Abstract: The objective was to detect the relationship of methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism and pulmonary thromboembolism(PTE) in Chinese Han nationality population and to investigate the possibility that hyperhomocysteinemia(HHc) is an independent risk factor related with pulmonary thromboembolism(PTE).Methods: 92 patients with PTE and 92 persons as controls, which were matched by age and sex, and analyzed the MTHFR C677T genotypes by the means of polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP), measured the serum homocysteine levels through the ways of Enzyme Linked Immuno Sorbent Assay(ELISA).Results:①The frequencies of the MTHFR gene C677T mutation TT genotype in PTE cases and controls were respectively 30.4% and 29.4%, the frequencies of T allele gene were 50% and 47%.There was no significant difference in the genotype distribution and allele frequencies between the two groups(P>0.05).The odds radios(OR) of TT genotype for PTE was 1.22(95%CI:0.59～2.51).This indicated that ① TT genotype didn't increase the risk of PTE.②The serum Hcy level in PTE group (17.1±9.39)μmol/L was significantly higher than that in control group(13.8± 7.4)μmol/L (P=0.034); HHc increased in risk of PTE.(odds radios= 3.67,95%CI:1.84～7.31);③The serum Hcy level in PTE group with CC,CT and TT genotype were (14.8±6.5)μmol/L,( 15.8±7.3)μmol/L,(21.5±11)μmol/L,versus (12.1±5.2)μmol/L,(11.9±7.0)μmol/L,(19.8±9.2)μmol/L in the control group.The serum Hcy level in PTE cases and control subjects with TT genotype was significantly higher that with CT or CC genotype in the same group(P<0.01).Indications: Hyperhomocysteinemia increase in risk of PTE, which may be an independent risk factor for PTE in Han nationality in China.MTHFR 677TT genotype is related to hyperhomocysteinemia ,but there is no direct link between MTHFR C677T gene polymorphism and PTE.

Key words: pulmonary thromboembolism, methylenetetrahydrofolate reductase, gene polymorphism, hyperhomocysteinemia, homocysteine