What you carry at this position in your DNA and what research says about it.
Joint Replacement Risk: 6/10 evidence, 8 publications.
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Sample genotype (not yours): G/G
Lower Joint Replacement Failure Risk
Having this genotype indicates you are highly unlikely to have blood type B. It is associated with a significantly lower risk of joint prosthesis failure or loosening after surgery.
What this genotype means: Lower risk of joint implant loosening; Unlikely to have blood type B; Typical plasma protein levels.
Sample genotype (not yours): C/C
Higher Joint Replacement Failure Risk
Carrying two copies of the minor allele indicates a high likelihood of having blood type B. This is linked to an increased risk of joint implant loosening and revision surgery.
What this genotype means: Higher risk of joint implant loosening; Likely blood type B; Elevated plasma protein levels.
Sample genotype (not yours): G/C
Carrying one copy of the minor allele indicates a high likelihood of having blood type B. This is linked to an increased risk of joint implant loosening and revision surgery.
What this genotype means: Higher risk of joint implant loosening; Likely blood type B or AB; Elevated plasma protein levels.
Gene function and biological role
Gene Function: The ABO gene encodes a glycosyltransferase enzyme that is responsible for determining an individual's primary blood group [1]. This enzyme works by adding specific sugar molecules to the surface of red blood cells and other tissues [1]. Depending on the genetic sequence, the enzyme can produce A antigens, B antigens, both, or remain inactive to leave only the precursor H antigen of type O [1]. Beyond blood transfusions, these surface sugars play a role in cell-to-cell adhesion, inflammation, and cardiovascular health [2]. Variations in this gene have been linked to susceptibility to vascular diseases, infections, and certain cancers [2].
Variant Impact: A single nucleotide change in the coding sequence of the ABO gene alters the resulting transferase enzyme. The presence of the cytosine (C) allele at this position is a key functional marker that differentiates the B blood group transferase from other forms [1]. Consequently, carrying at least one copy of this minor allele strongly predicts having blood type B or AB [1]. Beyond blood typing, this specific genetic change has been identified as a significant modifier of joint replacement outcomes [3]. It is also associated with altered circulating levels of several plasma proteins, including albumin and endoglin [4].
Key Insight: This genetic variant links your ABO blood group directly to the long-term survival of artificial joint implants. Individuals with blood type B have a significantly higher risk of experiencing implant loosening that requires revision surgery.
Location: ABO. Chromosome 9 · 9q34.2 · 133.3 Mb
Estimated prevalence by population
Global 75.8%; European 80.6%; African 70.0%; East Asian 67.0%; South Asian 54.0%; Americas 82.5%; Ashkenazi 74.2%; Finnish 71.8%; Middle Eastern 83.7%; Amish 76.4%.
Estimated GG genotype frequency.
Global 22.4%; European 18.4%; African 27.4%; East Asian 29.7%; South Asian 39.0%; Americas 16.6%; Ashkenazi 23.9%; Finnish 25.9%; Middle Eastern 15.6%; Amish 22.0%.
Estimated GC genotype frequency.
Global 1.9%; European 1.0%; African 2.7%; East Asian 3.3%; South Asian 7.0%; Americas 0.8%; Ashkenazi 1.9%; Finnish 2.3%; Middle Eastern 0.7%; Amish 1.6%.
Estimated CC genotype frequency.
Showing effects for G/G genotype
Organ Systems
Bone, Joint & Connective Tissue Health
Joint Replacement Failure. Evidence: 4/10. Source: PMID 34982741. Typical Risk.
Cardiovascular & Metabolic
Blood Cell & Iron Traits
Blood Type. Evidence: 3/10. Source: PMID 21257350. Not Blood Group B.
Nutrition & Metabolism
Blood Chemistry & Metabolites
Blood Albumin Levels. Evidence: 6/10. Source: PMID 40436827. Typical.
Immunity & Inflammation
Inflammatory & Circulating Protein Markers
Endoglin Levels. Evidence: 6/10. Source: PMID 36168886. Typical.
Semaphorin-6B Levels. Evidence: 6/10. Source: PMID 36168886. Typical.
Showing effects for C/C genotype
Joint Replacement Failure. Evidence: 4/10. Source: PMID 34982741. ~3.5x Higher Risk.
Blood Type. Evidence: 3/10. Source: PMID 21257350. Likely Blood Group B.
Blood Albumin Levels. Evidence: 6/10. Source: PMID 40436827. Higher.
Endoglin Levels. Evidence: 6/10. Source: PMID 36168886. Higher.
Semaphorin-6B Levels. Evidence: 6/10. Source: PMID 36168886. Higher.
Showing effects for G/C genotype
What this genotype means for the people who carry it
Sample genotype: GG (Homozygous)
Homozygosity for the major G allele indicates that the blood type is highly unlikely to be group B [1]. In the context of joint replacement surgeries, such as hip or knee arthroplasty, this genotype is associated with a much lower risk of aseptic loosening [2]. Aseptic loosening occurs when a joint implant becomes loose without an active infection, often requiring a complex revision surgery [2]. Research shows that patients who do not have blood type B have a ten-year joint implant survival rate of approximately ninety-five percent [2]. This is significantly higher than the survival rate observed in those with blood type B [2]. Additionally, this genotype is associated with typical baseline levels of plasma albumin and endoglin [3] [4].
Lower risk of joint implant loosening; Unlikely to have blood type B; Typical plasma protein levels.
Sample genotype: CC (Homozygous)
Inheriting two copies of the minor C allele strongly indicates a blood type B phenotype [1]. This genotype is linked to a significantly increased risk of aseptic loosening after undergoing joint replacement surgery [2]. When aseptic loosening occurs, the artificial joint separates from the bone without any active infection [2]. Clinical data shows that individuals with blood type B have a ten-year implant survival rate of only eighty-five percent [2]. Non-B individuals, by comparison, experience a much higher survival rate of ninety-five percent [2]. The risk of requiring a revision surgery is more than three times higher for carriers of this genetic marker [2]. Furthermore, this homozygous state is associated with elevated levels of plasma proteins like albumin and endoglin [3] [4].
Higher risk of joint implant loosening; Likely blood type B; Elevated plasma protein levels.
Sample genotype: GC (Heterozygous)
Presence of one copy of the minor C allele suggests a high probability of having blood type B or AB [1]. This genetic marker is associated with an elevated risk of aseptic loosening following joint replacement surgery [2]. Aseptic loosening is a common complication where the implant detaches from the bone, often requiring a revision procedure [2]. Research indicates that patients with blood type B have a ten-year joint implant survival rate of approximately eighty-five percent [2]. In contrast, those without blood type B enjoy a survival rate of ninety-five percent [2]. The hazard ratio for joint revision surgery associated with this variant is estimated at over three-fold [2]. Additionally, this genetic profile is linked to higher circulating levels of plasma albumin and endoglin [3] [4].
Higher risk of joint implant loosening; Likely blood type B or AB; Elevated plasma protein levels.
Variants with shared genetic architecture
rs507666 · ABO Gene · Chr 9 · Heart Disease Risk
rs550057 · ABO Gene · Chr 9 · COVID-19 Severity
rs495828 · ABO Gene · Chr 9 · Blood Clot Risk
DNA-based methods in the immunohematology reference laboratory.
Content updated August 2026.
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