What you carry at this position in your DNA and what research says about it.
Type 1 Diabetes Risk: 10/10 evidence, 25 publications.
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Sample genotype (not yours): A/A
Significantly Lower Type 1 Diabetes Risk
Inheriting two copies of the protective A allele is associated with a substantially reduced risk of developing type 1 diabetes. This genotype promotes optimal insulin expression in the thymus, helping the immune system recognize insulin as safe. It is also linked to slightly higher typical blood glucose and C-peptide levels.
What this genotype means: Substantially lower risk of type 1 diabetes; Slightly higher baseline C-peptide levels; Lower risk of latent autoimmune diabetes.
Sample genotype (not yours): A/T
Increased Type 1 Diabetes Risk
Carrying one copy of the risk-associated T allele is linked to an elevated risk of developing type 1 diabetes and latent autoimmune diabetes. This genetic variation slightly reduces insulin expression in the thymus, which can impair the immune system's ability to tolerate insulin.
What this genotype means: Moderately increased risk of type 1 diabetes; Increased risk of latent autoimmune diabetes; Slightly lower baseline C-peptide levels.
Sample genotype (not yours): T/T
Highly Elevated Type 1 Diabetes Risk
Inheriting two copies of the T allele is associated with a highly elevated risk of developing type 1 diabetes, often more than doubling the baseline susceptibility. This genotype leads to reduced insulin expression in the thymus, making it harder for the immune system to tolerate insulin.
What this genotype means: Highly elevated risk of type 1 diabetes; Increased risk of latent autoimmune diabetes; Earlier average age of type 1 diabetes onset.
Gene function and biological role
Gene Function: The INS gene encodes proinsulin, the precursor molecule to the vital hormone insulin. Produced by specialized beta cells in the pancreas, insulin is the primary regulator of glucose storage and energy metabolism in the body. Beyond its metabolic role, insulin expression in the thymus is critical for training the immune system. This thymic expression helps establish central immune tolerance, preventing the body from attacking its own insulin-producing cells [1]. Disruptions in this pathway are central to the development of autoimmune diabetes [2].
Variant Impact: Located in the 5 prime untranslated region of the insulin gene, rs689 is a key regulatory variant that influences how insulin is produced. This single nucleotide change directly alters the splicing efficiency of the insulin transcript [3]. The protective A allele enhances splicing efficiency, leading to higher levels of insulin expression in the thymus [3]. Conversely, the T allele reduces splicing efficiency, resulting in lower thymic insulin levels and a higher likelihood of autoimmune reactions [4]. This makes rs689 one of the most significant non-HLA genetic markers for autoimmune diabetes risk [4].
Key Insight: This variant acts as an immune system trainer by controlling how much insulin is shown to developing immune cells in the thymus. The protective version of this variant actually leads to slightly higher baseline blood sugar and insulin secretion markers in healthy people, showing a delicate trade-off between metabolic traits and autoimmune defense.
Location: INS. Chromosome 11 · 11p15.5 · 2.2 Mb
Estimated prevalence by population
Global 20.0%; European 7.9%; African 54.4%; East Asian 0.3%; South Asian 2.8%; Americas 7.5%; Ashkenazi 8.5%; Finnish 4.3%; Middle Eastern 4.3%; Amish 11.2%.
Estimated AA genotype frequency.
Global 38.0%; European 40.4%; African 38.7%; East Asian 9.9%; South Asian 28.0%; Americas 39.8%; Ashkenazi 41.2%; Finnish 32.9%; Middle Eastern 32.9%; Amish 44.5%.
Estimated AT genotype frequency.
Global 42.0%; European 51.6%; African 6.9%; East Asian 89.8%; South Asian 69.1%; Americas 52.6%; Ashkenazi 50.3%; Finnish 62.7%; Middle Eastern 62.8%; Amish 44.3%.
Estimated TT genotype frequency.
Showing effects for A/A genotype
Cardiovascular & Metabolic
Diabetes & Glycemic Traits
Type 1 Diabetes. Evidence: 10/10. Source: PMID 38453145. Reduced Risk.
Latent Autoimmune Diabetes. Evidence: 6/10. Source: PMID 30254083. Reduced Risk.
Blood Glucose. Evidence: 7/10. Source: PMID 39789286. Slightly Higher.
Insulin Secretion. Evidence: 3/10. Source: PMID 39556808. Slightly Higher.
Showing effects for A/T genotype
Type 1 Diabetes. Evidence: 10/10. Source: PMID 38453145. Increased Risk.
Latent Autoimmune Diabetes. Evidence: 6/10. Source: PMID 30254083. Increased Risk.
Blood Glucose. Evidence: 7/10. Source: PMID 39789286. Typical.
Insulin Secretion. Evidence: 3/10. Source: PMID 39556808. Typical.
Showing effects for T/T genotype
Type 1 Diabetes. Evidence: 10/10. Source: PMID 38453145. ~2.4x Higher Risk.
Blood Glucose. Evidence: 7/10. Source: PMID 39789286. Slightly Lower.
Insulin Secretion. Evidence: 3/10. Source: PMID 39556808. Slightly Lower.
What this genotype means for the people who carry it
Sample genotype: AA (Homozygous)
Optimal immune tolerance is established when the body successfully trains immune cells not to attack its own tissues. This genotype facilitates efficient splicing of the insulin gene transcript, leading to higher levels of insulin protein expression within the thymus [1]. Consequently, developing T-cells are thoroughly exposed to insulin, allowing the immune system to identify and eliminate self-reactive cells before they can cause harm [1]. This protective mechanism results in a more than 50 percent reduction in the risk of developing type 1 diabetes compared to the risk-associated genotype [2]. While it dramatically lowers autoimmune risk, studies suggest it is also associated with slightly higher baseline blood glucose and C-peptide levels in healthy individuals [3]. This minor metabolic variation is generally considered benign and does not outweigh the profound protective effect against autoimmunity [2].
Substantially lower risk of type 1 diabetes; Slightly higher baseline C-peptide levels; Lower risk of latent autoimmune diabetes.
Sample genotype: AT (Heterozygous)
Maintaining a balance of insulin expression is critical for preventing autoimmune reactions against pancreatic beta cells. Having one copy of the T allele reduces the efficiency of insulin gene splicing, which leads to lower levels of insulin protein in the thymus [1]. This reduction can allow some self-reactive T-cells to escape deletion, increasing the likelihood of an autoimmune attack on the pancreas later in life [1]. Clinical studies demonstrate that individuals with this intermediate genotype face a moderately increased risk of developing type 1 diabetes compared to those with the protective AA genotype [2]. It is also associated with an increased susceptibility to latent autoimmune diabetes in adults (LADA) [3]. Despite this elevated risk, environmental factors and other genetic loci, particularly HLA genes, play a major role in determining whether clinical diabetes actually develops [4].
Moderately increased risk of type 1 diabetes; Increased risk of latent autoimmune diabetes; Slightly lower baseline C-peptide levels.
Sample genotype: TT (Homozygous)
Severe disruption in the training of immune cells can lead to the destruction of insulin-producing beta cells in the pancreas. This genotype is characterized by the lowest levels of thymic insulin expression due to inefficient gene splicing [1]. Without adequate insulin present during immune cell development, the thymus fails to eliminate T-cells that target insulin, allowing them to enter circulation and eventually attack the pancreas [1]. Large-scale genetic studies show that this genotype is associated with a 2- to 2.5-fold increase in the risk of type 1 diabetes, making it the second most important genetic risk factor after the HLA region [2]. It is also linked to an earlier age of onset for type 1 diabetes in those who develop the condition [2]. Additionally, this variant increases susceptibility to latent autoimmune diabetes in adults (LADA) [3]. While the risk is highly elevated, developing the condition still requires environmental triggers and other genetic susceptibilities [4].
Highly elevated risk of type 1 diabetes; Increased risk of latent autoimmune diabetes; Earlier average age of type 1 diabetes onset.
Variants with shared genetic architecture
rs3842752 · INS Gene · Chr 11 · Diabetic Ketoacidosis Risk
rs2476601 · PTPN22 Gene · Chr 1 · Autoimmune Disease Risk
rs9272346 · HLA-DQA1 Gene · Chr 6 · Type 1 Diabetes Risk
A multi-ancestry genome-wide association study in type 1 diabetes.
A scalable variational inference approach for increased mixed-model association power.
Content updated August 2026.
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