title: The down syndrome biomarker initiative (DSBI) pilot: proof of concept for deep phenotyping of Alzheimer's disease biomarkers in down syndrome.
abstract: To gain further knowledge on the preclinical phase of Alzheimer's disease (AD), we sought to characterize cognitive performance, neuroimaging and plasma-based AD biomarkers in a cohort of non-demented adults with down syndrome (DS). The goal of the down syndrome biomarker Initiative (DSBI) pilot is to test feasibility of this approach for future multicenter studies. We enrolled 12 non-demented participants with DS between the ages of 30-60 years old. Participants underwent extensive cognitive testing, volumetric MRI, amyloid positron emission tomography (PET; 18F-florbetapir), fluorodeoxyglucose (FDG) PET (18F-fluorodeoxyglucose) and retinal amyloid imaging. In addition, plasma beta-amyloid (Aβ) species were measured and Apolipoprotein E (ApoE) genotyping was performed. Results from our multimodal analysis suggest greater hippocampal atrophy with amyloid load. Additionally, we identified an inverse relationship between amyloid load and regional glucose metabolism. Cognitive and functional measures did not correlate with amyloid load in DS but did correlate with regional FDG PET measures. Biomarkers of AD can be readily studied in adults with DS as in other preclinical AD populations. Importantly, all subjects in this feasibility study were able to complete all test procedures. The data indicate that a large, multicenter longitudinal study is feasible to better understand the trajectories of AD biomarkers in this enriched population. This trial is registered with ClinicalTrials.gov, number NCT02141971.
authors.affiliation: Alzheimer's Disease Cooperative Study, Department of Neurosciences, UC San Diego School of Medicine, University of California, San Diego La Jolla, CA, USA.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Rafii
authors.affiliation: Alzheimer's Disease Cooperative Study, Department of Neurosciences, UC San Diego School of Medicine, University of California, San Diego La Jolla, CA, USA.
authors.forename: Hannah
authors.initials: H
authors.lastname: Wishnek
authors.affiliation: Alzheimer's Disease Cooperative Study, Department of Neurosciences, UC San Diego School of Medicine, University of California, San Diego La Jolla, CA, USA.
authors.forename: James B
authors.initials: JB
authors.lastname: Brewer
authors.affiliation: Department of Neurology, University of Southern California Los Angeles, CA, USA.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Donohue
authors.affiliation: Janssen Research and Development LLC Titusville, NJ, USA.
authors.forename: Seth
authors.initials: S
authors.lastname: Ness
authors.affiliation: Alzheimer's Disease Cooperative Study, Department of Neurosciences, UC San Diego School of Medicine, University of California, San Diego La Jolla, CA, USA.
authors.forename: William C
authors.initials: WC
authors.lastname: Mobley
authors.affiliation: Department of Neurology, University of Southern California Los Angeles, CA, USA.
authors.forename: Paul S
authors.initials: PS
authors.lastname: Aisen
authors.affiliation: Alzheimer's Disease Cooperative Study, Department of Neurosciences, UC San Diego School of Medicine, University of California, San Diego La Jolla, CA, USA.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Rissman
keywords: Alzheimer’s disease; MRI; PET; amyloid; biomarkers; down syndrome; plasma; retinal