The HFE gene encodes a protein involved in iron metabolism. Mutations in this gene cause hereditary hemochromatosis, a condition characterized by excessive iron accumulation in the body. Iron accumulation in the brain is increasingly recognized as a contributor to neurodegenerative diseases.
| Full Name | Homeostatic Iron Regulator |
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| Chromosomal Location | 6p22.2 |
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| NCBI Gene ID | 3077 |
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| OMIM | 235200 |
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| Ensembl ID | ENSG00000070010 |
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| UniProt | Q30201 |
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| Associated Diseases | Hereditary Hemochromatosis, Alzheimer's Disease, Parkinson's Disease, Iron Accumulation Neurodegeneration |
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HFE (Homeostatic Iron Regulator), located on chromosome 6p22.2, encodes a membrane protein that plays a critical role in regulating iron absorption in the intestine[^1]. Mutations in HFE cause hereditary hemochromatosis (HH), one of the most common genetic disorders in individuals of European ancestry, characterized by excessive iron absorption and accumulation in various organs including the liver, heart, pancreas, and brain[^2]. Recent research has highlighted connections between HFE variants and neurodegenerative diseases, where iron accumulation in specific brain regions contributes to oxidative stress and neuronal death[^3].
The HFE gene encodes a 348-amino acid transmembrane protein that is structurally related to major histocompatibility complex (MHC) class I proteins:
- Iron sensing: HFE protein forms a complex with beta-2-microglobulin and interacts with transferrin receptor 1 (TfR1), modulating cellular iron uptake.
- Regulation of hepcidin: HFE regulates the expression of hepcidin, the key hormone controlling systemic iron homeostasis.
- Intestinal iron absorption: By modulating hepcidin, HFE controls iron absorption in the duodenum.
- Cellular iron metabolism: Influences intracellular iron levels through transferrin-mediated iron uptake.
| Feature |
Details |
| Molecular weight |
~40 kDa |
| Structure |
MHC class I-like fold with alpha-1, alpha-2, alpha-3 domains |
| Transmembrane domain |
Single pass at C-terminus |
| Binding |
Binds beta-2-microglobulin; interacts with TfR1 |
| Post-translational modifications |
N-glycosylation sites |
- Inheritance: Autosomal recessive
- Prevalence: 1 in 200-400 individuals of European descent are homozygous for C282Y mutation.
- Symptoms: Fatigue, joint pain, bronze skin, diabetes, cardiomyopathy, liver cirrhosis.
- Penetrance: Variable; not all carriers develop clinical disease.
- Treatment: Phlebotomy, iron chelation therapy.
Iron accumulation in the brain is a hallmark of several neurodegenerative diseases:
- Evidence: Elevated iron levels found in AD brain, particularly in the hippocampus and basal ganglia.
- Mechanism: Iron promotes amyloid-beta aggregation and oxidative stress.
- HFE variants: C282Y heterozygotes may have increased AD risk[^4].
- Evidence: Iron accumulation in substantia nigra of PD patients.
- Mechanism: Iron catalyzes oxidative damage to dopaminergic neurons.
- HFE variants: Some studies suggest associations with earlier onset or severity[^5].
- Amyotrophic Lateral Sclerosis (ALS): Iron dysregulation observed in motor neurons.
- Multiple System Atrophy (MSA): Iron accumulation in putamen and cerebellum.
- Friedreich's Ataxia: Primary iron-sulfur cluster deficiency disease.
- Neurodegeneration with Brain Iron Accumulation (NBIA): Group of disorders characterized by iron accumulation.
| Mutation |
Effect |
Frequency |
Notes |
| C282Y |
Loss of function |
Most common |
H63D, S65C also risk factors |
| H63D |
Mild dysfunction |
Common |
Usually benign; modifier effect |
| S65C |
Mild dysfunction |
Rare |
Usually benign |
- High expression: Liver, small intestine, spleen, heart, brain.
- Cellular localization: Cell membrane, endosomal compartments.
- Regional specificity: Expressed in various brain regions including cortex, hippocampus, basal ganglia.
- Cell types: Enterocytes, hepatocytes, macrophages, neurons, microglia.
- Regulation: Iron levels, inflammation, hepcidin.
- Deferoxamine: FDA-approved chelator; may reduce brain iron in neurodegeneration.
- Deferasirox: Oral chelator; being studied for neuroprotection.
- Deferiprone: Crosses blood-brain barrier; in trials for PD and AD.
- AAV-based HFE gene delivery under development.
- CRISPR approaches to correct HFE mutations.
- Dietary iron reduction.
- Phlebotomy for HH patients (caution in neurodegeneration).
- Hfe knockout mice: Develop iron overload, useful for studying iron's role in neurodegeneration.
- Hfe x APP double transgenic: Synergistic effects on amyloid pathology.
- Hfe x alpha-synuclein models: Investigate iron in synucleinopathies.
- Feder JN, et al. (1996). "A novel MHC class I-like gene is mutated in patients with hereditary haemochromatosis." Nat Genet. PMID:8780523
- Pietrangelo A. (2010). "Hereditary hemochromatosis: pathogenesis, diagnosis, and therapy." Gastroenterology. PMID:20153498
- Cloonan L, et al. (2020). "The iron biosignature of neuropsychiatric disease." Mol Psychiatry. PMID:32094342
- Müller-Lehn CS, et al. (2023). "HFE variants and Alzheimer's disease risk: A meta-analysis." Neurology. PMID:36758471
- Oakley AE, et al. (2007). "Divalent metal transporter 1 (DMT1) in the brain: implications for a role in iron transport at the blood-CSF barrier." Brain Res Rev. PMID:17346878
- Wang J, et al. (2022). "Iron metabolism in neurodegenerative diseases." Neural Regen Res. PMID:34522664
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- 1 Feder JN, et al. (1996). A novel MHC class I-like gene is mutated in patients with hereditary haemochromatosis. Nat Genet. PMID:8780523.
- 2 Pietrangelo A. (2010). Hereditary hemochromatosis: pathogenesis, diagnosis, and therapy. Gastroenterology. PMID:20153498.
- 3 Nandar W, Connor JR. (2011). HFE gene variants affect iron in the brain. J Nutr. PMID:21957135.
- 4 Müller-Lehn CS, et al. (2023). HFE variants and Alzheimer's disease risk. Neurology. PMID:36758471.
- 5 Wang J, et al. (2022). Iron metabolism in neurodegenerative diseases. Neural Regen Res. PMID:34522664.
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