"This is an incredibly impressive paper," says Daniel MacArthur, who studies genetics at Harvard and MIT but wasn't involved in the work, which was published Monday in Nature Biotechnology. He wrote a commentary accompanying the paper.
Researchers have long known that there are rare people who stay healthy despite profound genetic defects. Friend and his colleagues decided to systematically identify such individuals.
"We were interested in finding what might protect people from getting disease," Friend says. "If you're going to try to look at what protects people from getting disease, it is not necessarily the right thing to look at those who have disease. The right thing to do would be to look at those who have not gotten sick."
So Friend and colleagues at the Icahn School of Medicine at Mount Sinai in New York launched a massive search. They gathered genetic data from 586,306 people from around the world. The data came from private companies, hospitals, universities and elsewhere. The researchers then scanned the DNA sequences for known disease-causing mutations.
The researchers identified 13 people who had defects thought to always cause eight severe disorders, including cystic fibrosis. But none of the 13 individuals appeared to have developed any signs of these conditions, which Friend says is "very remarkable."
The absence of illness in these people suggests there may be something else in their genes, or in their environment, helping them. "There must be some protective element for them to have escaped the severity of the symptoms that would have been expected," Friend says.
Unfortunately, he says, none of the 13 had agreed ahead of time to allow researchers to contact them later for further studies. Ethical standards require prior consent to do that.
Had the subjects been asked to give consent upfront, researchers might have been able to determine what enabled them escape what should have been their genetic fate.
"It's extremely frustrating not to be able to go back and to recontact them," Friend says.
But other researchers say the study is nevertheless important because it shows that advances in genetic and data analysis technologies have made it possible to find large numbers of these people. Because many genetic disorders are rare, large numbers of people would have to be found to yield useful information.
"If you'd asked me five years ago, it would have seemed laughable," MacArthur says. "But it seems entirely reasonable that over the next five years we will certainly have in the millions of individuals who could potentially be studied in this kind of work."
In fact, Friend and his colleagues have already identified a handful of other "genetic superheroes" through other means and have begun studying them. They include people who didn't develop Alzheimer's disease even though they are carrying mutations linked to the devastating brain disorder.
"We're actively decoding those individuals to identify how are they did they avoid getting that horrible disease," says Icahn's Eric Schadt, one of Friend's colleagues. "We're very excited about it."
The team is also also launching The Resilience Project, which aims to recruit millions of volunteers who have agreed in advance to let researchers study them.