Hyperhomocysteinemia and the MTHFR C677T mutation in Budd‐Chiari syndrome

Hyperhomocysteinemia (HH) is a factor that predisposes individuals to thrombosis, and the C677T mutation in the 5,10‐methylenetetrahydrofolate reductase (MTHFR) is known to give increased plasma homocysteine. However, little is known about their roles in Budd‐Chiari syndrome (BCS). This study evaluated the roles of HH and the MTHFR C677T mutation in patients with BCS. We compared 41 BCS patients with 80 sex‐ and age‐matched healthy controls. The mean plasma homocysteine level was significantly higher in patients with BCS (20.15 ± 5.78 μmol/L) compared with normal controls (15.80 ± 6.58 μmol/L), P < 0.01. HH (>19.5 μmol/L in men and >15.0 μmol/L in women) was detected in 15 (36.59%) patients and in 14 (17.5%) controls (odds ratio [OR], 2.72; 95% confidence internal [CI], 1.17–6.32). The prevalence of the mutated MTHFR 677TT genotype and the 677T allele in normal controls was 10.0% and 31.3%, respectively. The mutant 677T homozygotes and alleles were more frequent in patients with BCS than in controls (22.0% vs. 10.0%, 0.025 < P < 0.05; 45.1% vs. 31.3%, 0.025 < P < 0.05). The relative risk of BCS among the carriers of 677TT was significantly increased (OR, 3.3; 95% CI, 1.1–10.0). The mutant MTHFR heterozygous 677C/T carriers were not significantly increased in patients with BCS compared with controls (46.3% vs. < 2.5%, P > 0.05). The relative risk OR of BCS among carriers of 677C/T was 1.6 (95% CI, 0.7–3.6). This study suggests that both HH and the homozygous C677T mutation in the MTHFR gene are important risk factors of BCS. Am. J. Hematol. 71:11–14, 2002. © 2002 Wiley‐Liss, Inc.