MAPT and tauopathy: Interestingly, although there is few information about GAGs expression in the healthy brain and about their differential expression in different brain areas, it has been shown that the AD brain accumulates highly sulfated GAGs in regions affected by the tauopathy, as cortex and hippocampus [24, 25, 26], and not in cerebellum [31], a brain region not affected by the tau pathology in AD.