FOXP3 -3279 and IVS9+459 polymorphisms are associated with genetic susceptibility to myasthenia gravis.

Myasthenia gravis (MG) is an autoimmune disorder in which CD4(+)CD25(+) FOXP3(+)regulatory T cells (Tregs) are thought to play important roles in driving the ongoing autoimmune response. Although it is known that single-nucleotide polymorphisms (SNPs) in the fork head/winged-helix transcription factor 3 (FOXP3) gene contribute to some autoimmune diseases, information about the role of this gene in MG is limited. We therefore evaluated the association between FOXP3 gene SNPs and susceptibility to MG in a Han Chinese population. In a hospital-based, case-control study, two SNPs in the FOXP3 gene (-3279 and IVS9+459) were investigated in 118 MG and 124 healthy controls, and their relationship with the four parameters of gender, onset age, thymus pathology, and clinical classification of MG were performed with a stratified analysis. We found that the frequency of the FOXP3 IVS9+459 G allele was significantly lower in MG patients than in healthy controls (P=0.041), while the frequency of the FOXP3 -3279 polymorphisms was not significantly different between the two groups. Our results suggest that FOXP3 IVS9+459 polymorphisms appear to have an effect on the risk of MG in a Han Chinese population, and the G allele may be a genetic protective factor to MG.