NCAN and Alzheimer disease: We combine our protein biochemical data with RNAseq data from The Aging, Dementia and TBI Study (http://aging.brain-map.org/; accessed on 5 January 2022) and we also provide measurements of neural proteoglycans brevican and neurocan and their major proteolytic fragments in human AD and control CSF samples to test if ECM changes within the brain parenchyma are reflected by changes in CSF levels.