HBB – Hemoglobin E disease

Hemoglobin E disease, an autosomal recessive hemoglobinopathy, results from a glutamic acid to lysine substitution at codon 27 (c.79G>A (p.Glu27Lys)) in the HBB gene associated with Hemoglobin E disease. In a North Indian case series, three unrelated probands homozygous for c.79G>A (p.Glu27Lys) exhibited microcytic anemia, elevated HbA₂ and HbF by HPLC, and early transfusion dependency (PMID:17654063). Segregation data are limited, but consistent genotype–phenotype correlation across probands supports pathogenicity. Functional assessment via RBC indices and HPLC profiling confirms the variant’s impact on hemoglobin composition and erythrocyte parameters (PMID:17654063). No conflicting evidence has been reported to date. Based on three probands and concordant laboratory evidence, the HBB–hemoglobin E disease association is classified as Limited.

Key Take-home: Testing for the c.79G>A (p.Glu27Lys) variant should be included in diagnostic panels for patients of Southeast Asian descent presenting with microcytic anemia and transfusion dependency.

References

• Hematology (Amsterdam, Netherlands) • 2007 • Hemoglobin E disease in North Indian population: a report of 11 cases. PMID:17654063

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