Original paper
The prevalence of combined pro-thrombotic polymorphisms in patients with recurrent deep vein thrombosis – does genetic testing provide any benefit?

Introduction: Deep vein thrombosis (DVT) constitutes a serious clinical, social, and economic problem. Factors predisposing to DVT development include acquired (immobilisation, injury) and inherited (genetic thrombophilia) forms. However, DVT itself is also the risk factor for disease recurrence. Diagnostic algorithms for DVT concern ultrasound examination and D-dimer measurement. Genetic tests, although potentially useful, are not performed routinely. Therefore, the aim of the study was to evaluate whether genetic tests provide any benefit in patients with DVT.

Material and methods: The frequency of common pro-thrombotic polymorphisms – FV R506Q, PT G20210A, and minor risk MTHFR C677T – was assessed in 40 patients with recurrent DVT, in correlation to patients’ clinical history. DNA samples from a former large population study (n = 102) were used as population control.

Results: The frequency of FV 506Q and PT 20210A in DVT patients was higher than in the control group (32.5% vs. 8.8% and 10.0% vs. 2.0%, respectively), whereas MTHFR 677T did not differ (57.5% vs. 54.9%). Twenty two and one-half percent of patients and 41.2% of controls revealed wild-type genotype, whereas single heterozygote concerned 40% of patients and 52.9% of controls. Two or more polymorphic alleles were found in 15 of 40 DVT patients (37.5%), but only in 12 of 102 controls (12.8%). Moreover, the allele coexistence correlated with the clinical course of DVT.

Conclusions: The results of the study suggest that assessment of main pro-thrombotic polymorphisms, including MTHFR C677T, may help to predict the course of DVT, so it could be recommended even after first episode of DVT. However, further prospective studies are necessary.