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Sidhu NS, Schreiber K, Pröpper K, Becker S, Usón I, Sheldrick GM, Gärtner J, Krätzner R, Steinfeld R. Structure of sulfamidase provides insight into the molecular pathology of mucopolysaccharidosis IIIA. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2014; 70:1321-35. [PMID: 24816101 PMCID: PMC4014121 DOI: 10.1107/s1399004714002739] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 02/05/2014] [Indexed: 11/10/2022]
Abstract
Mucopolysaccharidosis type IIIA (Sanfilippo A syndrome), a fatal childhood-onset neurodegenerative disease with mild facial, visceral and skeletal abnormalities, is caused by an inherited deficiency of the enzyme N-sulfoglucosamine sulfohydrolase (SGSH; sulfamidase). More than 100 mutations in the SGSH gene have been found to reduce or eliminate its enzymatic activity. However, the molecular understanding of the effect of these mutations has been confined by a lack of structural data for this enzyme. Here, the crystal structure of glycosylated SGSH is presented at 2 Å resolution. Despite the low sequence identity between this unique N-sulfatase and the group of O-sulfatases, they share a similar overall fold and active-site architecture, including a catalytic formylglycine, a divalent metal-binding site and a sulfate-binding site. However, a highly conserved lysine in O-sulfatases is replaced in SGSH by an arginine (Arg282) that is positioned to bind the N-linked sulfate substrate. The structure also provides insight into the diverse effects of pathogenic mutations on SGSH function in mucopolysaccharidosis type IIIA and convincing evidence for the molecular consequences of many missense mutations. Further, the molecular characterization of SGSH mutations will lay the groundwork for the development of structure-based drug design for this devastating neurodegenerative disorder.
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Affiliation(s)
- Navdeep S. Sidhu
- Department of Neuropediatrics, Faculty of Medicine, University of Göttingen, Robert-Koch-Strasse 40, 37075 Göttingen, Germany
- Department of Structural Chemistry, Institute of Inorganic Chemistry, University of Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Kathrin Schreiber
- Department of Neuropediatrics, Faculty of Medicine, University of Göttingen, Robert-Koch-Strasse 40, 37075 Göttingen, Germany
| | - Kevin Pröpper
- Department of Structural Chemistry, Institute of Inorganic Chemistry, University of Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Stefan Becker
- Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Isabel Usón
- Instituto de Biologia Molecular de Barcelona (IBMB–CSIC), Barcelona Science Park, Baldiri Reixach 15, 08028 Barcelona, Spain
- Institucio Catalana de Recerca i Estudis Avancats (ICREA), Spain
| | - George M. Sheldrick
- Department of Structural Chemistry, Institute of Inorganic Chemistry, University of Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Jutta Gärtner
- Department of Neuropediatrics, Faculty of Medicine, University of Göttingen, Robert-Koch-Strasse 40, 37075 Göttingen, Germany
| | - Ralph Krätzner
- Department of Neuropediatrics, Faculty of Medicine, University of Göttingen, Robert-Koch-Strasse 40, 37075 Göttingen, Germany
| | - Robert Steinfeld
- Department of Neuropediatrics, Faculty of Medicine, University of Göttingen, Robert-Koch-Strasse 40, 37075 Göttingen, Germany
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Parker EI, Xing M, Moreno-De-Luca A, Harmouche E, Terk MR. Radiological and clinical characterization of the lysosomal storage disorders: non-lipid disorders. Br J Radiol 2014; 87:20130467. [PMID: 24234586 PMCID: PMC3898971 DOI: 10.1259/bjr.20130467] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Revised: 10/29/2013] [Accepted: 11/08/2013] [Indexed: 01/05/2023] Open
Abstract
Lysosomal storage diseases (LSDs) are a large group of genetic metabolic disorders that result in the accumulation of abnormal material, such as mucopolysaccharides, glycoproteins, amino acids and lipids, within cells. Since many LSDs manifest during infancy or early childhood, with potentially devastating consequences if left untreated, timely identification is imperative to prevent irreversible damage and early death. In this review, the key imaging features of the non-lipid or extralipid LSDs are examined and correlated with salient clinical manifestations and genetic information. Disorders are stratified based on the type of excess material causing tissue or organ dysfunction, with descriptions of the mucopolysaccharidoses, mucolipidoses, alpha-mannosidosis, glycogen storage disorder II and cystinosis. In addition, similarities and differences in radiological findings between each of these LSDs are highlighted to facilitate further recognition. Given the rare and extensive nature of the LSDs, mastery of their multiple clinical and radiological traits may seem challenging. However, an understanding of the distinguishing imaging characteristics of LSDs and their clinical correlates may allow radiologists to play a key role in the early diagnosis of these progressive and potentially fatal disorders.
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Héron B, Mikaeloff Y, Froissart R, Caridade G, Maire I, Caillaud C, Levade T, Chabrol B, Feillet F, Ogier H, Valayannopoulos V, Michelakakis H, Zafeiriou D, Lavery L, Wraith E, Danos O, Heard JM, Tardieu M. Incidence and natural history of mucopolysaccharidosis type III in France and comparison with United Kingdom and Greece. Am J Med Genet A 2011; 155A:58-68. [PMID: 21204211 DOI: 10.1002/ajmg.a.33779] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Sanfilippo syndrome, or mucopolysaccharidosis type III (MPSIII) is a lysosomal storage disease with predominant neurological manifestations in affected children. It is considered heterogeneous with respect to prevalence, clinical presentation, biochemistry (four biochemical forms of the disease referred to as MPSIIIA, B, C, and D are known), and causative mutations. The perspective of therapeutic options emphasizes the need for better knowledge of MPSIII incidence and natural history. We performed parallel retrospective epidemiological studies of patients diagnosed with MSPIII in France (n = 128), UK (n = 126), and Greece (n = 20) from 1990 to 2006. Incidences ranged from 0.68 per 100,000 live-births in France to 1.21 per 100,000 live-births in UK. MPSIIIA, which predominates in France and UK, was absent in Greece, where most patients have MPSIIIB. The study confirmed the large allelic heterogeneity of MPSIIIA and MPSIIIB and detected several yet undescribed mutations. Analysis of clinical manifestations at diagnosis and over a 6-7 years follow-up indicated that almost all patients, whatever the disease subtype, expressed neurological manifestations before the age of 5 years, including language acquisition delay, cognitive delay, and/or abnormal behavior. In contrast to relatively homogeneous early onset manifestations, disease progression showed significant variation depending on subtype and age at diagnosis. Different severities of disease progressions and different allele distribution between France and UK suggested that mutations are not equally deleterious, although genotype-phenotype correlation could not be established. Notwithstanding the rapidity of further clinical deterioration, all MPSIII patients suffer early onset devastating neurological manifestations that deserve early treatment when available.
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Affiliation(s)
- Bénédicte Héron
- Hôpital Trousseau, Centre de référence des maladies lysosomales, Paris, France
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