Can Genetic Testing Predict Type 1 Diabetes? Experts Say Earlier Treatment Is PossibleNEWS | 14 October 2025This article is part of “Innovations In: Type 1 Diabetes,” an editorially independent special report that was produced with financial support from Vertex.
In 2024 Stephen Rich and his colleagues published a study in which they assessed the genetic risk of developing type 1 diabetes for more than 3,800 children from across Virginia. Almost immediately Rich, a genetic epidemiologist at the University of Virginia, was inundated by e-mails and calls from parents who had read the article and wanted their kids tested, too. Unfortunately the study was over, so Rich couldn’t help them. But the experience exemplified the growing interest in genetic risk tests for the disease, he says.
There is currently no cure for type 1 diabetes, a chronic condition in which the body’s immune system attacks and kills insulin-producing beta cells in the pancreas. Knowing someone’s genetic predisposition to type 1 diabetes, however, can help doctors identify whom to flag for follow-up tests. It can also lead to earlier adoption of therapeutics to manage the disease or delay its onset. “There’s tremendous power in terms of understanding the genetics of type 1 diabetes,” says Todd Brusko, director of the Diabetes Institute at the University of Florida. As more therapies become available, he adds, the eventual hope is to use genetic profiling to determine who will respond best to one drug versus another.
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Recent advances in genetic screening tools have not only revealed an intricate interaction between a person’s genes and their immune system but also made it possible to imagine a future in which every newborn is screened for type 1 diabetes risk. Some health-care authorities are already beginning to consider universal screening. “It’s very exciting times,” says Maria Jose Redondo, a physician and professor of pediatric diabetes and endocrinology at the Baylor College of Medicine. “A lot of progress has been made, and now we’re at the point of applying it.”
In the U.S., around one in 300 people develops type 1 diabetes. Although the disease is best known for manifesting in children, adults account for almost half of new diagnoses. Scientists still don’t know what triggers it. Environmental factors seem to play a crucial role in promoting the disease’s development and progression, but the exact causative agents are unknown. “We know less about the environmental factors than we know about the genetic factors,” Redondo says.
In a large study called TEDDY (for “the environmental determinants of diabetes in the young”), launched in 2004 in Europe and the U.S., researchers followed 8,676 individuals with high genetic risk to try to identify triggers for type 1 diabetes. They found just one consistent environmental factor linked to higher likelihood of acquiring the disease: early infection with enteroviruses, a type of virus that can infect beta cells. Not all children who get these common infections go on to develop type 1 diabetes, though, so additional factors are probably at play. In addition, the incidence of the disease has been increasing steadily over the past 60 years, suggesting that some change in environmental exposures or the removal of protective factors—or both—may be involved.
Genetics accounts for about half of a person’s risk of developing the disease, meaning what is written into someone’s DNA is “not destiny,” Rich says. “If you have a high [genetic] risk, it doesn’t mean you’ll get it, and if you have a not-high risk, that doesn’t mean you’re protected.”
For people with a close relative with type 1 diabetes, the risk goes up to about 18 in 300. Those with an identical twin with the disease have the highest risk—about one in two. They are 150 times likelier to develop the illness than someone with no family history and eight times likelier than someone with a parent or sibling who has been diagnosed. Even so, around 90 percent of people who are diagnosed with type 1 diabetes have no relatives with the disease. Until recently, population-level genetic screening, which would include individuals regardless of their known risk factors for the condition, was not a practical option. But new breakthroughs have begun to change that.
Scientists have identified at least 90 regions in the human genome that hold genes connected to type 1 diabetes. Researchers are most interested in a gene cluster called the human leukocyte antigen system (HLA), which encodes proteins that help the immune system distinguish self from nonself. This gene group accounts for around half of a person’s genetic risk of developing the disease. Because it helps to protect us from infections, HLA is also highly variable, says Mark Anderson, director of the Diabetes Center at the University of California, San Francisco. “There’s selective pressure for us to have different HLA genes because that way, a virus or bacterium that comes along won’t wipe everyone out.”
Most people who acquire type 1 diabetes have at least one of two specific-risk-conferring gene variants, or alleles, in this region. “This region is so critically important to whether we’re susceptible to autoimmune diseases that just by measuring variation there, we can capture risk,” says Richard Oram, a professor of diabetes and nephrology at the University of Exeter in England. Some HLA variants increase risk up to 20-fold, he adds, whereas others decrease risk by the same amount. In effect, it’s as if 10 to 15 percent of people with European ancestry carried a genetic vaccine to type 1 diabetes, Oram says, referring to the HLA gene alleles that decrease risk.
In 2015 Oram and his colleagues developed the first version of what is now one of the most widely used tests for type 1 diabetes genetic risk, administered primarily in research settings (the U.S. has yet to approve any test for type 1 diabetes risk for real-world use in doctor offices). Rather than just adding up the contribution of each variant, Oram and his colleagues’ test incorporates the complex interactivity of various alleles with one another, including ones with protective effects. They also incorporated dozens of other non-HLA sites—mostly from genes also related to the immune system—that contribute small amounts of individual risk but can add up to larger cumulative risk.
The original version of the test examined just 10 alleles and “worked pretty well,” Oram says. The latest version, developed in 2019, uses 67 alleles and produces “highly sophisticated” results, Redondo says, adding that it now represents “the golden standard to date.”
When Oram originally developed his test, he did not have risk prediction in mind; rather he was trying to decipher the type of diabetes in a group of his patients. The individuals he was working with, who were 20 to 40 years old, had overlapping features of type 1 and type 2 diabetes. People who fall into this “gray area” of symptoms are commonly misdiagnosed, he says. While brainstorming solutions over coffee with a colleague, Oram realized a genetic test could offer clues for people with a less clear presentation of the disease.
After successfully developing the test, Oram learned that other research groups were interested in tests to determine genetic risk for type 1 diabetes. Fortunately his test “also turned out to be really good for that,” he says.
With Oram’s test, doctors can identify the highest-risk individuals, who can then get tested for the antibodies that attack the body’s beta cells. “If you do HLA screening followed by antibody testing at specific ages, you’ll pick up far and away the vast majority of cases,” says William Hagopian, a research professor of pediatrics at the Indiana University School of Medicine. Investigators leading vaccine and pharmaceutical trials for type 1 diabetes are also using genetic tests to maximize efficiency and funding by identifying participants who are most likely at risk for the disease.
Genetic risk scores can also help doctors identify people who should be prescribed teplizumab, the first therapy able to delay the onset of an autoimmune condition. Approved by the U.S. Food and Drug Administration in 2022, this monoclonal antibody is given before the body becomes dependent on insulin, and it can delay more severe illness by two to three years. “The whole field has changed because now we have something we can do to delay progression to clinical diabetes,” says Kevan Herold, an immunologist and endocrinologist at Yale University. “Any time without diabetes is a gift, particularly for children and their families.” Other drugs are in various stages of clinical testing.
People aware of their risk might also be on the lookout for symptoms such as excessive urination and lethargy; when those pop up, people can seek treatment before they develop diabetic ketoacidosis (DKA), a potentially life-threatening condition caused by a lack of insulin. Among those who don’t know they are at risk, about 40 percent wind up in this critical state, but that number drops as low as 4 percent for those who are aware. “If people can identify some of the symptoms of progression toward disease, they could go to a GP instead of an ER and prevent a real crisis,” Brusko says.
There is some evidence to support these benefits, based on outcomes from one of the largest testing efforts to date, launched in 2020 by investigators at Sanford Health, a nonprofit health-care system based in Sioux Falls, S.D. As of July 2025, the study had enrolled more than 13,000 children for genetic risk testing and antibody screening for type 1 diabetes and celiac disease. Children with persistent positive antibodies are offered ongoing monitoring. Of the 75-plus children in monitoring, five have progressed to hyperglycemia, warranting clinical care, and none of these children developed DKA. Kurt Griffin, principal investigator of the study and a pediatric endocrinologist at the Benaroya Research Institute in Seattle, says the findings have already demonstrated that it is feasible to integrate type 1 diabetes screening into routine pediatric care.
Type 1 diabetes has been most prevalent among people of European ancestry. It does occur in those of African, Hispanic and Asian ancestry, but the vast majority of data used to inform genetic screening results is from people of white, European descent, Rich says. This lack of representation is problematic for people of different ancestries because genetic risk factors differ across populations.
In an unpublished study, Rich and his colleagues tested how well the most common HLA variants used in genetic tests predicted risk in people with European, Hispanic, African American or Finnish ancestry. They found that genetic ancestry for important HLA regions—and the many other regions of the genome associated with type 1 diabetes risk—does not transfer well from one population to another. “One of the biggest needs in the field is to understand what confers genetic risk in a much more diverse genetic ancestry,” Brusko says.
Scientists are working to fill this gap. For instance, Breakthrough T1D, a nonprofit organization funding research on type 1 diabetes, provides grants of up to $900,000 for research aimed at improving the prediction power of genetic risk scores across diverse populations. For the next version of the genetic risk score test, the plan is to incorporate specific HLA types present in Africans, East Asians, and several other groups, says Hagopian, who collaborates with Oram.
Genetic risk tests for type 1 diabetes are inching closer to use in clinical care. Last year Randox , a company based in Northern Ireland, released one developed with Oram and his colleagues. Commercial tests are not available yet in the U.S., but they are becoming more affordable for researchers who use them in laboratory-based settings. This affordability will translate to clinical settings once tests make their way to doctor offices. “The price has dropped and is predicted to drop even more,” Redondo says. Now the biggest remaining obstacles are political and logistical rather than scientific or financial, experts say. “All the tools are there; we just haven’t quite got countries over the line to figure out how they’re going to do it,” says Colin Dayan, a professor of clinical diabetes and metabolism at Cardiff University in Wales.
Europe has been at the forefront of these efforts, Brusko says. In 2023 Italy became the first nation to pass a law mandating type 1 diabetes genetic screening across its population, but it has yet to implement this screening in practice, Dayan says. Other countries, including the U.K., are debating whether they should do the same. This past June the U.K. also announced plans to sequence the genomes of all babies within the next decade. The data obtained could be used for risk screening as well, says Emily K. Sims, a pediatric endocrinologist at the Indiana University School of Medicine. In the U.S., genetic screening for type 1 diabetes is still done primarily in research environments. “We really need federal and state authorities to decide that this testing is worth it and that they want to adopt it into general practice,” Hagopian says. The easiest way to implement such a program would be to screen at birth.
What to do with the information that testing would generate, though, is a more complicated question. Health-care officials would have to set up a system for contacting the families of babies at high risk to appropriately communicate the results. There would also need to be a system to remind families to get their child checked for autoantibodies at certain intervals. States handle newborn screenings differently, so each would have to come up with its own solutions. This issue is “a major complication that has to be figured out,” says Rich, who continues to field e-mails and calls from parents interested in the testing.
As the science is refined, more treatment options will be made available, and the uncertainty surrounding who will and will not go on to develop type 1 diabetes is likely to be narrowed. Redondo and her colleagues are pursuing a large project using genetic risk scores and other variables to try to more accurately predict disease development. They are also working on models to determine who will respond best to new disease-modifying therapies. As Redondo says, “personalizing prevention of type 1 diabetes is the goal.”Author: Jeanna Bryner. Rachel Nuwer. Source
