Molecular characterization of beta globin gene in beta thalassemia patients at Hue Central Hospital

Abstract

Background: Thalassemia is the most common monogenic disease worldwide. The severity of thalassemia depends on the degree of imbalance between the α-globin and β-globin chains. The aims of the current study were (1) to describe clinical and hematological characteristics of β-thalassemia patients; and (2) to investigate mutations of β-globin gene using Sanger sequencing, as well as the association between β-globin genotype and severity of β-thalassemia. Materials and method: 57 β-thalassemia patients treated at Hue Central Hospital were examined by sequencing the whole β-globin gene. Results: 80.7% with β-thalassemia intermedia, 19.3% with β-thalassemia major. Patients had 100% anemia, 75.4% splenomegaly, 50.9% hepatomegaly, 38.6% thalassemia facies, 28.1% jaundice and 15.8% iron overload; The red blood cell indices were decreased: Hb 7.5 ± 1.3 g/dL, MCV 70.9 ± 8.4 fL, MCH 20.5 ± 2.1 pg. Hemoglobin composition included HbA 35.2 ± 33.9%, HbA2 6.1 ± 2.7%, HbF 24.8 ± 18.0%, and HbE 38.6 ± 15.2%. Nine β-globin gene mutations were observed. The most common genotype was βE/β0, which occupied 80.7%. The βE/βA, β0/βA and βE/β+ genotypes were only found in β-thalassemia intermedia individuals, while the β0/β0 genotype was limited to β-thalassemia major patients. The βE/β0 genotype was seen in both types. Conclusion: There was differences in age of blood transfusion initiation between the genotypes. Among them, the β0/β0 genotype was the most severe. Key words: β-thalassemia intermedia, β-thalassemia major, genotype.