Methylenetetrahydrofolate reductase C677T gene mutation and hyperhomocysteinemia in Budd-Chiari syndrome and portal vein thrombosis: A systematic review and meta-analysis of observational studies

AimA systematic review and meta-analysis were conducted to explore the role of the methylenetetrahydrofolate reductase (MTHFR) C677T gene mutation and hyperhomocysteinemia in patients with Budd-Chiari syndrome (BCS) and portal vein thrombosis (PVT). MethodsPubMed, EMBASE, Cochrane Library and ScienceDirect databases were searched. Eligible studies should compare the prevalence of the MTHFR C677T mutation or hyperhomocysteinemia or the homocysteine levels between BCS or non-cirrhotic PVT patients and healthy controls or between cirrhotic patients with and without PVT. A pooled odds ratio or weighted mean difference with 95% confidence interval was calculated. ResultsOf the 484 articles retrieved, 20 were included. BCS and non-cirrhotic PVT patients had a higher prevalence of homozygous MTHFR mutation than healthy controls. The difference was statistically significant in BCS patients, but not in non-cirrhotic PVT patients. BCS and non-cirrhotic PVT patients had a significantly higher prevalence of hyperhomocysteinemia and homocysteine level than healthy controls. Cirrhotic patients with PVT had a significantly higher prevalence of homozygous MTHFR mutation than those without PVT. However, the association between homocysteine level and PVT in cirrhotic patients was inconsistent among three studies. ConclusionHomozygous MTHFR mutation and hyperhomocysteinemia may be associated with the occurrence of BCS and non-cirrhotic PVT. In addition, homozygous MTHFR mutation may increase the risk of PVT in cirrhotic patients. However, the current evidence failed to support the association of hyperhomocysteinemia with PVT in cirrhotic patients.