Methylenetetrahydrofolate reductase gene C677t mutation and apolipoprotein E gene mutation in recurrent aphthous stomatitis

Background: Recurrent aphthous stomatitis (RAS) is usually the earliest sign of Behcet's disease. Hyperhomocys-teinemia can damage endothelial cells and progress to obstructive vascular disease. It has been reported that hyper-homocysteinemia is a marker of activation in Behcet's disease. Enzyme 5,10-methylenetetrahydrofolate reductase may be one of the main factors that regulates plasma homocysteine levels. Homozygosity for the C677T (MTHFR C677T) mutation is associated with reduced activity of this enzyme and considered the most common genetic cause of elevated serum homocyteine levels. However its relationship to vascular injury in Behcet's disease remains controversial, and its relationship to RAS is unknown. Apolipoprotein E (Apo E) has both immunoregulatory and anti-infective features. Search for Apo E polymorphism and lipid composition in RAS patients might be a clue to pathogenesis of RAS. Objective: To analyze the relationship of MTHFR gene C677T polymorphism, several epidemiologic factors such as age and sex, smoking, lipid composition and Apo E polymorphism to vasculitis in RAS, we assessed the MTHFR gene C677T polyrnorphism, Apo E polymorphism and lipid composition in RAS and normal population. Methods: We analyzed data from the General Health survey conducted on 1,243 participants (M : F=281 : 962) over a 20 year-old in Incheon city. Medical interview and laboratory test for methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism, apolipoprotein E polymorphism were completed. Statistical significance was analyzed by x² test and multistep logistic regression analysis. Results: Among normal population over the age of twenty, a total of 34.2% (426/1,243) had RAS. Female predominance (4.5 : 1, p-0.003) was noted. The incidence of RAS in age group 20 to 39 year old is higher than the over 40 age group. The incidence is higher in smoking group compared to the nonsmoking group in multistepwise logistic regression analysis. Frequency of the MTHFR C677T genotypes was highest at CT compared to CC and TT homozygous genotype in normal and RAS patients group. There was no significant statistical differences in MTHFR genotypes in RAS patients compared to the control group. Similarly, Apo E genotype analysis revealed no significant statistical differences either. Apo E genotype and total cholesterol, HDL-cholesterol, triglyceride level didn't show any associations. Conclusion: This study revealed insignificant association between the MTHFR C677T mutation and RAS. Apo E genotype didn't show a significant statistical difference in RAS patients compared to normal controls.