What you carry at this position in your DNA and what research says about it.
Immunodeficiency Risk: 5/10 evidence, 18 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
Typical Immune Function and Antibody Production
Presence of two typical alleles supports normal TACI receptor function. This genotype is associated with standard levels of antibodies and blood cell counts.
What this genotype means: Standard antibody levels; Typical immune response; Normal blood cell counts.
Sample genotype (not yours): A/G
Healthy Carrier of an Immunodeficiency Variant
A single copy of the variant allele generally maintains normal immune function. While antibody levels are typically sufficient, there may be subtle differences in blood cell counts.
What this genotype means: Healthy carrier status; Slightly lower average immune cell counts; Generally normal antibody levels.
Sample genotype (not yours): G/G
Increased Risk of Antibody Deficiency and Immunodeficiency
Two copies of the variant allele impair TACI receptor function. This genotype is linked to lower antibody levels and an increased susceptibility to recurrent infections.
What this genotype means: Impaired antibody production; Higher susceptibility to respiratory infections; Lower blood cell counts.
Gene function and biological role
Gene Function: The TNFRSF13B gene encodes a transmembrane receptor protein known as TACI, which is primarily found on the surface of B cells [1]. This receptor plays a critical role in the immune system by regulating B cell survival, maturation, and antibody production [1]. TACI interacts with specific signaling molecules to promote immunoglobulin class-switch recombination, allowing B cells to produce different types of antibodies like IgG and IgA [2]. When TACI function is compromised, the body struggles to mount an effective antibody response against foreign pathogens [2]. Consequently, mutations in this gene are frequently associated with primary antibody deficiencies [3].
Variant Impact: The rs34557412 variant represents a missense mutation in the TNFRSF13B gene, resulting in the substitution of cysteine with arginine at position 104 of the TACI protein [1]. This specific change, often designated as C104R, occurs in a highly conserved ligand-binding domain [1]. The alteration disrupts the receptor's ability to interact with its primary ligands, BAFF and APRIL, which are essential for downstream immune signaling [4]. Without proper ligand binding, B cells cannot mature normally or produce adequate levels of immunoglobulins [4]. This variant is recognized as one of the most common genetic risk factors linked to common variable immunodeficiency [5].
Key Insight: Although this variant is a primary genetic risk factor for common variable immunodeficiency, many people carrying it remain completely healthy, suggesting other factors are required to trigger the condition.
Location: TNFRSF13B. Chromosome 17 · 17p11.2 · 16.9 Mb
Estimated prevalence by population
Global 99.2%; European 98.8%; African 99.7%; East Asian 100.0%; South Asian > 99.9%; Americas 98.6%; Ashkenazi 99.7%; Finnish 99.8%; Middle Eastern 99.3%; Amish 100.0%.
Estimated AA genotype frequency.
Global 0.8%; European 1.2%; African 0.3%; East Asian 0.0%; South Asian < 0.1%; Americas 1.4%; Ashkenazi 0.3%; Finnish 0.2%; Middle Eastern 0.7%; Amish 0.0%.
Estimated AG genotype frequency.
Global < 0.1%; European < 0.1%; African < 0.1%; East Asian 0.0%; South Asian < 0.1%; Americas < 0.1%; Ashkenazi < 0.1%; Finnish < 0.1%; Middle Eastern < 0.1%; Amish 0.0%.
Estimated GG genotype frequency.
Showing effects for A/A genotype
Immunity & Inflammation
Immunodeficiency
Immunodeficiency Risk. Evidence: 5/10. Source: PMID 16007087. Typical Risk.
Cardiovascular & Metabolic
Blood Cell & Iron Traits
Platelet Count. Evidence: 10/10. Source: PMID 27863252. Typical Count.
Lymphocyte Count. Evidence: 10/10. Source: PMID 27863252. Typical Count.
Monocyte Count. Evidence: 10/10. Source: PMID 27863252. Typical Count.
Showing effects for A/G genotype
Immunodeficiency Risk. Evidence: 5/10. Source: PMID 16007087. Healthy Carrier.
Platelet Count. Evidence: 10/10. Source: PMID 27863252. Slightly Lower.
Lymphocyte Count. Evidence: 10/10. Source: PMID 27863252. Slightly Lower.
Monocyte Count. Evidence: 10/10. Source: PMID 27863252. Slightly Lower.
Showing effects for G/G genotype
Immunodeficiency Risk. Evidence: 5/10. Source: PMID 16007087. Increased Risk.
Platelet Count. Evidence: 10/10. Source: PMID 27863252. Lower Count.
Lymphocyte Count. Evidence: 10/10. Source: PMID 27863252. Lower Count.
Monocyte Count. Evidence: 10/10. Source: PMID 27863252. Lower Count.
What this genotype means for the people who carry it
Sample genotype: AA (Homozygous)
Standard immune system architecture relies on fully functional TACI receptors to coordinate B cell maturation [1]. Two typical A alleles ensure that these receptors can bind ligands properly and signal for antibody production [1]. This genotype is associated with typical levels of immunoglobulins, including IgG and IgA, which help defend against infections [2]. It also correlates with typical counts of platelets, lymphocytes, and monocytes in the blood [3]. Because this is the most common genetic profile globally, it represents the baseline for immune defense and blood cell composition [3]. There is no elevated risk of common variable immunodeficiency or selective IgA deficiency associated with this genotype [2]. Healthy antibody levels allow the body to efficiently recognize and neutralize foreign pathogens. Clinical assessments typically find standard immune responses to vaccines and common exposures.
Standard antibody levels; Typical immune response; Normal blood cell counts.
Sample genotype: AG (Heterozygous)
A single copy of the C104R variant results in some TACI receptors on B cells being altered, but immune function usually remains intact [1]. Clinical studies show that single-copy carriers are generally healthy and do not develop immunodeficiency unless other genetic or environmental factors are present [2]. Some research suggests that heterozygous carriers may occasionally exhibit minor alterations in B cell tolerance or antibody levels [2]. Blood cell measurements from large-scale genetic studies indicate slightly lower average counts of platelets, lymphocytes, and monocytes compared to the typical genotype [3]. Despite these subtle shifts, the immune system is typically capable of defending against common pathogens [1]. This genotype is considered a healthy carrier state with no standalone clinical diagnosis [2]. Most people with this genetic profile live healthy lives without any awareness of the variant. Routine medical evaluations generally show standard immune health and normal antibody responses.
Healthy carrier status; Slightly lower average immune cell counts; Generally normal antibody levels.
Sample genotype: GG (Homozygous)
Two copies of the C104R variant severely compromise the function of the TACI receptor on B cells [1]. This impairment prevents normal B cell maturation and significantly reduces the production of essential antibodies like IgG and IgA [1]. Clinical studies link this genotype to an increased risk of developing common variable immunodeficiency (CVID) or selective IgA deficiency [2]. Recurrent respiratory infections, sinus infections, and pneumonia are common clinical manifestations of this antibody shortage [2]. Large-scale genetic analyses also show significantly lower counts of platelets, lymphocytes, and monocytes in the blood [3]. While not everyone with this genotype will develop severe symptoms, it represents a notable genetic risk factor for immune system challenges [2]. Proactive health strategies, such as staying up to date on vaccinations, can help support overall immune defense. Consulting with an immunologist may provide personalized insights into managing potential antibody deficiencies.
Impaired antibody production; Higher susceptibility to respiratory infections; Lower blood cell counts.
Variants with shared genetic architecture
rs34562254 · TNFRSF13B Gene · Chr 17 · Multiple Myeloma Risk
rs72553883 · TNFRSF13B Gene · Chr 17 · Antibody Deficiency Risk
rs2186369 · SMARCB1 Gene · Chr 22 · Antibody Glycosylation
Mutations in TNFRSF13B encoding TACI are associated with common variable immunodeficiency in humans.
The Polygenic and Monogenic Basis of Blood Traits and Diseases.
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