Thrombosis is the presence of a blood clot in the arteries or veins that may block the lumen
1, and may cause serious conditions such as stroke, pulmonary embolism, myocardial infarction, or ischemia of various organs and tissues
2. This phenomenon is one of the major health problems worldwide and it is a multifactorial disorder that also includes genetic problems in its pathogenesis. Deep vein thrombosis (DVT) can be defined as the development of a blood clot in the deep veins. It usually occurs in the deep veins of the lower extremities and abdomen, and may resolve spontaneously without being noticed
3. However, DVT is a prevalent cardiovascular disease with an incidence of about 1-2/1000 per year and it can lead to a large number of mortality or significant morbidity
4. A blood clot in the venous system is not so dangerous actually but if a piece of the blood clot detaches from elsewhere and travels in the body through the bloodstream, it can block up the main artery of the lung or one of its branches. It is called pulmonary thromboembolism (PTE). Thrombosis in the venous system is the main cause of the development of pulmonary embolism
5. This condition is a common life-threatening problem in the departments of chest diseases and cardiology. Some cases such as; immobilization, surgery, cancer, trauma, oestroprogestative therapy, fractures, pregnancy and postpartum period have been declared as a common risk factors for DVT. Pulmonary embolism one of the significant causes of cardiovascular death in the United States and is the third most common cause of cardiovascular events after myocardial infarction and stroke
6. Most patients with pulmonary embolism also have signs of DVT.
Some genetic determinants may have a significant role in the pathogenesis of DVT and PTE 7. Inherited thrombophilias can be considered as risk factors for pulmonary embolism, with or without DVT 8. Methylenetetrahydrofolate reductase (MTHFR) is an enzyme involved in the metabolism of homocysteine and folate by catalyzing the conversion of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate 9. MTHFR variants (C677T and A1298C) reduce enzyme activity to some extent. These polymorphisms may be associated with the development of thrombosis due to increased homocysteine levels. MTHFR 677TT variant causes a moderate increase in homocysteine levels which may have a significance in venous thrombosis and other similar conditions 10. Machado et al. declared that a combined mutation of the MTHFR gene as heterozygous for C677T and A1298C is associated with venous thromboembolism independent of hyperhomocysteinemia 11. The plasminogen activator inhibitor-1 (PAI-1) gene -675 4G/5G polymorphism is linked with PAI-1 level, and the 4G allele may pose a risk for DVT with increased PAI-1 activity 12. Some researchers claimed that people with 4G/4G genotype of PAI-1 have a higher risk of venous thromboembolism 13. On the other hand, angiotensin converting enzyme (ACE) transforms angiotensin-I to angiotensin-II 14 and the ACE gene on chromosome 17q comprises an insertion/deletion (I/D) polymorphism that affects ACE activity 15. There may be a synergistic effect between angiotensin-converting enzyme (ACE) DD genotype and the thrombophilic elements and this position supports the multicausality of recurrent venous thromboembolism (VTE) 16.
We aimed to analyze the association of four gene polymorphisms (MTHFR C677T and A1298C, PAI-1 4G/5G and ACE I/D) with DVT and PTE in this study.