HBB Gene

HBB Gene

Overview

HBB Gene

Overview

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">HBB Gene</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>HBB</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>Hemoglobin Subunit Beta</td>
</tr>
<tr>
<td class="label">Aliases</td>
<td>beta-globin, HBB1</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>11p15.5</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>[3043](https://www.ncbi.nlm.nih.gov/gene/3043)</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>[ENSG00000244734](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000244734)</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>[P68871](https://www.uniprot.org/uniprot/P68871)</td>
</tr>
<tr>
<td class="label">Protein Name</td>
<td>Hemoglobin subunit beta</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/inflammation" style="color:#ef9a9a">Inflammation</a>, <a href="/wiki/sickle-cell" style="color:#ef9a9a">Sickle Cell</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">17 edges</a></td>
</tr>
</table>

HBB (Hemoglobin Subunit Beta) encodes the beta-globin chain of hemoglobin, which pairs with alpha-globin to form the functional hemoglobin tetramer. Beyond its essential role in oxygen transport, HBB expression has been detected in the central nervous system, where neuronal hemoglobin may serve protective functions against oxidative stress and mitochondrial dysfunction["@biagioli2009"].

The discovery of hemoglobin expression in [neurons](/entities/neurons) has opened new perspectives on brain oxygen handling and neuroprotection, with implications for Alzheimer's disease, Parkinson's disease, and other neurodegenerative conditions["@richter2017"].

Gene Information

Function

Canonical Hemoglobin Function

HBB encodes the beta chain of hemoglobin A (HbA), the predominant hemoglobin in adults. The α2β2 tetramer[@storz2023]:

• Exhibits cooperative oxygen binding
• Undergoes allosteric transitions (R and T states)
• Transports oxygen from lungs to tissues
• Carries carbon dioxide and protons back to lungs
• Buffers blood pH through the Bohr effect

Non-Erythroid Functions in the CNS

Neuronal hemoglobin (both α and β chains) may serve several functions[@wang2021]:

Neuronal Hemoglobin

The discovery of neuronal hemoglobin expression revealed that[@schelshorn2012]:

• Dopaminergic neurons express significant hemoglobin
• Expression is upregulated by hypoxia
• May protect against oxidative stress
• Is evolutionarily conserved across species

Expression

Peripheral Expression

• Erythroid cells: Primary and most abundant expression
• Erythroblasts: During erythropoiesis

CNS Expression[@adam2021]

• Substantia nigra dopaminergic neurons: High expression
• Cortical neurons: Moderate expression
• Hippocampal neurons: Detected at low levels
• [Astrocytes](/entities/astrocytes): Induced under stress conditions
• Retinal ganglion cells: Protective expression

Disease Associations

Hemoglobinopathies

Mutations in HBB cause several disorders:

Sickle Cell Disease (HbS)

• Mutation: Glu6Val (E6V) substitution
• Effect: Hemoglobin polymerization under deoxygenation
• CNS complications: Stroke, cognitive impairment, silent infarcts

Beta-Thalassemia

• Types: β0 (no production) and β+ (reduced production)
• CNS effects: Iron overload, neurodegeneration, cognitive deficits

Neurodegenerative Diseases

Alzheimer's Disease

• Decreased neuronal expression in affected regions
• Reduced antioxidant capacity in neurons
• Hemoglobin-[Aβ](/proteins/amyloid-beta) interaction at senile plaques
• Potential source of heme iron in plaques

Parkinson's Disease

• Expressed in dopaminergic neurons of substantia nigra
• May protect against oxidative stress
• Expression altered with disease progression
• Possible interaction with [α-synuclein](/proteins/alpha-synuclein)

Amyotrophic Lateral Sclerosis

• Expression changes in motor neurons
• May reflect compensatory antioxidant response
• Potential therapeutic target

Cerebrovascular Disease

In stroke and cerebrovascular disease[@chenroetling2019]:

• Hemoglobin released from hemolysis contributes to injury
• Free hemoglobin and heme are neurotoxic
• Hemoglobin scavengers may be therapeutic

Neuroprotective Mechanisms

Antioxidant Properties

Neuronal hemoglobin may provide protection through[@fleming2018]:

• Heme-mediated radical scavenging: Direct neutralization of ROS
• Peroxidase activity: Enzymatic detoxification of peroxides
• Iron sequestration: Safe iron storage in heme

Mitochondrial Protection

Hemoglobin may support mitochondrial function:

• Oxygen delivery to mitochondria during stress
• Protection against electron transport chain damage
• Reduced oxidative phosphorylation dysfunction

Hypoxia Response

During hypoxic/ischemic stress:

• Hemoglobin expression may be induced
• Provides oxygen buffering capacity
• May limit ischemic injury

Genetic Variants

Common HBB Variants

• HbS (rs334): Sickle cell mutation
• HbC (rs33930165): Benign variant
• HbE (rs33950507): Common in Southeast Asia

Neurological Implications

• Sickle cell trait carriers may have altered stroke risk
• Thalassemia carriers may have subtle cognitive effects
• Interactions with neurodegenerative disease risk (under investigation)

Interactions

Hemoglobin beta chain interacts with:

• Alpha globin (HBA1/HBA2): Forms functional tetramer
• Haptoglobin: Scavenger receptor ligand
• CD163: Hemoglobin-haptoglobin receptor
• Heme oxygenase: Heme degradation
• Ferritin: Iron storage

Related Pages

• [HBA1](/genes/hba1)
• [Oxidative Stress](/mechanisms/oxidative-stress-neurodegeneration)
• [Mitochondrial Dysfunction](/mechanisms/mitochondrial-dysfunction-neurodegeneration)
• [Parkinson's Disease](/diseases/parkinsons-disease)
• [Iron Metabolism](/mechanisms/iron-metabolism-neurodegeneration)
• [Alpha-Synuclein](/proteins/alpha-synuclein)

Key Publications

See Also

• [HBB Protein](/proteins/alpha-synuclein)
• [Oxidative Stress](/mechanisms/oxidative-stress-neurodegeneration)
• [Mitochondrial Dysfunction](/mechanisms/mitochondrial-dysfunction-neurodegeneration)
• [Parkinson's Disease](/diseases/parkinsons-disease)
• [Iron Metabolism](/mechanisms/iron-metabolism-neurodegeneration)

External Links

• [NCBI Gene: HBB](https://www.ncbi.nlm.nih.gov/gene/3043)
• [Ensembl: ENSG00000244734](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000244734)
• [UniProt: P68871](https://www.uniprot.org/uniprot/P68871)
• [GeneCards: HBB](https://www.genecards.org/cgi-bin/carddisp.pl?gene=HBB)
• [OMIM: HBB](https://omim.org/search?search=HBB)
• [Allen Brain Atlas: HBB](https://human.brain-map.org/microarray/search/show?search_term=HBB)

References

Pathway Diagram

The following diagram shows the key molecular relationships involving HBB Gene discovered through SciDEX knowledge graph analysis: