Thrombosis - General Information

Thrombosis, caused by blood coagulation in vessels and the heart cavity, is one of the most widespread causes of death in developed countries. The pathogenesis lies in the formation of a thrombus in the vein lumen and the disturbance of blood circulation in affected extremities. Approximately 95% of all venous thromboses occur in the lower extremities. The most dangerous complication of deep vein thrombosis is pulmonary embolism, often the first and only manifestation of venous thrombosis and ranking third among causes of sudden death.

The most understood markers of hereditary thrombosis are polymorphisms of several genes:

• F5 (Leiden mutation) encoding factor V, a protein cofactor involved in transforming prothrombin into thrombin.
• F2 encoding prothrombin, one of the main components of the blood coagulation system. Polymorphism +20210G>A intensifies the expression of F2 gene, leading to a significant increase in the prothrombin concentration in blood (1.5–2 times). The frequency of the F2 +20210G>A genotype reaches 1–4% in European populations.
• MTHFR – the most widespread polymorphism encoding the methylenetetrahydrofolate reductase enzyme which influences homocysteine levels in the blood and causes hyperhomocysteinemia.[1, 2]

A genetic predisposition to develop thrombosis, together with the moderate influence of adverse environmental factors, can trigger severe complications up to pulmonary embolism. Detecting high risk groups allows prevention of disease development in the presymptomatic period.

Indications for use of thrombosis test kits:

• Following first occurrence of venous embolism in patients under 50 years.
• Patients with venous embolism after 50 years without apparent reasons.
• Repeated venous embolism.
• Patients with venous embolism during pregnancy, postnatal period, during use of contraceptives or hormone replacement therapy.
• Members of families with expressed hereditary thrombophilia.
• Women with unexplained prenatal abnormalities of a foetus in the second and third trimesters of pregnancy.
• Patients with a first occurrence of venous embolism in atypical locations.

1. Den Heijer M, Lewington S, Clarke R. ‘Homocysteine, MTHFR and risk of venous thrombosis: a meta-analysis of published epidemiological studies’. J Thromb Haemost, 2005, 3(2), 292–9.
2. Joffe HV, Goldhaber SZ. ‘Laboratory thrombophilias and venous thromboembolism’. Vascular Medicine, 2002, 7, 93–102.