The methylenetetrahydrofolate reductase 677C>T gene polymorphism is not associated with chronic plaque psoriasis

Abstract

Methylenetetrahydrofolate reductase (MTHFR) is involved in the formation of methyl donors, which contribute to DNA methylation. DNA methylation is an essential epigenetic feature playing a critical role in gene regulation and cellular differentiation. In addition, MTHFR activity affects plasma homocysteine levels. A functional polymorphism in the MTHFR gene (677C>T, rs1801133) leading to reduced enzyme activity has been associated with chronic plaque psoriasis in a Chinese population. This finding, however, has not yet been either confirmed or refuted in other populations. The purpose of the present study was to investigate a hypothesized association between the MTHFR 677C>T polymorphism and the presence of chronic plaque psoriasis in a Caucasian population. Genotypes for the MTHFR 677C>T polymorphism were determined in 310 patients and 247 control subjects. In a subgroup of 33 patients and 33 sex- and age-matched control subjects, fasting plasma homocysteine concentrations were determined by high-performance liquid chromatography and immunological assays were used for the measurement of folate and vitamin B(12). Prevalence of the homozygous MTHFR 677TT genotype did not significantly differ between patients and controls (15.2% vs 11.7%, P = 0.24). Mean plasma homocysteine concentrations were significantly higher in psoriasis patients than among control subjects (13.5 +/- 5.3 micromol/l vs 11.0 +/- 2.2 micromol/l, P = 0.026). No significant differences between either mean plasma folate or vitamin B(12) concentrations were observed between both groups. Our data suggest that the MTHFR 677C>T gene polymorphism is not associated with chronic plaque psoriasis among Caucasians.