Possible Association Between the Methylenetetrahydrofolate Reductase Gene C677T Polymorphism and Preexisting Portal Vein Thrombosis in Liver Transplant Recipients

Liver transplant in patients with preexisting portal vein thrombosis involves complicated surgical procedures and increased blood loss, indicating the need for further surgical innovations to overcome these difficulties. Patients who are at high risk of developing portal vein thrombosis may benefit from prophylactic anticoagulant therapy while on the transplant wait list. Homozygosity for C677T polymorphism in the methylenetetrahydrofolate reductase gene has been associated with a high plasma homocysteine concentration, which is a risk factor for venous thrombosis. This study investigated the association between C677T polymorphism in the methylenetetrahydrofolate reductase gene and preexisting portal vein thrombosis in patients with liver cirrhosis undergoing liver transplant. C677T polymorphism in the methylenetetrahydrofolate reductase gene was investigated in 48 patients who underwent liver transplant at Nagoya University. Of 48 patients, 7 (14.6%) had preexisting portal vein thrombosis confirmed at transplant. The frequency of methylenetetrahydrofolate reductase gene C677T genotype in recipients was significantly associated with preexisting portal vein thrombosis (P = .009, with P ≤ .013 considered significant). Logistic regression analysis showed that the TT genotype of the methylenetetrahydrofolate reductase gene was significantly associated with a higher incidence of preexisting portal vein thrombosis compared with the CC and CT genotypes (odds ratio of 14.6, 95% confidence interval, 1.86-115.21; P = .011). The TT genotype of the methylenetetrahydrofolate reductase gene may be associated with a higher incidence of preexisting portal vein thrombosis, as confirmed at liver transplant. Identification of this genotype in patients with liver cirrhosis at the time of placement on a wait list for liver transplant may enable preventive therapy for portal vein thrombosis in these patients, reducing the complexity of surgical procedures.