The Down syndrome brain in the presence and absence of fibrillar β–amyloidosis

Publication date: Available online 17 January 2017
Source:Neurobiology of Aging
Author(s): Tiina Annus, Liam R. Wilson, Julio Acosta-Cabronero, Arturo Cardenas-Blanco, Young T. Hong, Tim D. Fryer, Jonathan P. Coles, David K. Menon, Shahid H. Zaman, Anthony J. Holland, Peter J. Nestor
People with Down syndrome (DS) have a neurodevelopmentally distinct brain and invariably develop amyloid neuropathology by age 50. This cross-sectional study aimed to provide a detailed account of DS brain morphology and the changes occuring with amyloid neuropathology. Forty-six adults with DS underwent structural and amyloid imaging—the latter using Pittsburgh Compound–B (PIB) to stratify the cohort into PIB–positive (n=19) and PIB–negative (n=27). Age-matched controls (n=30) underwent structural imaging. Group differences in deep grey matter volumetry and cortical thickness were studied. PIB-negative people with DS have neurodevelopmentally atypical brain, characterised by disproportionately thicker frontal and occipitoparietal cortex and thinner motor cortex and temporal pole with larger putamina and smaller hippocampi than controls. In the presence of amyloid neuropathology, the DS brains demonstrated a strikingly similar pattern of posterior dominant cortical thinning and subcortical atrophy in the hippocampus, thalamus and the striatum, to that observed in non-DS Alzheimer's disease. Care must be taken to avoid underestimating amyloid–associated morphological changes in DS due to disproportionate size of some subcortical structures and thickness of the cortex.



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