MSACL 2026 Abstract

Enhanced Targeted Proteomics and Machine Learning Enable Accurate Blood-Based Detection of Hypertrophic Cardiomyopathy

Jessica Fontes (1, 2), Ivan Doykov (1, 2), Jenny Hällqvist (1, 2), Natacha Loison (1, 2), Tomas Baldwin (1, 2), James Moon (1, 3), Kevin Mills (1, 2), Wendy Heywood (1, 2)
(1) Guilford Street Laboratories, London, UK, (2) Translational Mass Spectrometry Research Group, UCL Institute of Child Health and Great Ormond Street Hospital, London, UK, (3) Institute of Cardiovascular Science, University College London, London, UK

Jessica Fontes, MSc (Presenter) Guilford Street Laboratories

Relevant Financial Disclosures (within past 24 months, reported on Apr 22, 2026) Salary Guilford Street Laboratories Discussing Products? NO, presenter will NOT present educational content related to products/services of the ineligible company(ies) listed above. Conflict mitigation NOT REQUIRED.

INTRODUCTION:
Hypertrophic cardiomyopathy (HCM) is a cardiac muscle disorder characterized by abnormal enlargement of heart muscle cells, leading to thickening of the ventricular walls and impaired cardiac function. It is the most common inherited cardiac disease, with a prevalence of approximately 1 in 500 individuals, and is one of the leading causes of sudden cardiac death in young people.

There is no clinically available blood test for HCM. Diagnosis and monitoring rely largely on cardiac imaging and genetic testing which are limited and costly. The need for faster, cheaper monitoring has increased due to the introduction of treatment for HCM in 2022. We developed a multiplex targeted proteomic blood biomarker assay, which has been validated in 3 separate adult and paediatric patient cohorts with 85% accuracy. We describe here evaluation of the test against a different mechanistic form of cardiomyopathy caused by Fabry disease an inherited metabolic disorder and development of the assay towards clinical application with improvements to increase diagnostic accuracy.

OBJECTIVES:
To improve accuracy and assess disease specificity of the assay originally described by Captur et al. (2020) for its suitability diagnosing patients with HCM and potentially monitoring treatment.

METHODS:
The existing assay, based on precipitation of 30 µL of plasma, was further optimised to include standardisation using a custom-synthesised internal standard. Protein origin was confirmed using recombinant protein external standards and correlation with secondary peptides. New proteins were added to the panel[JF1.1], and each peptide was assessed for linearity, sensitivity, and variability. The effects of varying haematocrit levels, lipaemia, and repeated freeze–thaw cycles were also evaluated.

Digests were analysed using a 50 mm C18 column with a 12-minute gradient and a Multiple Reaction Monitoring (MRM) LC–MS/MS method. Peptide data were integrated and quality-checked, and a machine learning model was applied to classify disease status. To assess disease specificity, a cohort of confirmed apical HCM (n = 43), Fabry disease patients with left ventricular hypertrophy (LVH) (n = 144), and healthy volunteer samples (n=81) were compared.
In a second stage, 100 obstructive HCM plasma samples and 92 healthy volunteers were assessed using the improved panel.

RESULTS:
Comparison with Fabry LVH samples showed that the sarcomercic HCM protein signature was not detected, thereby confirming specificity of the assay towards sarcomeric HCM. Improved sensitivity was achieved with an optimal plasma volume of 20 µL, which was confirmed to be within the linear range. Correlation[JF2.1] between peptides for the same protein was confirmed by a Pearson’s r>0.75 A modified machine learning model incorporating new biomarkers was developed for disease prediction. Analysis using the improved assay on the obstructive HCM cohort demonstrated considerable increase in the test accuracy.

CONCLUSION:
An improved version of the multiplex targeted proteomic plasma assay for detecting HCM was developed, demonstrating an important increase in accuracy compared to the original. The test proved to be specific for HCM when compared to a different form of cardiomyopathy in Fabry disease patients. The assay has now reached a stage where it could potentially be used for treatment monitoring, which represents an important and promising next step toward clinical application.

REFERENCES:
1. Captur G, et al. Identification of a multiplex biomarker panel for hypertrophic cardiomyopathy using quantitative proteomics and machine learning. Molecular & Cellular Proteomics. 2020;19(1). doi:10.1074/mcp.RA119.001586.
2. Captur G, et al. Novel multiplexed plasma biomarker panel has diagnostic and prognostic potential in children with hypertrophic cardiomyopathy. Circulation: Genomic and Precision Medicine. 2024;17:e004448. doi:10.1161/CIRCGEN.123.004448.