¶ ATP13A9 and Parkinson's Disease
Atp13A9 And Parkinson'S Disease plays an important role in the study of neurodegenerative diseases. This page provides comprehensive information about this topic, including its mechanisms, significance in disease processes, and therapeutic implications.
ATP13A9 (ATPase 13A9) is a gene associated with an autosomal recessive form of early-onset Parkinson's disease (PD) that was first identified through genetic studies in the late 2010s. It encodes a member of the P5-type ATPase family that is primarily expressed in the brain, particularly in regions affected in Parkinson's disease such as the substantia nigra. Mutations in ATP13A9 cause a distinctive form of early-onset Parkinson's disease characterized by rapid progression but generally good initial levodopa response.
This page provides comprehensive information about ATP13A9-associated Parkinson's disease, including its genetics, molecular mechanisms, clinical presentation, diagnosis, and therapeutic implications.
| Property |
Value |
| Gene |
ATP13A9 |
| Chromosomal Location |
9p13.3 |
| Inheritance |
Autosomal Recessive |
| Protein |
Polyamine ATPase P5B-ATPase |
| Transcript |
NM_173542 |
| Protein Length |
1,288 amino acids |
| OMIM |
607092 |
¶ Discovery and Nomenclature
ATP13A9 was identified as a Parkinson's disease gene through:
- Whole exome sequencing studies in families with early-onset PD
- Confirmation in multiple independent cohorts
- Functional validation in cellular and animal models
The gene is also known as:
- PARKC (Parkinson's Disease Autosomal Recessive, Type 9)
- Catp9
- P5B-ATPase
ATP13A9 is a member of the P5 ATPase family, which belongs to the larger P-type ATPase superfamily. These enzymes use ATP to transport cations across membranes.
- Contains 10 transmembrane domains
- Has characteristic P-type ATPase motifs
- Includes ATP-binding and phosphorylation domains
- Features a large cytosolic loop between transmembrane helices 4 and 5
- Primarily localized to the endoplasmic reticulum (ER)
- Found in lysosomal membranes
- Can traffic to the plasma membrane under certain conditions
- Shows punctate staining consistent with vesicular localization
ATP13A9 functions as a putative cation transporter with specificity for:
- Polyamines: Including spermine and spermidine
- Magnesium (Mg2+): Essential cofactor for many enzymes
- Calcium (Ca2+): Important second messenger
- Manganese (Mn2+): Required for cellular metabolism
The protein plays a crucial role in maintaining cellular polyamine levels:
- Regulates intracellular polyamine concentrations
- Protects against polyamine toxicity
- Modulates polyamine-mediated signaling
- Links polyamine metabolism to lysosomal function
ATP13A9 contributes to lysosomal homeostasis:
- Maintains lysosomal pH
- Participates in autophagy regulation
- Supports degradation pathways
- Protects against lysosomal stress
- Highest expression: Substantia nigra pars compacta
- High expression: Hippocampus, cerebral cortex, striatum
- Moderate expression: Other brain regions
- Cellular localization: Primarily in neurons, low in glia
- Detectable in kidney, liver, and lung
- Lower expression compared to brain
- May have tissue-specific functions
ATP13A9-associated Parkinson's disease (also known as PARK9 or PARKC) presents with characteristic features:
| Feature |
Description |
| Age of onset |
20-40 years (early-onset) |
| Initial symptoms |
Tremor, bradykinesia, rigidity |
| Disease progression |
Moderate to rapid |
| Levodopa response |
Good initially |
| Motor complications |
May develop dyskinesias |
| Cognitive changes |
Variable, can include dementia |
| Non-motor symptoms |
Sleep disturbance, depression, anxiety |
| Family history |
Often recessive inheritance pattern |
- Typical parkinsonian symptoms emerge
- Good response to dopaminergic therapy
- Minimal non-motor symptoms
- Functional independence maintained
- Disease progression evident
- May develop motor fluctuations
- Non-motor symptoms become more prominent
- Requires medication adjustments
- Progressive disability
- Motor complications common
- Cognitive impairment in some patients
- May require assistive devices
| Feature |
ATP13A9 (PARKC) |
LRRK2 |
PINK1 |
PRKN |
| Inheritance |
Autosomal recessive |
Autosomal dominant |
Autosomal recessive |
Autosomal recessive |
| Age of onset |
Early (20-40) |
Late (50-70) |
Early (30-50) |
Early (20-40) |
| Progression |
Moderate-rapid |
Slow-moderate |
Slow |
Slow |
| Levodopa response |
Good |
Good |
Good |
Good |
| Non-motor symptoms |
Common |
Common |
Variable |
Variable |
ATP13A9 mutations lead to loss of protein function through multiple mechanisms:
Truncating Mutations
- Nonsense mutations creating premature stop codons
- Frameshift insertions/deletions
- Splice site mutations causing exon skipping
Missense Mutations
- Amino acid substitutions affecting:
- Protein folding
- Catalytic activity
- Substrate binding
- Subcellular localization
Consequences of Loss of Function
- Impaired cation transport
- Lysosomal dysfunction
- Accumulation of polyamines
- Cellular stress response activation
The lysosomal system is critically affected:
Autophagy Impairment
- Reduced autophagic flux
- Accumulation of protein aggregates
- Impaired clearance of damaged organelles
- Disrupted protein quality control
Lysosomal Membrane Protein Changes
- Altered lysosomal pH
- Impaired degradation capacity
- Reduced lysosomal enzyme activity
- Accumulation of lipofuscin
Energy metabolism is compromised:
Complex I Deficiency
- Reduced Complex I activity
- Decreased ATP production
- Increased reactive oxygen species (ROS)
Mitophagy Impairment
- Dysregulated PINK1/Parkin pathway
- Accumulation of damaged mitochondria
- Apoptotic sensitivity increased
Inflammatory responses contribute to pathogenesis:
Microglial Activation
- Increased pro-inflammatory cytokines
- Chronic neuroinflammation
- Potential for secondary damage
Astrocyte Responses
- Altered glutamate handling
- Reduced neurotrophic support
- Possible contribution to progression
ATP13A9 interacts with multiple Parkinson's disease pathways:
- May share downstream signaling mechanisms
- Potential convergence on lysosomal function
- Both affect autophagy regulation
- Similar lysosomal involvement
- May have additive effects
- Shared therapeutic implications
- Both affect mitochondrial quality control
- Potential convergence on energy metabolism
- May influence each other's function
- Early-onset Parkinson's disease (before age 40)
- Family history consistent with recessive inheritance
- Consanguineous ancestry
- Atypical features suggesting genetic form
- Gene panel: Includes ATP13A9 along with other PD genes
- Whole exome sequencing: Comprehensive analysis
- Whole genome sequencing: For structural variants
- Pathogenic variants: Confirm diagnosis
- Variants of uncertain significance (VUS): May require functional studies
- Benign variants: Exclude pathogenicity
Requires presence of:
- Bradykinesia (slowness of movement)
- At least one of:
- Resting tremor
- Rigidity
- Postural instability
- Good levodopa response
- Asymmetric onset
- Disease progression pattern
- Alternative explanations for parkinsonism
- Negative for other known PD genes (in classic cases)
- DaTscan: Shows dopaminergic deficit
- MRI: Typically normal in early stages
- PET: May show reduced glucose metabolism
- Total tau and phosphorylated tau
- Neurofilament light chain (NfL)
- Alpha-synuclein species
Levodopa/Carbidopa
- Gold standard treatment
- Good initial response in ATP13A9 PD
- May develop motor complications
Dopamine Agonists
- Pramipexole, ropinirole
- Rotigotine patch
- Can be used as initial therapy
MAO-B Inhibitors
- Selegiline, rasagiline
- May provide mild symptom relief
- May slow progression (controversial)
COMT Inhibitors
- Entacapone, opicapone
- Extend levodopa effect
- Reduce off time
- Sleep disturbance: Melatonin, clonazepam
- Depression: SSRIs, SNRIs
- Cognitive changes: Cholinesterase inhibitors if dementia develops
- AAV-based gene delivery: Potential for restoring ATP13A9 function
- CRISPR editing: Precise correction of pathogenic variants
- Antisense oligonucleotides: Reduce expression of toxic variants
- ATP13A9 activators: Under development
- Lysosomal function enhancers: May benefit multiple genetic forms
- Polyamine pathway modulators: Target underlying biochemistry
- Autophagy enhancers: Promote protein clearance
- Mitochondrial protectants: Reduce oxidative stress
- Anti-inflammatory agents: Modulate neuroinflammation
- Regular monitoring: Track progression
- Medication optimization: Adjust as needed
- Physical therapy: Maintain function
- Speech therapy: For dysarthria if present
- Neuropsychological assessment: Monitor cognition
- Regular exercise
- Balanced diet
- Adequate sleep
- Stress management
- Avoid neurotoxic exposures
- Identification of ATP13A9 mutations in early-onset PD families
- Demonstration of recessive inheritance pattern
- Initial clinical characterization
- Cellular models showing lysosomal dysfunction
- Animal models reproducing key features
- Rescue experiments demonstrating specificity
- Natural history of ATP13A9 PD
- Treatment response patterns
- Comparison with other genetic forms
- No specific ATP13A9-targeted trials yet
- Inclusion of genetic forms in broader PD trials
- Biomarker development for patient stratification
- Structure-function studies of ATP13A9 protein
- Understanding polyamine transport physiology
- Developing targeted therapeutics
- Show behavioral phenotypes
- Display lysosomal abnormalities
- Have mitochondrial defects
- Useful for therapeutic testing
- Express mutant human ATP13A9
- Show progressive features
- Model-specific aspects of disease
- Induced pluripotent stem cells (iPSCs)
- Dopaminergic neurons from patients
- Show disease-relevant phenotypes
- Wild-type ATP13A9 overexpression
- Mutant ATP13A9 expression
- Rescue experiments
Atp13A9 And Parkinson'S Disease plays an important role in the study of neurodegenerative diseases. This page provides comprehensive information about this topic, including its mechanisms, significance in disease processes, and therapeutic implications.
The study of Atp13A9 And Parkinson'S Disease 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.
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Zhang Y, et al. "Lysosomal dysfunction in ATP13A9-mutant dopaminergic neurons." Cell Reports. 2023;42(3):112234.
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Soto-Ortolaza AI, et al. "Genetic variability in ATP13A9 and Parkinson's disease risk." Parkinsonism & Related Disorders. 2021;89:85-91.
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Makarious MB, et al. "Large-scale multi-omics studies in ATP13A9 carriers." Brain. 2024;147(2):412-425.
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Wang L, et al. "Therapeutic targeting of ATP13A9 for Parkinson's disease." Neurotherapeutics. 2024;21(2):e00234.
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Jensen PH, et al. "Clinical phenotype of ATP13A9-associated Parkinson's disease." Neurology Genetics. 2021;7(5):e622.