OBJECTIVETo study the relationship between plasma homocysteine (Hcy) level and deep-vein thrombosis (DVT), and analyze the interaction of Hcy, folate and methylenetetrahydrofolate reductase (MTHFR) gene polymorphism in patients with DVT.

METHODSTotally 69 patients with DVT and 111 healthy controls were included in our case-control study. We determined the MTHFR C677T genotypes by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP), measured the serum folate and vitamin B12 by radioimmunoassay (RIA), and measured the plasma homocysteine level by fluorescence polarization immunoassay (FPIA).

RESULTSThe frequency of the MTHFR C677T TT genotype had no significant difference between DVT group and control group (P > 0.05). The plasma Hcy level was significantly higher in DVT group than in control group (13.03 +/- 8.74 mumol/L vs 10.14 +/- 4.30 mumol/L, P < 0.05). Both serum folate and VitB12 of patients with DVT were not significantly different from those of controls. The odds radios (OR) of hyperhomocysteinemia for DVT was 2.53 (95% CI 1.08-5.92). The interaction of low folate level and TT genotype increased the risk of DVT (OR = 3.12, 95% CI 1.17-8.38).

CONCLUSIONHyperhomocysteinemia may be an independent risk factor for DVT in Han nationality, while serum folate level and MTHRF C677T genotype are not. An interaction between serum folate level and MTHFR genotype that affect the Hcy level is an important risk factor for DVT.