Hb E-β-Thalassemia in Five Indian States

Abstract

Hb E [β26(B8)Glu→Lys; HBB: c.79G > A]-β-thalassemia (β-thal) has an extremely variable clinical presentation. We report the clinical features of these patients from five Indian states together with their hematological and molecular characteristics. Seventy-eight Hb E-β-thal patients from different regions [West Bengal (30), Maharashtra (21), Uttar Pradesh (13), Bihar (11), Orissa (3)] were clinically evaluated along with hematological profiles and molecular characteristics (β-thal mutations, XmnI polymorphisms, α genotypes). Twenty-nine of the 78 patients had a mild clinical presentation (clinical score 2.2 ± 1.1), while 15 had moderate severity (clinical score 6.1 ± 1.2) with occasional transfusion needs, and 34 patients were severely affected (clinical score 8.2 ± 0.5) requiring regular blood transfusions. The age at clinical presentation in the severely affected patients was lower (6 months-10 years) as compared to those with milder symptoms (2 years-34 years). Thirty-four patients showed splenomegaly (spleen ≥3 cm below the costal margin) and five patients were splenectomized. The severe βIVS1-5 (G > C) (HBB: c.92 + 5G > C) was the most common β-thal mutation, while seven other mutations were also seen. The XmnI [+/+] and [-/-] polymorphisms were seen in 24.1 and 10.3% of mildly affected patients and 14.7 and 17.6% of severely affected patients respectively. A single α gene deletion (-α/αα) was found in 20.7% of mildly affected and 5.9% of severely affected patients, respectively. No specific differences in the clinical, hematological or molecular characteristics were observed in the Hb E-β-thal patients from various geographic regions or different ethnic groups.

MOLECULAR ANALYSIS OF NON-TRANSFUSION DEPENDENT THALASSEMIA ASSOCIATED WITH HEMOGLOBIN E-Β-Thalassemia DISEASE WITHOUT Α--Thalassemia

“…The most common thalassemia disease found in northeast Thailand is hemoglobin E - β - thalassemia ( Hb E - β - thal) 2. It has been shown that clinical severity of this disease is variable, ranging from mild to severe transfusion-dependent thalassemia 3–6. Patients with transfusion - dependent Hb E - β - thal disease require lifelong regular blood transfusion for survival, while NTDT patients generally have mild anemia and do not require regular blood transfusion for survival.…”

Prenatal Diagnosis of HbE-β-Thalassemia: Experience of a Center in Western India

“…This results in a dilemma while offering genetic counselling to couples at-risk. Our recent study on HbE-b-thalassemia patients showed that 37.2% of patients had a mild phenotype [19] which was higher than that reported in Southeast Asia. Also, there are many severe patients who do not take regular blood transfusions due to various social and economic reasons and commonly present with severe ineffective erythropoiesis, peripheral hemolysis, iron overload and hypercoagulability leading to organ damage particularly in low and middle income countries including India [20].…”

“…Recent reports have shown that HbE-b-thalassemia is also seen in other states of the country in different ethnic groups both due to migration of people in search of a better livelihood and due to inter-marriages between communities which was not common earlier. Thus, certain population groups in West Bengal, Maharashtra, Uttar Pradesh, Bihar, Chhattisgarh, Jharkhand and Orissa have an overlapping distribution of both the b-thalassemia gene and the HbE gene [3,19,21] resulting in a high number of HbE-bthalassemia cases.…”

Genotype Spectrum and Hematological Features of β–Thalassemia with or without Different Forms of α-Thalassemia in Shenzhen

“…However, the clinical manifestations varied widely from mild form of thalassemia intermedia to severe thalassemia major when β E -thalassemia co-inherited with other type of β-thalassemia [17]. Some severe patients would present with hepatosplenomegaly, severe anemia, skeletal disease and need receive intermittent or regular blood transfusions [18]. For this reason, HbA 2 parameter should be considered in case of β E /β N being ignored in the β-thalassemia screening in high risk couples.…”