MMP2 and mucopolysaccharidosis: Some examples of underexpressed genes are B3GNT8 (encodes for β-1,3-N acetylglucosaminotransferase 8, important for N-linked glycosylation, an enzyme regulating MMP2 and TIMP2), SGSH (encodes N-sulfoglucosamine sulfohydrolase, an enzyme degrading heparin sulfate, and likely playing a role in mucopolysaccharidoses, at least in people), GLT8D2 (encoding glycosyltransferase 8 domain 2), and B3GALT2 (beta-1-3-galactosyltransferase 2).