Recent research suggests that the genetic underpinnings of type 1 diabetes are more diverse than previously thought, with implications for risk assessment and personalised prevention strategies.
A new analysis from researchers at the University of Exeter and the University of California, San Diego suggests that type 1 diabetes may be less genetically uniform than many clinicians have assumed. Writing in Diabetologia, the team examined 9,091 people with type 1 diabetes and 14,157 without the disease, then separated the genetics by the two HLA haplotypes that carry most of the inherited risk: DR3 and DR4. The result was a noticeably wider gap between those groups than between people split by sex or by age at diagnosis.
That matters because HLA type is fixed from birth, whereas age at diagnosis is only a rough proxy for how the disease may unfold. In the new paper, the genetic correlation between DR3 and DR4 carriers was about 0.68, compared with 0.88 when the same cohort was split by sex and 0.96 when divided by whether diabetes appeared before or after age 8. The finding builds on earlier work from the same research network, including studies in TEDDY and other cohorts that have linked different HLA backgrounds with different first antibodies, different pancreatic changes and different patterns in the small minority of patients who do not carry either high-risk haplotype.
The clearest signal came near IL2, a gene involved in T-cell activation. According to the paper, variants in that region had a stronger effect in DR4 carriers than in DR3 carriers, and it was the only locus to survive correction for multiple testing. The broader picture also points to divergence in the biological pathways that seem to be doing the work in each group, although the researchers say some of the weaker signals need more confirmation.
The study is also notable for what it does not settle. HLA status is only an imperfect stand-in for the order in which autoantibodies appear, and the analysis excluded people who carry both DR3 and DR4, even though that combination is the highest-risk pattern. It also focused only on people of European ancestry, which limits how far the findings can be stretched. Some authors disclosed industry ties, including funding from Randox Laboratories and consulting or honoraria relationships with drugmakers.
For now, the work changes little in day-to-day care. HLA typing is not part of routine type 1 diabetes management, and nothing in the study suggests a new treatment choice for people already using insulin, pumps or continuous glucose monitoring. Where it may matter sooner is in prevention trials and risk studies, where the Exeter and UC San Diego team argues that DR3 and DR4 status should be reported separately. That could help explain why a therapy works in one group and not another, and why some patients are diagnosed late or misclassified in the first place.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
