In a small but ground-breaking study, researchers have discovered a genetic fingerprint for type 1 diabetes—a sort of early warning marker that emerges years before diagnosis. Depending on the results of future studies, this fingerprint could serve as a diagnostic tool that allows for prevention of the disease.

Generally, type 1 is predicted—primarily in research studies—when blood tests identify the antibodies that wage war against the insulin-producing beta cells of the pancreas. The use of antibodies as a predictive tool has drawbacks, however. Preventing full-blown type 1 should ideally happen before or during the immune attack, while there are still beta cells left to save. But since antibodies never fully recede and are sometimes found in the absence of type 1, they don’t give good information about when or in whom to initiate potentially risky experimental preventive therapies—like insulin or immunosuppressive agents—or about whether the therapies are working.

The advantage of this new genetic signature is that it seems to appear only while beta cells are being actively targeted by the immune system. “One day we will be able to find the kids with beta cells being destroyed and keep these kids from becoming diabetic,” says the study’s principal investigator Martin Hessner, PhD, associate professor at the Medical College of Wisconsin in Milwaukee. “That’s the dream.”

For the study, researchers used blood samples from 12 people with recent-onset type 1, 12 people with long-standing type 1, 12 nondiabetic controls, and nine “at-risk” siblings of people with type 1. The researchers incubated the samples with healthy cells. After six hours, proteins in the blood from the recent-onset group entered the healthy cells and activated the type 1 genetic pattern, but the blood proteins of the control and long-standing type 1 group did not. Since the signature was able to differentiate between recent-onset and long-standing diabetes patients, the researchers concluded it may be a hallmark of an active immune attack.

The findings on the at-risk siblings were especially provocative: Three presented the signature up to five years before being diagnosed with type 1—one of them before the antibodies showed up. Meanwhile, two other siblings possess the signature, but as yet have not developed diabetes. “If the approach is predictive, [these two] would be the two that develop type 1,” says Hessner. Interestingly, the remaining four at-risk siblings have the antibodies, but neither the signature nor diabetes. “They had some immune activation,” he says, “but it’s been turned off.”

The results are promising but far from conclusive, says Hessner. “We’ve got a long way to go, but there’s reason to be optimistic.” The study was published in the Feb. 1, 2008, issue of the Journal of Immunology.