Genetic polymorphism of BCL11A (rs11886868) in Egyptian patients with β-thalassemia

Abstract

ObjectivesTo study the effect of BCL11A (rs11886868) gene polymorphism on clinical status of Egyptian patients with β-thalassemia.Backgroundβ-thalassemia is a genetic disorder that results from β-globin gene mutations leading to defective synthesis of adult hemoglobin (Hb A). Clinical consequences vary tremendously from nearly asymptomatic to severely anemic and transfusion-dependent patients. Phenotypic variations have been linked not only to the type of β-globin gene mutations and amount of synthesized Hb A but also to recently discovered genetic modifiers mapping outside the β-globin gene cluster including BCL11A gene polymorphism. These modifiers are associated with increased fetal hemoglobin (Hb F) levels.Patients and methodsBlood samples were collected from 120 patients with β-thalassemia before transfusion of blood. Complete blood count, quantitative measurement of different Hb types by high-performance liquid chromatography, and analysis of single nucleotide polymorphism rs11886868 in the BCL11A gene by Taqman single nucleotide polymorphism genotyping assay and real-time PCR were done.ResultsThe genotype distribution of BCL11A gene polymorphism showed low frequency of CC genotype (15%) among Egyptian patients with β-thalassemia. The CT genotype was 41.7% and TT genotype was 43.3%. There was a significant relation between BCL11A (rs11886868) genotypes and Hb F levels, with the highest Hb F levels were observed in the CC genotype followed by CT genotype, whereas Hb F levels were the lowest in TT genotype. Patients with CC genotype had mild disease phenotype owing to increased Hb F production. Hb F utilizes some of the free α-chain and ameliorates clinical presentation.ConclusionScreening of BCL11A gene variants may be used as a marker for severity risk in newly diagnosed patients with β-thalassemia and as a predictor of clinical outcome of this disorder.