FK506-binding protein 51 (FKBP5) gene polymorphism is not associated with glucocorticoid therapy outcome in patients with idiopathic thrombocytopenic purpura.

The FKBP5 gene codes for the FK506-binding protein 51 (FKBP5), a co-chaperone of hsp90, which regulates glucocorticoid (GC) receptor sensitivity. The FKBP5 gene single nucleotide polymorphisms (SNP), rs1360780, has been found to modulate GC sensitivity in stress-related psychiatric disorders. The aim of the present study was to examine the effects of rs1360780 on the treatment outcome of patients suffering from idiopathic thrombocytopenic purpura (ITP) administered with GC. The polymorphism of FKBP5, rs1360780, was genotyped in 55 GC-resistant ITP patients, 157 GC-sensitive ITP patients and 110 unrelated healthy individuals using real-time PCR and cycling probe technology with DNA extracted from peripheral blood. No significant differences in FKBP5 rs1360780 genotypes (P=0.51) and alleles (P=0.89) were observed between the GC-resistant ITP patients and the healthy controls. There were no significant differences observed between the GC-sensitive ITP patients and the healthy controls (P=0.40 for genotypes and P=0.62 for T allele), as well as between the GC-sensitive ITP patients and the GC-resistant patients (P=0.67 for genotypes and for T allele). The present study demonstrates that the FKBP5 polymorphism may not affect the response of ITP patients to GC treatment.