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Bernsen PL, Wevers RA, Gabreëls FJ, Lamers KJ, Sonnen AE, Stekhoven JH. Phenotypic expression in mucopolysaccharidosis VII. J Neurol Neurosurg Psychiatry 1987; 50:699-703. [PMID: 3112309 PMCID: PMC1032073 DOI: 10.1136/jnnp.50.6.699] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
beta-glucuronidase deficiency is an extremely rare disorder which is known to have a considerable phenotypic variation. A survey of the clinical findings in 19 previously reported patients with mucopolysaccharidosis VII is presented together with the results of clinical and biochemical studies in two further patients. Because a similar clinical picture is present in a heterozygotic sister it is doubted whether all signs and symptoms can be attributed to the beta-glucuronidase deficiency. The probability of a concomitant disorder is discussed. Diagnosis was made both by demonstration of the deficiency in plasma and leucocytes, and by means of hair root analysis. The phenotypic variation and the fact that increased levels of glycosaminoglycans were not found in the urine of the two patients lead to the suggestion that in certain cases a correct diagnosis may be missed if the beta-glucuronidase activity in plasma and leucocytes is not determined and only routine urine investigation is performed as a screening for a mucopolysaccharidosis. Hair root analysis may be a useful method to measure the beta-glucuronidase activity.
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Burch M, Fensom AH, Jackson M, Pitts-Tucker T, Congdon PJ. Multiple sulphatase deficiency presenting at birth. Clin Genet 1986; 30:409-15. [PMID: 3100114 DOI: 10.1111/j.1399-0004.1986.tb01899.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A new case of multiple sulphatase deficiency with onset at birth is described. The patient had many dysmorphic features and hydrocephalus, similar to one other case with early onset described in the literature. The new patient differed from the other case in having chondrocalcificans congenita, heart abnormalities and an abnormal fold of tissue present between the laryngeal inlet and the oesophagus. Excessive mucopolysacchariduria was present and there was profound deficiency of all sulphatases examined in plasma, leucocytes and cultured skin fibroblasts.
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Abstract
Acetyl-CoA:alpha-glucosaminide N-acetyltransferase is a lysosomal-membrane enzyme deficient in a genetic disorder, Sanfilippo disease type C. The enzyme catalyzes the transfer of an acetyl group from cytoplasmic acetyl-coenzyme A (acetyl-CoA) to terminal alpha-glucosamine residues of heparan sulfate within the organelle. Previous kinetic experiments indicated that the enzyme carries out a transmembrane acetylation via a ping-pong mechanism; the reaction can therefore be dissected into two half reactions--acetylation of the enzyme, and transfer of the acetyl group to glucosamine. Cells derived from patients were found to differ in their ability to perform each half reaction. Five cell lines (derived from three families) were able to catalyze acetylation of the lysosomal membrane and to carry out acetyl-CoA/CoA exchange, whereas a sixth cell line was devoid of this activity.
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Abstract
The Sanfilippo A syndrome is characterized by a deficiency in heparin sulfamidase, which removes the N-sulfate groups of heparan sulfate and heparin in the course of normal catabolism of these polysaccharides. [N-35S]Heparin is the most commonly used substrate for the assay of sulfamidase activity but has certain disadvantages which have prompted us to search for alternative substrates. We report here on the use of heparin oligosaccharides for this purpose. The trisaccharide, GlcN-IdoUA-GlcN, and the pentasaccharide, GlcN-GlcUA-GlcN-GlcUA-GlcN, were N-sulfated with [35S]sulfur trioxide-trimethylamine complex; the tetrasaccharide, GlcN-UA-GlcN-UA, and the pentasaccharide, GlcN-IdoUA-GlcN-IdoUA-GlcN, were labeled by reduction with sodium borotritide followed by chemical N-sulfation. When incubated with sonicates of cultured skin fibroblasts from normal individuals, all four oligosaccharides were found to serve as substrates for heparin sulfamidase. Fibroblast sonicates from patients with the Sanfilippo A syndrome had little or no activity toward these substrates. Optimal activity of the enzyme was at pH 4.4-4.5. Comparison of the kinetic parameters showed that heparin had a lower Km than the oligosaccharides, whereas the Vmax values of the latter were higher than for heparin.
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Wassman ER. Variation in neuronal storage in alpha-L-iduronidase deficiency. AMERICAN JOURNAL OF MEDICAL GENETICS 1985; 22:827-9. [PMID: 3934972 DOI: 10.1002/ajmg.1320220418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Wehnert M, Machill G, Petruschka L. Genetic complementation analysis in somatic cell hybrids of alpha-L-iduronidase deficient cells. Hum Genet 1985; 69:287. [PMID: 3920140 DOI: 10.1007/bf00293044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Guise KS, Korneluk RG, Waye J, Lamhonwah AM, Quan F, Palmer R, Ganschow RE, Sly WS, Gravel RA. Isolation and expression in Escherichia coli of a cDNA clone encoding human beta-glucuronidase. Gene 1985; 34:105-10. [PMID: 3924735 DOI: 10.1016/0378-1119(85)90300-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Mucopolysaccharidosis type VII is a lysosomal storage disease resulting from a deficiency of beta-glucuronidase (BG) activity. To facilitate the investigation of mutation in the disease and provide molecular diagnostic tools for affected families, we have isolated human BG cDNA clones. The SV40-transformed human fibroblast cDNA library of Okayama and Berg [Mol. Cell. Biol. 3 (1982) 280-289] was screened with a fragment of a murine BG cDNA clone (pGUS-1). The 17 human cDNA clones (pHUG) isolated were identical by restriction mapping, varying only in length. The pHUG clones show 80% DNA sequence homology with pGUS-1 in a 198-bp PvuII-SstI restriction fragment. Both pGUS-1 and the pHUG clones contained an open reading frame (ORF) throughout the sequenced region with a predicted amino acid sequence homology of 73%. Expression in Escherichia coli of a 1150-bp fragment of pHUG-1 subcloned in pUC9 resulted in an isopropyl-thio-beta-galactoside (IPTG)-inducible 35-kDal fusion protein which was specifically immunoprecipitated by goat anti-human BG immunoglobulin G (IgG). This evidence provides direct confirmation that the pHUG cDNA clones correspond to human BG.
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Lee JE, Falk RE, Ng WG, Donnell GN. Beta-glucuronidase deficiency. A heterogeneous mucopolysaccharidosis. AMERICAN JOURNAL OF DISEASES OF CHILDREN (1960) 1985; 139:57-9. [PMID: 3155909 DOI: 10.1001/archpedi.1985.02140030059029] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
We studied two cases of beta-glucuronidase deficiency. One patient's disease was present at birth and the other patient's disease appeared in early childhood. The symptoms observed in both patients, although of differing severity, included peculiar facies, cloudy cornea, hepatosplenomegaly, hernia, kyphosis, recurrent infections, short stature, and developmental delay, as well as increased excretion of urinary chondroitin sulfate A/C and decreased levels of beta-glucuronidase activity. We reviewed all of the reported cases and examined the biochemical and clinical heterogeneity observed in this disorder.
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Haskins ME, Desnick RJ, DiFerrante N, Jezyk PF, Patterson DF. Beta-glucuronidase deficiency in a dog: a model of human mucopolysaccharidosis VII. Pediatr Res 1984; 18:980-4. [PMID: 6436780 DOI: 10.1203/00006450-198410000-00014] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
This report describes a third mucopolysaccharidosis in animals: canine mucopolysaccharidosis VII. The affected dog was the offspring of a father-daughter mating. Weakness in the rear legs was evident at 8 weeks of age and became progressively worse. He had a large head, a shortened maxilla, and corneal granularities. Most joints were extremely lax, easily subluxated, with joint capsules that were swollen and fluctuant. The dog was alert and had apparently normal pain perception. At 13 months of age, there was radiographic evidence of extensive skeletal disease including bilateral femoral head luxation, abnormalities in the shape and density of the carpal and tarsal bones, radiolucent lesions of the epiphyseal regions of most long bones, and cervical vertebral dysplasia and platyspondylia. The electrophoretic pattern of precipitated glycosaminoglycans indicated a predominance of chondroitin sulfate. The animal died suddenly from gastric dilatation. There was generalized hepatomegaly, thickening of the atrioventricular heart valves, and generalized polyarthropathy. Vacuolated cytoplasm was observed in hepatocytes, keratocytes, fibroblasts, chondrocytes and cells of the synovial membrane, retinal pigment epithelium, and cardiac valves. Neurons had cytoplasmic vacuoles. Electron microscopy demonstrated membrane-bound cytoplasmic inclusions in polymorphonuclear leukocytes, hepatocytes, synovium, heart valves and spleen. The activities of 12 lysosomal hydrolases were determined in liver from the affected and control dogs: beta-glucuronidase (EC 3.2.1.31), beta-hexosaminidases A and B (EC 3.2.1.30), alpha-hexosaminidase (EC 3.2.1.-), alpha-L-iduronidase (EC 3.2.1.76), alpha-galactosidase A (EC 3.2.1.22), beta-galactosidase (EC 3.2.1.23), arylsulfatases A and B (EC 3.1.6.1), acid alpha-mannosidase (EC 3.2.1.24), acid beta-mannosidase (EC 3.2.1.25), and N-acetyl-D-galactosamine-6-sulfate sulfatase (EC 3.1.6.-).(ABSTRACT TRUNCATED AT 250 WORDS)
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Adinolfi M, Brown S. Strategies for the correction of enzymatic deficiencies in patients with mucopoly saccharidoses. Dev Med Child Neurol 1984; 26:404-8. [PMID: 6428954 DOI: 10.1111/j.1469-8749.1984.tb04461.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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62
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Ballabio A, Pallini R, Di Natale P. Mucopolysaccharidosis III B: hybridization studies on fibroblasts from a mild case and fibroblasts from severe patients. Clin Genet 1984; 25:191-5. [PMID: 6231143 DOI: 10.1111/j.1399-0004.1984.tb00484.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Cell fusion with polyethylene glycol (PEG) was performed on fibroblasts from a previously studied patient with a mild form of Sanfilippo B disease and altered residual enzyme activity and fibroblasts from several patients with the classical, severe form of the disease. No complementation was found in heterokaryons. This suggests that the mild phenotype in our patient can be ascribed to an allelic mutation.
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von Figura K, Hasilik A, Steckel F, van de Kamp J. Biosynthesis and maturation of alpha-N-acetylglucosaminidase in normal and Sanfilippo B-fibroblasts. Am J Hum Genet 1984; 36:93-100. [PMID: 6421152 PMCID: PMC1684371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The biosynthesis of alpha-N-acetylglucosaminidase in normal and Sanfilippo B fibroblasts was studied by labeling cells with [35S]methionine and isolation of the enzyme by immunoprecipitation. The immunoprecipitated polypeptides were separated by polyacrylamide gel electrophoresis and visualized by fluorography. alpha-N-acetylglucosaminidase is synthesized as a precursor of an apparent mol. wt. of 87,000. Intracellular processing of the precursor yields two polypeptides of apparent mol. wts. of 73,000 and 76,000 via several intermediates. It is accomplished within 3 days after synthesis. Less than 30% of the newly synthesized precursor is secreted. In the presence of 10 mM NH4Cl, secretion is enhanced to more than 80%. In our study, no alpha-N-acetylglucosaminidase polypeptides could be detected in fibroblasts from patients affected with either the severe or mild form of Sanfilippo disease, type B.
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Baumkötter J, Cantz M. Decreased ganglioside neuraminidase activity in fibroblasts from mucopolysaccharidosis patients. Inhibition of the activity in vitro by sulfated glycosaminoglycans and other compounds. BIOCHIMICA ET BIOPHYSICA ACTA 1983; 761:163-70. [PMID: 6418214 DOI: 10.1016/0304-4165(83)90225-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The neuraminidase activities towards the ganglioside substrates GD1a, GD3 and GM3 were found to be markedly diminished in homogenates of fibroblasts cultured from patients with various genetic mucopolysaccharidoses. Mixing normal and patients' fibroblast homogenates revealed this effect to be due to the presence of diffusible inhibitors. The neuraminidase acting on the trisaccharide sialyllactose, on the other hand, showed normal activity in all the cell lines tested. Experiments in vitro revealed the sulfated glycosaminoglycans chondroitin 4-sulfate and heparin, the polysaccharide dextran sulfate, and the trypanocidal drug suramin to be strongly inhibitory on the ganglioside GD1a neuraminidase activity of normal fibroblast homogenates. Regarding chondroitin 4-sulfate, this inhibition was of the non-competitive type. A disulfated tetrasaccharide prepared from chondroitin 4-sulfate, on the other hand, was not at all inhibitory. These and additional findings led us to propose a model for the interaction between enzyme and inhibitor, involving a 'clamping' mechanism by the polysulfated compounds. We conclude that the decreased ganglioside neuraminidase activities of mucopolysaccharidosis fibroblasts are due to an inhibition by the accumulated sulfated glycosaminoglycans and that such inhibition is responsible for the storage of certain gangliosides in the tissues of the patients.
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65
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Neufeld EF. The William Allan Memorial Award address: cell mixing and its sequelae. Am J Hum Genet 1983; 35:1081-5. [PMID: 6417999 PMCID: PMC1685960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
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66
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Hopwood JJ, Muller VJ. Selective depolymerisation of dermatan sulfate: production of radiolabelled substrates for alpha-L-iduronidase, sulfoiduronate sulfatase, and beta-D-glucuronidase. Carbohydr Res 1983; 122:227-39. [PMID: 6423280 DOI: 10.1016/0008-6215(83)88334-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Radiolabelled disaccharide substrates for alpha-L-iduronidase, beta-D-glucuronidase, and sulfoiduronate sulfatase have been prepared from dermatan sulfate by application in sequence of N-deacetylation, deaminative cleavage, and reduction with NaBT4. The yield of disaccharides was approximately 87% of the total oligosaccharide fraction. Five disaccharides were isolated and tentatively identified. The major disaccharide, O-(alpha-L-idopyranosyluronic acid)-(1 leads to 3)-2,5-anhydro-D-[1-3H]talitol 4-sulfate (IdoA-anT4S), represented approximately 75% of the total disaccharide fraction. The other disaccharides were O-(alpha-L-idopyranosyluronic acid 2-sulfate)-(1 leads to 3)-2,5-anhydro-D-[1-3H]talitol 4-sulfate (IdoA2S-anT4S), O-(beta-D-glucopyranosyluronic acid)-(1 leads to 3)-2,5-anhydro-D-[1-3H]talitol 4-sulfate (GlcA-anT4S), O-(beta-D-glucopyranosyluronic acid)-(1 leads to 3)-2,5-anhydro-D-[1-3H]talitol 6-sulfate (GlcA-anT6S), and O-(alpha-L-idopyranosyluronic acid)-(1 leads to 3)-2,5-anhydro-D-[1-3H]talitol (IdoA-anT), which represented approximately 4.5, 11.2, 1.0, and 1.8%, respectively, of the total disaccharide fraction. When incubated with cultured skin-fibroblasts from normal controls, IdoA-anT4S was shown to be a sensitive substrate for alpha-L-iduronidase to produce 2,5-anhydro-D-talitol 4-sulfate (anT4S). Activity toward IdoA-anT4S was not observed with fibroblast homogenates from alpha-L-iduronidase-deficient patients (Mucopolysaccharidosis Type I). Similarly, normal-fibroblast homogenates degraded GlcA-anT6S to anT6S, and GlcA-anT4S to anT4S, at a rate 6 to 8 times greater than found for fibroblasts from beta-D-glucuronidase-deficient patients (Mucopolysaccharidosis Type VII). IdoA-anT4S was hydrolysed by alpha-L-iduronidase at a rate 365 times greater than that for IdoA-anT. Sulfation of the anhydro-D-[1-3H]talitol residues is an important structural determinant in the mechanism of action of alpha-L-iduronidase on disaccharide substrates. IdoA2S-anT4S was degraded to IdoA-anT4S and then to anT4S by normal-fibroblast homogenates, whereas fibroblasts from alpha-L-iduronidase-deficient and sulfoiduronate sulfatase-deficient (Mucopolysaccharidosis Type II) patients produced considerably decreased levels of anT4s and IdoA-anT4S (and anT4S), respectively.
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Crow J, Gibbs DA, Cozens W, Spellacy E, Watts RW. Biochemical and histopathological studies on patients with mucopolysaccharidoses, two of whom had been treated by fibroblast transplantation. J Clin Pathol 1983; 36:415-30. [PMID: 6403596 PMCID: PMC498237 DOI: 10.1136/jcp.36.4.415] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Biochemical and pathological observations on tissues from two patients with Hurler disease (mucopolysaccharidosis IH; alpha-L-iduronidase deficiency) who had been treated by fibroblast transplants as a means of enzyme replacement treatment are reported. These results and those obtained in three surgical specimens [ligamentum flavum with dura mater from a case of Scheie disease (mucopolysaccharidosis IS; alpha-L-iduronidase deficiency); a fetus with Hurler disease; and tonsil from a patient with Hunter disease (mucopolysaccharidosis II; alpha-L-idurono-2-sulphate sulphatase deficiency)] illustrate the inadequacy of routine histological processing to demonstrate the abnormal glycosaminoglycan accumulation in this group of diseases. A combined approach using histochemistry and electron microscopy enables the extent of both extracellular and intracellular involvement to be assessed. The fetus (20 wk gestation) already showed evidence of Hurler disease. The pathological appearances in both of the fibroblast-transplanted patients were those which would have been expected in patients dying with unmodified Hurler disease. There was no detectable alpha-L-iduronidase activity in the brain, liver, kidney or in fibroblasts cultured from either the transplantation sites or from remote subcutaneous sites in either of the transplanted patients. These results are discussed from the viewpoint of their bearing on the pathophysiology of the mucopolysaccharidoses and proposals for their treatment by enzyme replacement.
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Muller VJ, Hopwood JJ. Radiolabelled disaccharides for the assay of beta-D-glucuronidase activity and the detection of mucopolysaccharidosis type VII. Clin Chim Acta 1982; 123:357-60. [PMID: 6811165 DOI: 10.1016/0009-8981(82)90182-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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69
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Fluharty AL. The mucopolysaccharidoses: a synergism between clinical and basic investigation. J Invest Dermatol 1982; 79 Suppl 1:38s-44s. [PMID: 6806398 DOI: 10.1111/1523-1747.ep12545724] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The mucopolysaccharidoses are a family of genetic diseases involving faulty degradation of one or more type of mucopolysaccharide or glycosaminoglycan. These conditions are characterized by skeletal, connective tissue, and intellectual manifestations. Biochemical investigations over the past 10-20 yr have enhanced our understanding of the clinical conditions and advanced our knowledge of catabolic pathways for complex biological structures. Identification of stored and excreted materials as partially degraded glycosaminoglycans allowed classification of these conditions on clinical and chemical criteria. The development of a cell culture model for studying the mucopolysaccharidoses lead to the identification of a variety of lysosomal sulfatases and glycosidases as deficient enzymes. This stimulated the identification of several new conditions. Knowledge of primary biochemical defects improved genetic services by providing accurate diagnosis, facilitating carrier identification and improving prenatal diagnosis. Glycosaminoglycan excretion patterns associated with individual enzyme defects suggested sequential degradative pathways for GAGs and related macromolecules. Attempts at enzyme replacement revealed a complex system of recognition markers and membrane receptors for the uptake of extracellular proteins. Multiple enzyme deficiencies are providing information on lysosomal enzyme synthesis and processing. The mucopolysaccharide storage diseases offer an excellent example of a productive synergism between basic biology and clinical medicine.
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Sewell AC, Gehler J, Mittermaier G, Meyer E. Mucopolysaccharidosis type VII (beta-glucuronidase deficiency): a report of a new case and a survey of those in the literature. Clin Genet 1982; 21:366-73. [PMID: 6813001 DOI: 10.1111/j.1399-0004.1982.tb01389.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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71
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Rozenfel'd EL. [Characteristics of biochemical disorders in hereditary enzymopathies in humans and animals]. VOPROSY MEDITSINSKOI KHIMII 1982; 28:2-7. [PMID: 6125053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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72
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Kobrinskiĭ BA. [Possible genetic nature of phenotypical differences of mucopolysaccharidosis 1]. VOPROSY MEDITSINSKOI KHIMII 1982; 28:55-7. [PMID: 6808766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Vine DT, McGovern MM, Schuchman EH, Haskins ME, Desnick RJ. Enhancement of residual arylsulfatase B activity in feline mucopolysaccharidosis VI by thiol-induced subunit association. J Clin Invest 1982; 69:294-302. [PMID: 6799547 PMCID: PMC370978 DOI: 10.1172/jci110452] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The molecular pathology of the deficient arylsulfatase B activity in feline mucopolysaccharidosis (MPS) VI was investigated. Compared with the highly purified normal feline hepatic enzyme, the purified MPS VI residual activity had a 100-fold higher Michaelis constant (K(m)), an altered electrophoretic mobility, half the apparent native molecular weight, and markedly decreased thermo-, cryo-, and pH stabilities. Molecular weight and alkylation studies were consistent with the normal enzyme being a homodimer and the residual MPS VI enzyme a monomer. When incubated with various sulfhydryl reagents, the residual specific activity was enhanced several-fold, whereas the activity of the purified normal enzyme was un-affected or slightly inhibited. In the presence of dithiothreitol (DTT) and cysteamine, a lysosomotropic aminothiol, the residual activity had an electrophoretic mobility and native molecular weight similar to those of the normal feline enzyme. These findings suggested that the monomeric residual enzyme was dimerized in the presence of thiol-reducing agents. To determine if thiol-induced subunit association could therapeutically increase the residual activity and degrade the accumulated dermatan sulfate, in vitro and in vivo experiments were undertaken. When 2 mM DTT or cysteamine was incubated with heparinized whole blood from an MPS VI cat, the leukocyte residual arylsulfatase B activity increased 11- and 20-fold, respectively, and the accumulated dermatan sulfate was degraded in the presence of both thiol reagents. Intravenous administration of DTT (50 mg/kg) effected an immediate, but transient, increase in leukocyte residual activity; however, the substrate levels were not significantly decreased. In contrast, intravenous administration of cysteamine (15 mg/kg) increased leukocyte residual activity more than sixfold 30 min postinfusion; concomitantly, the leukocyte substrate was decreased to 35% of the initial level immediately after infusion and to about 45% of preinfusion values during the 120-min period studied. These results suggest that the defective residual activity in feline MPS VI can be therapeutically manipulated by thiol-induced subunit association. Furthermore, this animal analog provides a prototype for the investigation of human inborn errors of metabolism resulting from enzymatic defects that might be amenable to enzyme manipulation therapy.
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Kresse H, von Figura K, Klein U, Glössl J, Paschke E, Pohlmann R. Enzymic diagnosis of the genetic mucopolysaccharide storage disorders. Methods Enzymol 1982; 83:559-72. [PMID: 6808304 DOI: 10.1016/0076-6879(82)83052-8] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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