OBJECTIVETo study the relationship between the plasma homocysteine (HCY) level and the polymorphism of N(5), N(10)-methylenetetrahydrofolate reductase (MTHFR) gene C667T in liver cirrhosis.

METHODS112 normal subjects and 87 liver cirrhosis patients were recruited in the study. Their plasma HCY levels were measured using high performance liquid chromatography with fluorescence detection and polymorphisms of their MTHFR gene were analyzed using PCR-RFLP.

RESULTSThe mean level of plasma HCY was significantly higher in patients with liver cirrhosis (21.71+/-4.86) micromol/L than that in healthy individuals (8.34+/-3.59) micromol/L. There were three kinds of MTHFR genotypes: +/+ (TT, homozygous mutation), +/- (CT, heterozygous mutation) and -/- (CC, wild type). The frequencies of the three genotypes were as follows: +/+, 29.9%; +/-, 52.9%; -/-, 17.2% in cirrhosis patients and +/+, 19.6%; +/-, 33.9%; -/-, 46.4% in normal subjects. The frequency of homozygous or heterozygous mutation was significantly higher in cirrhosis patients than that in the normal control. Moreover, plasma homocysteine level was markedly higher in patients with MTHFR genetic mutation than those without mutation.

CONCLUSIONSHyperhomocysteinemia may be an independent risk factor for liver cirrhosis. MTHFR is the main enzyme related to homocysteine metabolism. The genetic mutation of MTHFR C667T is possibly an important mechanism of hyperhomocysteinemia in liver cirrhosis. The level of plasma homocysteine may be an early indicator for liver cirrhosis.