Topic overview

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GAGs are long, linear chains of repeating disaccharides, typically containing a hexosamine and a uronic acid. Their negative charge attracts sodium and water, supporting tissue turgor and shock absorption. In proteoglycans, GAG chains attach to a core protein; examples such as aggrecan, decorin, perlecan, and syndecan have distinct connective-tissue or signaling roles. Hyaluronic acid is an important exception: it is unsulfated and not protein-bound. The topic also introduces GAG synthesis and lysosomal breakdown, along with clinical links to mucopolysaccharidoses. Examples include differences between Hurler and Hunter syndromes and the role of heparan sulfate in filtration at the renal glomerulus.