MSACL 2026 Abstract

Identifying a Breath Volatile Signature for Parkinson’s Disease: The Panorama Pilot Study

Ilaria Belluomo (1), Munir Tarazi (1), Vanessa Velez-Perez (1), James Murray (2), Aldazier Jakiran (3), Zahra Abass (1), Bradley Lonergan (4), Linda Sharples (2), Patrik Spanel (1, 5), Yen F Tai (3, 4), George B Hanna (1).
(1) Surgery and Cancer Department, Imperial College London, London, UK; (2) Department of Medical Statistics, London School of Hygiene and Tropical Medicine, London, UK; (3) Neurosciences Research Team, Imperial College Healthcare Trust, London, UK; (4) Department of Brain Sciences, Imperial College London, London, UK; (5) Department of Chemistry of Ions in Gaseous Phase, J. Heyrovsky Institute of Physical Chemistry of the Czech Academy of Sciences, Prague, Czech Republic.

Ilaria Belluomo, PhD (Presenter) Imperial College London

Presenter Bio: Ilaria is currently a Research Fellow at Imperial College London. Her main research interest is the discovery and validation of volatile biomarkers in human breath using mass spectrometry, for the development of novel non-invasive diagnostic and monitoring techniques for neurological diseases.

Relevant Financial Disclosures (within past 24 months, reported on Apr 22, 2026) No relevant financial relationship(s) to disclose.

INTRODUCTION:
Parkinson's disease (PD) is the second most common neurodegenerative disorder and the fastest-growing neurological condition worldwide, with prevalence projected to exceed 25 million by 2050. Diagnosis relies on clinical motor symptoms, which emerge only after 50-60% of dopaminergic neurons have been lost, precluding early intervention to stop the disease. Recent evidence suggests that in a significant proportion of patients PD may originate in the gut, with gastrointestinal symptoms and gut microbiome alterations preceding motor manifestations by years. Gut bacteria influence the production of volatile organic compounds (VOCs), small molecules detectable in exhaled breath that reflect systemic biochemical processes. Given the rapidly growing global burden of PD, breath VOC analysis offers a particularly attractive diagnostic strategy, being rapid, non-invasive, scalable, and suitable for large-scale deployment in both primary and secondary care.

OBJECTIVE(S):
The PANORAMA pilot study was designed to establish the foundation for a non-invasive breath test for PD diagnosis, combining breath VOC profiling with gut microbiome characterisation. The specific objectives were to: (i) Identify a panel of breath VOCs capable of discriminating people with Parkinson's (PwP) from controls and develop a diagnostic model (ii) Characterise the gut microbiome of PwP and controls using high-resolution metagenomics (iii) Investigate associations between breath VOC profiles and gut microbiome composition to explore the putative microbial origin of discriminatory compounds.

METHODS:
This was a single-site observational study conducted at Charing Cross Hospital, Imperial College NHS Trust, London. 92 confirmed PwP and 57 age-matched controls were recruited. Breath samples were collected in thermal desorption sorbent tubes following overnight fasting and analysed using gas chromatography time-of-flight mass spectrometry (GC-ToF-MS). A regularised logistic regression model was developed using cross-validation and bootstrap resampling to identify a stable panel of discriminatory VOCs and estimate diagnostic performance.

RESULTS:
The model identified a panel of VOCs capable of discriminating PwP from controls, achieving a bias-corrected area under the curve (AUC) of 0.814 (95% CI: 0.753–0.879). Some of the discriminatory compounds have known or putative microbial origins, consistent with our hypothesis that gut dysbiosis in PD influences the breath volatile metabolome. Additional compounds with potential links to oxidative stress and lipid peroxidation were also identified. A subset of compounds requires further chemical characterisation using authentic standards. DNA extraction from stool samples has been completed and samples submitted for shotgun metagenomic sequencing.

CONCLUSION:
The PANORAMA pilot study demonstrates that breath VOC analysis using GC-ToF-MS can discriminate PwP from age-matched controls with promising diagnostic performance. The identification of VOCs with putative microbial origins supports the hypothesis that gut bacterial alterations in PD influence systemic volatile production, opening a new mechanistic avenue for understanding the gut-brain axis in PD. A larger, longitudinal study currently in development will build upon these preliminary findings to develop a more robust and generalisable diagnostic model.