Early striatal amyloid deposition distinguishes Down syndrome and autosomal dominant Alzheimer's disease from late-onset amyloid deposition

Introduction: The objective of this study was to evaluate amyloid beta (A beta) deposition patterns in different groups of cerebral beta amyloidosis: (1) nondemented with amyloid precursor protein overproduction (Down syndrome); (2) nondemented with abnormal processing of amyloid precursor protein (preclinical autosomal dominant Alzheimer disease); (3) presumed alteration in A beta clearance with clinical symptoms (late-onset AD); and (4) presumed alterations in A beta clearance (preclinical AD). Methods: We performed whole-brain voxelwise comparison of cerebral A beta between 23 Down syndrome, 10 preclinical autosomal dominant Alzheimer disease, 17 late-onset AD, and 16 preclinical AD subjects, using Pittsburgh Compound B-positron emission tomography. Results: We found both Down syndrome and preclinical autosomal dominant Alzheimer disease shared a distinct pattern of increased bilateral striatal and thalamic A beta deposition compared to late-onset AD and preclinical AD. Conclusion: Disorders associated with early-life alterations in amyloid precursor protein production or processing are associated with a distinct pattern of early striatal fibrillary A beta deposition before significant cognitive impairment. A better understanding of this unique pattern could identify important mechanisms of A beta deposition and possibly important targets for early intervention. (C) 2018 the Alzheimer's Association. Published by Elsevier Inc. All rights reserved.