Chondroitin 4- and 6-sulfaturia in Morquio-Ullrich's syndrome

Abstract

The urinary acid mucopolysaccharide-peptide complexes were analyzed from a child with the clinical characteristics of Morquio-Ullrich's syndrome. The child excreted increased quantities of chondroitin 4-sulfates and chondroitin 6-sulfates. Dermatan sulfate concentration was only slightly elevated while keratan sulfate excretion was normal. The major urinary acid mucopolysaccharides were fractionated from 20–60% ethanol as calcium salts and showed identical migrations on electrophoresis as chondroitin4/6-sulfate isolated from normal tissue and urine. However, enzymatic digestion with either testicular hyaluronidase or chondroitinase AC from Proteus vulgaris showed that over 30% of this fraction was resistant to the enzymes. Amino acid analyses of the peptide core of the chondroitin4/6-sulfates showed the total amino acid content to be low in comparison to normal urinary chondroitin4/6-sulfate, with serine as the predominant amino acid. This pattern of a smaller peptide core with a predominance of serine is similar to the composition of dermatan sulfate-peptides isolated from Hurler's urine and, together with hybrid structure in uronic acid composition, suggests that the primary defect in a number of genetic mucopolysaccharidoses may be related to both the formation of the peptide core and the acid mucopolysaccharide chain.