What you carry at this position in your DNA and what research says about it.
Inflammatory Disease Risk: 10/10 evidence, 90 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): A/A
Higher Risk of Inflammatory and Autoimmune Conditions
Carrying two copies of the high-binding allele is associated with an increased risk of inflammatory bowel disease and Kawasaki disease. However, this genotype may respond better to certain monoclonal antibody therapies.
What this genotype means: Elevated risk of ulcerative colitis and Crohn's disease; Higher susceptibility to Kawasaki disease; Potentially better response to monoclonal antibody therapies.
Sample genotype (not yours): A/G
Moderately Higher Risk of Inflammatory Conditions
Carrying one copy of the high-binding allele is linked to a moderately increased risk of inflammatory bowel disease and Kawasaki disease. It also presents a mixed profile for response to biologic therapies.
What this genotype means: Moderately elevated risk of ulcerative colitis; Slightly higher susceptibility to Kawasaki disease; Intermediate response to certain monoclonal antibody therapies.
Sample genotype (not yours): G/G
Typical Risk of Inflammatory and Autoimmune Conditions
Carrying two copies of the low-binding allele is associated with a typical risk of inflammatory bowel disease and Kawasaki disease. However, it may result in a reduced response to certain monoclonal antibody therapies.
What this genotype means: Typical risk of ulcerative colitis and Crohn's disease; Lower susceptibility to Kawasaki disease; Potentially reduced response to certain monoclonal antibody therapies.
Gene function and biological role
Gene Function: FCGR2A encodes the Fc gamma receptor IIa, a crucial protein found on the surface of various immune cells like macrophages and neutrophils [1]. This receptor binds to the Fc region of IgG antibodies, which helps the immune system engulf pathogens and clear circulating immune complexes [2]. It acts as a vital bridge between the antibody-mediated immune response and cellular defense mechanisms [3]. Variations in this gene can significantly alter how tightly the receptor binds to antibodies, directly impacting immune activation and susceptibility to autoimmune conditions [4].
Variant Impact: The rs1801274 variant is a missense mutation in the FCGR2A gene that alters the amino acid at position 167 from histidine to arginine [5]. This change occurs in the extracellular domain of the receptor, directly modifying its antibody-binding pocket [6]. The histidine (A) allele represents a high-affinity receptor for IgG2 antibodies, whereas the arginine (G) allele represents a low-affinity receptor [2]. Consequently, this single letter change determines how aggressively immune cells respond to antibody-coated targets and autoimmune complexes [4].
Key Insight: A single amino acid change in this receptor determines whether your immune cells bind tightly or loosely to antibodies, balancing the risk of autoimmune disease against the effectiveness of cancer immunotherapies.
Location: FCGR2A. Chromosome 1 · 1q23.3 · 161.5 Mb
Estimated prevalence by population
Global 25.0%; European 24.2%; African 21.0%; East Asian 48.3%; South Asian 35.9%; Americas 26.2%; Ashkenazi 33.4%; Finnish 23.8%; Middle Eastern 22.7%; Amish 39.9%.
Estimated AA genotype frequency.
Global 49.5%; European 50.0%; African 49.7%; East Asian 42.4%; South Asian 48.0%; Americas 50.0%; Ashkenazi 48.8%; Finnish 50.0%; Middle Eastern 49.9%; Amish 46.5%.
Estimated AG genotype frequency.
Global 25.5%; European 25.8%; African 29.4%; East Asian 9.3%; South Asian 16.0%; Americas 23.8%; Ashkenazi 17.8%; Finnish 26.3%; Middle Eastern 27.4%; Amish 13.6%.
Estimated GG genotype frequency.
Showing effects for A/A genotype
Immunity & Inflammation
Chronic Inflammatory Diseases
Ulcerative Colitis. Evidence: 10/10. Source: PMID 19915573. ~1.21x Higher Risk.
Kawasaki Disease. Evidence: 7/10. Source: PMID 22081228. ~1.38x Higher Risk.
Crohn's Disease. Evidence: 6/10. Source: PMID 26192919. ~1.08x Higher Risk.
Cancer & Oncology
Cancer Prognosis & Treatment Outcome
Cancer Progression. Evidence: 4/10. Source: PMID 18633131. Increased Risk.
Pharmacogenomics
Immunosuppressant & Biologic Response
Biologic Drug Response. Evidence: 6/10. Source: PMID 21109570. Stronger Response.
Showing effects for A/G genotype
Ulcerative Colitis. Evidence: 10/10. Source: PMID 19915573. Increased Risk.
Kawasaki Disease. Evidence: 7/10. Source: PMID 22081228. Increased Risk.
Crohn's Disease. Evidence: 6/10. Source: PMID 26192919. Increased Risk.
Biologic Drug Response. Evidence: 6/10. Source: PMID 21109570. Moderate Response.
Showing effects for G/G genotype
Ulcerative Colitis. Evidence: 10/10. Source: PMID 19915573. Typical Risk.
Kawasaki Disease. Evidence: 7/10. Source: PMID 22081228. Typical Risk.
Crohn's Disease. Evidence: 6/10. Source: PMID 26192919. Typical Risk.
Cancer Progression. Evidence: 4/10. Source: PMID 18633131. Typical Risk.
Biologic Drug Response. Evidence: 6/10. Source: PMID 21109570. Poorer Response.
What this genotype means for the people who carry it
Sample genotype: AA (Homozygous)
Having two copies of the A allele leads to the production of the high-affinity histidine isoform of the Fc gamma receptor IIa [1]. This high-binding receptor triggers stronger immune responses, which can elevate the risk of developing inflammatory bowel disease, including ulcerative colitis and Crohn's disease [2]. It is also linked to a significantly higher risk of Kawasaki disease, an inflammatory blood vessel condition [3]. On the positive side, this high-affinity receptor binds more effectively to therapeutic monoclonal antibodies like trastuzumab and cetuximab, often leading to better treatment outcomes in cancer therapies [4]. However, the overall risk profile for chronic inflammatory conditions is elevated [5].
Elevated risk of ulcerative colitis and Crohn's disease; Higher susceptibility to Kawasaki disease; Potentially better response to monoclonal antibody therapies.
Sample genotype: AG (Heterozygous)
Carrying one A allele and one G allele results in a mixture of high-affinity and low-affinity Fc gamma receptors on immune cells [1]. This intermediate state is associated with a moderately increased risk of inflammatory bowel disease, particularly ulcerative colitis [2]. It also elevates the susceptibility to Kawasaki disease compared to carrying two copies of the G allele [3]. In the context of cancer immunotherapy, this genotype generally shows an intermediate response to monoclonal antibodies like cetuximab [4]. While it does not carry the maximum risk of the A/A genotype, it still presents an elevated risk for chronic inflammatory and autoimmune responses [5].
Moderately elevated risk of ulcerative colitis; Slightly higher susceptibility to Kawasaki disease; Intermediate response to certain monoclonal antibody therapies.
Sample genotype: GG (Homozygous)
Having two copies of the G allele leads to the production of the low-affinity arginine isoform of the Fc gamma receptor IIa [1]. This lower binding strength is protective against the overactive immune responses that drive inflammatory bowel disease, resulting in a typical or lower risk of ulcerative colitis and Crohn's disease [2]. It also correlates with a lower risk of developing Kawasaki disease [3]. However, because the receptor binds less tightly to IgG antibodies, individuals with this genotype may experience a reduced response or lower survival rates when treated with certain monoclonal antibody therapies like cetuximab or trastuzumab [4]. Despite the potential for reduced efficacy with specific biologics, the baseline risk for chronic inflammatory diseases is favorable [5].
Typical risk of ulcerative colitis and Crohn's disease; Lower susceptibility to Kawasaki disease; Potentially reduced response to certain monoclonal antibody therapies.
Variants with shared genetic architecture
rs10761659 · ZNF365 Gene · Chr 10 · Crohn's Disease Risk
rs2836878 · PSMG1 Gene · Chr 21 · Gut Inflammation Risk
rs6017342 · Chr 20 · Ulcerative Colitis Risk
Complex genetic signatures in immune cells underlie autoimmunity and inform therapy.
C-reactive protein binding to FcgammaRIIa on human monocytes and neutrophils is allele-specific.
Fcgamma receptors: structure, function and role as genetic risk factors in SLE.
Genome-wide association study identifies FCGR2A as a susceptibility locus for Kawasaki disease.
The rs150311303 polymorphism in FcγRIIa enhances IgG binding capacity.
Host-microbe interactions have shaped the genetic architecture of inflammatory bowel disease.
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