ABO rs635634: What Your Genotype Means
The genetic variant rs635634 is a specific location in the human genome located within the ABO gene, which is famously responsible for determining your ABO blood group. Research has associated this variant with variations in plasma alkaline phosphatase levels and certain cardiovascular-related health traits.
What each genotype means
Common ABO variant profile
This genotype represents the major allele configuration for this variant in the ABO gene. Research indicates that variants in this region are associated with variations in plasma alkaline phosphatase levels and other blood-related biomarkers, though the specific functional impact of this individual SNP remains limited in clinical literature.
This is the most common genotype globally, carried by the majority of the population.
Heterozygous ABO variant profile
Carrying one copy of the minor allele is associated with the broader genetic landscape of the ABO locus, which influences various plasma proteins. Because the evidence for this specific variant is limited, it is unclear how this genotype influences individual physiology compared to the common CC genotype.
Carried by roughly 1 in 3 people globally, though frequencies vary significantly by ancestry.
Minor allele ABO profile
This genotype represents the homozygous minor allele state for this variant. While the ABO gene is well-known for determining blood type and influencing various circulating proteins, the specific contribution of this variant to health outcomes is not well-defined and remains a subject of ongoing GWAS research.
This is the least common genotype, occurring in approximately 1 in 25 individuals globally.
Understanding the Variant and Gene
The ABO gene is located on chromosome 9 (specifically at 9q34.2) and encodes a glycosyltransferase enzyme. This enzyme acts like a molecular architect, modifying the sugar structures on the surface of your red blood cells and other tissues to create the A, B, or O blood type antigens. The SNP rs635634 is an intergenic variant found near this gene. While it does not change the protein sequence of the ABO enzyme itself, it is frequently studied as a tagging variant. In genetics, a tagging variant acts as a marker that is often inherited alongside the actual functional changes that dictate blood type or regulate gene expression. Because it sits in a region that influences how the ABO gene is controlled, scientists use this SNP to explore how blood-type-related genetics might influence broader physiological processes beyond simple blood transfusion compatibility.
Research and Associations
Scientific research has linked rs635634 to several quantitative traits and biomarkers, though the evidence for most of these associations is considered limited or exploratory. The most consistent research identifies an association between this variant and plasma alkaline phosphatase (ALP) levels, an enzyme found throughout the body. Furthermore, because ABO variants influence the proteins on the surfaces of blood vessels and platelets, researchers have investigated the role of rs635634 in cardiovascular health, including traits related to lipid levels and stroke risk. Some genome-wide association studies (GWAS) have reported correlations between this SNP and various inflammatory markers or metabolic traits. However, it is important to note that these findings are often specific to certain populations or observed only in large-scale statistical models. As with many genetic associations, these results describe broad trends in groups of people and cannot be used to predict individual health outcomes or diagnose any medical condition.
What This Information Means
Learning about your genotype at rs635634 provides insight into your genetic architecture, specifically regarding the ABO locus. What you can do: You can use this information to better understand your genetic heritage and satisfy your curiosity about how DNA influences human biology. What you cannot do: You should never use this information to make medical decisions, assume your risk for specific diseases, or alter your diet or lifestyle. This variant does not provide a diagnostic result. If you have concerns about your blood markers, such as alkaline phosphatase levels, or cardiovascular health, please consult your primary care physician. They can order validated clinical tests and interpret them in the context of your overall health history.
How common is this variant?
The rs635634 variant is common across diverse human populations with a minor allele frequency of approximately 0.20 globally.
Frequently asked questions
Is rs635634 a test for my blood type?
No, rs635634 is not a clinical test for blood typing. While it is located in the ABO gene region and is associated with blood group markers, standard clinical blood typing should always be performed by a healthcare professional using verified serological methods.
Does this variant mean I am at risk for heart disease?
The evidence connecting rs635634 to cardiovascular traits is statistical and limited, meaning it does not indicate a personal medical risk. Genetic association studies identify trends in large populations, not individual diagnoses; always consult a doctor for a personalized heart health assessment.
Can I change my alkaline phosphatase levels based on this SNP?
No. Alkaline phosphatase levels are influenced by many factors, including liver and bone health. This genetic variant is just one of many factors that might play a very small role in biomarker levels, and there is no evidence that you can or should attempt to change your health based on this genotype.
Where can I find more information on this SNP?
You can explore the GWAS Catalog or the National Center for Biotechnology Information (NCBI) SNP database for technical summaries. These resources provide access to published research and data regarding genetic variants.
Sources & further reading
Educational information only, last refreshed 9/28/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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A missense variant (Leu266Met) in the ABO gene that, in combination with other SNPs, determines ABO blood group status and is associated with cardiovascular and metabolic traits.
A common variant in the ABO blood group locus robustly associated with circulating levels of soluble adhesion molecules (sICAM-1) and venous thromboembolism risk.
Located near the ABO locus and associated in GWAS with circulating lipid levels and markers of cardiovascular disease risk.
This single nucleotide polymorphism in the ABO locus is strongly associated with circulating E-selectin, soluble ICAM-1 levels, and thrombosis risk.
Tagging variant in ABO associated with blood group phenotypes and longevity.
Regulatory variant at the ABO locus influencing plasma von Willebrand factor levels and venous thromboembolism risk.