Genetic risk score (GRS) newborn screening

Genetic risk screening flips the usual order of detection. Instead of waiting for the immune attack to show up as autoantibodies, it reads risk straight from a baby's DNA — usually from the same heel-prick blood spot taken for routine newborn screening — and flags the small fraction of infants who carry the highest inherited risk of Type 1 diabetes (T1D).¹

What is measured. Most T1D risk sits in the HLA region (the immune-system genes), which alone explains more than half of heritability; over 70 further regions add smaller effects.² Modern scores combine both. The widely used "T1D GRS2" uses 67 markers plus key HLA haplotype interactions and discriminates T1D with an area under the curve of about 0.92 — and about 0.96 for early-onset disease — making it nearly twice as efficient as HLA typing alone for newborn screening.³ Programs flag the roughly top ~1% of infants: in the European POInT screen, 1.14% of 241,977 newborns crossed the high-risk threshold (a >10% chance of developing multiple autoantibodies in early childhood).⁴

How it fits the staging model. T1D is now staged by autoantibodies: stage 1 is two or more islet autoantibodies with normal glucose, stage 2 adds dysglycaemia, stage 3 is clinical onset.⁵ A genetic score sits before stage 1 — it cannot diagnose presymptomatic disease, only prioritise who should be watched. The diagnostic signal still comes from antibodies: children who develop multiple islet autoantibodies have roughly a 70% chance of clinical diabetes within 10 years and near-certainty over a lifetime.⁶ The genetic step simply concentrates antibody monitoring where it pays off.

Why it matters — what early detection enables. The headline benefit is avoiding crisis at diagnosis. In Germany, ~20–25% of children are in diabetic ketoacidosis (DKA) when first diagnosed; among children found early through public-health screening, that fell to about 2.5%, with lower HbA1c and better preserved insulin production at onset.⁷ Genetic newborn screening is the front of that funnel: it identifies at-risk infants from birth and channels them into monitoring and trials.⁸

Reach and cost. Its biggest advantage is reach. More than 85% of new T1D occurs in people with no affected relative, so screening only families misses most cases — a population blood-spot score does not.¹ SNP genotyping is cheap and scalable, which is why this is seen as a plausible route to whole-population screening.³ The costs are organisational: consent, genome-wide platforms, and the counselling needed to return a probabilistic risk result responsibly.⁹

Therapy link and what's coming. Genetic screening exists largely to enable primary prevention — intervening before autoantibodies appear. The flagship test of that idea, POInT, gave high-risk infants daily oral insulin from ages 4–7 months; in 2025 it reported that oral insulin did not prevent islet autoantibodies (10% vs 9% with placebo), with only a genotype-specific signal warranting further study.⁴ So the first primary-prevention drug tested through this pipeline failed — an honest reminder that the screen is ahead of the therapy. What's coming is the infrastructure scaling up regardless: EDENT1FI aims to screen ~200,000 European children for early-stage T1D, harmonising capillary autoantibody screening that genetic flags feed into, while next-generation primary-prevention agents are sought.¹⁰ The genetic newborn score is the on-ramp; the field is still building the road.

References

1. Sims EK, et al. Screening for Type 1 Diabetes in the General Population: A Status Report and Perspective. Diabetes (2022). https://pmc.ncbi.nlm.nih.gov/articles/PMC9114719/ ↩ ↩²

2. Sims EK, Cuthbertson D, Felton JL. Utility of genetic risk scores in type 1 diabetes. Diabetologia (2023). https://pmc.ncbi.nlm.nih.gov/articles/PMC10390619/ ↩

3. Sharp SA, et al. Development and Standardization of an Improved Type 1 Diabetes Genetic Risk Score for Use in Newborn Screening and Incident Diagnosis. Diabetes Care (2019). https://doi.org/10.2337/dc18-1785 ↩ ↩²

4. Ziegler AG, et al. Efficacy of once-daily, high-dose, oral insulin immunotherapy in children genetically at risk for type 1 diabetes (POInT): a European, randomised, placebo-controlled, primary prevention trial. Lancet (2025); ClinicalTrials.gov NCT03364868. https://doi.org/10.1016/S0140-6736%2825%2901726-X ↩ ↩²

5. Insel RA, et al. Staging presymptomatic type 1 diabetes: a scientific statement of JDRF, the Endocrine Society, and the American Diabetes Association. Diabetes Care (2015). https://pubmed.ncbi.nlm.nih.gov/26404926/ ↩

6. Ziegler AG, et al. Seroconversion to multiple islet autoantibodies and risk of progression to diabetes in children. JAMA (2013). https://doi.org/10.1001/jama.2013.6285 ↩

7. Hummel S, et al. Children diagnosed with presymptomatic type 1 diabetes through public health screening have milder diabetes at clinical manifestation. Diabetologia (2023). https://doi.org/10.1007/s00125-023-05953-0 ↩

8. Winkler C, et al. Identification of infants with increased type 1 diabetes genetic risk for enrollment into Primary Prevention Trials — GPPAD-02 study design and first results. Pediatric Diabetes (2019). https://pmc.ncbi.nlm.nih.gov/articles/PMC6851563/ ↩

9. Weiss A, et al. Progression likelihood score identifies substages of presymptomatic type 1 diabetes in childhood public health screening (Fr1da). Diabetologia (2022). https://pmc.ncbi.nlm.nih.gov/articles/PMC9630406/ ↩

10. Hoffmann L, et al. EDENT1FI Master Protocol for screening of presymptomatic early-stage type 1 diabetes in children and adolescents. BMJ Open (2025). https://pmc.ncbi.nlm.nih.gov/articles/PMC11749223/ ↩