RELN and Alzheimer disease: While a recent review detailing PNN changes in AD found that a majority of PNN components are upregulated in AD (HA, HSPGs, CSPGs, DSPGs, TNC, and TNR) with two components decreased (reelin and keratin sulfate proteoglycans; Sun et al., 2021), Bruckner and colleagues showed no change in fluorescent intensity using pan-Anti-CSPG antibody in AD frontal and temporal sections compared to controls (ntotal = 12; Brückner et al., 1999).