Meta-analysis of the association of the C677T polymorphism of the methylenetetrahydrofolate reductase gene with hyperuricemia.

Background: The association between the MTHFR C677T polymorphism and hyperuricemia has been investigated in several studies. Although these epidemiological studies have shown that genetic factors are determinants of serum uric acid levels, the power of the association is weak due to the small sample size.

Methods: To study whether the MTHFR C677T polymorphism has an effect on hyperuricemia, we carried out a meta-analysis of case-control studies from PubMed, EMBASE and CNKI (China National Knowledge Infrastructure) databases mainly in English and Chinese. We used the odds ratio (OR) as main effect size; explored potential sources of heterogeneity; performed subgroup analyses by race and performed sensitivity analyses of studies meeting the Hardy-Weinberg equilibrium (HWE).

Results: Six studies with 1,470 subjects were included in the meta-analysis. Tests for heterogeneity showed the difference in OR among studies was not statistically significant (p = 0.63, I(2) = 0). When excluding the study of Caucasians not in HWE, the association remained robust (OR = 1.82, 95% CI 1.52-2.17) in the East Asian subgroup and sensitivity analyses.

Conclusions: Although the mechanism of the relationship between the C677T polymorphism and uric acid still remains unclear, these original articles showed that the MTHFR C677T polymorphism may be an independent risk factor for hyperuricemia.