The SERPINC1 gene gives your body the instructions for antithrombin, a protein that helps keep blood clotting under control. If this gene does not work well, clots may form more easily than they should, which can raise the chance of deep vein thrombosis or a clot traveling to the lungs. This gene plays an important role in the balance between bleeding and clotting. People with a harmful variant may have inherited antithrombin deficiency, although clot risk can vary from person to person.
What is a gene?
Within DNA, a gene is a segment that holds instructions your cells use to make molecules or regulate processes in the body. Some genes carry the directions for producing proteins, the working parts of cells. Others mainly help determine when certain processes happen, where they take place, and how strongly they run. Taken together, genes affect how the body develops and functions, and they can influence how you respond to food, stress, or medications. To go into this topic in more detail, you can find more in the LearnHub.
Overview
SERPINC1Gene function
What if the gene works
The SERPINC1 gene provides instructions for antithrombin, a blood protein that helps keep clotting under control. It slows several clotting proteins, helping your body form clots when needed without letting them grow too much.
Risk
What if the gene does not work
Variants in the SERPINC1 gene can cause antithrombin deficiency, raising the chance of abnormal blood clots, especially in veins. Milder variants may lead to later or fewer clotting episodes, while more severe variants can cause earlier, more pronounced thrombosis.
Treatment
What does that mean for your treatment
Pathogenic variants in the SERPINC1 gene can reduce response to heparin, because heparin depends on antithrombin to work. This can influence treatment during a clot, surgery, pregnancy, or childbirth, when clinicians may use antithrombin concentrate and may choose a different blood thinner if needed. Long term clot prevention is usually based on personal clot history.
Conditions associated with SERPINC1
Gene function
What if the gene works
Blood needs to clot after an injury, but it also needs a built-in brake. The SERPINC1 gene helps provide that brake by making antithrombin, a protein that keeps clotting activity in balance. Understanding what the SERPINC1 gene does in blood clotting helps explain how blood can seal a cut while still flowing smoothly through healthy vessels.
The SERPINC1 gene makes antithrombin, a blood protein that slows key clotting enzymes. This helps keep clotting active when needed but more controlled once a clot has started.
Antithrombin attaches to thrombin and factor Xa, two major clotting proteins, and reduces their activity. It can also limit several other clotting factors as part of the body’s normal checks and balances.
Antithrombin works much faster when it binds natural heparin-like molecules on blood vessel surfaces. This helps focus clot control in areas where blood is moving through intact vessels.
What is a variant?
A genetic variant is a small difference in the DNA sequence within a gene. These differences are common and help explain normal human diversity, such as variation in appearance, metabolism, or the way the body responds to environmental factors. Many do not produce any noticeable effect and are simply part of natural genetic variation. At times, though, a variant can change how a gene works more strongly and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Variants in the SERPINC1 gene may lower the amount of antithrombin your body makes or change its shape so it works less well. Milder variants can leave some activity, while more severe variants may lead to very low levels or a protein that cannot bind and control clotting proteins properly. This range helps explain how SERPINC1 gene variants affect protein function and why inherited antithrombin deficiency can appear earlier or be more pronounced in some people.
How variants are linked to conditions
Pathogenic variants in the SERPINC1 gene cause inherited antithrombin deficiency, a condition linked to a higher risk of blood clots. People with this diagnosis are more likely to develop deep vein thrombosis or a pulmonary embolism, sometimes at a younger age or more than once. Risk varies from person to person and is often influenced by factors such as surgery, pregnancy, estrogen use, or long periods of immobility.
A variant is not necessarily a diagnosis
Genetic variants are a routine feature of human biology, and they are widespread in the general population. Most do not directly affect health and simply contribute to normal human diversity. For many genes, having a variant associated with a condition suggests a possible link rather than a definitive diagnosis, especially when multiple genes and environmental factors also play a part. In other cases, though, a single well-characterized variant in a specific gene can be enough to confirm the diagnosis.
Are there things that can increase or change my risk?
For people with a harmful change in the SERPINC1 gene, the main risk is blood clots, and that risk can rise further during pregnancy, after surgery, with long periods of not moving, or when using estrogen-containing birth control or hormone therapy. Family history and other inherited clotting conditions can also add to risk.
Inheritance of SERPINC1 variants
SERPINC1-related antithrombin deficiency is usually inherited in an autosomal dominant pattern. That means a person with a disease-causing variant in one copy of the SERPINC1 gene can pass it to a child, with a 50% chance in each pregnancy. In practical terms, this answers how SERPINC1 variants are inherited: the variant can be passed from an affected mother or father to sons or daughters equally. Family members across several generations may carry the same variant.
What does my SERPINC1 result mean for my family?
SERPINC1 results linked to inherited antithrombin deficiency often matter for close relatives, because this condition usually runs in families in a dominant way. Parents, brothers, sisters, and children may also carry the same change and may have a higher chance of abnormal blood clotting, even if they have never had a clot. The exact family meaning depends on whether the result is a disease-causing change or a different kind of finding.
Genetic information
Genetic testing
How you find out about variants
Genetic testing for SERPINC1 variants is usually done with a blood or saliva sample. A lab reads the SERPINC1 gene and looks for DNA changes linked to inherited antithrombin deficiency. Results may show a clearly harmful variant, no relevant variant, or a variant of uncertain significance.
When should I consider getting a genetic test?
You may want to ask about SERPINC1 testing if you or close relatives have had repeated blood clots, a clot at a young age, or a clot without a clear trigger. It can also be helpful when blood tests show low antithrombin, a natural protein that helps prevent clotting.
A genetic result is only one part of your health story
Genetic results can provide useful insight, but how much they explain depends on the condition and the kind of variant involved. Over time, many factors, including lifestyle, environment, age, and medical history, also influence how the body functions. In some conditions, especially those shaped by many genes, genetic information offers context rather than certainty and is best viewed alongside other parts of care. In other situations, a genetic result can give a clear answer. In areas such as medication response, genetic results can also help put individual experiences into perspective.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how people respond to medicines. Some people break down a drug more slowly or more quickly, while others are more or less sensitive to its effects. These inherited differences are common and can help explain why the same treatment works well for one person but not as well for another. They can influence both how much benefit a medicine provides and the chance of side effects.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences can shape a person’s response to medications. It studies gene and drug patterns to better explain why the same treatment may work differently from one person to another. For many medicines, genes influence either how strongly a drug works or how the body handles it. This information can support treatment decisions that are more informed and more individualized. You can read more about this topic in the LearnHub.
Drugs influenced by the SERPINC1 gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding routine medication choices, so questions about medicines, clotting, or unusual bleeding are best discussed with your doctor. SERPINC1 has been studied because changes in this gene can lower antithrombin, a natural protein that helps control blood clotting. In some situations, this may affect how well the blood thinner heparin works.
History
Throughout history, some families were known to have repeated episodes of unusual blood clots, long before the cause was clear. A major step came in 1965, when the Norwegian physician Olav Egeberg described an inherited antithrombin deficiency in a family with thrombosis, helping define a new genetic cause of clotting risk. From these first observations, research expanded steadily. Scientists later mapped and identified the SERPINC1 gene as the gene linked to this inherited condition, which made genetic testing possible. Over time, descriptions became more precise as different SERPINC1 variants were found in families from many countries. These historical steps shaped today’s understanding of inherited antithrombin deficiency and how it can run in families.