Metabolism of collagen in aspartylglycosaminuria: urinary excretion of hydroxyproline.

Aspartylglycosaminuria (AGU) is a lysosomal storage disorder of glycoprotein degradation characterized by severe mental retardation and connective tissue alterations. We have previously described low collagen production in skin fibroblast cultures from AGU patients. In the present work we showed that the urinary excretion of hydroxyproline (total, non-dialysable and free hydroxyproline as indicators of collagen metabolism) was reduced in young AGU patients in comparison with age-matched controls. In adult patients no significant difference was detected. The results support the view that reduced collagen production is associated with the connective tissue abnormalities in this disorder.