THE XmnI AND BCL11A SINGLE NUCLEOTIDE POLYMORPHISMS MAY HELP PREDICT HYDROXYUREA RESPONSE IN IRANIAN β-THALASSEMIA PATIENTS

Hydroxyurea (HU), a drug which can reactivate fetal hemoglobin (Hb F) production, is frequently prescribed to beta-thalassemia (beta-thal) patients. However, transfusion requirements of only a subset of patients are reduced upon HU treatment. Because of its potential side-effects, targeted prescription of HU is imperative. To identify genetic markers that correlate with drug response, we have carried out a retrospective association study of single nucleotide polymorphisms (SNPs) in three Hb F quantitative trait loci (QTLs): the XmnI polymorphism, BCL11A, and the HBS1L-MYB intergenic region, with the response to HU in a cohort of 81 transfusion-dependent Iranian beta-thal patients. An increase in blood transfusion intervals post-therapy was used to measure drug response. Our results suggest that presence of the XmnI T/T genotype or the BCL11A rs766432 C allele correlates strongly with response to HU (p < 0.001). Accordingly, these markers may be used to accurately predict the HU response of Iranian beta-thal patients.