Table of Contents
Introduction
A condition where blood clots are formed in veins deep within the body is called deep vein thrombosis. It usually occurs because of an injury in the vein or the sluggish blood flow in that region. The clots may be complete or partial, blocking the blood flow through the vein. Studies show a link between genetics and deep vein thrombosis. This article unfolds the hidden relationship between the two.
What Is Deep Vein Thrombosis?
A serious condition where the blood clots in the deeper parts of the body is termed deep vein thrombosis. A clump of blood that has solidified is called a clot. The common sites for deep vein thrombosis include the lower leg, thigh, or pelvis. However, it can develop in any part of the body, like the arm, brain, intestines, liver, or kidneys. The condition can develop spontaneously without any underlying conditions or due to some issues with the blood flow.
What Are the Symptoms of Deep Vein Thrombosis?
The Centers for Disease Control and Prevention (CDC) state that the symptoms of deep vein thrombosis may not be visible in about half of the population with the condition. The common symptoms of the condition can include:
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Swelling in the foot, ankle, or leg, usually seen on one side.
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Severe pain that may not have any explanations.
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Cramping pain in the affected leg, which usually originates from the calf.
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The skin in the affected area is warmer than the surrounding area.
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The skin of the affected area appears pale reddish or bluish in color.
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The veins under the skin in the affected area appear larger.
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If the veins within the abdomen are affected, there can be abdominal pain.
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Severe headache or seizures if the veins to the brain are affected.
What Are the Genetic Causes of Deep Vein Thrombosis?
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Deficiencies of Natural Coagulation Inhibitors: Less than one percent of the population faces deficiency of antithrombin (a protein produced by the liver that inactivates many enzymes of the coagulation system), protein C (proteins that help in the coagulation process) and its cofactor protein S (a vitamin K-dependent protein that enhances the action of activated protein C, or APC). This increases the risk of thrombosis. However, these deficiencies are very rare and, hence, are a cause in a very small percentage of people. Studies have shown the risk to be scarce due to the low prevalence of these deficiencies. People who carry these genes may not exhibit an increase in the risk by threefold as they work through elevated prothrombin levels.
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Blood Group: The link between blood groups and deep vein thrombosis has been evident since the late 1960s. The blood groups that are non-O carry two to four times the risk than the O group. This is because they have higher higher von Willebrand factor levels and higher factor VIII levels, which increases the risk of blood clotting. In addition, those who are non-O and carry factor V Leiden have an even higher risk for the condition.
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MTHFR 677T: It is a variant of methylene dihydrofolate reductase (MTHFR) and is an important factor for homocysteine metabolism. It causes elevated levels of homocysteine (a type of amino acid that can destroy the lining of artery walls when in high levels). The variant is common, but elevated homocysteine levels are very uncommon, and the risk due to this is very small.
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Genetic Variation in GP6: GP6 is a gene that is related to platelet collagen receptor. There are two receptors for platelets, and they are mainly important for the activation of the platelets. A mutation in this gene affects the coagulation process as the platelet is affected. This increases the risk of deep vein thrombosis.
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Heritability and Family History: Venous thrombosis is a highly heritable condition. About fifty to sixty percent of the condition occurs due to mutations in the genes inherited. The inheritance of the condition is multifactorial and is influenced by the environment, genetics, and many other factors. The risk of the condition is higher in monozygotic twins (twins formed from the same zygote) than in dizygotic twins (twins developed from two different zygotes). Studies show that the risk is greater when there is a first family member with the condition.
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Prothrombin: A mutation in the gene coding for prothrombin is the second most common cause of deep vein thrombosis. The prothrombin is an important factor in blood coagulation. Hence, a defect in it can lead to clotting disorders. This increases the risk of the condition.
Conclusion
Deep vein thrombosis is a multifactorial condition, and genetics play an important role in it. An individual with a close family member with the condition poses a higher risk of carrying the condition than the general population. Other risk factors can include environmental factors like physical activity, diet, medication, and many more. Some factors can be modified to eliminate the risk, while genetic factors are hard to eliminate.
