What you carry at this position in your DNA and what research says about it.
Autoimmune and Cancer Risk: 10/10 evidence, 79 publications.
You're viewing every possible genotype for this variant.
None of these is your result. Use the genotype toggle to compare them, then sign up and upload your DNA to see which one is yours.
Sample genotype (not yours): G/G
Higher Autoimmune Risk but Lower Skin Cancer Risk
Having two copies of the G allele is linked to an increased risk of autoimmune conditions like rheumatoid arthritis and thyroid disease. However, this active immune state may offer protection against certain skin cancers.
What this genotype means: Increased risk of rheumatoid arthritis; Increased risk of thyroid disorders; Lower risk of skin cancers.
Sample genotype (not yours): A/A
Lower Autoimmune Risk but Higher Skin Cancer Risk
Having two copies of the A allele is associated with a typical or lower risk of autoimmune diseases. However, this calmer immune state is linked to a higher risk of developing certain skin cancers.
What this genotype means: Lower risk of rheumatoid arthritis; Lower risk of thyroid disorders; Increased risk of skin cancers.
Sample genotype (not yours): G/A
Moderately Higher Autoimmune and Skin Cancer Risk
Carrying one G allele and one A allele means you carry a risk allele for each side of this trade-off, giving a modest increase in both autoimmune susceptibility and certain skin cancers rather than a net benefit on either.
What this genotype means: Moderate risk of rheumatoid arthritis; Moderate risk of thyroid disorders; Moderate risk of skin cancers.
Gene function and biological role
Gene Function: The CTLA4 gene encodes cytotoxic T-lymphocyte associated protein 4, a crucial receptor that acts as an immune checkpoint [1]. It is primarily expressed on T-cells, where it functions as a brake to prevent the immune system from overreacting and attacking the body's own tissues [2]. Proper regulation of this gene is essential for maintaining immune tolerance and preventing autoimmune diseases [3]. However, because it dampens immune responses, its activity can also allow cancer cells to evade detection by the immune system [4]. Consequently, CTLA-4 is a major target for cancer immunotherapy drugs designed to unleash the immune system against tumors [5].
Variant Impact: The rs3087243 variant, also known as CT60, is located in the downstream region of the CTLA4 gene and influences how the protein is expressed [2]. The G allele is associated with lower levels of soluble CTLA-4, which reduces the immune system's natural braking mechanism [1]. This leads to more active T-cells, increasing the risk of autoimmune conditions like rheumatoid arthritis and thyroid disease [6]. Conversely, the A allele is linked to higher CTLA-4 expression, which calms immune activity but can reduce the body's ability to clear abnormal cells, slightly raising the risk of certain skin cancers [7]. This variant represents a classic evolutionary trade-off between autoimmune defense and cancer surveillance [3].
Key Insight: This variant presents a direct biological trade-off where the genetic allele that protects you from autoimmune diseases simultaneously increases your risk for certain skin cancers.
Location: CTLA4. Chromosome 2 · 2q33.2 · 203.9 Mb
Estimated prevalence by population
Global 40.8%; European 31.5%; African 59.6%; East Asian 57.0%; South Asian 15.5%; Americas 34.6%; Ashkenazi 25.0%; Finnish 47.0%; Middle Eastern 22.4%; Amish 33.2%.
Estimated GG genotype frequency.
Global 44.4%; European 49.2%; African 35.2%; East Asian 37.0%; South Asian 47.7%; Americas 48.5%; Ashkenazi 50.0%; Finnish 43.1%; Middle Eastern 49.9%; Amish 48.8%.
Estimated GA genotype frequency.
Global 14.8%; European 19.2%; African 5.2%; East Asian 6.0%; South Asian 36.7%; Americas 17.0%; Ashkenazi 25.0%; Finnish 9.9%; Middle Eastern 27.8%; Amish 18.0%.
Estimated AA genotype frequency.
Showing effects for G/G genotype
Immunity & Inflammation
Autoimmune Diseases
Rheumatoid Arthritis. Evidence: 8/10. Source: PMID 20453842. ~1.14x Risk.
Graves' Disease. Evidence: 8/10. Source: PMID 39024449. Increased Risk.
Endocrine & Reproductive
Hormone Levels & Endocrine Regulation
Hypothyroidism. Evidence: 10/10. Source: PMID 27182965. ~1.16x Risk.
Cancer & Oncology
Skin Cancer
Basal Cell Carcinoma. Evidence: 8/10. Source: PMID 33549134. Typical Risk.
Melanoma. Evidence: 8/10. Source: PMID 39024449. Typical Risk.
Showing effects for A/A genotype
Rheumatoid Arthritis. Evidence: 8/10. Source: PMID 20453842. Typical Risk.
Graves' Disease. Evidence: 8/10. Source: PMID 39024449. Typical Risk.
Hypothyroidism. Evidence: 10/10. Source: PMID 27182965. Typical Risk.
Basal Cell Carcinoma. Evidence: 8/10. Source: PMID 33549134. Increased Risk.
Melanoma. Evidence: 8/10. Source: PMID 39024449. Increased Risk.
Showing effects for G/A genotype
Rheumatoid Arthritis. Evidence: 8/10. Source: PMID 20453842. Slightly Increased.
Graves' Disease. Evidence: 8/10. Source: PMID 39024449. Slightly Increased.
Hypothyroidism. Evidence: 10/10. Source: PMID 27182965. Slightly Increased.
Basal Cell Carcinoma. Evidence: 8/10. Source: PMID 33549134. Slightly Increased.
Melanoma. Evidence: 8/10. Source: PMID 39024449. Slightly Increased.
What this genotype means for the people who carry it
Sample genotype: GG (Homozygous)
The G allele at rs3087243 is associated with reduced expression of soluble CTLA-4, a key protein that acts as a brake on the immune system [1]. With fewer brakes, T-cells are more active, which increases the likelihood of the immune system mistakenly attacking healthy tissues [2]. This elevated immune activity is linked to a higher risk of rheumatoid arthritis, Graves' disease, and hypothyroidism [3] [4]. Conversely, this heightened immune surveillance makes the body more efficient at detecting and destroying abnormal cells, resulting in a lower risk of skin cancers such as basal cell carcinoma and melanoma [5].
Increased risk of rheumatoid arthritis; Increased risk of thyroid disorders; Lower risk of skin cancers.
Sample genotype: AA (Homozygous)
The A allele at rs3087243 is associated with higher expression of soluble CTLA-4, which helps maintain strong regulatory control over T-cell activation [1]. This robust braking mechanism keeps the immune system from overreacting, resulting in a lower risk of autoimmune conditions like rheumatoid arthritis and Graves' disease [2] [3]. However, a calmer immune system is less vigilant at scanning for and eliminating mutated cells, which is why this genotype is linked to an increased risk of skin cancers, including basal cell carcinoma and melanoma [4]. This classic evolutionary trade-off demonstrates how genetic protection against one class of disease can increase susceptibility to another [5].
Lower risk of rheumatoid arthritis; Lower risk of thyroid disorders; Increased risk of skin cancers.
Sample genotype: GA (Heterozygous)
This heterozygous genotype produces intermediate levels of soluble CTLA-4 [1]. The G allele slightly reduces the immune system's brakes, modestly increasing the risk of autoimmune disorders such as rheumatoid arthritis and thyroid conditions [2] [3], while the A allele is associated with a higher risk of skin cancers such as basal cell carcinoma [4]. Because this genotype carries one of each allele, it is modestly elevated on both axes at once rather than protected on either, unlike the homozygotes, which trade a higher risk on one axis for a lower risk on the other [5].
Moderate risk of rheumatoid arthritis; Moderate risk of thyroid disorders; Moderate risk of skin cancers.
Variants with shared genetic architecture
rs231775 · CTLA4 Gene · Chr 2 · Autoimmune Disease Risk
rs5742909 · CTLA4 Gene · Chr 2 · Immune System Balance
rs16840252 · CTLA4 Gene · Chr 2 · Autoimmune and Cancer Risk
Association of the T-cell regulatory gene CTLA4 with susceptibility to autoimmune disease.
Genetics of rheumatoid arthritis contributes to biology and drug discovery.
Genome-wide association study meta-analysis identifies seven new rheumatoid arthritis risk loci.
Diversity and scale: Genetic architecture of 2068 traits in the VA Million Veteran Program.
A cross-population atlas of genetic associations for 220 human phenotypes.
Content updated August 2026.
ReadYourDNA provides educational interpretation of DNA data you already have. It is not diagnostic, not a substitute for professional medical advice, diagnosis, or treatment, and is not intended to diagnose, treat, cure, or prevent any disease. Talk to a clinician before acting on any result.
Raw DNA Data Reports for 23andMe & AncestryDNA · About ReadYourDNA · FAQ · Methodology & Science · Pricing · Support and complaints · Legal & Contact · Health Traits · Pharmacogenomics · Carrier Status · Variant Explorer · The Human Karyotype · Privacy Policy · Terms of Service · Accessibility · Consumer Health Data Privacy · Your Privacy Choices · Editorial Standards · Your Data, Checkable · Sample Report · ReadYourDNA and Promethease compared · What is inside a 23andMe raw data file · What is inside an AncestryDNA raw data file · What a chatbot can and cannot do with your raw DNA file · Where a raw DNA file can still be uploaded in 2026
Written, maintained and operated by Martin Pechhacker, sole proprietor, Vienna, Austria. Trade register GISA 40064420. support@readyourdna.com