What you carry at this position in your DNA and what research says about it.
Asthma and Heart Risk: 5/10 evidence, 50 publications.
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Sample genotype (not yours): C/C
Typical Risk of Asthma and Heart Attacks
Standard levels of interleukin-4 production are maintained by this common genetic profile. This results in typical risks for both allergic asthma and early-onset cardiovascular events.
What this genotype means: Standard baseline risk for allergic asthma; Typical risk for early-onset myocardial infarction.
Sample genotype (not yours): C/T
Reduced Heart Attack Risk with Higher Allergy Susceptibility
A genetic trade-off defines this profile, which links a lower risk of early-onset heart attacks to a higher likelihood of developing allergic asthma.
What this genotype means: Moderately increased risk of allergic asthma; Approximately 40% lower risk of early-onset heart attacks.
Sample genotype (not yours): T/T
Lowest Heart Attack Risk with Highest Allergy Susceptibility
The strongest protection against early-onset heart attacks and aspirin-induced asthma is paired with the highest risk for allergic asthma and elevated IgE levels.
What this genotype means: Highest risk of allergic asthma and elevated IgE; Approximately 67% lower risk of early-onset heart attacks; Reduced risk of aspirin-induced asthma.
Gene function and biological role
Gene Function: Interleukin 4 encodes a key cytokine that drives the activation and differentiation of helper T cells into Th2 cells. This process is essential for humoral immunity and plays a central role in stimulating B cells to produce IgE antibodies. Elevated levels of interleukin-4 are heavily implicated in allergic inflammatory responses, including asthma and atopic dermatitis. Interestingly, interleukin-4 also exerts anti-inflammatory effects in other contexts, such as vascular tissues, which may influence cardiovascular health.
Variant Impact: The rs2243250 variant is located in the promoter region of the gene, often referred to as the -589C to T polymorphism. This single nucleotide change alters the binding affinity of transcription factors, thereby modulating the rate of gene transcription. The T allele increases promoter activity, leading to higher baseline production of interleukin-4. Consequently, this variant acts as a molecular dial that balances allergic inflammatory pathways against protective vascular mechanisms.
Key Insight: The same genetic variant that increases your susceptibility to allergic asthma actually helps protect your blood vessels, significantly lowering the risk of early-onset heart attacks.
Location: IL4. Chromosome 5 · 5q31.1 · 132.7 Mb
Estimated prevalence by population
Global 47.7%; European 72.0%; African 12.2%; East Asian 5.1%; South Asian 66.0%; Americas 43.5%; Ashkenazi 57.2%; Finnish 41.1%; Middle Eastern 66.1%; Amish 96.7%.
Estimated CC genotype frequency.
Global 35.1%; European 25.7%; African 45.4%; East Asian 34.9%; South Asian 30.5%; Americas 44.9%; Ashkenazi 36.9%; Finnish 46.0%; Middle Eastern 30.4%; Amish 3.2%.
Estimated CT genotype frequency.
Global 17.1%; European 2.3%; African 42.4%; East Asian 60.0%; South Asian 3.5%; Americas 11.6%; Ashkenazi 5.9%; Finnish 12.9%; Middle Eastern 3.5%; Amish < 0.1%.
Estimated TT genotype frequency.
Showing effects for C/C genotype
Organ Systems
Respiratory Health
Asthma. Evidence: 4/10. Source: PMID 22652416. Typical Risk.
Cardiovascular & Metabolic
Heart Disease
Early Heart Attack. Evidence: 3/10. Source: PMID 20416077. Typical Risk.
Pharmacogenomics
Adverse Drug Reactions
Aspirin Sensitivity. Evidence: 5/10. Source: PMID 20921925. Typical Risk.
Showing effects for C/T genotype
Asthma. Evidence: 4/10. Source: PMID 22652416. Increased Risk.
Early Heart Attack. Evidence: 3/10. Source: PMID 20416077. ~40% Lower Risk.
Showing effects for T/T genotype
Asthma. Evidence: 4/10. Source: PMID 22652416. Highest Risk.
Early Heart Attack. Evidence: 3/10. Source: PMID 20416077. ~67% Lower Risk.
Aspirin Sensitivity. Evidence: 5/10. Source: PMID 20921925. Reduced Risk.
What this genotype means for the people who carry it
Sample genotype: CC (Homozygous)
Baseline levels of interleukin-4 expression are maintained by this genotype, representing the most common genetic profile globally. Research indicates that this typical expression level does not elevate the risk for allergic conditions like atopic asthma or eczema. However, it also lacks the protective cardiovascular benefits associated with the alternative T allele. Clinical studies have shown that young adults with this genotype have a standard, baseline risk of early-onset myocardial infarction compared to those carrying the T allele. Additionally, when taking aspirin, there is a standard baseline response without the specific protective effect against aspirin-induced respiratory symptoms observed in other genotypes.
Standard baseline risk for allergic asthma; Typical risk for early-onset myocardial infarction.
Sample genotype: CT (Heterozygous)
A single copy of the T allele increases the promoter activity of the gene, leading to moderately elevated levels of interleukin-4. This elevation enhances the Th2 immune response, which is associated with a higher susceptibility to allergic asthma and elevated IgE antibody levels. Conversely, the increased interleukin-4 levels appear to exert a protective, anti-inflammatory effect on the vascular system. Clinical studies have demonstrated that carriers of this genotype have an approximate 40% reduced risk of experiencing a myocardial infarction before the age of 50. This dual effect highlights how a single genetic variant can simultaneously act as a risk factor for inflammatory airway diseases while offering protection against early cardiovascular events.
Moderately increased risk of allergic asthma; Approximately 40% lower risk of early-onset heart attacks.
Sample genotype: TT (Homozygous)
Two copies of the T allele maximize the promoter activity of the gene, resulting in the highest baseline production of interleukin-4. This strong Th2 immune polarization significantly increases the risk of developing atopic asthma and experiencing more severe allergic symptoms. On the positive side, this elevated interleukin-4 level provides a powerful protective effect against vascular inflammation. Research shows that this genotype is associated with an approximate 67% reduction in the risk of early-onset myocardial infarction. Furthermore, in the context of medication response, this genetic profile is linked to a decreased risk of developing aspirin-intolerant asthma when using aspirin.
Highest risk of allergic asthma and elevated IgE; Approximately 67% lower risk of early-onset heart attacks; Reduced risk of aspirin-induced asthma.
Variants with shared genetic architecture
rs2070874 · IL4 Gene · Chr 5 · Asthma and Vaccine Response
rs2243248 · IL4 Gene · Chr 5 · Allergy and Immune Response
rs11071559 · RORA Gene · Chr 15 · Asthma Risk
Content updated August 2026.
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