ABO rs12644265: Understanding Your Genetic Link to Blood Factors
The rs12644265 variant is an intergenic regulatory marker located near the ABO blood group locus. It is associated with variations in plasma levels of von Willebrand factor and factor VIII, which are proteins involved in blood clotting and venous thromboembolism risk.
What each genotype means
Typical VWF levels and baseline VTE risk
You carry two copies of the major A allele at rs12644265. In genome-wide association studies, this genotype is generally correlated with standard circulating levels of von Willebrand factor (VWF) and a baseline population risk for venous thromboembolism (VTE). This marker serves as a proxy tag for variation in the ABO region rather than a direct causative mutation, so individual risk remains predominantly shaped by overall health, lifestyle, and other clinical factors.
Carried by approximately 60% to 65% of individuals of European ancestry and roughly 40% to 45% of individuals of African ancestry.
Slightly altered VWF levels and VTE predisposition
You carry one copy of the G allele and one copy of the A allele at rs12644265. Published association studies link the G allele to modest variations in plasma von Willebrand factor (VWF) concentrations and a minor shift in relative susceptibility to venous thromboembolism. Because evidence is limited and linkage disequilibrium patterns across the ABO region vary significantly between ancestral backgrounds, this result represents a small statistical correlation rather than a medical diagnosis.
Carried by roughly 30% to 35% of individuals of European ancestry and approximately 45% of individuals of African ancestry.
Altered VWF levels and VTE predisposition
You carry two copies of the minor G allele at rs12644265. Research indicates that this genotype is linked to altered plasma von Willebrand factor (VWF) levels and an adjusted statistical likelihood of developing venous thromboembolism compared to non-carriers. However, the evidence for this specific tag variant remains limited, and absolute cardiovascular or clotting risks are heavily influenced by clinical history, activity levels, and broader genetic background.
Carried by approximately 4% to 5% of individuals of European ancestry and roughly 10% to 12% of individuals of African ancestry.
What is rs12644265?
The rs12644265 variant is a single nucleotide polymorphism (SNP) situated in the regulatory regions surrounding the ABO gene on chromosome 9. In genomics, an intergenic variant like this does not necessarily change the protein structure of the ABO enzyme itself, but rather influences how the gene is expressed or regulated. Because it sits in a region that controls the activity of the ABO locus, it is frequently studied in the context of how blood group-related genetics influence systemic health. Researchers use this SNP as a marker to understand the complex interplay between the ABO blood group system and various physiological traits, particularly those related to the circulatory system and blood coagulation.
The Role of the ABO Gene
The ABO gene is best known for determining an individual's ABO blood type by encoding glycosyltransferase enzymes that modify sugar chains on the surface of red blood cells. Beyond blood typing, the ABO locus has a profound impact on the composition of human plasma. Specifically, the ABO gene influences the circulating levels of von Willebrand factor (VWF) and coagulation factor VIII (FVIII). These proteins are essential for normal hemostasis, the process that stops bleeding. Because the ABO gene products are also expressed on the surface of VWF proteins, variations in this gene can alter the stability and clearance of these clotting factors from the bloodstream, thereby affecting an individual's overall coagulation profile.
Research and Associations
Scientific research has consistently linked the ABO locus to differences in plasma VWF and FVIII levels. Individuals with certain ABO genotypes tend to have higher concentrations of these proteins, which has been statistically associated with an increased risk of venous thromboembolism (VTE). While the evidence linking the ABO locus to these clotting factors is robust, the specific contribution of the rs12644265 variant is considered to have limited or moderate evidence strength in isolation. It is important to note that these associations are based on population-level statistical trends rather than individual clinical predictions. Many factors, including environment, lifestyle, and other genetic markers, contribute to the risk of thrombosis, and this variant represents only one small piece of a much larger biological puzzle.
What You Can Do With This Information
Genetic information regarding variants like rs12644265 is primarily for educational purposes and should not be used to diagnose or predict personal health outcomes. Because the association between this variant and clinical conditions like VTE is complex and influenced by many other variables, it cannot be used to determine your individual risk of developing a blood clot. If you are concerned about your cardiovascular health or clotting risk, it is essential to consult with a healthcare professional who can evaluate your medical history, lifestyle, and clinical blood markers. Never make changes to medications or health routines based on genetic data without first discussing them with your doctor or a qualified pharmacist.
How common is this variant?
The minor allele frequency for rs12644265 is approximately 0.21 in European populations and 0.35 in African populations, indicating significant variation across different ancestral groups.
Frequently asked questions
Does having this variant mean I will have a blood clot?
No. This variant is associated with statistical trends in blood protein levels across large populations, not individual clinical outcomes. Many factors contribute to clotting risk, and this genetic marker alone is not diagnostic.
Is rs12644265 the same as my ABO blood type?
No. While rs12644265 is located near the ABO gene and is linked to the same biological pathways, it is a specific genetic marker. Your ABO blood type is determined by different functional variations within the ABO gene.
Can I use this information to change my medication?
Absolutely not. You should never alter your medication regimen based on genetic test results. Always discuss any concerns about your health or medications with your clinician or pharmacist.
Why is the evidence for this variant considered limited?
Evidence is often labeled as limited when studies show a statistical association, but the functional mechanism is not fully understood or the effect size is small. It means the finding is a subject of ongoing research rather than a definitive clinical tool.
Sources & further reading
Educational information only, last refreshed 10/18/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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