IL13 rs1006145: Genetics of Allergy and Asthma Risk
The rs1006145 single nucleotide polymorphism is an intronic non-coding variant located within or adjacent to the IL13 gene on chromosome 5. Research links this variant to subtle differences in type 2 immune response regulation, influencing an individual's susceptibility to allergic conditions such as atopic asthma, allergic rhinitis, and altered total serum IgE levels. However, its overall clinical effect size is modest, and it acts as one small piece within a broader polygenic and environmental landscape.
What each genotype means
Typical IL13 expression profile
This genotype represents the homozygous state for the major allele at this locus. Research suggests this variant is located in a non-coding region near the IL13 gene, which plays a role in immune regulation and cytokine production. While this variant has been studied in the context of allergic rhinitis and asthma, the evidence remains limited and associations can vary significantly by ancestry.
This is the most common genotype in many populations, though frequencies vary by ancestry.
Intermediate IL13 variant profile
This heterozygous genotype carries one copy of each allele. Studies indicate that variants in this region may modulate cytokine production, potentially influencing susceptibility to allergic conditions like asthma or rhinitis. Because this is a complex trait, this genotype does not determine health outcomes on its own and should be viewed as one of many factors in your overall health profile.
This genotype is frequently observed, appearing in a significant portion of individuals across European and Asian populations.
Elevated IL13 variant profile
This genotype represents the homozygous state for the minor allele. Some research suggests that variants in the IL13 locus are associated with altered cytokine levels and a potential increase in susceptibility to allergic rhinitis or atopic asthma. Please note that these associations are statistical in nature and do not imply a diagnosis; discuss any concerns about allergic symptoms with your healthcare provider.
This genotype is present in a substantial minority of the population, with frequencies reflecting the minor allele prevalence of approximately 35-45% in European and Asian groups.
Genomic Location and Variant Characteristics
The single nucleotide polymorphism designated as rs1006145 is situated on chromosome 5q31, a genomic region recognized as a major cytokine cluster housing several key immune-regulatory genes, including interleukin-4 (IL4), interleukin-5 (IL5), and interleukin-13 (IL13). The variant itself represents a common biallelic substitution—typically reported with cytosine (C) and thymine (T) alleles. Because rs1006145 is positioned in a non-coding region, it does not alter the amino acid sequence of the resulting protein. Instead, variants in this cluster frequently act as regulatory single nucleotide polymorphisms that modulate transcriptional efficiency, enhancer-promoter interactions, or mRNA splicing kinetics. As a result, rs1006145 often functions either directly as an expression quantitative trait locus (eQTL) or as a proxy in high linkage disequilibrium with neighboring functional variations across the 5q31 locus.
The Biological Role of Interleukin-13 (IL13)
The IL13 gene encodes interleukin-13, a pivotal immunoregulatory cytokine secreted primarily by activated T helper type 2 (Th2) cells, innate lymphoid cells (ILC2s), basophils, and mast cells. Interleukin-13 plays an essential physiological role in protecting against parasitic worm infections and orchestrating tissue repair. However, dysregulated or excessive IL-13 production is a hallmark driver of allergic inflammation and type 2 immune pathways. IL-13 acts on airway smooth muscle cells, structural epithelial barriers, and B cells, driving immunoglobulin class switching toward immunoglobulin E (IgE) synthesis. It also promotes airway hyperresponsiveness, goblet cell metaplasia, and excessive mucus secretion. Genetic variations that alter the expression or stability of IL13 can therefore influence baseline mucosal barrier integrity and shift systemic thresholds toward allergic hyperreactivity.
Associated Traits and Strength of Evidence
Observational genetic studies and association screenings have evaluated rs1006145 alongside other 5q31 markers in cohorts examining atopic phenotypes, including bronchial asthma, allergic rhinitis, elevated circulating total serum IgE, and atopic dermatitis. While the cytokine cluster itself is among the most well-validated genetic regions in asthma pathophysiology, the specific evidence for rs1006145 remains categorized as limited. Individual effect sizes reported in complex trait associations are modest, typically producing odds ratios ranging between 1.1 and 1.3 per risk allele. Furthermore, association strengths vary considerably across distinct study populations, and significant linkage disequilibrium with other prominent IL13 polymorphisms (such as rs20541/R130Q) makes distinguishing isolated causal effects challenging. Consequently, rs1006145 should be understood as a statistical contributor to polygenic risk rather than a definitive standalone biomarker.
Population Patterns and Genetic Diversity
According to large-scale population genetic databases such as gnomAD and dbSNP, the minor allele for rs1006145 is widely distributed across diverse global ancestries. Its minor allele frequency generally ranges between 0.35 and 0.45 across European and East Asian ancestral groups, indicating that a substantial portion of the population carries at least one copy of the variant allele. Because of its common frequency, inheriting the variant is considered a standard human genetic difference rather than a rare pathology. Slight frequency fluctuations exist between continental populations, which reinforces why genomic associations must be contextualized within an individual's specific ancestral background and why risk alleles do not manifest identically across varying environments.
Interpreting Genetic Associations in Daily Life
Discovering an individual genotype at rs1006145 provides informational context about one component of immune biology, but it cannot be used to diagnose asthma, predict allergy onset, or determine disease severity. Complex allergic diseases arise from the interplay of dozens of genetic loci alongside environmental determinants like indoor allergen exposure, ambient air pollution, early-life microbial encounters, and tobacco smoke. A genetic marker cannot replace formal allergy testing, spirometry, or clinical evaluations. Individuals experiencing chronic respiratory or allergic symptoms should consult qualified healthcare professionals for diagnosis and evidence-based management plans. Furthermore, personal genetic variants must never be used to initiate, alter, or discontinue asthma or allergy medications without clinical guidance.
How common is this variant?
The minor allele frequency for rs1006145 is commonly observed between 0.35 and 0.45 across European and Asian ancestries, making heterozygous and homozygous genotypes frequent across broad global populations.
Frequently asked questions
Can rs1006145 tell me if I will develop asthma?
No, rs1006145 cannot predict or diagnose asthma. Complex traits like asthma depend on hundreds of genetic factors combined with lifestyle and environmental triggers, and many people carrying the risk allele never experience any symptoms.
Does this genetic variant change how my asthma medications work?
There is currently no direct evidence from pharmacogenomic bodies like CPIC or PharmGKB establishing rs1006145 as a therapeutic biomarker for specific asthma or allergy medications. You should never alter your inhaler regimen, allergy immunotherapy, or medications without speaking directly to your doctor or pharmacist.
Why is the evidence for rs1006145 considered limited?
The evidence is considered limited because association studies have shown mixed or modest effect sizes across different ethnic groups, and rs1006145 frequently co-inherits with other influential variants in the IL13 cluster. This makes it difficult to prove that rs1006145 itself is the direct causal driver of allergic traits.
How does IL13 influence allergies and IgE levels?
IL13 codes for an immune signaling protein that directs white blood cells to produce allergic antibodies called IgE and promotes airway inflammation. Slight variations in how this gene is expressed can subtly alter an individual's inflammatory response to common environmental allergens.
Sources & further reading
Educational information only, last refreshed 9/8/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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A well-studied coding missense variant (Arg130Gln) in IL13 that increases receptor affinity, predisposing individuals to elevated IgE levels and atopic reactions.
Variant in the TERT gene (often misattributed to IL13 in older literature) associated with cancer risk across multiple populations.
IL13 variant associated with elevated IgE and allergic/atopic tendencies.
IL13 R110Q alters cytokine signaling; associated with asthma and atopy.