Assessment of Hematological Characteristics among β -Trait & Hb-E Trait Individuals in Bangladesh

Special Article - Thalassemia

J Blood Disord. 2020; 7(1): 1057.

Assessment of Hematological Characteristics among β -Trait & Hb-E Trait Individuals in Bangladesh

Aziz A1,2*, Bilkis A1 and Khan WA2

1Department of Biotechnology and Genetic Engineering, Mawlana Bhashani Science and Technology University, Bangladesh

2Department of Biochemistry and Molecular Biology, Dhaka Shishu (Children) Hospital, Bangladesh

*Corresponding author: Aziz A, Department of Biotechnology and Genetic Engineering, Mawlana Bhashani Science and Technology University, Department of Biochemistry and Molecular Biology, Dhaka Shishu (Children) Hospital, Bangladesh

Received: January 11, 2020; Accepted: February 19, 2020; Published: February 26, 2019


Thalassemia are an outfit of autosomal recessive disorders caused by reduction or absent production of one or more of the globin chains. About 3% people are carriers of β-thalassemia and 4% are E- β-thalassemia in Bangladesh. The study was undertaken to determine hematological characteristics among β-thalassemia trait & Hb E trait individual & the effect of different mutations with hematologic parameters. A total 280 blood samples were included for this study and the samples were analyzed by Siemens Advia 2000i Hematology Analyzer and automated capillarys-2 flex piercing system. The samples were analyzed in the Department of Biochemistry and Molecular Biology of Dhaka Shishu (Children) Hospital, Dhaka, Bangladesh. After extraction of DNA, beta globin gene mutations were detected by DNA sequencing method & data were analyzed by SPSS, Version 20, IBM Cor. The study found a statistically significant comparison of mean Hb A2 (%) between common mutations & rare mutations of beta trait population (p‹0.05). In Hb E trait population, Hb A2 was (3.44±0.6%) & (p‹0.001) and Hb E was (26.5±2.54%) & p value was 0.000. Hb E trait population showed comparatively higher values of HCT, MCV and MCH than beta thalassemia trait groups (p‹0.05). No significant difference was observed in RDW, MCHC & Hb (g/dl) between the two groups (p›0.05). The study will be helpful in improving population screening for identification the carriers of β-thalassemia in Bangladesh.

Keywords: Autosomal; β-thalassemia; Mutations; Hematological characteristics


Thalassemia is a conditions in which there are reduced rate of synthesis of one or more of the globin chains leading to an imbalanced synthesis of globin chains and production of defective hemoglobin [1]. The incidence for this disease is high in the tropical and subtropical areas including Southeast Asia [2]. The carrier rate of β-thalassemia is 3.0% and Hb-E/β- thalassemia is 4.0% and affected birth per thousand of β-thalassemia and Hb-E/ β-thalassemia is 0.106 & 3.000 respectively in Bangladesh [3,4]. About 10% of the world’s thalassemia major kiddies are born in India [5]. The carrier circumstance varies from country to country. Hb E is the most common abnormal found in Southeast Asia including Bangladesh, India, Cambodia, Laos, Myanmar and Thailand [6]. Haemoglobin E allele, point mutation (G > A) in codon 26 of β - globin gene that can induce alternative splicing and thus result in decreased β -globin E chains [7]. Hb E/β-thalassemia results from co-inheritance of a β-thalassemia allele from one parent and Hb E from other parent [8]. HbE/ β thalassemia causes a surprisingly variable anaemia, ranging from nearly asymptomatic states to severe anemia [7]. The average beta thalassemia carrier prevalence is 5% in Pakistan, 3.1% in Tunisia & 3.3% in India [9-11]. In Arab countries, the prevalence of beta thalassemia trait was 3% in Oman, 8.7% in United Arab Emirates, 2.9% in Bahrain [12-14]. Almost every possible defect affecting gene expression at transcription or post-transcriptional level including translation had been identified in β thalassemia [15]. These genetic defects lead to a variable reduction in β globin output that ranges from a minimal deficit (mild β+ thalassemia alleles) to complete absence (β° thalassemia). β-thalassemia can be divided into three main types depending on clinical phenotypes: thalassemia major, thalassemia trait and thalassemia intermediate [16]. β-thalassemia major is a severe form that requires blood transfusions from infancy for survival. This clinical phenotypic variability of β-thalassemia occurs due to the mutation in three exons and two intervening sequences 5´ UTR and the 3´ UTR of β-globin (HBB) gene [17,18]. Mutation in exons and intervening sequences that may produce nonfunctional beta globin protein or β0 allele [19]. Approximately 600 mutations have been found in the β-globin (HBB) gene of which more than 200 are associated with β-thalassemia phenotype [20]. The distribution and frequency of different mutations pertaining thalassemia vary from population to population. One reason of prevalence of thalassemia are intermarriage between different ethnic groups, lack of awareness for blood test before marriage [21]. Many countries have started control programme to prevent the births of thalassemic children as prevention is more cost effective than treating thalassemic patients [22]. The study was undertaken to determine hematological characteristics & the effect of different mutations on hematologic parameters in beta-thalassemia & Hb E trait individual to improve population-screening program in Bangladesh.

Materials and Methods

The study was conducted in dept. of biochemistry and molecular biology, Dhaka Shishu (Children) Hospital, Dhaka, Bangladesh.

Study subject

The study included 280 individuals, all of whom were selected by testing Hb capillary electrophoresis. Estimation carried out by fully automated capillarys-2 flex piercing system. Individual who had Hb A2 level › 3.5% were diagnosed as beta thalassemia carrier and Hb E carrier when E band constituted 22-30%. Hb capillary electrophoresis data of each sample was documented for analysis.

Sample collection

About 5.0 mL of venous blood was drawn & taken in an EDTA coated tube from each individual following all aseptic precautions with the help of a trained person. Complete blood counts and red blood cells were estimated by automated Hematology analyzer. These hematological data of each sample were recorded in order to performing analysis. Blood samples were stored at -20o c until molecular analysis.

Extraction of genomic DNA

Genomic DNA was extracted from whole blood sample using the Invitrogen Kit (Invitrogen, USA) by manufacturing process. The extracted DNA was stored at –20 °C for further use.

Polymerase chain reaction amplification and sequencing

Firstly, the genomic DNA was amplified by Exon I, II and III specific primer and the polymerase chain reaction (PCR) method. These PCR products were run in 2% agarose gel and the bands were visualized using the trans UV illuminator. Sequencing reaction was performed by Big Dye terminator cycle sequencing kit (Applied Bio systems, USA). Analysis was done by automated capillary electrophoresis in the 310 genetic analyzer (Applied Bio systems, USA).The sequences that are obtained from the capillary electrophoresis were aligned using the Reference Sequence of the β globin gene [NCBI Ref Seq entry of HBB (NG_000007.3)] in the Seqscape sequence alignment version 2.5 (Applied Bio systems, USA). Then clinical significance and genetic variants were observed by HbVar database ( of haemoglobin variants and thalassemia mutations.

Statistical analysis

Data were entered and analyzed, using SPSS, Version 20, IBM Cor. Data were expressed as (mean±SD) and number (percentage). The (mean±SD) of each hematologic parameter were calculated & t-tests & chi square test were performed where p‹0.05 was considered significant.


Among the study subject, 70% population had beta trait & 30% had Hb E trait. 36.43% were male and 33.57% were female among the beta trait population & 15.36% male and 14.64% female were Hb E trait individual (Tables 1 & 2).