title: Gγ-Xmn I polymorphism: a significant determinant of β-thalassemia treatment without blood transfusion.
abstract: β-thalassemia is characterized by impaired β-chain synthesis leading to ineffective erythropoiesis, severe anemia, and a need for blood transfusion. Presence of Xmn I polymorphism (-158 C-T nucleotide change) in γ-globin gene is associated with a higher fetal hemoglobin and a lesser clinical severity. This prospective study attempted to find out the effect of hydroxyurea (HU) on β-thalassemia patients in the presence or absence of Xmn I polymorphism. A total of 143 consecutive β-thalassemia patients received HU (16 mg/kg/d). Sixty-four (44.7%) had Xmn I polymorphism (either homozygous or heterozygous). Patients were evaluated at a median duration of 3 years (range, 6 mo to 9 y). Responders became transfusion independent after 6 months, partial responders had a least 50% reduction in transfusion requirement and nonresponders had no significant reduction. Of the 64 patients with Xmn I polymorphism, 44 (69%) showed response (P<0.01), whereas in those who lacked Xmn I polymorphism (n=79), only 17 (21%) were responders. This study showed that the presence of Xmn I polymorphism in β-thalassemia is a predictor of response to HU and highlights the possibility of managing this subset of patients without blood transfusion.
authors: National Institute of Blood Disease and Bone Marrow Transplantation, Karachi, Sindh Pakistan. muddasirsaqib@yahoo.com
authors: Saqib H
authors: SH
authors: Ansari
authors: Tahir S
authors: TS
authors: Shamsi
authors: Saima
authors: S
authors: Munzir
authors: Mohammed T
authors: MT
authors: Khan
authors: Sajida
authors: S
authors: Erum
authors: Kousar
authors: K
authors: Perveen
authors: Tasneem
authors: T
authors: Farzana
authors: Mushtaq
authors: M
authors: Ashraf
authors: Tabassum
authors: T
authors: Mehboob
authors: Moinuddin
authors: M
authors: Moinuddin
mesh_terms: D002675:Child, Preschool; D015252:Deoxyribonucleases, Type II Site-Specific / Q000235:genetics*; D005260:Female; D006801:Humans; D006918:Hydroxyurea / Q000009:adverse effects / Q000627:therapeutic use*; D008297:Male; D011110:Polymorphism, Genetic; D011446:Prospective Studies; D017086:beta-Thalassemia / Q000097:blood / Q000188:drug therapy* / Q000201:enzymology / Q000235:genetics*
chemical_list: C028649:endodeoxyribonuclease XmnI; D015252:Deoxyribonucleases, Type II Site-Specific; D006918:Hydroxyurea