Genetic polymorphism of methylenetetrahydrofolate reductase G1793A, hyperhomocysteinemia, and folate deficiency correlate with ulcerative colitis in central China

Background and Aims: Methylenetetrahydrofolate reductase (MTHFR) encoding genes were associated with ulcerative colitis in Chinese in our previous study. We further studied association of a new polymorphism of MTHFR G1793A with ulcerative colitis and assessed relationship of this polymorphism with hyperhomocysteinemia (HHcy, ≥ 15 mmol/L) and deficiency of folate (≤ 7 nmol/L) and vitamin B12 (≤ 150 pmol/L) in a cohort of patients with ulcerative colitis in central China. Methods: A total of 252 patients and 654 healthy controls were recruited. Polymorphism of MTHFR G1793A was examined using a polymerase chain reaction‐restriction fragment length polymorphism method. Plasma levels of homocysteine (Hcy), folate and vitamin B12 were determined by enzymatic cycling assay and corpuscle immune chemiluminescence assay, respectively. Results: Frequencies of alleles and genotypes in MTHFR G1793A gene differed significantly between ulcerative colitis patients and the healthy controls (20.83% vs 10.47%, 95% confidence interval [CI]: 1.703–2.972, P = 0.0006; 40.48% vs 19.88%, 95% CI: 1.997–3.761, P = 0.0002, respectively). Plasma Hcy levels were higher and folate and vitamin B12 concentrations were lower in the patients than in the healthy controls (21.72 ± 6.59 vs 12.47 ± 5.02, 95% CI: −10.93–−7.58, P