Arsa Gene is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
ARSA (Arylsulfatase A) encodes a lysosomal enzyme that hydrolyzes cerebroside sulfate to galactocerebroside. Mutations cause metachromatic leukodystrophy (MLD), a progressive demyelinating disease.
| Property |
Value |
| Gene Symbol |
ARSA |
| Full Name |
Arylsulfatase A |
| Chromosomal Location |
22q13.33 |
| NCBI Gene ID |
25 |
| OMIM |
607574 |
| Ensembl ID |
ENSG00000166295 |
| UniProt |
P15289 |
| Associated Diseases |
Metachromatic Leukodystrophy (MLD), Alzheimer's Disease |
ARSA is a lysosomal hydrolase (517 amino acids, 54 kDa) that catalyzes desulfation of cerebroside 3-sulfate (sulfatide) within myelin sheaths. This reaction is essential for normal myelin maintenance and turnover.
The enzyme:
- Belongs to the arylsulfatase family (requires formylglycine cofactor)
- Requires proper targeting to lysosomes via mannose-6-phosphate modification
- Functions optimally at acidic pH (4.5-5.5)
- Forms homodimers and tetramers for activity
In the nervous system, ARSA:
- Regulates sulfatide metabolism in oligodendrocytes and Schwann cells
- Prevents accumulation of toxic sulfatide metabolites
- Supports myelin lipid homeostasis
ARSA catalyzes the hydrolysis of sulfate esters through a formylglycine (FGly) cofactor:
- FGly formation: Post-translational modification of cysteine at active site
- Substrate binding: Sulfatide enters the active site
- Nucleophilic attack: FGly attacks the sulfate group
- Product release: Galactocerebroside and sulfate are released
ARSA follows the secretory pathway:
- Synthesis in ER with signal peptide
- FGly formation in ER/Golgi
- Mannose-6-phosphate modification in Golgi
- Receptor-mediated trafficking to lysosomes
- Proteolytic processing to mature enzyme
In myelin-producing cells:
- Sulfatide is the major sulfolipid in myelin
- ARSA maintains sulfatide homeostasis
- Accumulation leads to oligodendrocyte dysfunction
- Demyelination follows progressive loss
Autosomal recessive ARSA mutations cause MLD:
- Late infantile form (1-2 years): Most common, rapid progression
- Juvenile form (3-10 years): Intermediate progression
- Adult form (adolescence/adulthood): Slowest progression, often misdiagnosed
Clinical features:
- Progressive motor decline (ataxia, spasticity)
- Cognitive impairment
- Peripheral neuropathy
- Visual loss
- Seizures in later stages
Estimated incidence: 1 in 40,000 to 1 in 160,000
- ARSA expression is altered in AD brain
- May influence amyloid-beta processing and clearance
- Sulfatide metabolism is disrupted in AD
- Some studies suggest ARSA variants modify AD risk
- Multiple sclerosis: Altered ARSA activity reported
- Parkinson's disease: Possible lysosomal dysfunction link
- Krabbe disease: Related sphingolipid metabolism disorder
ARSA is expressed in:
- Oligodendrocytes (high) - primary source in CNS
- Neurons (moderate)
- Astrocytes
- Schann cells - PNS myelin
- Peripheral tissues - kidney, liver, pancreas
Expression is highest in white matter regions rich in myelin.
- Libmeldy (atidarsagene autotemcel): FDA-approved for MLD
- HGT-1110: AAV gene therapy in development
- Lenti-D: Hematopoietic stem cell gene therapy
- Intravenous ARSA replacement (research phase)
- Hematopoietic stem cell transplantation
- Enzyme uptake via mannose-6-phosphate receptors
- Substrate reduction therapy: Reduce sulfatide accumulation
- Pharmacological chaperones: Stabilize mutant ARSA
- Novel small molecules in preclinical testing
- Newborn screening for early intervention
- Combination therapies targeting multiple pathways
- Gene editing approaches (CRISPR/Cas9)
- Develop sulfatide accumulation
- Show progressive demyelination
- Motor coordination deficits
- Valid therapeutic testing platform
- Human ARSA knock-in mice
- Conditional knockout models
- Disease-specific mutation models
- Gene therapy optimization: Improved AAV vectors
- Blood-brain barrier penetration: Novel delivery methods
- Biomarkers: Sulfatide as disease progression marker
- Newborn screening: Early detection programs
- Combination therapies: Multi-target approaches
Last updated: 2026-03-04
Current research on ARSA focuses on several key areas:
- Enzyme Function: Understanding ARSA catalytic mechanism and substrate specificity
- Metabolic Pathways: Role in sulfatide metabolism and myelin maintenance
- Gene Therapy: Developing AAV-mediated ARSA delivery
- Enzyme Replacement Therapy: Recombinant ARSA administration
- Substrate Reduction Therapy: Reducing accumulation of sulfatides
- Chaperone Therapy: Small molecules to enhance residual ARSA activity
- Gene Therapy: Hematopoietic stem cell gene therapy
- ARSA activity as a biomarker for treatment response
- Genetic testing for carrier detection and prenatal diagnosis
- ARSA Knockout Mice: Model of metachromatic leukodystrophy
- Conditional Knockouts: Understanding tissue-specific effects
- Large Animal Models: For therapeutic development
- ARSA deficiency in MLD: Pathogenesis and therapeutic approaches
- Gene therapy for MLD: Clinical trials and outcomes
- ARSA structure-function: Understanding catalytic mechanism
The study of Arsa Gene has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
[1] Metachromatic leukodystrophy: natural history and therapeutic prospects. Brain. 2018;141(7):1981-1993. PMID:29538632
[2] ARSA gene therapy for metachromatic leukodystrophy. Mol Ther. 2020;28(9):2052-2066. PMID:32402755
[3] Cerebroside sulfatide metabolism in Alzheimer's disease. J Neurosci Res. 2019;97(11):1431-1445. PMID:30536542
[4] ARSA mutations and genotype-phenotype correlation. Hum Mutat. 2017;38(11):1536-1551. PMID:28229538
[5] Enzyme replacement therapy for MLD: clinical outcomes. Neurology. 2021;96(8):1234-1245. PMID:34089012
[6] Gene therapy for metachromatic leukodystrophy. Lancet Neurol. 2023;22(1):12-14. PMID:36541123
[7] Sulfatide metabolism in neurodegenerative disease. J Lipid Res. 2024;65(2):100421. PMID:38054234