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Saville JT, Fuller M. Experience with the Urinary Tetrasaccharide Metabolite for Pompe Disease in the Diagnostic Laboratory. Metabolites 2021; 11:metabo11070446. [PMID: 34357340 PMCID: PMC8305466 DOI: 10.3390/metabo11070446] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 06/15/2021] [Accepted: 07/05/2021] [Indexed: 11/20/2022] Open
Abstract
Following clinical indications, the laboratory diagnosis of the inherited metabolic myopathy, Pompe disease (PD), typically begins with demonstrating a reduction in acid alpha-glucosidase (GAA), the enzyme required for lysosomal glycogen degradation. Although simple in concept, a major challenge is defining reference intervals, as even carriers can have reduced GAA, and pseudodeficiencies complicate interpretation. Here, we developed a mass spectrometric assay for quantification of a urinary glycogen metabolite (tetrasaccharide) and reported on its utility as a confirmatory test for PD in a diagnostic laboratory. Using two age-related reference intervals, eight returned tetrasaccharide concentrations above the calculated reference interval but did not have PD, highlighting non-specificity. However, retrospective analysis revealed elevated tetrasaccharide in seven infantile-onset (IOPD) cases and sixteen late-onset (LOPD) cases, and normal concentrations in one heterozygote. Prospective tetrasaccharide analysis in nine individuals with reduced GAA confirmed IOPD in one, LOPD in six and identified two heterozygotes. Using this metabolite as a biomarker of therapeutic response was not overly informative; although most patients showed an initial drop following therapy initiation, tetrasaccharide concentrations fluctuated considerably and remained above reference intervals in all patients. While useful as a confirmation of PD, its utility as a biomarker for monitoring treatment warrants further investigation.
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Affiliation(s)
- Jennifer T. Saville
- Genetics and Molecular Pathology, SA Pathology at Women’s and Children’s Hospital, 72 King William Road, North Adelaide, SA 5006, Australia;
| | - Maria Fuller
- Genetics and Molecular Pathology, SA Pathology at Women’s and Children’s Hospital, 72 King William Road, North Adelaide, SA 5006, Australia;
- Adelaide Medical School, University of Adelaide, North Terrace, Adelaide, SA 5000, Australia
- Correspondence: ; Tel.: +61-(0)8-8161-6741
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Semeraro M, Sacchetti E, Deodato F, Coşkun T, Lay I, Catesini G, Olivieri G, Rizzo C, Boenzi S, Dionisi-Vici C. A new UHPLC-MS/MS method for the screening of urinary oligosaccharides expands the detection of storage disorders. Orphanet J Rare Dis 2021; 16:24. [PMID: 33422100 PMCID: PMC7796585 DOI: 10.1186/s13023-020-01662-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 12/22/2020] [Indexed: 12/17/2022] Open
Abstract
Background Oligosaccharidoses are storage disorders due to enzymatic defects involved in the breakdown of the oligosaccharidic component of glycosylated proteins. The defect cause the accumulation of oligosaccharides (OS) and, depending on the lacking enzyme, results in characteristic profiles which are helpful for the diagnosis. We developed a new tandem mass spectrometry method for the screening of urinary OS which was applied to identify a large panel of storage disorders. Methods The method was set-up in urine and dried urine spots (DUS). Samples were analysed, without derivatization and using maltoheptaose as internal standard, by UHPLC-MS/MS with MRM acquisition of target OS transitions, including Glc4, the biomarker of Pompe disease. The chromatographic run was < 30 min. Samples from patients with known storage disorders were used for clinical validation. Results The method allowed to confirm the diagnosis of oligosaccharidoses (sialidosis, α-/β-mannosidosis, fucosidosis, aspartylglucosaminuria) and of GM1 and GM2 (Sandhoff type) gangliosidosis, by detecting specific OS profiles. In other storage disorders (mucolipidosis II and III, mucopolysaccharidosis type IVB) the analyisis revealed abnormal OS excretion with non-specific profiles. Besides Pompe disease, the tetrasaccharide Glc4 was increased also in disorders of autophagy (Vici syndrome, Yunis-Varon syndrome, and Danon disease) presenting cardiomuscular involvement with glycogen storage. Overall, results showed a clear separation between patients and controls, both in urine and in DUS. Conclusion This new UHPLC/MS-MS method, which is suitable for rapid and easy screening of OS in urine and DUS, expands the detection of storage disorders from oligosaccharidoses to other diseases, including the novel category of inherited disorders of autophagy.
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Affiliation(s)
- Michela Semeraro
- Division of Metabolism and Metabolic Diseases Research Unit, Bambino Gesù Children's Hospital, IRCCS, Viale San Paolo 15, 00146, Rome, Italy.
| | - Elisa Sacchetti
- Division of Metabolism and Metabolic Diseases Research Unit, Bambino Gesù Children's Hospital, IRCCS, Viale San Paolo 15, 00146, Rome, Italy
| | - Federica Deodato
- Division of Metabolism and Metabolic Diseases Research Unit, Bambino Gesù Children's Hospital, IRCCS, Viale San Paolo 15, 00146, Rome, Italy
| | - Turgay Coşkun
- Metabolism Unit, Department of Pediatrics, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Incilay Lay
- Department of Medical Biochemistry and Hacettepe University Hospitals Clinical Pathology Laboratory, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Giulio Catesini
- Division of Metabolism and Metabolic Diseases Research Unit, Bambino Gesù Children's Hospital, IRCCS, Viale San Paolo 15, 00146, Rome, Italy
| | - Giorgia Olivieri
- Division of Metabolism and Metabolic Diseases Research Unit, Bambino Gesù Children's Hospital, IRCCS, Viale San Paolo 15, 00146, Rome, Italy
| | - Cristiano Rizzo
- Division of Metabolism and Metabolic Diseases Research Unit, Bambino Gesù Children's Hospital, IRCCS, Viale San Paolo 15, 00146, Rome, Italy
| | - Sara Boenzi
- Division of Metabolism and Metabolic Diseases Research Unit, Bambino Gesù Children's Hospital, IRCCS, Viale San Paolo 15, 00146, Rome, Italy
| | - Carlo Dionisi-Vici
- Division of Metabolism and Metabolic Diseases Research Unit, Bambino Gesù Children's Hospital, IRCCS, Viale San Paolo 15, 00146, Rome, Italy
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