At first, no one believed that Michael Snyder, PhD, a slender bicycle enthusiast in his mid-50s, could possibly have type 2 diabetes. “When I went to see my doctor, she said there was no way,” recalls Snyder. But, as it turned out, he did. “Scientifically, it sort of all made sense,” Snyder says. “My genome did predict the disease I got.”
Having your genome sequenced requires little more than a blood sample and maybe some saliva. Cells in the blood contain DNA, the molecule that encodes the genes. DNA is made from four related chemicals, often abbreviated as A, T, C, and G, stitched together to form chains 3 billion chemicals long. Sequencing the genome means figuring out the order of those chemicals in the chain, so the genome can be read like a book.
Genome-sequencing methods have changed over the years to make the process faster and less expensive. Though costs are coming down, insurance is still unlikely to cover the procedure, though that may change as the health benefits of sequencing become more tangible. Today, genomes can be sequenced for as little as $5,000, and various companies offer the service in an emerging genome market. Each company has its own method for sequencing, and the quality of the sequences can vary. Most companies don’t offer an analysis of the genome to help people interpret their results, though this may change as commercialization proceeds.
To date, few people have had their genomes sequenced (“Genome Sequencing,” right), and scientists still debate how useful the information could be in preventing and treating illness. But for Snyder, who volunteered to have his genes and body studied in unprecedented detail, knowing his genome helped him identify diabetes early and gave him an edge against the disease. If genome sequencing becomes commonplace, many people may have the same opportunity to read their health fortunes and act to make their future the best one possible.
Snyder is the head of a biology laboratory at Stanford University and has an unusual approach to science: He is his own lab’s research subject. The goal is to help integrate medicine with state-of-the-art technology that allows scientists to chronicle many of the molecules that make up the body. One of the most important molecules in the body is DNA, the substance that carries genetic information from generation to generation. People have 40,000 genes encoded in their DNA, the complete set of which is called the genome. Snyder wants to harness this formidable block of information to say something useful about human health.
As a first step, Snyder decided to gather as much data as possible about a single person, for years, to see how genes translate into that person’s health status over a lifetime. He quickly realized that such an experiment was going to take a lot of time and a lot of tests. Because Snyder already spent most days at the laboratory, it made sense that he should be the guinea pig. Plus, he had philosophical reasons to volunteer. “I’m a big believer that genomics should be an important part of health care and medicine,” he says. “If you’re a believer, you should participate.”
Type 2 Attacks
For the genome sequencing, Snyder provided a blood and saliva sample. Several months later, in early 2010, he received the results of the sequencing. His lab immediately got to work figuring out what his genome revealed about how likely he was to develop a host of diseases, which took another couple of months. The results showed that the disease he was most likely to get was glaucoma. Snyder says he pretty much expected that; glaucoma genes are common among people of European descent. What he wasn’t expecting was his high genetic risk for type 2 diabetes. “It’s not in my family,” he says. Even with these odds, he wasn’t worried. Snyder thought that his active lifestyle and healthy weight would protect him from his diabetes genes.
For scientific reasons, Snyder started to pay more attention to his blood glucose levels anyway. “Because of my genome, I signed up for fancy glucose metabolism tests,” he says. Those revealed that while his metabolism wasn’t exactly typical and his glucose levels tended to be on the high side of normal, he didn’t have diabetes. At least, not yet.
That’s when Snyder caught a nasty case of respiratory syncytial virus (RSV), which is common in children, from one of his kids. “I was out for two days,” he says. “For anyone who knows me, that’s quite a long time.” After that, something strange happened; Snyder’s blood glucose levels shot up, placing him firmly in diabetes territory. While viruses have been linked to the development of type 1 diabetes, few people have suggested that they play a role in the onset of type 2. Snyder can’t prove it yet, but he thinks that it was indeed the infection that led to his sudden development of diabetes. “If you look at the timing, it doesn’t look coincidental,” he says. “The obvious interpretation is that my genome has me at risk, and this viral stress response triggered it.”
The Road to Recovery
After talking with his doctor, Snyder decided to make some big lifestyle changes to see if he could bring his glucose levels down with an eating plan and exercise. “I did not have a good diet, but on April 13 of last year, I completely changed my diet,” he says, chuckling over how he remembers the exact date. “I used to eat a lot of ice cream and sweets. … After this diagnosis, I went cold turkey.” That helped him cut calories to foster weight loss. In addition, he doubled his biking and started to run. “I didn’t know if it was going to work,” he says.
All he could do was watch his body under so many microscopes, and wait. Over the next six months, Snyder lost 15 pounds, about 9 percent of his body weight. As his weight crept down, so too did his blood glucose levels. “I didn’t know what the answer was going to be, if it was going to have a happy ending,” Snyder recalls. “But it has had a happy ending.” His blood glucose levels normalized and remain stable to this day.
What Snyder finds particularly striking about this study—what really cements his belief that genomics is the way to better health in the future—is what might have happened to him if he wasn’t a lab rat. “As a healthy person, I’d go to the doctor every two or three years,” he says. “I probably wouldn’t have caught my high blood glucose for 20 months after I did.” And with a disease like diabetes, such a delay has real health consequences. “In general medicine, if you catch things after they become symptomatic, they’re harder to control,” he says. Type 2 diabetes is a progressive disease, and Snyder isn’t sure he’d have been able to normalize his blood glucose levels without medication if he’d been diagnosed a year and a half later.
Snyder admits his approach to health is not for everyone. “If you are a worrier, you should not get your genome sequenced because it will tell you that you are at risk for something,” he says. Snyder’s genome also hinted that he’s at risk for heart disease, and it’s something he’s keeping an eye on. By the time you read this article, Snyder will be approaching his 900th day of life as a science experiment. How long does Snyder plan to study himself? For the rest of his life, he says, and with good reason: “I think this could transform medicine.”