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.

Early Prenatal Diagnosis of Hurler's Syndrome with Termination of Pregnancy and Confirmatory Findings on the Fetus

“…In our case the uronic acid content of the amniotic fluid was 20-5 ,ug/ml, and since glycosaminoglycans normally contain some 30%/ by weight of uronic acid (Olsson, 1969;Dean et al, 1971) this value corresponded to a glycosaminoglycan content of about 60 ,tg/ml. Of this total 78%' was resistant to digestion with hyaluronidase, ie, consisted of dermatan and heparan sulphates, the remainder consisted of hyaluronic acid together with the chondroitin sulphates.…”

“…The cell-free amniotic fluid was dialysed in Visking tubing, previously heated at 95°C to reduce its porosity, for 24 hours against 1 litre of water at 4°C, re-centrifuged, and polyanions precipitated from the clarified supematant solution by dropwise addition of aqueous 9-aminoacridine hydrochloride (saturated at 60°C). After standing overnight at 4°C the precipitate was collected by centrifugation and the glycosaminoglycans converted to their sodium salts by shaking with a suspension of Zeo-Karb 225 (Na + form) and 1 ml of a sodium acetate buffer (Dean, Muir, and Ewins, 1971). The total uronic acid content of the sample was determined (Bitter and Muir, 1962), and the remainder of the material incubated at 370 C for 24 hours with 3000 turbidity reducing units of testicular hyaluronidase (EC 3.2.1.35).…”

“…Glycosaminoglycans were isolated from fetal liver by extraction with 0-2M sodium acetate, pH 6-8, and the proportions of heparan, dermatan, and chondroitin sulphates determined as described by Dean et al (1971). Gel chromatography of a 2 mg sample of glycosaminoglycans isolated from the liver was carried out on a .…”

A review and selection of simple laboratory methods used for the study of glycosaminoglycan excretion and the diagnosis of the mucopolysaccharidoses.

“…Separation of GAG from interfering substances has been achieved in a number of ways. Hexuronic acid may be measured on the dialysed sample directly (Segni et al, 1964;Rosenfeld, 1971) or after a further purification step, such as fractionation on ECTEOLA cellulose columns, which enables sulphated and non-sulphated GAG to be measured separately (Wessler, 1967;Blackham and Raine, 1970), or by precipitation with CTAB or CPC (Thompson and Castor, 1966;Teller et al, 1962) or aminoacridine (Bitter et al, 1970;Dean et al, 1971). CPC and CTAB are poor precipitants of GAG in the absence of salts, and it is preferable to use the method described by Di Ferrante and Rich (1956) in which these agents are added to untreated urine.…”

Enzyme replacement therapy by fibroblast transplantation: long-term biochemical study in three cases of Hunter's syndrome.

“…Glycosaminoglycans were precipitated from 100-to 200-ml aliquots of each urine specimen with 5-aminoacridine HCI (20) converted to their sodium salts by shaking with a suspension of Dowex 50 (Na+ form) reprecipitated in 80% (vol/vol) ethanol, removed by centrifugation, and dried (21). Inorganic sulfate and phosphate were re~- trifugation and the process repeated.…”