ENG rs121918402: Understanding Hereditary Hemorrhagic Telangiectasia
The variant rs121918402 is a rare genetic alteration located within the ENG gene. It is clinically significant due to its established association with hereditary hemorrhagic telangiectasia (HHT), a condition characterized by abnormal blood vessel development.
What each genotype means
Typical ENG genotype
This is the common, wild-type genotype for the ENG gene. It is not associated with the pathogenic changes linked to hereditary hemorrhagic telangiectasia (HHT) at this specific location.
This is the most common genotype found in the general population.
Associated with HHT risk
This genotype involves one copy of the variant associated with hereditary hemorrhagic telangiectasia (HHT), an autosomal dominant vascular disorder. Individuals with this variant may have an increased risk of developing symptoms such as recurrent nosebleeds or abnormal blood vessel formations, and should discuss these findings with a medical professional or genetic counselor.
This is a very rare genotype observed in clinical databases.
Associated with HHT risk
This genotype indicates the presence of the variant associated with hereditary hemorrhagic telangiectasia (HHT). Because HHT is an autosomal dominant condition, carrying this variant is clinically significant and warrants consultation with a healthcare provider to discuss potential health implications and screening.
This is a very rare genotype observed in clinical databases.
Associated with HHT risk
This genotype indicates the presence of the variant associated with hereditary hemorrhagic telangiectasia (HHT). As this is a clinically significant variant, individuals with this result should consult with a clinician to understand their personal health risks and appropriate management strategies.
This is a very rare genotype observed in clinical databases.
What is rs121918402?
The variant rs121918402 is a specific change in the DNA sequence of the ENG gene, which is located on chromosome 9. In genetic databases, this variant is recognized for its clinical relevance in the context of vascular health. When scientists refer to this SNP, they are identifying a precise location in the human genome where a single nucleotide substitution has been observed. Because this variant is classified as pathogenic in clinical settings, it is often studied in the context of hereditary conditions. It is important to note that the presence of a variant does not automatically imply a specific health outcome for every individual, as genetic expression can be influenced by a variety of factors, including other genetic modifiers and environmental interactions.
The Role of the ENG Gene
The ENG gene provides instructions for producing a protein called endoglin. This protein is a critical component of the transforming growth factor-beta (TGF-beta) receptor complex, which plays a vital role in cell signaling, particularly in the development and maintenance of blood vessels. Endoglin is highly expressed in the cells that line the interior of blood vessels, known as endothelial cells. When the ENG gene is altered, the resulting endoglin protein may not function correctly, which can disrupt the signaling pathways necessary for proper vascular structure. This disruption is the underlying mechanism for hereditary hemorrhagic telangiectasia type 1 (HHT1), a multisystemic vascular dysplasia that can lead to the formation of arteriovenous malformations.
Research and Clinical Associations
Research has strongly associated pathogenic variants in the ENG gene with hereditary hemorrhagic telangiectasia, also known as Osler-Weber-Rendu syndrome. This condition is inherited in an autosomal dominant pattern, meaning that a single copy of an altered gene is sufficient to increase the risk of developing the disorder. Clinical evidence for variants like rs121918402 is derived from studies of families affected by HHT, where researchers observe the segregation of the variant with clinical symptoms such as recurrent nosebleeds, telangiectasias, and more severe internal arteriovenous malformations. The evidence strength for this association is considered moderate to high in clinical genetics, as it is documented in databases like ClinVar and supported by molecular diagnostic findings in patients presenting with HHT symptoms.
Population Frequency
The variant rs121918402 is classified as very rare in the general population. Because it is a pathogenic variant associated with a specific hereditary condition, it is not typically found at high frequencies in large-scale genomic databases like gnomAD. Its presence is usually identified through targeted clinical genetic testing in individuals or families who already exhibit symptoms of HHT. Because the variant is rare, it does not have a significant impact on the overall genetic architecture of the general population. Most individuals will not carry this specific variant, and its detection is almost exclusively linked to clinical diagnostic workflows rather than population-wide screening efforts.
Navigating Genetic Information
If you or a family member have been identified as a carrier of a variant in the ENG gene, it is essential to consult with a qualified healthcare provider or a genetic counselor. Genetic information can be complex, and clinical interpretation requires a thorough review of your personal and family medical history. You cannot diagnose yourself or determine your health risks based solely on a single SNP result. A clinician can help you understand the implications of your genetic status, discuss appropriate screening or monitoring for vascular health, and provide guidance on how to manage potential symptoms. Always rely on professional medical advice rather than online databases when making decisions about your health or medical care.
How common is this variant?
The variant rs121918402 is very rare across all global populations, appearing primarily in clinical cohorts rather than the general population.
Frequently asked questions
What is hereditary hemorrhagic telangiectasia?
Hereditary hemorrhagic telangiectasia (HHT) is a genetic disorder that causes abnormal blood vessel formation, often leading to bleeding issues like nosebleeds and internal vascular malformations.
Is rs121918402 a cause of HHT?
Yes, this variant is considered a pathogenic mutation in the ENG gene, which is one of the primary genes known to cause HHT type 1.
Should I get tested for this variant?
Genetic testing is typically recommended by a doctor if you or your family members show clinical symptoms of HHT. You should discuss the necessity of testing with a genetic counselor or your primary care physician.
Can I change my risk if I have this variant?
While you cannot change your DNA, early diagnosis allows for proactive medical management and monitoring of vascular health to prevent complications. Discuss a personalized care plan with your healthcare provider.
Sources & further reading
Educational information only, last refreshed 10/3/2026. 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.
This ENG variant is documented in clinical databases regarding vascular health.