Aberrant composition of chondroitin sulfates in the cartilage-type proteoglycan isolated from the iliac crest of patients with some lysosomal storage diseases

Abstract

In order to investigate the involvement of cartilage proteoglycans in the pathogenesis of human congenital skeletal disorders, proteoglycans were extracted with 4 M guanidine HCl from the iliac crest cartilage of children with various skeletal diseases; lysosomal storage diseases (group I), osteochondrodysplasias (group II) and controls (group III). The cartilage-type proteoglycan (PG-H) was purified and its chondroitin sulfate moiety was analyzed by digestion with chondroitinase-ABC. In group II and group III, the relative amounts of the unsaturated disaccharide products changed in an age-related manner; decrease (from 50% to 30%) of delta Di-4S with a compensatory increase (from 40% to 60%) of delta Di-6S with increasing age from 0 to 15 years. On the other hand, some cases in group I showed aberrant composition of the disaccharide products; a lower content of delta Di-4S with a correspondingly higher content of delta Di-6S. Patients in group I have clinically similar skeletal disorders, and the extent of the compositional abnormality seems to reflect the severity of the skeletal disorder. Therefore, one may consider that the aberrant composition of the glycosaminoglycans in PG-H is involved in the pathogenesis of the skeletal disorder of lysosomal storage diseases.