HBA2
Chr 16ADhemoglobin subunit alpha 2
The alpha-2 globin protein combines with beta globin chains to form hemoglobin A, the primary oxygen-carrying protein that comprises 97% of normal adult hemoglobin. Mutations cause alpha thalassemia (ranging from mild anemia to severe hemoglobin H disease), familial erythrocytosis, and Heinz body anemia with autosomal dominant inheritance. The gene has low constraint against loss-of-function variants, reflecting the functional redundancy with the nearly identical HBA1 gene.
Limited evidence — not for standalone diagnostic reporting
4 total gene-disease associations curated
Some data sources returned errors (1)
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Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Highly tolerant — LoF variants common in population
Mild missense constraint
The highest-scoring mechanism for this gene is gain-of-function.
Literature Evidence
Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.
ClinVar Variant Classifications
0 submitted variants in ClinVar
Protein Context — Lollipop Plot
HBA2 · protein map & ClinVar variants
Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.
3D Protein StructureAlphaFold
External Resources
Links to major genomics databases and tools
Clinical Trials
Active and recruiting trials from ClinicalTrials.gov
Long-term Follow-up of Subjects with Sickle Cell Disease Treated with Ex Vivo Gene Therapy
ENROLLING BY INVITATIONInvestigation Into the Use of BAH243 Lentiviral Vector for Gene Therapy in Treating Sickle Cell Disease
RECRUITINGA Study Evaluating Gene Therapy With BB305 Lentiviral Vector in Sickle Cell Disease
ACTIVE NOT RECRUITINGExternal Resources
Links to major genomics databases and tools