What you carry at this position in your DNA and what research says about it.
Autoimmune and Obesity Risk: 7/10 evidence, 44 publications.
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Sample genotype (not yours): A/A
Higher Risk of Autoimmune Conditions and Obesity
A stronger immune response increases susceptibility to autoimmune diseases like lupus and rheumatoid arthritis, alongside a higher likelihood of abdominal fat accumulation.
What this genotype means: Higher risk of systemic lupus erythematosus; Increased likelihood of abdominal fat accumulation; Lower risk of persistent HPV and cervical cancer.
Sample genotype (not yours): A/G
Typical Risk of Autoimmune Conditions and Obesity
An intermediate immune response profile results in average susceptibility to autoimmune diseases, metabolic changes, and viral infections.
What this genotype means: Typical risk of autoimmune diseases; Average metabolic and body shape profile; Slightly higher cognitive performance scores.
Sample genotype (not yours): G/G
Lower Autoimmune Risk but Higher Cervical Cancer Risk
Reduced immune receptor expression protects against lupus and obesity, but increases susceptibility to persistent viral infections and cervical cancer.
What this genotype means: Lower risk of systemic lupus erythematosus; Reduced likelihood of obesity and high waist circumference; Higher risk of persistent HPV and cervical cancer.
Gene function and biological role
Gene Function: The TLR9 gene encodes toll-like receptor 9, a key component of the innate immune system that detects foreign viral and bacterial DNA [1]. Located in endosomes, this receptor triggers inflammatory pathways to defend against pathogens [2]. However, overactivation of these pathways can lead to chronic inflammation and autoimmune diseases [3]. TLR9 also plays a role in metabolic regulation and tissue remodeling, influencing fat accumulation and body shape [4].
Variant Impact: The rs187084 variant is located in the promoter region of the TLR9 gene, where it directly influences gene transcription and expression levels [5]. The ancestral A allele is associated with higher baseline expression of TLR9, leading to a more active immune response [1]. Conversely, the G allele reduces promoter activity and decreases TLR9 expression [2]. This expression difference alters the balance between pathogen defense and autoimmune susceptibility [3].
Key Insight: The same genetic variant that increases the risk of autoimmune diseases like lupus actually provides protection against cervical cancer by altering how the immune system detects viral DNA.
Location: TLR9. Chromosome 3 · 3p21.2 · 52.2 Mb
Estimated prevalence by population
Global 38.9%; European 35.5%; African 48.8%; East Asian 36.8%; South Asian 42.2%; Americas 32.6%; Ashkenazi 35.0%; Finnish 33.4%; Middle Eastern 38.3%; Amish 29.6%.
Estimated AA genotype frequency.
Global 46.5%; European 48.2%; African 42.1%; East Asian 47.7%; South Asian 45.5%; Americas 49.0%; Ashkenazi 48.3%; Finnish 48.8%; Middle Eastern 47.2%; Amish 49.6%.
Estimated AG genotype frequency.
Global 14.5%; European 16.3%; African 9.1%; East Asian 15.5%; South Asian 12.3%; Americas 18.4%; Ashkenazi 16.7%; Finnish 17.8%; Middle Eastern 14.5%; Amish 20.8%.
Estimated GG genotype frequency.
Showing effects for A/A genotype
Immunity & Inflammation
Autoimmune Diseases
Lupus. Evidence: 4/10. Source: PMID 22948541. Increased Risk.
Rheumatoid Arthritis. Evidence: 4/10. Source: PMID 23420357. Increased Risk.
Cardiovascular & Metabolic
Obesity & Body Composition
Obesity. Evidence: 7/10. Source: PMID 40796553. Increased Risk.
Cancer & Oncology
Gynecological Cancers
Cervical Cancer. Evidence: 4/10. Source: PMID 23990988. Lower Risk.
Neurology & Mental Health
Cognitive Performance
Cognitive Function. Evidence: 6/10. Source: PMID 29844566. Typical.
Showing effects for A/G genotype
Lupus. Evidence: 4/10. Source: PMID 22948541. Typical Risk.
Rheumatoid Arthritis. Evidence: 4/10. Source: PMID 23420357. Typical Risk.
Obesity. Evidence: 7/10. Source: PMID 40796553. Typical Risk.
Cervical Cancer. Evidence: 4/10. Source: PMID 23990988. Increased Risk.
Cognitive Function. Evidence: 6/10. Source: PMID 29844566. Slightly Higher.
Showing effects for G/G genotype
Lupus. Evidence: 4/10. Source: PMID 22948541. Lower Risk.
Rheumatoid Arthritis. Evidence: 4/10. Source: PMID 23420357. Lower Risk.
Obesity. Evidence: 7/10. Source: PMID 40796553. Lower Risk.
What this genotype means for the people who carry it
Sample genotype: AA (Homozygous)
Higher baseline expression of the TLR9 receptor leads to a highly active innate immune system [1]. While this robust response is highly effective at clearing certain viral infections, it significantly increases the risk of developing systemic lupus erythematosus [2]. Research also links this genotype to a higher susceptibility to rheumatoid arthritis [3]. On the metabolic side, genomic studies associate these genetic coordinates with larger waist circumferences and an elevated risk of obesity [4]. Conversely, the highly active immune surveillance associated with these markers is protective against cervical cancer and persistent HPV infections [5].
Higher risk of systemic lupus erythematosus; Increased likelihood of abdominal fat accumulation; Lower risk of persistent HPV and cervical cancer.
Sample genotype: AG (Heterozygous)
A balanced immune profile is maintained by carrying one copy of each allele at this promoter locus [1]. Susceptibility to autoimmune conditions like systemic lupus erythematosus and rheumatoid arthritis remains at baseline levels [2]. Metabolic measurements, including waist circumference and overall obesity risk, align with average population statistics [3]. However, carrying a single G allele slightly increases the risk of persistent HPV infection and cervical cancer compared to the ancestral baseline [4]. On the other hand, large-scale cognitive studies suggest a minor positive association with general intelligence and cognitive performance [5].
Typical risk of autoimmune diseases; Average metabolic and body shape profile; Slightly higher cognitive performance scores.
Sample genotype: GG (Homozygous)
Lower baseline expression of the TLR9 receptor reduces the risk of chronic inflammatory conditions [1]. This genetic profile is strongly associated with a lower risk of developing systemic lupus erythematosus and rheumatoid arthritis [2]. Metabolic studies also show that these markers correlate with smaller waist circumferences and a lower overall risk of obesity [3]. However, the quieter immune response makes it harder for the body to clear certain pathogens, leading to a significantly higher risk of persistent HPV infection and cervical cancer [4]. Additionally, large-scale genetic analyses link this profile to slightly higher general cognitive function [5].
Lower risk of systemic lupus erythematosus; Reduced likelihood of obesity and high waist circumference; Higher risk of persistent HPV and cervical cancer.
Variants with shared genetic architecture
rs352139 · TLR9 Gene · Chr 3 · Immune Defense and Gut Health
rs352140 · TLR9 Gene · Chr 3 · Lupus and Autoimmune Risk
rs5743836 · TLR9 Gene · Chr 3 · Immune System Activity
Meta-analysis demonstrates association between TLR polymorphisms and rheumatoid arthritis.
Modeling the genomic architecture of adiposity and anthropometrics across the lifespan.
A genetic variant in the promoter region of Toll-like receptor 9 and cervical cancer susceptibility.
The TLR9 gene polymorphisms and the risk of cancer: evidence from a meta-analysis.
Content updated August 2026.
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