NCT04724941: Prodromal Alpha-Synuclein Screening
Overview
NCT04724941 (Prodromal Alpha-Synuclein Screening in Parkinson's Disease Study) is an observational clinical trial designed to identify individuals in the prodromal stage of Parkinson's disease using alpha-synuclein seed amplification assays. The study aims to characterize risk marker profiles in at-risk populations, enabling early detection and potential intervention before manifest motor symptoms develop [@nct].
This mechanistic page integrates the trial's approach with the underlying biology of alpha-synuclein pathology propagation, prodromal biomarkers, and the emerging role of seed amplification assays in early PD detection.
Clinical Trial Overview
| Attribute | Details |
|-----------|---------|
| Trial ID | NCT04724941 |
| Status | Recruiting |
| Enrollment | 2,000 participants (estimated) |
| Sponsor | University Hospital Schleswig-Holstein |
| Collaborators | UCB Biopharma SRL; University of Kiel |
| Location | Kiel, Germany |
| Start Date | June 2021 |
| Completion | December 2027 |
| Study Type | Observational |
| Primary Outcome | Risk marker profile |
The Rationale for Prodromal Screening
Why Detect PD Before Motor Symptoms?
Parkinson's disease is characterized by a long prodromal period during which pathological changes occur but clinical motor symptoms have not yet manifested. This window represents a critical opportunity for:
...NCT04724941: Prodromal Alpha-Synuclein Screening
Overview
NCT04724941 (Prodromal Alpha-Synuclein Screening in Parkinson's Disease Study) is an observational clinical trial designed to identify individuals in the prodromal stage of Parkinson's disease using alpha-synuclein seed amplification assays. The study aims to characterize risk marker profiles in at-risk populations, enabling early detection and potential intervention before manifest motor symptoms develop [@nct].
This mechanistic page integrates the trial's approach with the underlying biology of alpha-synuclein pathology propagation, prodromal biomarkers, and the emerging role of seed amplification assays in early PD detection.
Clinical Trial Overview
| Attribute | Details |
|-----------|---------|
| Trial ID | NCT04724941 |
| Status | Recruiting |
| Enrollment | 2,000 participants (estimated) |
| Sponsor | University Hospital Schleswig-Holstein |
| Collaborators | UCB Biopharma SRL; University of Kiel |
| Location | Kiel, Germany |
| Start Date | June 2021 |
| Completion | December 2027 |
| Study Type | Observational |
| Primary Outcome | Risk marker profile |
The Rationale for Prodromal Screening
Why Detect PD Before Motor Symptoms?
Parkinson's disease is characterized by a long prodromal period during which pathological changes occur but clinical motor symptoms have not yet manifested. This window represents a critical opportunity for:
Early intervention: Disease-modifying therapies may be most effective before extensive neuronal loss
Neuroprotective strategies: Protecting remaining dopaminergic neurons in the substantia nigra
Patient stratification: Identifying at-risk individuals for clinical trial enrollment
Understanding disease progression: Characterizing the biological sequence of eventsProdromal Markers in PD
The prodromal phase of PD is characterized by several non-motor features that precede motor symptoms by years to decades:
Mermaid diagram (expand to render)
Alpha-Synuclein Biology in Prodromal PD
Normal Alpha-Synuclein Function
Alpha-synuclein (α-syn) is a 140-amino acid protein encoded by the [SNCA gene](/genes/snca) that plays important roles in synaptic vesicle trafficking and neurotransmitter release. In its native state, α-syn exists as an intrinsically disordered monomer that transiently interacts with lipid membranes [@sato2023].
Pathological Conversion
In PD, α-syn undergoes a conformational change from native monomer to misfolded oligomers and fibrils that accumulate as [Lewy bodies](/mechanisms/lewy-body-formation-pathway) and [Lewy neurites](/mechanisms/alpha-synuclein-aggregation-pathway). This conversion is templated by pathological seeds—a process known as seeding [2](https://doi.org/10.1126/science.1220361).
The key steps in pathological α-syn conversion:
Misfolding: Native monomer adopts β-sheet rich conformation
Oligomerization: Misfolded monomers form toxic oligomers
Fibrillization: Oligomers aggregate into amyloid fibrils
Deposition: Fibrils accumulate as Lewy pathologyPrion-Like Propagation
The pathological α-syn species exhibit prion-like properties, able to template the conversion of normal endogenous α-syn in recipient cells. This template-directed misfolding drives the spread of pathology throughout the nervous system [3](https://doi.org/10.1084/jem.20112457).
Key propagation mechanisms:
- Intercellular transfer: Pathological α-syn can transfer between neurons via tunneling nanotubes, extracellular vesicles, and synaptic release
- Template-directed conversion: Seeds induce misfolding of native α-syn in recipient cells
- Strain diversity: Different conformational variants ("strains") may encode disease specificity
See [Alpha-Synuclein Propagation Models](/mechanisms/alpha-synuclein-propagation-models) for detailed mechanisms.
Seed Amplification Assays (SAA)
Technology Overview
Seed amplification assays are ultrasensitive detection methods that exploit the prion-like property of misfolded α-syn. These assays can detect pathological seeds at concentrations as low as 10⁻¹⁵ to 10⁻¹⁶ M [4](https://doi.org/10.1212/WNL.0000000000207291).
RT-QuIC (Real-Time Quaking-Induced Conversion)
RT-QuIC detects α-syn seeds by their ability to template the conversion of recombinant α-syn monomer into amyloid fibrils:
Patient sample (CSF, blood, or tissue) is incubated with recombinant α-syn monomer
Cyclic shaking and incubation promote fibril formation
Thioflavin T (ThT) fluorescence monitors fibril growth in real-time
Positive signal indicates presence of pathological seedsPerformance characteristics:
- Sensitivity: 85-95% in manifest PD
- Specificity: >95% in healthy controls
- Sample types: CSF, blood, skin, olfactory mucosa
- Turnaround: 2-4 days
PMCA (Protein Misfolding Cyclic Amplification)
PMCA uses sonication cycles to amplify α-syn seeds in a manner analogous to PCR:
Patient sample incubated with substrate α-syn
Fibrils form during incubation
Sonication breaks fibrils into smaller seeds
Cycles repeat, exponentially amplifying the seed signalSAA vs. Traditional Biomarkers
| Method | Target | Sensitivity | Sample Type | Clinical Use |
|--------|--------|-------------|-------------|--------------|
| SAA | Pathological seeds | 85-95% | CSF, Blood | Diagnostic, Prodromal |
| Total α-syn | All α-syn | Variable | CSF, Blood | Research |
| pSer129 | Phosphorylated α-syn | ~90% | CSF, Blood | Pathological confirmation |
| Oligomers | Toxic oligomers | Moderate | CSF | Research |
Comparison: CSF vs. Blood Biomarkers
Cerebrospinal Fluid (CSF) Biomarkers
CSF provides direct access to the central nervous system and is the most validated sample type for α-syn detection:
Advantages:
- Direct reflection of CNS pathology
- Highest sensitivity for SAA
- Well-established collection protocols
- Rich in additional biomarkers (tau, amyloid)
Limitations:
- Invasive (lumbar puncture required)
- Variable collection protocols
- Lower throughput for screening
Key CSF biomarkers:
- Total α-syn: Reduced in PD vs. controls
- Phosphorylated α-syn (pSer129): Increased in PD
- Oligomeric α-syn: Elevated in PD
- Neurofilament light chain (NfL): Marker of neurodegeneration
Blood-Based Biomarkers
Blood-based testing offers significant advantages for population screening:
Advantages:
- Minimally invasive
- High-throughput screening feasible
- Lower cost than CSF
- Suitable for repeated sampling
Challenges:
- Peripheral α-syn may confound CNS signal
- Lower sensitivity than CSF in some assays
- Requires ultra-sensitive methods
Emerging approaches:
- Blood-derived exosomes containing α-syn
- Plasma SAA with enhanced sensitivity
- Multiplexed protein panels
- Combined with genetic testing
NCT04724941's Screening Approach
The trial aims to leverage both CSF and blood-based SAA approaches to characterize the "risk marker profile" in prodromal individuals. This comprehensive approach will:
Validate blood-based SAA against CSF
Identify optimal biomarker combinations
Establish cutoffs for prodromal detection
Enable large-scale screening programsClinical Significance of Prodromal Detection
Therapeutic Implications
Early detection through seed amplification enables several intervention strategies:
| Strategy | Approach | Timing |
|---------|----------|--------|
| Neuroprotection | Protect surviving neurons | Prodromal/Early |
| Disease modification | Halt seed propagation | Prodromal |
| Symptomatic | Dopaminergic therapy | Manifest |
| Preventive | Lifestyle modifications | At-risk |
Clinical Trial Enrichment
SAA-positive prodromal individuals represent ideal participants for disease-modifying therapy trials:
Advantages:
- Biologically confirmed pathology
- Likely to progress to manifest PD
- Earlier intervention window
- Smaller required sample sizes
- Clearer mechanism targeting
See [Alpha-Synuclein Seed Kinetic Staging](/biomarkers/alpha-synuclein-seed-kinetics-pd) for kinetic stratification approaches.
Disease Pages
- [Parkinson's Disease](/diseases/parkinsons-disease) - Main disease page
- [Dementia with Lewy Bodies](/diseases/dementia-with-lewy-bodies) - Related α-synucleinopathy
Mechanism Pages
- [Alpha-Synuclein Aggregation Pathway](/mechanisms/alpha-synuclein-aggregation-pathway) - Aggregation mechanism
- [Alpha-Synuclein Propagation Models](/mechanisms/alpha-synuclein-propagation-models) - Spreading mechanisms
- [Lewy Body Formation Pathway](/mechanisms/lewy-body-formation-pathway) - Pathology formation
Gene/Protein Pages
- [SNCA Gene](/genes/snca) - Alpha-synuclein encoding gene
- [Alpha-Synuclein Protein](/proteins/alpha-synuclein) - Protein page
Biomarker Pages
- [Alpha-Synuclein Seed Kinetic Staging](/biomarkers/alpha-synuclein-seed-kinetics-pd) - SAA kinetics
- [CSF Biomarker Comparison](/biomarkers/csf-biomarker-comparison) - CSF markers
Cell Type Pages
- [Dopaminergic Neurons (SNpc)](/cell-types/dopaminergic-neurons-substantia-nigra) - Vulnerable neurons
- [Enteric Neurons](/cell-types/enteric-neurons) - Origin of pathology spread
Clinical Trials
- [Nouvneu001 PD Trial](/clinical-trials/nouvneu001-pd) - Other PD trial
See Also
- [SNCA gene](/genes/snca)
- [Lewy bodies](/mechanisms/lewy-body-formation-pathway)
- [Lewy neurites](/mechanisms/alpha-synuclein-aggregation-pathway)
- [Alpha-Synuclein Propagation Models](/mechanisms/alpha-synuclein-propagation-models)
- [Parkinson's Disease](/diseases/parkinsons-disease)
- [Dementia with Lewy Bodies](/diseases/dementia-with-lewy-bodies)
- [Alpha-Synuclein Aggregation Pathway](/mechanisms/alpha-synuclein-aggregation-pathway)
- [Lewy Body Formation Pathway](/mechanisms/lewy-body-formation-pathway)
- [SNCA Gene](/genes/snca)
- [Alpha-Synuclein Protein](/proteins/alpha-synuclein)
External Links
- [PubMed](https://pubmed.ncbi.nlm.nih.gov/)
- [KEGG Pathways](https://www.genome.jp/kegg/pathway.html)