Genetic defects in proteoglycan biosynthesis.

An overview on the structure of proteoglycans and on genetic defects in proteoglycan biosynthesis is given. Several patients with progeroid-like symptoms have been shown to have abnormalities in the biosynthesis of chondroitin/dermatan sulfate proteoglycans. A partial inactivity of galactosyltransferase I which catalyzes the second glycosyl transfer reaction in the assembly of glycosaminoglycan chains has been shown to represent the primary defect in one of the patients. A diminished concentration of a collagen-associated proteoglycan is considered to play a pathogenetic role in the development of loose skin.