An association study of single nucleotide polymorphisms of the FOXP3 intron-1 and the risk of Psoriasis vulgaris.

Psoriasis vulgaris (PV) is a common autoimmune disease that involves the dysfunction of CD4+CD25+ regulatory T cells. FOXP3 is a key transcription factor in the development and function of CD4+CD25+ regulatory T cells. Previous studies have demonstrated a genetic association between the FOXP3 gene and some autoimmune diseases. To elucidate the association between the FOXP3 gene and the risk of PV, 408 patients diagnosed with PV and 363 age and sex-matched healthy controls from a cohort of the Chinese majority Han population were recruited. Four single nucleotide polymorphisms (rs2232365, rs3761547, rs3761548 and rs3761549) of the FOXP3 gene were analyzed using the polymerase chain reaction and ligase detection reaction. The major allele of three single nucleotide polymorphisms (SNPs - rs2232365 A, rs3761547 A and rs3761549 C) were associated with an increased risk of PV in a clinical subgroup of female patients, who were less than 40 yrs of age, had a family history of the disease and did not have disease complications (p < 0.05 for all parameters). The haplotype was structured between rs3761547 and rs3761549. An increased risk of PV was observed in haplotype A/A-T/T (p = 0.0055; adjusted OR = 3.188; 95% CI = 0.4354-23.34) and A/G-C/C (p = 0.0082; adjusted OR = 1.288; 95% CI = 0.1529-10.85) between rs3761547 and rs3761549. A synergistic effect was found among the three SNPs. Subjects with the rs2232365AA- rs3761547 AG + GG genotype were more susceptible to PV (p = 0.0393; OR = 2.90; 95% CI = 1.05-7.97). No correlation was found between rs3761548 and the onset of PV. Therefore, the FOXP3 polymorphisms appear to contribute to the risk of psoriasis among the Chinese majority Han population. These findings may aid in our understanding of the pathogenesis of psoriasis.