HBA1: Hemoglobin Subunit Alpha 1
Essential component of hemoglobin, critical for oxygen transport; mutations cause alpha-thalassemia and related hemoglobinopathies.
Gene Information Card
| Symbol | HBA1 |
|---|---|
| Full Name | Hemoglobin Subunit Alpha 1 |
| Gene Type | Protein coding |
| Chromosomal Location | 16p13.3 |
| NCBI Gene ID | 3039 ncbi.nlm.nih.gov/gene/3039 |
| Ensembl ID | ENSG00000206172 |
| UniProt ID | P69905 |
| OMIM ID | 141800 |
| HGNC ID | 4823 |
| Aliases | HBA-T1, HBH, alpha-1 globin |
Description
The HBA1 gene encodes the alpha-1 globin subunit of hemoglobin, a tetrameric protein responsible for oxygen transport in red blood cells. It is located on chromosome 16 in a cluster with HBA2 and other globin genes. Mutations in HBA1 can lead to alpha-thalassemia, a condition characterized by reduced or absent alpha-globin synthesis, resulting in microcytic anemia and, in severe cases, hydrops fetalis.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Alpha-thalassemia | Deletion or point mutations in HBA1 reduce alpha-globin production, causing imbalance in globin chain synthesis and ineffective erythropoiesis. | ClinVar, OMIM |
| Hemoglobin H disease | Compound heterozygosity for HBA1 mutations (e.g., --SEA/ -alpha3.7) leads to excess beta-globin tetramers (HbH), causing hemolytic anemia. | ClinVar, OMIM |
| Hb Bart's hydrops fetalis | Homozygous deletion of all four alpha-globin genes (including HBA1) results in no alpha-globin production, incompatible with life. | OMIM |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Bone Marrow | 1500.0 | High |
| Blood (whole) | 1200.0 | High |
| Spleen | 300.0 | Medium |
| Liver | 50.0 | Low |
| Lung | 10.0 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| Erythroblast | 1800.0 | Primary erythroid cells |
| K562 | 800.0 | Chronic myeloid leukemia cell line |
| HEL | 600.0 | Erythroleukemia cell line |
| HepG2 | 5.0 | Hepatocellular carcinoma, low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.95+1G>A (IVS-I-1) | Splice site | Rare | Loss of function, alpha-thalassemia |
| c.427T>C (p.Ter143Gln) | Nonsense | Rare | Extended alpha-globin chain, unstable hemoglobin |
| --SEA deletion | Large deletion | Common in Southeast Asia | Complete loss of HBA1 and HBA2, alpha-thalassemia |
| -alpha3.7 deletion | Single alpha-globin deletion | Common worldwide | Mild alpha-thalassemia (silent carrier) |
Mutation functional classification
Loss of Function (LOF)
Most HBA1 mutations are loss-of-function, leading to reduced or absent alpha-globin synthesis, causing alpha-thalassemia.
Gain of Function (GOF)
No known gain-of-function mutations in HBA1.
Dominant Negative (DN)
Rare dominant-negative mutations (e.g., Hb Constant Spring) produce elongated alpha-globin chains that form unstable tetramers, causing mild hemolytic anemia.
View complete mutation data：
Gene Ontology (GO)
| • oxygen carrier activity (GO:0005344) | • heme binding (GO:0020037) |
| • hemoglobin complex (GO:0005833) | • oxygen transport (GO:0015671) |
| • hydrogen peroxide catabolic process (GO:0042744) |
Pathways
• Erythropoiesis (Reactome: R-HSA-983147)
• Oxygen transport (Reactome: R-HSA-1483249)
• Metabolism of hemoglobin (Reactome: R-HSA-6798695)
Protein Summary
Hemoglobin subunit alpha 1 (141 amino acids, ~15.2 kDa) is a globin protein that binds heme and oxygen. It forms a heterotetramer with beta-globin (HbA) or gamma-globin (HbF). The alpha-globin chain contains eight alpha-helices and is essential for hemoglobin stability and function. Post-translational modifications include acetylation of the N-terminal methionine.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| HBA1 Knockout HEK293 Cell Line | EDJ-KQ50340 | Human | 3039 | Details Get a Quote |
| HBA1 Knockout HeLa Cell Line | EDJ-KQ53492 | Human | 3039 | Details Get a Quote |
| HBA1 Knockout A-549 Cell Line | EDJ-KQ61963 | Human | 3039 | Details Get a Quote |
| HBA1 Knockout HCT 116 Cell Line | EDJ-KQ70444 | Human | 3039 | Details Get a Quote |
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