ENG rs1800956: What Your Genotype Means
The rs1800956 variant is a genetic change located within the ENG gene, which provides instructions for making the endoglin protein. This variant has been studied for its potential role in vascular conditions, including hereditary hemorrhagic telangiectasia and intracranial aneurysms.
What each genotype means
Common genetic profile
This is the most frequently observed genotype for this variant in many populations. Research into this specific variant has explored its potential role in vascular health, including studies on intracranial aneurysms, but it is not considered a primary cause of hereditary hemorrhagic telangiectasia.
This is the major allele genotype and is found in the vast majority of individuals across global populations.
Variant carrier profile
Carrying one copy of the G allele results in a D366H amino acid substitution in the endoglin protein. Some studies have investigated whether this change might influence susceptibility to vascular conditions like intracranial aneurysms, though findings have been mixed and often limited to specific ancestral groups.
This heterozygous genotype is relatively uncommon, with the G allele occurring at a minor allele frequency of approximately 3% in some populations.
Rare variant profile
This genotype results in two copies of the D366H substitution in the endoglin protein. While this variant is located in a gene associated with hereditary hemorrhagic telangiectasia, this specific SNP is generally studied in the context of complex vascular traits rather than as a direct diagnostic marker for HHT.
This homozygous genotype is rare and observed at a very low frequency in the general population.
Understanding the rs1800956 Variant
The rs1800956 variant is a single nucleotide polymorphism (SNP) located on chromosome 9. In this specific position, the DNA sequence can feature either a cytosine (C) or a guanine (G) base. This change results in a missense mutation, specifically an amino acid substitution where aspartic acid is replaced by histidine at position 366 (p.Asp366His) in the endoglin protein. Because this change alters the protein's primary structure, researchers have investigated whether it impacts the protein's ability to fold correctly or function within the cell. Genetic variants like this are cataloged by researchers to understand how subtle changes in our DNA sequence might influence biological processes, particularly those related to the development and maintenance of blood vessels throughout the body.
The Role of the ENG Gene
The ENG gene is responsible for producing a protein called endoglin. Endoglin is primarily found on the surface of endothelial cells, which line the interior of blood vessels. It acts as a co-receptor for signaling molecules, playing a critical role in the TGF-beta signaling pathway. This pathway is essential for the proper development of the vascular system, helping to regulate the formation of boundaries between arteries and veins. When the ENG gene is disrupted, the resulting endoglin protein may be absent, reduced, or dysfunctional. This leads to a condition known as hereditary hemorrhagic telangiectasia (HHT) type 1, which is characterized by abnormal connections between arteries and veins, known as arteriovenous malformations. These malformations can lead to frequent nosebleeds, anemia, and more severe complications if they occur in organs like the lungs or brain.
Research and Clinical Associations
Research into rs1800956 has explored its potential involvement in vascular disease, though the evidence is nuanced. Some studies have examined this variant in the context of intracranial aneurysms, particularly within specific populations, suggesting it may play a role in the pathogenesis of these vascular weaknesses. However, it is important to distinguish between common variants and the highly penetrant, pathogenic mutations that typically cause HHT. While HHT is primarily caused by loss-of-function mutations in ENG, the clinical significance of rs1800956 is often categorized as 'other' or requires further investigation to determine its exact impact on disease risk. The evidence for this specific SNP is considered moderate, and it is not typically used as a primary diagnostic marker for HHT in clinical settings. As with all genetic research, findings can vary based on ancestry and the specific genetic background of the individuals studied.
Population Frequency and Interpretation
The rs1800956 variant is considered rare in the general population. Because it is not a common polymorphism, most individuals will carry the reference genotype. When interpreting genetic information, it is vital to remember that the presence of a variant does not equate to a medical diagnosis. Genetic associations are statistical observations made across large groups of people and do not predict the health outcome of any single individual. If you have concerns about your vascular health or a family history of conditions like HHT, the most appropriate step is to consult with a healthcare provider or a genetic counselor. They can provide context based on your personal and family medical history, which is far more informative than looking at a single genetic variant in isolation. Never make medical decisions based solely on genetic test results without professional guidance.
How common is this variant?
The rs1800956 variant is rare across most global populations, with the majority of individuals carrying the reference C/C genotype.
Frequently asked questions
Is rs1800956 a cause of HHT?
Hereditary hemorrhagic telangiectasia is typically caused by pathogenic loss-of-function mutations in the ENG or ACVRL1 genes. While rs1800956 is located in the ENG gene, it is not a standard diagnostic marker for HHT.
What should I do if I have the G allele?
Finding a specific variant in your genetic data does not mean you have a disease. You should discuss your results with a doctor or genetic counselor who can interpret them in the context of your overall health.
Does this variant affect my risk of aneurysms?
Some research has suggested a potential association between this variant and intracranial aneurysms in specific populations. However, these findings are statistical associations and do not mean that carrying the variant will lead to an aneurysm.
Where can I find more information about the ENG gene?
MedlinePlus Genetics provides comprehensive, plain-language information about the ENG gene and its role in human health. You can also search the NCBI Gene database for technical details.
Sources & further reading
Educational information only, last refreshed 10/8/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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Genetic variant identified in the ENG gene, relevant for clinical screening of vascular disorders.
A known pathogenic mutation in the ENG gene linked to vascular malformations.
Pathogenic variant in the ENG gene associated with hereditary hemorrhagic telangiectasia type 1.
A variant in the ENG gene potentially impacting protein function related to vascular development.
This variant is located within the ENG gene, which is associated with hereditary hemorrhagic telangiectasia.
Clinically significant variant in the ENG gene associated with hereditary hemorrhagic telangiectasia.