifestyle changes that will impact your health in a positive way.”

- Written by Selene Yeager