View Full Version : NIH researchers sequence healthy volunteersí DNA ,find they arenít so healthy

rock hunter
06-15-2015, 12:02 AM
A few years ago, a team at the National Institutes of Health set out to study healthy people's DNA. They recruited 1,000 volunteers who appeared to be free of disease based on blood tests, echocardiograms, self-reported symptoms and other things your personal doctor would normally check.

Then the scientists looked at their genomes.

What they found surprised them. In studying the A's, T's, C's and G's of the DNA they discovered that more than 100 of the volunteers had mutations that made them more susceptible to a condition like cancer, kidney disease, or even things like Birt-Hogg Dube, which is associated with skin tumors, that are very rare. And when the researchers investigated further, they verified that 34 of those individuals or their family members had been living with the disease the mutation pinpointed but had no indication this was the case. All of the participants in the study were adults 45 to 65 years of age, a time when the signs of many genetic diseases would likely already be obvious.

"It was very startling," said Leslie Biesecker, chief of the medical genomics branch at the National Human Genome Research Institute. "To say this is a lot of people is an understatement."

As DNA testing becomes more common, such findings are likely to redefine the concept of healthy. Previous studies have estimated the number of people with a genetic condition at less than 0.02 percent. The new study, published in the American Journal of Human Genetics on Thursday, indicates that the number may actually be 3 percent or more. Translated to the population of the United States that means that some 9 million people, a group the size of the population of New Jersey, may be living with a genetic condition they don't know about.

In the DNA of one volunteer, researchers found a gene for hearing loss. When they called the volunteer to inquire about any hearing issues, they were told there were none. But when the volunteer was brought in to NIH's clinical center for further testing, an audiologists found moderate to severe hearing loss.

"He probably had this his whole life and had absolutely no idea," Biesecker said.

In other man, scientists located a gene for breast and ovarian cancer. Biesecker said that the volunteer shared the information with his sister who ended up getting herself tested privately and found that she had the mutation as well. She decided to undergo preventative surgery for ovarian cancer and during the procedure the doctors found a tumor.

Equally fascinating to scientists as the 3 percent of volunteers who had mutations and had diseases they didn't know about are the 3 percent of volunteers they found who had mutations but no sign of disease. In the future this information may help scientists gain insights about whether there are other mutations or factors that can protect humans from specific diseases.

There was one participant, for instance, who had had a gene for Coffin-Siris Syndrome which is a severe intellectual disability but the volunteer actually had a higher than average intellect.

Biesecker said that in the future he believes that people will get their genomes sequenced early in life and that doctors will refer to it throughout their lives as a kind of reference about people's bodies. "It will become part of routine health care," he said. "In most cases, genes pinpoint a susceptibility, not a fate. It will be a clue for doctors and patients about what you should look for -- and how to stop it."