Genetic Testing Could Help Doctors Distinguish Type 1 Diabetes from Look-Alike Conditions

Type 1 diabetes can sometimes be confused with Type 2 diabetes or rare monogenic forms of diabetes, especially early on. Getting the diagnosis right is crucial because it determines which treatments and management strategies will actually help. Misdiagnosis can delay effective care and prevent people from accessing interventions that might slow disease progression.

Researchers have been exploring whether genetic information could serve as a diagnostic tool—helping doctors distinguish Type 1 from other diabetes types and identifying people at highest risk before symptoms appear.

Scientists in Spain analyzed genetic data from over 2,200 people of European ancestry, including 816 with Type 1 diabetes, 469 with Type 2 diabetes, 457 with monogenic diabetes, and 473 healthy controls. They tested four different genetic risk scoring approaches to see which one best identified Type 1 diabetes and separated it from the other conditions.

The research team evaluated both existing genetic scores developed from European populations and a new score they created specifically for the Spanish population.

The European-derived T1D-GRS2 score outperformed the newly created Spanish-specific score at identifying Type 1 diabetes. When used to screen children for Type 1 diabetes, the T1D-GRS2 achieved 80% sensitivity (correctly identifying people who had Type 1) and 81% specificity (correctly identifying people who did not have it) at a standard cutoff point.

The genetic score also performed well at distinguishing Type 1 diabetes from Type 2 and monogenic diabetes, suggesting it could help prevent misdiagnosis across different diabetes types. People in the highest genetic risk category had 26 times higher odds of Type 1 diabetes compared to low-risk individuals.

The study found that genetic risk scores were higher in people who developed Type 1 diabetes during childhood compared to those who developed it as adults. This suggests that genetic factors play a particularly strong role in childhood-onset Type 1 diabetes, with immune-related genes (particularly HLA genes) driving much of this age-related difference.

These findings suggest that genetic risk scores could become a useful diagnostic tool to help clinicians accurately identify Type 1 diabetes and distinguish it from other diabetes forms. However, this research was conducted in a Spanish population of European ancestry, so genetic scores developed or validated in other populations may perform differently in different ethnic groups.

While genetic information alone cannot diagnose Type 1 diabetes, it could work alongside other clinical tests and symptoms to improve accuracy and potentially help identify higher-risk individuals who might benefit from early monitoring or preventive approaches as they become available.

Source: European journal of endocrinology. Evidence type: PubMed indexed literature. Type1Cure is an information and intelligence hub, not a medical advice service. This article summarizes published research and does not provide diagnosis, treatment, or personal medical guidance. Always talk to your own care team before changing anything about your Type 1 diabetes management.