After calculation of FI (FOXP3 exon 2/total) parameter (Table 5) we have found that the ratio of FOXP3-FL to all FOXP3 was significantly increased in the MDS-primary group relative to the age control group, but after treatment, in E-MDS and L-MDS groups, the ratio returned to normal. This evidence concerns the gene FOXP3 and myelodysplastic syndrome.