Genotype–phenotype relationship of patients with β-thalassemia taking hydroxyurea: a 13-year experience in Iran

Abstract

We evaluated the clinical responses to hydroxyurea (HU), adverse effects, and β-globin gene variants in a large series of β-thalassemic patients over a 13-year period in Iran. The patients (n=232) were divided into two groups: transfusion-dependent β-thalassemia patients 2years of age and older (n=126; Group 1), and β-thalassemia intermedia (βTI) patients without any history of blood transfusion or with a long-interval transfusion (n=106; Group 2). In Group 1, 86 patients became transfusion-free, and 25 patients needed 1-2 transfusions per year at the end of study. All except three patients in Group 2 were completely transfusion free with a significant increase in Hb level after 1year compared to the baseline Hb value (P<0.0001). We did not find a significant correlation of response to HU with XmnI polymorphism or IVS II-I (G>A) mutation (P>0.05). In our study, HU at a dose of 8-15mg/kg/day was effective in decreasing or effecting cessation of the need for regular blood transfusion, as well as in increasing Hb levels in β-thalassemia patients, without any major side effects. Hydroxyurea may thus represent a safe alternative to blood transfusion in transfusion-dependent β-thalassemia patients, or help to increase Hb level in untransfused βTI patients.