ABO rs2075244: Biomarkers and Venous Thrombosis Risk

What each genotype means

Genomic Location and Variant Characteristics

The single nucleotide polymorphism rs2075244 is located on chromosome 9 within the ABO locus. In standard genetic assays, it typically represents a biallelic single nucleotide substitution (C/T on the forward strand). Because this variant resides in a dense genomic region characterized by extensive linkage disequilibrium, it frequently segregates alongside functional variants that determine human ABO blood groups. While rs2075244 itself does not directly alter protein-coding sequences in a manner that creates new blood group antigens, it serves in genetic epidemiology as an informative proxy or tagging variant for underlying haplotypes in the ABO region.

Function of the ABO Gene

The ABO gene encodes a glycosyltransferase enzyme responsible for transferring specific monosaccharide units onto precursor H antigens. This enzymatic activity produces the distinct A and B oligosaccharide antigens expressed on erythrocyte membranes, vascular endothelial surfaces, and secreted glycoproteins. Beyond defining serological transfusion compatibility, ABO glycosylation plays a direct biological role in modulating the clearance and biological half-life of key plasma proteins. For instance, individuals carrying non-O blood group alleles tend to show higher circulating levels of von Willebrand factor and factor VIII, influencing coagulation pathways and cellular adhesion mechanisms throughout the vascular tree.

Associations with Adhesion Molecules and Thrombosis

Multiple genome-wide association studies and epidemiological analyses have identified signals at the ABO locus, including rs2075244, associated with circulating levels of soluble E-selectin and soluble intercellular adhesion molecule-1 (sICAM-1). These adhesion molecules facilitate leukocyte rolling and recruitment across activated endothelial linings. In addition, large observational cohorts have evaluated variants in this locus in relation to deep vein thrombosis and pulmonary embolism risk. Because alleles tagging non-O blood groups correlate with altered vascular inflammatory markers and elevated procoagulant factor levels, carriers of associated alleles display a modest statistical elevation in venous thromboembolism liability compared to those carrying blood type O proxies.

Strength of Scientific Evidence

The scientific evidence linking rs2075244 directly to individual clinical outcomes is classified as limited. While the statistical relationship between the broader ABO gene locus, endothelial biomarker concentrations, and venous thromboembolism is reproducible across major populations, rs2075244 is rarely assessed as an independent causal driver in clinical practice. Instead, the observed associations are predominantly driven by its correlation with broader ABO blood group structures. Additionally, traditional prothrombotic mutations such as Factor V Leiden and prothrombin G20210A carry much higher individual odds ratios, meaning rs2075244 accounts for only a minor fraction of overall thrombotic susceptibility.

Clinical Utility and Lifestyle Context

Information regarding rs2075244 genotype cannot be used to diagnose a clotting disorder, nor does it replace established clinical blood typing methods. Possessing an allele associated with increased endothelial markers or non-O status indicates only a minor relative shift in statistical odds rather than a definitive health outcome. Real-world thrombosis risk is heavily dictated by acquired triggers, including surgery, extended immobility, pregnancy, smoking, obesity, and advanced age. Anyone with a personal or familial history of unprovoked blood clots should consult a qualified physician for comprehensive evaluation, rather than relying on direct-to-consumer genetic variants.

Frequently asked questions

Sources & further reading

Related variants in ABO