UQ-led study finds shared grey matter signature in Alzheimer's and Parkinson's

A groundbreaking study published on arXiv (arXiv:2606.02099) has unveiled the first quantitative shared grey-matter signature between Alzheimer's disease (AD) and Parkinson's disease (PD). Led by Vishaak Gangasandra and Baptiste Couvy-duchesne from the University of Queensland, the team leveraged a novel statistical framework called SumR2 regression, adapted from genetic correlation analysis, to analyze high-resolution brain maps aggregated from large MRI datasets. Their approach allowed vertex-level correlation estimation beyond traditional ROI-based methods. The results showed a significant positive brain-wide grey-matter correlation of rGM=0.24 (95% CI 0.20-0.28) between AD and PD, with the correlation persisting across disease stages and successfully replicated using UK Biobank data.

Further analysis pinpointed 9 vertex-wise clusters (106 vertices) that drive the shared signature, highlighting reduced cortical thickness in the bilateral putamen and right accumbens as common features. These regions are involved in motor control and reward processing, respectively, linking both diseases' early degenerative pathways. The findings suggest that shared neuroanatomical features emerge early in neurodegeneration, offering potential biomarkers for early screening, disease monitoring, and targeted therapeutic interventions. This work represents a significant step toward understanding comorbidity and shared mechanisms in neurodegenerative disorders, with implications for clinical trial design and personalized medicine.