Literature collection of the CovAmInf workgroup.
Editors Joshua T. Berryman Abdul Mannan Baig Artemi Bendandi Daniel Bonhenry Mattheos A.G. Koffas
Alpha-synuclein seeds in olfactory mucosa of patients with isolated REM sleep behaviour disorder (2021)
Ambra Stefani, Alex Iranzo, Evi Holzknecht, Daniela Perra, Matilde Bongianni, Carles Gaig, Beatrice Heim, Monica Serradell, Luca Sacchetto, Alicia Garrido, Stefano Capaldi, Almudena Sánchez-Gómez, Maria Paola Cecchini, Sara Mariotto, Sergio Ferrari, Michele Fiorini, Joachim Schmutzhard, Pietro Cocchiara, Isabel Vilaseca, Lorenzo Brozzetti, Salvatore Monaco, M Jose Marti, Klaus Seppi, Eduardo Tolosa, Joan Santamaria, Birgit Högl, Werner Poewe, Gianluigi Zanusso
DOI: 10.1093/brain/awab005 PubMed: 33855335
Over 80% of patients with isolated REM sleep behavior disorder (RBD) will subsequently convert to Parkinson’s disease, Lewy body dementia or multiple system atrophy within 10-15 years. RBD is therefore considered to be an early warning sign of neurodegenerative disease affecting the central nervous system. RBD is characterized in part by the presence of alpha-synuclein seeds within the olfactory mucosa which can be detected using an amyloid amplification method called real-time quaking-induced conversion (RT-QuIC). The study included 163 participants: 63 with RBD, 41 with Parkinson’s disease and 59 healthy controls. Alpha-synuclein RT-QuIC was positive for 47.6% in RBD, 61% in Parkinson’s disease and 10.2% controls. The overall sensitivity and specificity was 45.2% and 89.8%. Patients with RBD and olfactory dysfunction were more likely to test positive.
A separate study demonstrated an increase in sensitivity of the RT-QuIC assay from 45% to 84% by modifying the sampling technique in patients with Parkinson’s disease (https://doi.org/10.1186/s40035-022-00311-3).
The University of Innsbruck in Austria is conducting a clinical trial to screen individuals for alpha-synuclein seeding in the olfactory mucosa following recovery from COVID-19 infection. They will be using RT-QuIC as a diagnostic tool. 200 participants will be enrolled: a group of COVID-19 patients with and without olfactory dysfunction; a group of patients with Parkinson’s disease; and a group of healthy controls. The study will be completed by the end of 2023 (https://clinicaltrials.gov/ct2/show/NCT05401773).