Objectives: The present study aimed to investigate the associations between genetic polymorphism of methylenetetrahydrofolate reductase (MTHFR) G1793A, plasma homocysteine (Hcy) levels, vitamin status and ulcerative colitis (UC) in a cohort of patients in Hubei Han nationality.
Methods: Two hundred and ninety-nine UC patients and 764 age- and sex-matched healthy controls were recruited in this study. Polymorphism of MTHFR G1793A was examined using a PCR-RELP method. Plasma levels of Hcy, folate and vitamin B12 were determined by enzymatic cycling assay and corpuscle immune chemiluminescence assay, respectively.
Results: Both variant allele and genotype frequencies in MTHFR G1793A gene were significantly higher in the UC patients compared to the controls (22.24% vs 14.20%, P < 0.001; 42.81% vs 26.97%, P<0.001, respectively). Plasma Hcy levels were increased in UC patients compared to the controls [(20.67 ± 6.42) mmol/L vs (13.21±5.11) mmol/L, P<0.001] while folate and vitamin B12 concentrations were significantly decreased [(11.37±6.34) nmol/L vs (14.89±7.21) nmol/L, P<0.001; (324.15±127.53) pmol/L vs (421.54±128.45) pmol/L, P<0.001, respectively]. Furthermore, hyperhomocysteinaemia (HHcy) and folate deficiency were also more prevalent in the UC patients (32.44% vs 25.78%, P=0.029; 23.41% vs 17.01%, P=0.016, respectively).
Conclusions: Genetic polymorphism of MTHFR G1793A was strongly associated with UC. HHcy, folate deficiency and low vitamin B12 concentration were common phenomena in the UC patients of Hubei Han nationality. Our findings demonstrate that the genes related to Hcy metabolism may play an important role in the pathogenesis of UC.