The Prevalence of HBB Mutations among the Transfusion-Dependent and Non Transfusion-Dependent Hb E/β-Thalassemia Children in a Tertiary Center of West Bengal, India

Hb E (HBB: c.79G>A)/β-thalassemia (Hb E/β-thal) is responsible for nearly half of all the different kinds of severe β-thal. This disorder is characterized by a wide range of clinical variability ranging from mild, asymptomatic non transfusion-dependent thalassemia (NTDT) to severe transfusion-dependent thalassemia (TDT). The aim of the present study was to determine the prevalence of different β-globin gene (HBB) mutations in Hb E/β-thal subjects and their potential role in transfusion dependence. One hundred and ten consecutive children with Hb E/β-thal attending the Pediatric Department of Burdwan Medical College, Burdwan, West Bengal, India were enrolled. Based on hemoglobin (Hb) electrophoresis or high-performance liquid chromatography (HPLC), patients were recruited and later β-globin gene sequencing was done to find out the prevalence of different HBB mutations. Transfusion-dependent thalassemia was seen in 42 children (38.2%), while NTDT was seen in 68 children (61.8%). A total of 10 different β-globin mutant alleles were characterized. The most frequent mutation on the β-globin gene was IVS-I-5 (G>C) (HBB: c0.92+5G>C) in both groups. The β-globin gene mutations alone cannot determine transfusion dependence among the Hb E/β-thal patients.

HBB mutations and HbA2 level: Escaping the carrier screening programs

HbA2 level alone for beta thalassemia trait may not be accurate and reliable even without iron deficiency so molecular genetic testing is important and should be considered for some individuals.