Deep vein thrombosis

Deep vein thrombosis is a condition that occurs when a clot or thrombus forms in a vein deep inside a part of the body. It mainly affects the lower extremities, but can occur anywhere in the body. If the clots or thrombi travel through the bloodstream, they can deposit in the lungs leading to pulmonary embolism, a serious and potentially fatal condition.

Risk factors that can lead to clot formation include:

  • Bed rest or maintaining a static posture for a long time such as, for example, on a long airplane trip.
  • Family history of blood clots.
  • Fractures in the pelvis or legs.
  • Having given birth in the last 6 months.
  • Pregnancy.
  • Obesity.
  • Recent surgery, especially hip or knee surgery.
  • Having an indwelling catheter in a blood vessel.
  • Some pathologies such as polycythemia vera, some types of cancer or autoimmune disorders.
  • Smoking.
  • Some medications such as oral estrogens.

Deep vein thrombosis is a multifactorial disease influenced by genetic factors. Although the weight of environmental factors is much greater than heritable factors, genetic markers associated with the pathology have been identified. Among the GWAS studies carried out to date, one of the most important is one performed in more than 7000 patients and 360000 controls in which 9 associated loci were identified. Among them, the one that showed the strongest association was the one known as Leiden factor V, rs6025, located in the F5 gene and associated on multiple occasions with blood coagulation problems. In addition, an association was also found in the ABO gene, which codes for the enzyme of the blood group system, and other genes involved in coagulation, such as F2 or F11.


The disorder mainly affects the large veins of the lower extremities, although many people have no symptoms. Among the symptoms that may occur are:

  • Swelling of the leg (edema).
  • Pain in the leg that may only be felt when standing or walking.
  • More warmth in the area of the leg that is swollen or painful.
  • Redness or changes in skin color.

Occasionally, the symptoms that occur are associated with complications such as pulmonary embolism, a potentially serious condition characterized by shortness of breath, pain when taking a deep breath or coughing up blood.


Generally speaking, the most effective preventive measures include elevation of the legs, early mobilization and the use of anticoagulants. More specifically:

  • Starting to move as soon as possible after having been bedridden for a while, following surgery or illness.
  • Use of compression stockings if you are a person at risk.
  • Use of anticoagulant medications in people at higher risk.
  • On long journeys, get up and walk around every 1-2 hours, wear loose clothing and keep your legs moving while sitting.
  • Healthy lifestyle, maintaining a healthy weight, regular exercise and a diet rich in fruit, vegetables and whole grains.

Number of observed variants

13.5 million variants

Number of risk loci analyzed in the study

7 loci

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