In addition, in a mouse model of Sanfilippo syndrome, in which HS accumulates as a result of the defects of an HS-degrading enzyme, HS from the cerebral cortex of mutant mice showed enhanced ability to increase the AMPA receptor GluA2 subunit on the cell surface (Dwyer et al., 2017). This evidence concerns the gene GRIA2 and mucopolysaccharidosis type 3.