Genetic Links To Disease Found With DNA

NEW YORK — Scientists are scanning human DNA with a precision and scope once unthinkable and rapidly finding genes linked to cancer, arthritis, diabetes, and other diseases.

It's a payoff from a landmark achievement completed five years ago — the identification of all the building blocks in the human DNA. Follow-up research and leaps in DNA-scanning technology have opened the door to a flood of new reports about genetic links to disease.

On a single day in February, for example, three separate research groups reported finding several genetic variants tied to the risk of getting prostate cancer.

And over the past year or so, scientists have reported similar results for conditions ranging from heart attack to multiple sclerosis to gallstones. The list even includes restless legs syndrome.

Interviews with scientists at the center of this revolution and a review of published studies over the past six months by the Associated Press make clear the rapid adoption of the new technology and the high expectations for it.

Since 2005, studies with the gene-scanning technique have linked nearly 100 DNA variants to as many as 40 common diseases and traits, scientists noted this month in the Journal of the American Medical Association.

"There have been few, if any, similar bursts of discovery in the history of medical research," two Harvard researchers declared last summer in the New England Journal of Medicine.

What does all this excitement mean for ordinary people? Not so much just yet. Simply finding the genes that can raise the risk of an illness doesn't mean you can prevent the disease. And developing a treatment for it can take years.

But there have been some payoffs already.

One involves a leading cause of blindness in older people, age-related macular degeneration. A series of genome-wide scans, the most recent in 2005, "led to huge breakthroughs in understanding" that disease, a Houston scientist, Daiger, said.

What's made this and other hopeful findings possible is the "genome-wide association study," which lets scientists scan the entire complement of DNA from thousands of people in unprecedented detail.

"It lets you go searching for that needle in the haystack," says Michael Watson, executive director of the American College of Medical Genetics.