Consistency of Serial Cerebrospinal Fluid α-Synuclein Seed Amplification Assay Results in the Parkinson's Precision Medicine Initiative.

Authors

David G Coughlin, Caroline Gochanour, Jie Yin, Luis Concha-Marambio, Carly Farris, Yihua Ma, David-Erick Lafontant, Edwin Jabbari, Tanya Simuni, Ken Marek, Thomas F Tropea, Parkinson's Precision Medicine Initiative

Published in

Movement disorders : official journal of the Movement Disorder Society. Oct 12, 2026. Epub Oct 12, 2026.

Abstract

Studies reporting α-synuclein seed amplification assay (aSyn-SAA) results are often cross-sectional.
In this study, we investigated the intraindividual consistency of aSyn-SAA results (Amprion) over time from participants in the Parkinson's Precision Medicine Initiative (PPMI).
A total of 1238 participants had >1 cerebrospinal fluid (CSF) aSyn-SAA result for analysis (Parkinson's disease [PD] = 633, prodromal = 563, healthy control [HC] = 42), collected over a median (minimum, maximum) of 2.0 (0.4, 11.4) years. Emphasis was placed on evaluating consistency in aSyn-SAA-PD participants, aSyn-SAA + HC participants, and conversion rates from aSyn-SAA negative to positive results prodromal participants.
Of aSyn-SAA + PD participants, 96% (474/493, 95% confidence interval [CI]: 94%-98%) remained positive in subsequent samples, and 92% (116/126, 95% CI: 86%-96%) of aSyn-SAA-PD participants remained negative. Ninety-nine percent (303/307, 95% CI: 97%-99%) of aSyn-SAA + prodromal participants remained positive, and 95% (234/247, 95% CI: 91%-97%) of aSyn-SAA-prodromal participants remained negative. Eighty-nine percent (16/18, 95% CI: 67%-97%) of aSyn-SAA + HC participants remained positive, and 87% (20/23, 95% CI: 68%-95%) of aSyn-SAA-HC participants remained negative.
aSyn-SAA testing is highly consistent over time, even in less expected scenarios. © 2026 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

PMID:
42865036
Bibliographic data and abstract were imported from PubMed on 13 Oct 2026.

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