Consistent with these immunostaining and biochemical analyses, the transcripts of several HS-related genes were up-regulated in the AD brain, including Hs3st2 in Sepulveda-Diaz, J.E. et al. study [110], Ndst2, Hs3st2, Hs3st4 and Glce in Huynh et al. study, [92], Hspe and Hspe2 in Garcia et al. study [140], and Extl3, Hs6st1, Hs3st1, Hs3st2, Hs3st3A1, Hs3stB1, Hs6st5 and Hs6st6 in severe AD in Pérez-López et al. study [139], and down-regulated, including HS 6-O-endosulfatase-2 (Sulf2) in Roberts et al. study [138] and Sepulveda-Diaz, J.E. et al. study [110]. Here, HS3ST4 is linked to Alzheimer disease.