IL4R rs1800926: What Your Genotype Means
The rs1800926 variant is a missense single nucleotide polymorphism in the IL4R gene, historically referred to in scientific literature as Q576R or Q551R depending on transcript numbering. It alters an amino acid within the cytoplasmic domain of the interleukin-4 receptor alpha chain, influencing downstream STAT6 signaling pathways. In population research, this variant has been investigated for modest associations with atopic conditions, including asthma and allergic sensitization.
What each genotype means
| Genotype | What the research suggests | Reading |
|---|---|---|
| GG | Homozygous for the common major allele. Individuals with this genotype produce standard IL-4 receptor alpha chains and exhibit baseline cytokine signaling in epidemiological cohorts. | Informational |
| AG | Heterozygous carrier of one copy of the missense variant allele. Studies indicate a slight statistical modulation of STAT6 pathway activity, though impact on individual allergic risk remains small. | Informational |
| AA | Homozygous for the minor variant allele associated with the arginine substitution. Epidemiological research links this genotype to increased STAT6 activation and a modest statistical predisposition to atopic asthma and severe sensitization. | Higher attention |
Genomic Location and the Q576R Alteration
The single nucleotide polymorphism rs1800926 is situated on human chromosome 16 within the IL4R gene, which encodes the interleukin-4 receptor alpha subunit (IL-4Rα). At the genomic level, this variant involves an A-to-G base transition (commonly tracked across forward or reverse complement strands across clinical databases). This coding change leads to an amino acid substitution where glutamine (Q) is replaced by arginine (R) in the intracellular signaling tail of the receptor, commonly designated as Q576R (or Q551R in older nomenclature). Because this variation occurs directly inside the cytoplasmic domain responsible for intracellular signal transduction, researchers have focused on it as a potential functional modulator of immune signaling rather than a silent bystander tag.
Biological Role: Interleukin Signaling and STAT6
The IL-4Rα chain is an essential component of both type I and type II receptor complexes that bind the cytokines interleukin-4 (IL-4) and interleukin-13 (IL-13). These cytokines drive type 2 helper T-cell (Th2) immune responses, promote immunoglobulin E (IgE) class switching in B lymphocytes, and regulate allergic inflammation. In cellular and animal models, the presence of the arginine substitution at residue 576 has been shown to potentiate downstream Janus kinase and signal transducer and activator of transcription 6 (STAT6) activation. Enhanced STAT6 signaling can prolong inflammatory cascade activity, influence regulatory T-cell plasticity, and alter mucosal immune responses in the airways and skin.
Evaluating Research on Asthma and Atopic Disease
Because of its direct impact on type 2 inflammatory cascades, rs1800926 has been widely evaluated in candidate-gene case-control cohorts and meta-analyses examining asthma, atopic dermatitis, and elevated serum IgE levels. Published studies report that carrying the variant allele is associated with a modest increase in susceptibility to allergic asthma and more pronounced airway reactivity in certain cohorts. However, across broad multi-ethnic populations and genome-wide association studies (GWAS), the overall clinical evidence strength remains limited and heterogeneous. Observed effects are often modest, variable across ancestral backgrounds, and heavily dependent on environmental exposures such as airborne allergen load and tobacco smoke.
Interpreting Your Results Responsibly
A specific genotype at rs1800926 cannot diagnose asthma, atopic dermatitis, or allergic rhinitis, nor does it guarantee that an individual will ever develop an allergic condition. Complex allergic diseases are classic polygenic traits governed by dozens of interacting genetic loci together with significant environmental triggers like pollution, childhood microbial exposures, and seasonal allergens. Direct-to-consumer genetic findings should never be used to initiate, alter, or discontinue asthma inhalers, biologics, or allergy medications. Anyone experiencing respiratory difficulties, chronic wheezing, or allergic symptoms should consult a qualified physician or allergist for standardized diagnostic testing and evidence-based clinical management.
How common is this variant?
The minor allele frequency for rs1800926 is roughly 0.15 to 0.25 in European populations, with significant variation in frequency observed across other global ancestral groups in gnomAD.
Frequently asked questions
Does having the rs1800926 variant mean I will get asthma?
No, carrying the variant does not mean you will develop asthma. The variant confers only a small statistical shift in relative risk across population studies, and many carriers never experience any allergic or respiratory symptoms.
What is the difference between Q576R and Q551R?
Both Q576R and Q551R refer to the exact same missense mutation in the IL-4 receptor alpha chain caused by rs1800926. The difference in numbering comes from whether historical protein references included or omitted the 25-amino-acid signal peptide.
Can this genetic test determine which allergy medications I should take?
No, rs1800926 is not currently endorsed by pharmacogenomic guidelines such as CPIC to guide medication choice or dosing. Any decisions about inhalers, antihistamines, or biologics should be discussed directly with your healthcare provider or pharmacist.
How does the IL4R gene affect the body's immune system?
The IL4R gene provides instructions for the IL-4 receptor alpha subunit, which binds immune signaling molecules IL-4 and IL-13. These pathways govern allergic defenses, directing B cells to produce IgE antibodies and promoting Th2 inflammation.
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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