Brown, Ethan G.Chahine, Lana M.Siderowf, AndrewGochanour, CarolineKurth, RyanMarshall, Micah J.Caspell-Garcia, ChelseaBrumm, Michael C.Stanley, Craig E., Jr.Korell, MonicaMcMahon, BridgetKuhl, MaggieFabrizio, KimberlyHeathers, LauraConcha-Marambio, LuisSoto, ClaudioChowdhury, SohiniCoffey, Christopher S.Foroud, Tatiana M.Simuni, TanyaMarek, KennethTanner, Caroline M.Parkinson Progression Marker Initiative2025-04-182025-04-182025Brown EG, Chahine LM, Siderowf A, et al. Staged Screening Identifies People with Biomarkers Related to Neuronal Alpha-Synuclein Disease. Ann Neurol. 2025;97(4):730-740. doi:10.1002/ana.27158https://hdl.handle.net/1805/47152Objective: Remote identification of individuals with severe hyposmia may enable scalable recruitment of participants with underlying alpha-synuclein aggregation. We evaluated the performance of a staged screening paradigm using remote smell testing to enrich for abnormal dopamine transporter single-photon emission computed tomography imaging (DAT-SPECT) and alpha-synuclein aggregation. Methods: The Parkinson's Progression Markers Initiative (PPMI) recruited participants for the prodromal cohort who were 60-years and older without a Parkinson's disease diagnosis. Participants were invited to complete a University of Pennsylvania Smell Identification Test (UPSIT) independently through an online portal. Hyposmic participants were invited to complete DAT-SPECT, which determined eligibility for enrollment in longitudinal assessments and further biomarker evaluation including cerebrospinal fluid alpha-synuclein seed amplification assay (aSynSAA). Results: As of January 29, 2024, 49,843 participants were sent an UPSIT and 31,293 (63%) completed it. Of UPSIT completers, 8,301 (27%) scored <15th percentile. Of 1,546 who completed DAT-SPECT, 1,060 (69%) had DAT-SPECT binding <100% expected for age and sex. Participants with an UPSIT <10th percentile (n = 1,221) had greater likelihood of low DAT-SPECT binding compared to participants with an UPSIT in the 10th to 15th percentile (odds ratio, 3.01; 95% confidence interval, 1.85-4.91). Overall, 55% (198/363) of cases with UPSIT <15th percentile and DAT-SPECT <100% had positive aSynSAA, which increased to 70% (182/260) when selecting for more severe hyposmia (UPSIT <10th percentile). Interpretation: Remote screening for hyposmia and reduced DAT-SPECT binding identifies participants with a high proportion positive aSynSAA. Longitudinal data will be essential to define progression patterns in these individuals to ultimately inform recruitment into disease modification clinical trials.en-USAttribution-NonCommercial 4.0 InternationalParkinson diseaseDopamine plasma membrane transport proteinsSynucleinopathiesOlfaction disordersArticle