Task: gap003 | Last Updated: 2026-03-15 | Kind: gap-analysis | Total Ranked Gaps: 20
This page connects to the broader neurodegenerative disease knowledge graph:
This page prioritizes the most actionable unanswered questions in Parkinson's Disease research. The goal is to guide investigators, funders, and translational teams toward high-impact gaps that now have realistic paths to resolution.
Compared with older PD gap lists, this update is anchored to three concrete 2024-2026 advances:
Each gap is scored 0-10 on four dimensions:
| Dimension | What It Measures |
|---|---|
| Impact if Solved | Potential to change treatment, prevention, or trial success |
| Tractability | Feasibility with current tools/cohorts/assays |
| Under-exploration | High score = insufficient effort relative to importance |
| Data Availability | Availability of cohorts, biomarkers, models, and endpoints |
Maximum score = 40. Higher totals indicate high-impact gaps that are both important and actionable.
| Rank | Knowledge Gap | Impact | Tractability | Under-exploration | Data | Total |
|---|---|---|---|---|---|---|
| 1 | Do alpha-syn seed kinetics define biologically distinct progression trajectories? | 10 | 8 | 7 | 8 | 33 |
| 2 | Which early-PD subgroups truly benefit from GLP-1 pathway therapies? | 10 | 7 | 8 | 7 | 32 |
| 3 | Can LRRK2 inhibition demonstrate disease modification (not only target engagement)? | 10 | 7 | 8 | 7 | 32 |
| 4 | What drives selective vulnerability of substantia nigra dopaminergic neurons? | 10 | 6 | 8 | 7 | 31 |
| 5 | How should SAA and imaging be combined for prodromal-trial enrichment and staging? | 9 | 8 | 7 | 7 | 31 |
| 6 | Which neuroinflammation states are causal vs reactive? | 9 | 7 | 7 | 7 | 30 |
| 7 | What determines penetrance in LRRK2, GBA, and mixed-risk carriers? | 9 | 7 | 8 | 6 | 30 |
| 8 | Is there a tract-level sequence linking gut, vagal, and central synuclein pathology? | 9 | 6 | 8 | 7 | 30 |
| 9 | Which non-dopaminergic circuits best explain disabling non-motor progression? | 9 | 7 | 7 | 7 | 30 |
| 10 | What are the best pharmacodynamic markers for LRRK2 inhibitors? | 8 | 8 | 7 | 7 | 30 |
| 11 | Can lysosomal rescue in GBA pathway be matched to genotype-independent biomarkers? | 8 | 7 | 7 | 7 | 29 |
| 12 | Which alpha-syn species and compartments are the true therapeutic targets? | 9 | 6 | 8 | 6 | 29 |
| 13 | How should trial endpoints integrate digital, fluid, imaging, and functional data? | 8 | 8 | 6 | 7 | 29 |
| 14 | What is the optimal sequencing of exercise, rehab, and disease-modifying therapies? | 8 | 8 | 6 | 7 | 29 |
| 15 | Which mitochondrial failure nodes are upstream vs secondary in PD? | 8 | 6 | 8 | 7 | 29 |
| 16 | Can we identify "resilient" cell programs for therapeutic induction? | 8 | 6 | 8 | 6 | 28 |
| 17 | How should mixed pathologies (AD co-pathology, vascular burden, tau) alter PD trial design? | 8 | 7 | 7 | 6 | 28 |
| 18 | Which antibody/small-molecule alpha-syn strategies should advance after mixed late-stage results? | 8 | 6 | 7 | 6 | 27 |
| 19 | Can precision prevention be implemented for high-risk prodromal cohorts? | 8 | 6 | 7 | 6 | 27 |
| 20 | What implementation model best scales biomarker-driven care in routine clinics? | 7 | 8 | 6 | 6 | 27 |
Recent work supports moving from a symptom-defined PD framework to a biology-forward framework built around neuronal alpha-synuclein status and assay kinetics.[3:1][4:1][5:1] The remaining gap is not binary positivity; it is how kinetic parameters map to progression speed, phenotype, and treatment responsiveness.
Near-term experiments
The lixisenatide trial provides a credible signal that progression may be modifiable in early PD, but effect heterogeneity, mechanism attribution, and longer-term durability remain unresolved.[1:1][6][7]
Near-term experiments
Human translational data for BIIB122 significantly de-risks feasibility of LRRK2 pathway inhibition, but do not yet close the efficacy gap.[2:1][8][9]
Near-term experiments
We still lack a unifying causal model for why some Substantia Nigra Pars Compacta Dopamine Neurons in Parkinson's Disease degenerate early while neighboring populations are relatively resilient.
Near-term experiments
Prodromal cohorts can now be biologically defined with much higher confidence using SAA-centric frameworks, but prevention trial architecture remains immature.[3:2][10][11]
Near-term experiments
This section tracks recent publications and advances addressing the knowledge gaps listed above.
Recent findings from 2025 conferences and publications:
Pagano G, et al. Trial of Lixisenatide in Early Parkinson's Disease. The New England Journal of Medicine. 2024. ↩︎ ↩︎ ↩︎
Jennings D, et al. LRRK2 Inhibition by BIIB122 in Healthy Participants and Patients with Parkinson's Disease. Movement Disorders. 2023. ↩︎ ↩︎ ↩︎
Simuni T, et al. [Assessment of heterogeneity among participants in the Parkinson's Progression Markers Initiative cohort using alpha-synuclein seed amplification](https://pubmed.ncbi.nlm.nih.gov/37059509/). The Lancet Neurology. 2023. ↩︎ ↩︎ ↩︎
Siderowf A, et al. [A biological definition of neuronal alpha-synuclein disease: towards an integrated staging system for research](https://pubmed.ncbi.nlm.nih.gov/38267190/). The Lancet Neurology. 2024. ↩︎ ↩︎
Chahine LM, et al. [Diagnostic and prognostic value of alpha-synuclein seed amplification assay kinetic measures in Parkinson's disease: a longitudinal cohort study](https://pubmed.ncbi.nlm.nih.gov/40541208/). The Lancet Neurology. 2025. ↩︎ ↩︎ ↩︎
Stott SRW, et al. [Are glucagon-like peptide-1 receptor agonists useful in treating Parkinson's disease?](https://pubmed.ncbi.nlm.nih.gov/39864104/). Expert Opinion on Investigational Drugs. 2025. ↩︎ ↩︎
Zhang L, et al. Antidiabetic drugs in Parkinson's disease: a comprehensive meta-analysis on efficacy and safety. Inflammopharmacology. 2025. ↩︎ ↩︎
Hu Y, et al. [Recent advances in targeting leucine-rich repeat kinase 2 as a potential strategy for the treatment of Parkinson's disease](https://pubmed.ncbi.nlm.nih.gov/40629324/). Journal of Translational Medicine. 2025. ↩︎
McLeary FA, et al. [Type II kinase inhibitors that target Parkinson's disease-associated LRRK2](https://pubmed.ncbi.nlm.nih.gov/40465731/). Science Advances. 2025. ↩︎
Ruskey JA, et al. Alpha-synuclein Seed Amplification Assay Amplification Parameters and the Risk of Progression in Prodromal Parkinson Disease. Neurology. 2025. ↩︎
Quansah E, et al. [Quantitative measurements of alpha-synuclein seeds in CSF inform diagnosis of synucleinopathies](https://pubmed.ncbi.nlm.nih.gov/41042913/). Journal of Parkinson's Disease. 2025. ↩︎