Hurler's, Hunter's and Morquio's syndromes. A biochemical study in the light of current views of the underlying defects

Abstract

Glycosaminoglycans were isolated from the urine of three patients with Hurler's, Hunter's and Morquio's syndromes and also from the liver and spleen of the case of Hurler's syndrome by a procedure avoiding further degradation. A method of determining the proportions of dermatan sulphate, heparan sulphate and chondroitin sulphate in each preparation is described. The relative proportions of these glycosaminoglycans in the urine and organs of the case of Hurler's syndrome were very similar. Glycosaminoglycans from the organs were of much lower molecular weight than normal, consisting of single chains of molecular weight about 5000 together with multiples of up to four such chains attached to peptide moieties. The linkage region normally attaching glycosaminoglycan chains to protein in whole protein–polysaccharides of connective tissue was degraded progressively towards serine. The total output and relative proportions of abnormal glycosaminoglycans in the urine were compared in two brothers with Hunter's syndrome examined on two occasions 4 years apart. At comparable ages they excreted about the same amount, and the relative proportions of each glycosaminoglycan remained essentially constant. The composition and chromatographic behaviour of the glycosaminoglycan in the urine from the case of Morquio's syndrome indicated that it consisted of material containing about one-third keratan sulphate and two-thirds chondroitin sulphate as part of the same molecule, as in proteoglycans of cartilage. The total output of glycosaminoglycans, although higher than normal, was considerably less than in other types of Mucopolysaccharidoses.