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Caciotti A, Cellai L, Tonin R, Mei D, Procopio E, Di Rocco M, Andaloro A, Antuzzi D, Rampazzo A, Rigoldi M, Forni G, la Marca G, Guerrini R, Morrone A. Morquio B disease: From pathophysiology towards diagnosis. Mol Genet Metab 2021; 132:180-188. [PMID: 33558080 DOI: 10.1016/j.ymgme.2021.01.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 01/20/2021] [Accepted: 01/20/2021] [Indexed: 11/25/2022]
Abstract
Morquio B disease is an attenuated phenotype within the spectrum of beta galactosidase (GLB1) deficiencies. It is characterised by dysostosis multiplex, ligament laxity, mildly coarse facies and heart valve defects due to keratan sulphate accumulation, predominantly in the cartilage. Morquio B patients have normal neurological development, setting them apart from those with the more severe GM1 gangliosidosis. Morquio B disease, with an incidence of 1:250.000 to 1:1.000.000 live births, is very rare. Here we report the clinical-biochemical data of nine patients. High amounts of keratan sulfate were detected using LC-MS/MS in the patients' urinary samples, while electrophoresis, the standard procedure of qualitative glycosaminoglycans analysis, failed to identify this metabolite in any of the patients' samples. We performed molecular analyses at gene, gene expression and protein expression levels, for both isoforms of the GLB1 gene, lysosomal GLB1, and the cell-surface expressed Elastin Binding Protein. We characterised three novel GLB1 mutations [c.75 + 2 T > G, c.575A > G (p.Tyr192Cys) and c.2030 T > G (p.Val677Gly)] identified in three heterozygous patients. We also set up a copy number variation assay by quantitative PCR to evaluate the presence of deletions/ insertions in the GLB1 gene. We propose a diagnostic plan, setting out the specific clinical- biochemical and molecular features of Morquio B, in order to avoid misdiagnoses and improve patients' management.
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Affiliation(s)
- Anna Caciotti
- Molecular and Cell Biology Laboratory, Paediatric Neurology Unit and Laboratories, Neuroscience Department, A. Meyer Children's Hospital, Florence, Italy
| | - Lucrezia Cellai
- Molecular and Cell Biology Laboratory, Paediatric Neurology Unit and Laboratories, Neuroscience Department, A. Meyer Children's Hospital, Florence, Italy
| | - Rodolfo Tonin
- Molecular and Cell Biology Laboratory, Paediatric Neurology Unit and Laboratories, Neuroscience Department, A. Meyer Children's Hospital, Florence, Italy
| | - Davide Mei
- Neurogenetics, Paediatric Neurology Unit and Laboratories, Neuroscience Department, A. Meyer Children's Hospital, Florence, Italy
| | - Elena Procopio
- Metabolic and Muscular Unit, A. Meyer Children's Hospital, Florence, Italy
| | - Maja Di Rocco
- Unit of Rare Diseases, Dept of Pediatrics, IRCCS G. Gaslini, Genoa, Italy
| | - Antonio Andaloro
- Unit of Rare Diseases, Dept of Pediatrics, IRCCS G. Gaslini, Genoa, Italy
| | - Daniela Antuzzi
- Pediatric Clinic, Catholic University of "Sacro Cuore", Policlinico "Gemelli", Rome, Italy
| | | | - Miriam Rigoldi
- Mario Negri Institute for Pharmacological Research, IRCCS, Clinical Research Center for Rare Diseases "Aldo e Cele Daccò", Bergamo, Italy
| | - Giulia Forni
- Newborn Screening, Biochemistry and Pharmacology Laboratory, A. Meyer Children's Hospital, Florence, Italy
| | - Giancarlo la Marca
- Newborn Screening, Biochemistry and Pharmacology Laboratory, A. Meyer Children's Hospital, Florence, Italy; Department of Experimental and Clinical Biomedical Sciences, University of Florence, Italy
| | - Renzo Guerrini
- Molecular and Cell Biology Laboratory, Paediatric Neurology Unit and Laboratories, Neuroscience Department, A. Meyer Children's Hospital, Florence, Italy; Department of Neurosciences, Psychology, Pharmacology and Child Health, University of Florence, Italy
| | - Amelia Morrone
- Molecular and Cell Biology Laboratory, Paediatric Neurology Unit and Laboratories, Neuroscience Department, A. Meyer Children's Hospital, Florence, Italy; Department of Neurosciences, Psychology, Pharmacology and Child Health, University of Florence, Italy.
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Caciotti A, Tonin R, Mort M, Cooper DN, Gasperini S, Rigoldi M, Parini R, Deodato F, Taurisano R, Sibilio M, Parenti G, Guerrini R, Morrone A. Mis-splicing of the GALNS gene resulting from deep intronic mutations as a cause of Morquio a disease. BMC MEDICAL GENETICS 2018; 19:183. [PMID: 30305043 PMCID: PMC6180571 DOI: 10.1186/s12881-018-0694-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 09/24/2018] [Indexed: 11/30/2022]
Abstract
Background Mucopolysaccharidosis-IVA (Morquio A disease) is a lysosomal disorder in which the abnormal accumulation of keratan sulfate and chondroitin-6-sulfate is consequent to mutations in the galactosamine-6-sulfatase (GALNS) gene. Since standard DNA sequencing analysis fails to detect about 16% of GALNS mutant alleles, gross DNA rearrangement screening and uniparental disomy evaluation are required to complete the molecular diagnosis. Despite this, the second pathogenic GALNS allele generally remains unidentified in ~ 5% of Morquio-A disease patients. Methods In an attempt to bridge the residual gap between clinical and molecular diagnosis, we performed an mRNA-based evaluation of three Morquio-A disease patients in whom the second mutant GALNS allele had not been identified. We also performed sequence analysis of the entire GALNS gene in two patients. Results Different aberrant GALNS mRNA transcripts were characterized in each patient. Analysis of these transcripts then allowed the identification, in one patient, of a disease-causing deep intronic GALNS mutation. The aberrant mRNA products identified in the other two individuals resulted in partial exon loss. Despite sequencing the entire GALNS gene region in these patients, the identity of a single underlying pathological lesion could not be unequivocally determined. We postulate that a combination of multiple variants, acting in cis, may synergise in terms of their impact on the splicing machinery. Conclusions We have identified GALNS variants located within deep intronic regions that have the potential to impact splicing. These findings have prompted us to incorporate mRNA analysis into our diagnostic flow procedure for the molecular analysis of Morquio A disease. Electronic supplementary material The online version of this article (10.1186/s12881-018-0694-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Anna Caciotti
- Molecular and Cell Biology Laboratory of Neurometabolic Diseases, Paediatric Neurology Unit and Laboratories, Neuroscience Department, Meyer Children's Hospital, Viale Pieraccini n. 24, 50139, Florence, Italy
| | - Rodolfo Tonin
- Molecular and Cell Biology Laboratory of Neurometabolic Diseases, Paediatric Neurology Unit and Laboratories, Neuroscience Department, Meyer Children's Hospital, Viale Pieraccini n. 24, 50139, Florence, Italy.,Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, University of Florence, Florence, Italy
| | - Matthew Mort
- Institute of Medical Genetics, School of Medicine, Cardiff University, Cardiff, UK
| | - David N Cooper
- Institute of Medical Genetics, School of Medicine, Cardiff University, Cardiff, UK
| | | | - Miriam Rigoldi
- Metabolic Unit, San Gerardo Hospital, Monza, Milan, Italy
| | | | - Federica Deodato
- Division of Metabolism, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Roberta Taurisano
- Division of Metabolism, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Michelina Sibilio
- Department of Translational Medical Sciences, Section of Pediatrics, Federico II University of Naples, Naples, Italy
| | - Giancarlo Parenti
- Department of Translational Medical Sciences, Section of Pediatrics, Federico II University of Naples, Naples, Italy
| | - Renzo Guerrini
- Molecular and Cell Biology Laboratory of Neurometabolic Diseases, Paediatric Neurology Unit and Laboratories, Neuroscience Department, Meyer Children's Hospital, Viale Pieraccini n. 24, 50139, Florence, Italy.,Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, University of Florence, Florence, Italy
| | - Amelia Morrone
- Molecular and Cell Biology Laboratory of Neurometabolic Diseases, Paediatric Neurology Unit and Laboratories, Neuroscience Department, Meyer Children's Hospital, Viale Pieraccini n. 24, 50139, Florence, Italy. .,Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, University of Florence, Florence, Italy.
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Caciotti A, Tonin R, Rigoldi M, Ferri L, Catarzi S, Cavicchi C, Procopio E, Donati MA, Ficcadenti A, Fiumara A, Barone R, Garavelli L, Rocco MD, Filocamo M, Antuzzi D, Scarpa M, Mooney SD, Li B, Skouma A, Bianca S, Concolino D, Casalone R, Monti E, Pantaleo M, Giglio S, Guerrini R, Parini R, Morrone A. Optimizing the molecular diagnosis of GALNS: novel methods to define and characterize Morquio-A syndrome-associated mutations. Hum Mutat 2015; 36:357-68. [PMID: 25545067 DOI: 10.1002/humu.22751] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 12/18/2014] [Indexed: 12/31/2022]
Abstract
Morquio A syndrome (MPS IVA) is a systemic lysosomal storage disorder caused by the deficiency of N-acetylgalactosamine-6-sulfatase (GALNS), encoded by the GALNS gene. We studied 37 MPS IV A patients and defined genotype-phenotype correlations based on clinical data, biochemical assays, molecular analyses, and in silico structural analyses of associated mutations. We found that standard sequencing procedures, albeit identifying 14 novel small GALNS genetic lesions, failed to characterize the second disease-causing mutation in the 16% of the patients' cohort. To address this drawback and uncover potential gross GALNS rearrangements, we developed molecular procedures (CNV [copy-number variation] assays, QF-PCRs [quantitative fluorescent-PCRs]), endorsed by CGH-arrays. Using this approach, we characterized two new large deletions and their corresponding breakpoints. Both deletions were heterozygous and included the first exon of the PIEZO1 gene, which is associated with dehydrated hereditary stomatocitosis, an autosomal-dominant syndrome. In addition, we characterized the new GALNS intronic lesion c.245-11C>G causing m-RNA defects, although identified outside the GT/AG splice pair. We estimated the occurrence of the disease in the Italian population to be approximately 1:300,000 live births and defined a molecular testing algorithm designed to help diagnosing MPS IVA and foreseeing disease progression.
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Affiliation(s)
- Anna Caciotti
- Molecular and Cell Biology Laboratory, Paediatric Neurology Unit and Laboratories, Neuroscience Department, A. Meyer Children's Hospital, Florence, Italy
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Morrone A, Tylee KL, Al-Sayed M, Brusius-Facchin AC, Caciotti A, Church HJ, Coll MJ, Davidson K, Fietz MJ, Gort L, Hegde M, Kubaski F, Lacerda L, Laranjeira F, Leistner-Segal S, Mooney S, Pajares S, Pollard L, Ribeiro I, Wang RY, Miller N. Molecular testing of 163 patients with Morquio A (Mucopolysaccharidosis IVA) identifies 39 novel GALNS mutations. Mol Genet Metab 2014; 112:160-70. [PMID: 24726177 PMCID: PMC4203673 DOI: 10.1016/j.ymgme.2014.03.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2014] [Revised: 03/11/2014] [Accepted: 03/12/2014] [Indexed: 01/09/2023]
Abstract
Morquio A (Mucopolysaccharidosis IVA; MPS IVA) is an autosomal recessive lysosomal storage disorder caused by partial or total deficiency of the enzyme galactosamine-6-sulfate sulfatase (GALNS; also known as N-acetylgalactosamine-6-sulfate sulfatase) encoded by the GALNS gene. Patients who inherit two mutated GALNS gene alleles have a decreased ability to degrade the glycosaminoglycans (GAGs) keratan sulfate and chondroitin 6-sulfate, thereby causing GAG accumulation within lysosomes and consequently pleiotropic disease. GALNS mutations occur throughout the gene and many mutations are identified only in single patients or families, causing difficulties both in mutation detection and interpretation. In this study, molecular analysis of 163 patients with Morquio A identified 99 unique mutations in the GALNS gene believed to negatively impact GALNS protein function, of which 39 are previously unpublished, together with 26 single-nucleotide polymorphisms. Recommendations for the molecular testing of patients, clear reporting of sequence findings, and interpretation of sequencing data are provided.
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Affiliation(s)
- A Morrone
- Molecular and Cell Biology Laboratory, Pediatric Neurology Unit and Laboratories, Meyer Children's Hospital, Florence, Italy; Department of Neurosciences, Psychology, Pharmacology and Child Health, University of Florence, Florence Italy
| | - K L Tylee
- Willink Biochemical Genetics, Central Manchester University Hospitals NHS Foundation Trust, Saint Mary's Hospital Oxford Road, Manchester, UK
| | - M Al-Sayed
- Department of Medical Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - A C Brusius-Facchin
- Laboratório de Genética Molecular, Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Brazil
| | - A Caciotti
- Molecular and Cell Biology Laboratory, Pediatric Neurology Unit and Laboratories, Meyer Children's Hospital, Florence, Italy
| | - H J Church
- Willink Biochemical Genetics, Central Manchester University Hospitals NHS Foundation Trust, Saint Mary's Hospital Oxford Road, Manchester, UK
| | - M J Coll
- Sección de Errores Congénitos del Metabolismo-IBC, Servicio de Bioquímica y Genética Molecular, Hospital Clínic, CIBERER, IDIBAPS, Barcelona, Spain
| | - K Davidson
- BioMarin Pharmaceutical Inc., Novato, CA, USA
| | - M J Fietz
- SA Pathology, Women's and Children's Hospital, North Adelaide, SA, Australia
| | - L Gort
- Sección de Errores Congénitos del Metabolismo-IBC, Servicio de Bioquímica y Genética Molecular, Hospital Clínic, CIBERER, IDIBAPS, Barcelona, Spain
| | - M Hegde
- Emory Genetics Laboratory, Emory University School of Medicine, Atlanta, GA, USA
| | - F Kubaski
- Laboratório de Genética Molecular, Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Brazil
| | - L Lacerda
- Unidade de Bioquímica Genética, Centro de Genética Médica Jacinto Magalhães (CGMJM) do Centro Hospitalar do Porto (CHP), Porto, Portugal
| | - F Laranjeira
- Unidade de Bioquímica Genética, Centro de Genética Médica Jacinto Magalhães (CGMJM) do Centro Hospitalar do Porto (CHP), Porto, Portugal
| | - S Leistner-Segal
- Laboratório de Genética Molecular, Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Brazil
| | - S Mooney
- The Buck Institute for Research on Aging, Novato, CA, USA
| | - S Pajares
- Sección de Errores Congénitos del Metabolismo-IBC, Servicio de Bioquímica y Genética Molecular, Hospital Clínic, CIBERER, IDIBAPS, Barcelona, Spain
| | - L Pollard
- Biochemical Genetics Laboratory, Greenwood Genetic Center, Greenwood, SC, USA
| | - I Ribeiro
- Unidade de Bioquímica Genética, Centro de Genética Médica Jacinto Magalhães (CGMJM) do Centro Hospitalar do Porto (CHP), Porto, Portugal
| | - R Y Wang
- Children's Hospital of Orange County, Orange, CA, USA
| | - N Miller
- BioMarin Pharmaceutical Inc., Novato, CA, USA.
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The structure of human GALNS reveals the molecular basis for mucopolysaccharidosis IV A. J Mol Biol 2012; 423:736-51. [PMID: 22940367 PMCID: PMC3472114 DOI: 10.1016/j.jmb.2012.08.020] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 08/21/2012] [Accepted: 08/23/2012] [Indexed: 01/07/2023]
Abstract
Lysosomal enzymes catalyze the breakdown of macromolecules in the cell. In humans, loss of activity of a lysosomal enzyme leads to an inherited metabolic defect known as a lysosomal storage disorder. The human lysosomal enzyme galactosamine-6-sulfatase (GALNS, also known as N-acetylgalactosamine-6-sulfatase and GalN6S; E.C. 3.1.6.4) is deficient in patients with the lysosomal storage disease mucopolysaccharidosis IV A (also known as MPS IV A and Morquio A). Here, we report the three-dimensional structure of human GALNS, determined by X-ray crystallography at 2.2Å resolution. The structure reveals a catalytic gem diol nucleophile derived from modification of a cysteine side chain. The active site of GALNS is a large, positively charged trench suitable for binding polyanionic substrates such as keratan sulfate and chondroitin-6-sulfate. Enzymatic assays on the insect-cell-expressed human GALNS indicate activity against synthetic substrates and inhibition by both substrate and product. Mapping 120 MPS IV A missense mutations onto the structure reveals that a majority of mutations affect the hydrophobic core of the structure, indicating that most MPS IV A cases result from misfolding of GALNS. Comparison of the structure of GALNS to paralogous sulfatases shows a wide variety of active-site geometries in the family but strict conservation of the catalytic machinery. Overall, the structure and the known mutations establish the molecular basis for MPS IV A and for the larger MPS family of diseases.
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Catarzi S, Giunti L, Papadia F, Gabrielli O, Guerrini R, Donati MA, Genuardi M, Morrone A. Morquio A syndrome due to maternal uniparental isodisomy of the telomeric end of chromosome 16. Mol Genet Metab 2012; 105:438-42. [PMID: 22178352 DOI: 10.1016/j.ymgme.2011.11.196] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 11/23/2011] [Accepted: 11/23/2011] [Indexed: 11/23/2022]
Abstract
Morquio A syndrome (MPS IVA) is a recessive lysosomal storage disorder (LSD) caused by mutations in the GALNS gene leading to the deficiency of lysosomal enzyme N-acetylgalactosamine-6-sulfate sulfatase (GALNS). Patients show a broad spectrum of phenotypes ranging from classical severe type to mild forms. Classical forms are characterized by severe bone dysplasia and usually normal intelligence. So far, more than 170 unique mutations have been identified in the GALNS gene of MPS IVA patients. We report on a Morquio A patient with a classical phenotype who was found to be homozygous for a missense mutation (c.236 G>A; p.Cys79Tyr) in the GALNS gene. This alteration affects the highly conserved p.Cys79 that is transformed into formylglycine, the catalytic residue of the active site. The mutation was present in the proband's mother, but not in the father, whose paternity was confirmed by microsatellite analysis. In order to test the hypothesis of maternal uniparental disomy (UPD), we investigated the segregation of sixteen microsatellite markers from chromosome 16. The results showed a condition of maternal UPD due to an error in meiosis I. Maternal isodisomy of the 16q24 region led to homozygosity for the GALNS mutant allele, causing the patient's disease. These findings allow to add for the first time the LSD Morquio A syndrome to the list of conditions that can be caused by UPD. The possibility of UPD is relevant when giving genetic counseling to couples since the recurrent risk in future pregnancies is dramatically reduced.
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Affiliation(s)
- S Catarzi
- Metabolic and Muscular Unit, Clinical of Paediatric Neurology, Meyer Children's Hospital, University of Florence, Florence, Italy
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