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 β⁺IVS1-5 (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^3.7/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.

Keywords:

• α Genotypes
• clinical and hematological presentation
• Hb E-β-thalassemia (Hb E-β-thal)
• India
• XmnI polymorphisms

Disclosure statement

This study was supported by the Indian Council of Medical Research. The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

Funding

This study was supported by the Indian Council of Medical Research.