Theorist position for analysis 457c5bc3-21d8-42a3-bb99-b0fc6f3f9554: DPP6 GWAS Signal: Cell-Type Regulatory Networks for PD Cognitive Decline
Source basis: GWAS Identifies DPP6 as Risk Gene of Cognitive Decline in Parkinson's Disease (Journals of Gerontology, 2024, DOI 10.1093/gerona/glae155). The stored gap context says: DPP6 was identified as a novel PD cognitive-decline risk gene; the paper noted that functional validation and cell-type-specific mechanisms remain uncharacterised.
Primary hypothesis: DPP6-linked neuronal regulatory networks controlling synaptic excitability and cognitive resilience in PD is not merely an associated signature; it is a testable mechanism that can explain the open question: What cell-type-specific gene regulatory networks mediate the DPP6 GWAS signal for cognitive decline in Parkinson's disease — do they converge on synaptic plasticity pathways in hippocampal versus prefrontal neurons, and is DPP6 expression altered in prodromal PD before motor symptoms?
Three candidate claims should be carried forward. First, the strongest causal signal should appear in the cell type or tissue compartment named by the question, not only in bulk disease contrasts. Second, perturbing the axis should shift a proximal molecular phenotype before it shifts a late pathology phenotype, which would help separate cause from consequence. Third, the relevant readout should be stratified by DPP6, GWAS, because collapsing across those terms would erase the mechanism the analysis is trying to test.
The priority experiment is cell-type eQTL colocalization, enhancer perturbation, and prodromal PD single-nucleus validation in hippocampal and prefrontal neurons. A positive result would require concordance across human observational data, disease-relevant cellular models, and at least one perturbation that moves the predicted proximal readout in the expected direction.