Venous thromboembolism (VTE) which is manifested either as deep venous thrombosis
(DVT) or pulmonary embolism (PE) is the third most frequent cardiovascular disorder
after myocardial infarction and stroke. DVT is the thrombotic obstruction of deep
veins in the lower extremities, and is a significant cause of mortality and morbidity.
According to the studies, 1 in 1000 individuals in old age population is complicated
by DVT, annually 1]â€“3].
DVT is a multi-factorial disorder which may occur following a combination of some
acquired conditions including surgical procedures, hormonal therapy, trauma, cancer,
or immobilization condition (hospitalization), and inherited risk factors 1]. Based on the studies, genetic factors are responsible for approximately 60Â % DVT
cases 4]. Factor V (FV) Leiden which is the most common cause of inherited thrombophilia,
predisposes patients to DVT because of resistance to protein C. Prothrombin 20210,
another common cause of hereditary thrombophilia, is also a risk factor for DVT 5]. Two common polymorphisms in methylene tetrahydrofolate reductase (MTHFR) gene including
C677T and A1298C, lead to decreased enzyme activity and therefore elevation of homocysteine
level. Several studies have shown that these two polymorphisms might be associated
with DVT due to hyperhomocysteinemia 6]â€“9]. Another polymorphism which is known as a risk factor for DVT is Plasminogen activator
inhibitor-1 (PAI-1) 4G/5G. The 4G allele is associated with a higher level of PAI-1
in plasma which in turn results in a decreased fibrinolysis activity and therefore
a higher tendency to thrombus formation 8]â€“10].
There are several studies in the literature which assessed the genetic risk factors
of DVT in different ethnical populations 11]â€“15]. In this regard the aim of the current study was to analyze some previously reported
genetic risk factors including, MTHFR C677T and A1298C, PAI-1 4G/5G, Prothrombin 20210
and FV Leiden on occurrence of DVT in Iranian population.