1
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Morales-Romero B, Muñoz-Pujol G, Artuch R, García-Cazorla A, O'Callaghan M, Sykut-Cegielska J, Campistol J, Moreno-Lozano PJ, Oud MM, Wevers RA, Lefeber DJ, Esteve-Codina A, Yepez VA, Gagneur J, Wortmann SB, Prokisch H, Ribes A, García-Villoria J, Tort F. Genome and RNA sequencing were essential to reveal cryptic intronic variants associated to defective ATP6AP1 mRNA processing. Mol Genet Metab 2024; 142:108511. [PMID: 38878498 DOI: 10.1016/j.ymgme.2024.108511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 05/28/2024] [Accepted: 05/29/2024] [Indexed: 07/05/2024]
Abstract
The diagnosis of Mendelian disorders has notably advanced with integration of whole exome and genome sequencing (WES and WGS) in clinical practice. However, challenges in variant interpretation and uncovered variants by WES still leave a substantial percentage of patients undiagnosed. In this context, integrating RNA sequencing (RNA-seq) improves diagnostic workflows, particularly for WES inconclusive cases. Additionally, functional studies are often necessary to elucidate the impact of prioritized variants on gene expression and protein function. Our study focused on three unrelated male patients (P1-P3) with ATP6AP1-CDG (congenital disorder of glycosylation), presenting with intellectual disability and varying degrees of hepatopathy, glycosylation defects, and an initially inconclusive diagnosis through WES. Subsequent RNA-seq was pivotal in identifying the underlying genetic causes in P1 and P2, detecting ATP6AP1 underexpression and aberrant splicing. Molecular studies in fibroblasts confirmed these findings and identified the rare intronic variants c.289-233C > T and c.289-289G > A in P1 and P2, respectively. Trio-WGS also revealed the variant c.289-289G > A in P3, which was a de novo change in both patients. Functional assays expressing the mutant alleles in HAP1 cells demonstrated the pathogenic impact of these variants by reproducing the splicing alterations observed in patients. Our study underscores the role of RNA-seq and WGS in enhancing diagnostic rates for genetic diseases such as CDG, providing new insights into ATP6AP1-CDG molecular bases by identifying the first two deep intronic variants in this X-linked gene. Additionally, our study highlights the need to integrate RNA-seq and WGS, followed by functional validation, in routine diagnostics for a comprehensive evaluation of patients with an unidentified molecular etiology.
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Affiliation(s)
- Blai Morales-Romero
- Section of Inborn Errors of Metabolism-IBC, Biochemistry and Molecular Genetics Department, Hospital Clínic de Barcelona, IDIBAPS, CIBERER, ISCIII, Barcelona, Spain.
| | - Gerard Muñoz-Pujol
- Section of Inborn Errors of Metabolism-IBC, Biochemistry and Molecular Genetics Department, Hospital Clínic de Barcelona, IDIBAPS, CIBERER, ISCIII, Barcelona, Spain.
| | - Rafael Artuch
- Clinical Biochemistry Department, Institut de Recerca Sant Joan de Déu, Hospital Sant Joan de Déu, CIBERER, Esplugues de Llobregat, Barcelona, Spain.
| | - Angels García-Cazorla
- Neurology Department, Hospital Sant Joan de Déu, Institut de Recerca Hospital Sant Joan de Déu, CIBERER and MetabERN, Esplugues de Llobregat, Barcelona, Spain.
| | - Mar O'Callaghan
- Neurology Department, Hospital Sant Joan de Déu, Institut de Recerca Hospital Sant Joan de Déu, CIBERER and MetabERN, Esplugues de Llobregat, Barcelona, Spain.
| | - Jolanta Sykut-Cegielska
- Department of Inborn Errors of Metabolism and Pediatrics, Institute of Mother and Child, Warsaw, Poland
| | - Jaume Campistol
- Neurology Department, Hospital Sant Joan de Déu, Institut de Recerca Hospital Sant Joan de Déu, CIBERER and MetabERN, Esplugues de Llobregat, Barcelona, Spain.
| | - Pedro Juan Moreno-Lozano
- Inherited Metabolic Diseases and Muscle Disorders' Research Group, Department of Internal Medicine, Hospital Clinic de Barcelona, IDIBAPS, Faculty of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain.
| | - Machteld M Oud
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Ron A Wevers
- Department of Human Genetics, Translational Metabolic Laboratory (TML), Radboud University Medical Center, Nijmegen, the Netherlands; United for Metabolic Diseases, The Netherlands.
| | - Dirk J Lefeber
- Department of Human Genetics, Translational Metabolic Laboratory (TML), Radboud University Medical Center, Nijmegen, the Netherlands; Department of Neurology, Donders Institute for Brain, Cognition, and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands.
| | - Anna Esteve-Codina
- Centro Nacional de Análisis Genómico (CNAG), Parc Científic de Barcelona, Barcelona, Spain.
| | - Vicente A Yepez
- Institute of Human Genetics, School of Medicine, Technical University of Munich, 81675 Munich, Germany; TUM School of Computation, Information and Technology, Technical University of Munich, 85748 Garching, Germany.
| | - Julien Gagneur
- Institute of Human Genetics, School of Medicine, Technical University of Munich, 81675 Munich, Germany; TUM School of Computation, Information and Technology, Technical University of Munich, 85748 Garching, Germany.
| | - Saskia B Wortmann
- University Children's Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria; Amalia Children's Hospital, Department of Pediatrics, Radboudumc, Nijmegen, the Netherlands.
| | - Holger Prokisch
- Institute of Human Genetics, School of Medicine, Technical University of Munich, 81675 Munich, Germany; Institute of Neurogenomics, Helmholtz Zentrum München, 85764 Neuherberg, Germany.
| | - Antonia Ribes
- Section of Inborn Errors of Metabolism-IBC, Biochemistry and Molecular Genetics Department, Hospital Clínic de Barcelona, IDIBAPS, CIBERER, ISCIII, Barcelona, Spain.
| | - Judit García-Villoria
- Section of Inborn Errors of Metabolism-IBC, Biochemistry and Molecular Genetics Department, Hospital Clínic de Barcelona, IDIBAPS, CIBERER, ISCIII, Barcelona, Spain.
| | - Frederic Tort
- Section of Inborn Errors of Metabolism-IBC, Biochemistry and Molecular Genetics Department, Hospital Clínic de Barcelona, IDIBAPS, CIBERER, ISCIII, Barcelona, Spain.
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Jáñez Pedrayes A, Rymen D, Ghesquière B, Witters P. Glycosphingolipids in congenital disorders of glycosylation (CDG). Mol Genet Metab 2024; 142:108434. [PMID: 38489976 DOI: 10.1016/j.ymgme.2024.108434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 02/26/2024] [Accepted: 02/27/2024] [Indexed: 03/17/2024]
Abstract
Congenital disorders of glycosylation (CDG) are a large family of rare disorders affecting the different glycosylation pathways. Defective glycosylation can affect any organ, with varying symptoms among the different CDG. Even between individuals with the same CDG there is quite variable severity. Associating specific symptoms to deficiencies of certain glycoproteins or glycolipids is thus a challenging task. In this review, we focus on the glycosphingolipid (GSL) synthesis pathway, which is still rather unexplored in the context of CDG, and outline the functions of the main GSLs, including gangliosides, and their role in the central nervous system. We provide an overview of GSL studies that have been performed in CDG and show that abnormal GSL levels are not only observed in CDG directly affecting GSL synthesis, but also in better known CDG, such as PMM2-CDG. We highlight the importance of studying GSLs in CDG in order to better understand the pathophysiology of these disorders.
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Affiliation(s)
- Andrea Jáñez Pedrayes
- Laboratory of Applied Mass Spectrometry, Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven, 3000 Leuven, Belgium; Metabolomics Expertise Center, Center for Cancer Biology VIB, 3000 Leuven, Belgium; Department of Development and Regeneration, Katholieke Universiteit Leuven, 3000 Leuven, Belgium.
| | - Daisy Rymen
- Center for Metabolic Diseases, Department of Paediatrics, University Hospitals Leuven, 3000 Leuven, Belgium.
| | - Bart Ghesquière
- Laboratory of Applied Mass Spectrometry, Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven, 3000 Leuven, Belgium; Metabolomics Expertise Center, Center for Cancer Biology VIB, 3000 Leuven, Belgium.
| | - Peter Witters
- Department of Development and Regeneration, Katholieke Universiteit Leuven, 3000 Leuven, Belgium; Center for Metabolic Diseases, Department of Paediatrics, University Hospitals Leuven, 3000 Leuven, Belgium.
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3
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Costa J, Hayes C, Lisacek F. Protein glycosylation and glycoinformatics for novel biomarker discovery in neurodegenerative diseases. Ageing Res Rev 2023; 89:101991. [PMID: 37348818 DOI: 10.1016/j.arr.2023.101991] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/25/2023] [Accepted: 06/18/2023] [Indexed: 06/24/2023]
Abstract
Glycosylation is a common post-translational modification of brain proteins including cell surface adhesion molecules, synaptic proteins, receptors and channels, as well as intracellular proteins, with implications in brain development and functions. Using advanced state-of-the-art glycomics and glycoproteomics technologies in conjunction with glycoinformatics resources, characteristic glycosylation profiles in brain tissues are increasingly reported in the literature and growing evidence shows deregulation of glycosylation in central nervous system disorders, including aging associated neurodegenerative diseases. Glycan signatures characteristic of brain tissue are also frequently described in cerebrospinal fluid due to its enrichment in brain-derived molecules. A detailed structural analysis of brain and cerebrospinal fluid glycans collected in publications in healthy and neurodegenerative conditions was undertaken and data was compiled to create a browsable dedicated set in the GlyConnect database of glycoproteins (https://glyconnect.expasy.org/brain). The shared molecular composition of cerebrospinal fluid with brain enhances the likelihood of novel glycobiomarker discovery for neurodegeneration, which may aid in unveiling disease mechanisms, therefore, providing with novel therapeutic targets as well as diagnostic and progression monitoring tools.
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Affiliation(s)
- Júlia Costa
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, 2780-157 Oeiras, Portugal.
| | - Catherine Hayes
- Proteome Informatics Group, Swiss Institute of Bioinformatics, CH-1227 Geneva, Switzerland
| | - Frédérique Lisacek
- Proteome Informatics Group, Swiss Institute of Bioinformatics, CH-1227 Geneva, Switzerland; Computer Science Department, University of Geneva, CH-1227 Geneva, Switzerland; Section of Biology, University of Geneva, CH-1211 Geneva, Switzerland
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4
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Himmelreich N, Kikul F, Zdrazilova L, Honzik T, Hecker A, Poschet G, Lüchtenborg C, Brügger B, Strahl S, Bürger F, Okun JG, Hansikova H, Thiel C. Complex metabolic disharmony in PMM2-CDG paves the way to new therapeutic approaches. Mol Genet Metab 2023; 139:107610. [PMID: 37245379 DOI: 10.1016/j.ymgme.2023.107610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 05/15/2023] [Accepted: 05/15/2023] [Indexed: 05/30/2023]
Abstract
PMM2-CDG is the most common defect among the congenital disorders of glycosylation. In order to investigate the effect of hypoglycosylation on important cellular pathways, we performed extensive biochemical studies on skin fibroblasts of PMM2-CDG patients. Among others, acylcarnitines, amino acids, lysosomal proteins, organic acids and lipids were measured, which all revealed significant abnormalities. There was an increased expression of acylcarnitines and amino acids associated with increased amounts of calnexin, calreticulin and protein-disulfid-isomerase in combination with intensified amounts of ubiquitinylated proteins. Lysosomal enzyme activities were widely decreased as well as citrate and pyruvate levels indicating mitochondrial dysfunction. Main lipid classes such as phosphatidylethanolamine, cholesterol or alkyl-phosphatidylcholine, as well as minor lipid species like hexosylceramide, lysophosphatidylcholines or phosphatidylglycerol, were abnormal. Biotinidase and catalase activities were severely reduced. In this study we discuss the impact of metabolite abnormalities on the phenotype of PMM2-CDG. In addition, based on our data we propose new and easy-to-implement therapeutic approaches for PMM2-CDG patients.
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Affiliation(s)
- Nastassja Himmelreich
- Centre for Child and Adolescent Medicine, Department I, Heidelberg University, Im Neuenheimer Feld 669, 69120 Heidelberg, Germany
| | - Frauke Kikul
- Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Lucie Zdrazilova
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Czech Republic
| | - Tomáš Honzik
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Czech Republic
| | - Andreas Hecker
- Centre for Child and Adolescent Medicine, Department I, Heidelberg University, Im Neuenheimer Feld 669, 69120 Heidelberg, Germany
| | - Gernot Poschet
- Centre for Organismal Studies (COS), Plant Molecular Biology, Heidelberg University, Im Neuenheimer Feld 360, 69120 Heidelberg, Germany
| | - Christian Lüchtenborg
- Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Britta Brügger
- Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Sabine Strahl
- Centre for Organismal Studies (COS), Glycobiology, Heidelberg University, Im Neuenheimer Feld 360, 69120 Heidelberg, Germany
| | - Friederike Bürger
- Centre for Child and Adolescent Medicine, Department I, Heidelberg University, Im Neuenheimer Feld 669, 69120 Heidelberg, Germany
| | - Jürgen G Okun
- Centre for Child and Adolescent Medicine, Department I, Heidelberg University, Im Neuenheimer Feld 669, 69120 Heidelberg, Germany
| | - Hana Hansikova
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Czech Republic
| | - Christian Thiel
- Centre for Child and Adolescent Medicine, Department I, Heidelberg University, Im Neuenheimer Feld 669, 69120 Heidelberg, Germany.
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5
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Zhang Y, Xu B. Involvement of testicular N-glycoproteome heterogeneity in seasonal spermatogenesis of the American mink (Neovison vison). Front Vet Sci 2022; 9:1001431. [PMID: 36406079 PMCID: PMC9672844 DOI: 10.3389/fvets.2022.1001431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Accepted: 10/11/2022] [Indexed: 11/06/2022] Open
Abstract
Spermatogenesis in the American mink is characterized by an annual cycle of transition involving completely inactive and fully activated stages. N-glycosylation of proteins has emerged as an important regulator as it affects protein folding, secretion, degradation, and activity. However, the function of protein N-glycosylation in seasonal spermatogenesis of the American mink remains unclear. In the present study, we established a proteome-wide stoichiometry of N-glycosylation in mink testes at various phases of spermatogenesis using N-linked glycosylated-peptide enrichment in combination with liquid chromatography-tandem mass spectrometry analysis. A total of 532 N-glycosylated sites matching the canonical Asn-X-Ser/Thr motif were identified in 357 testicular proteins. Both the number of glycoproteins and the sites of N-glycosylated proteins in mink testes were highly dynamic at different stages. Functional analyses showed that testicular proteins with different N-glycosylation might play a vital role in spermatogenesis by affecting their folding, distribution, stability, and activity. Overall, our data suggest that the dynamics of N-glycosylation of testicular proteins are involved in seasonal spermatogenesis in the American mink.
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6
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Stanley P, Tanwar A. Regulation of myeloid and lymphoid cell development by O-glycans on Notch. Front Mol Biosci 2022; 9:979724. [PMID: 36406268 PMCID: PMC9672378 DOI: 10.3389/fmolb.2022.979724] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 10/13/2022] [Indexed: 10/06/2023] Open
Abstract
Notch signaling via NOTCH1 stimulated by Delta-like ligand 4 (DLL4) is required for the development of T cells in thymus, and NOTCH2 stimulated by Notch ligand DLL1 is required for the development of marginal zone (MZ) B cells in spleen. Notch signaling also regulates myeloid cell production in bone marrow and is an essential contributor to the generation of early hematopoietic stem cells (HSC). The differentiation program in each of these cellular contexts is optimized by the regulation of Notch signaling strength by O-glycans attached to epidermal growth factor-like (EGF) repeats in the extracellular domain of Notch receptors. There are three major types of O-glycan on NOTCH1 and NOTCH2 - O-fucose, O-glucose and O-GlcNAc. The initiating sugar of each O-glycan is added in the endoplasmic reticulum (ER) by glycosyltransferases POFUT1 (fucose), POGLUT1/2/3 (glucose) or EOGT (GlcNAc), respectively. Additional sugars are added in the Golgi compartment during passage through the secretory pathway to the plasma membrane. Of particular significance for Notch signaling is the addition of GlcNAc to O-fucose on an EGF repeat by the Fringe GlcNAc-transferases LFNG, MFNG or RFNG. Canonical Notch ligands (DLL1, DLL4, JAG1, JAG2) expressed in stromal cells bind to the extracellular domain of Notch receptors expressed in hematopoietic stem cells and myeloid and lymphoid progenitors to activate Notch signaling. Ligand-receptor binding is differentially regulated by the O-glycans on Notch. This review will summarize our understanding of the regulation of Notch signaling in myeloid and lymphoid cell development by specific O-glycans in mice with dysregulated expression of a particular glycosyltransferase and discuss how this may impact immune system development and malignancy in general, and in individuals with a congenital defect in the synthesis of the O-glycans attached to EGF repeats.
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Affiliation(s)
- Pamela Stanley
- Department of Cell Biology, Albert Einstein College Medicine, New York, NY, United States
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7
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Wang CD, Xu S, Chen S, Chen ZH, Dean N, Wang N, Gao XD. An in vitro assay for enzymatic studies on human ALG13/14 heterodimeric UDP-N-acetylglucosamine transferase. Front Cell Dev Biol 2022; 10:1008078. [PMID: 36200043 PMCID: PMC9527342 DOI: 10.3389/fcell.2022.1008078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 08/30/2022] [Indexed: 11/13/2022] Open
Abstract
The second step of eukaryotic lipid-linked oligosaccharide (LLO) biosynthesis is catalyzed by the conserved ALG13/ALG14 heterodimeric UDP-N-acetylglucosamine transferase (GnTase). In humans, mutations in ALG13 or ALG14 lead to severe neurological disorders with a multisystem phenotype, known as ALG13/14-CDG (congenital disorders of glycosylation). How these mutations relate to disease is unknown because to date, a reliable GnTase assay for studying the ALG13/14 complex is lacking. Here we describe the development of a liquid chromatography/mass spectrometry-based quantitative GnTase assay using chemically synthesized GlcNAc-pyrophosphate-dolichol as the acceptor and purified human ALG13/14 dimeric enzyme. This assay enabled us to demonstrate that in contrast to the literature, only the shorter human ALG13 isoform 2, but not the longer isoform 1 forms a functional complex with ALG14 that participates in LLO synthesis. The longer ALG13 isoform 1 does not form a complex with ALG14 and therefore lacks GnTase activity. Importantly, we further established a quantitative assay for GnTase activities of ALG13- and ALG14-CDG variant alleles, demonstrating that GnTase deficiency is the cause of ALG13/14-CDG phenotypes.
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Affiliation(s)
- Chun-Di Wang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Si Xu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Shuai Chen
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Zheng-Hui Chen
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Neta Dean
- Department of Biochemistry and Cell Biology, Stony Brook University, New York City, NY, United States
| | - Ning Wang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
- *Correspondence: Xiao-Dong Gao, ; Ning Wang,
| | - Xiao-Dong Gao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
- *Correspondence: Xiao-Dong Gao, ; Ning Wang,
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8
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Himmelreich N, Dimitrov B, Zielonka M, Hüllen A, Hoffmann GF, Juenger H, Müller H, Lorenz I, Busse B, Marschall C, Schlüter G, Thiel C. Missense variant c.1460 T > C (p.L487P) enhances protein degradation of ER mannosyltransferase ALG9 in two new ALG9-CDG patients presenting with West syndrome and review of the literature. Mol Genet Metab 2022; 136:274-281. [PMID: 35839600 DOI: 10.1016/j.ymgme.2022.06.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 06/20/2022] [Accepted: 06/21/2022] [Indexed: 12/01/2022]
Abstract
ALG9-CDG is a CDG-I defect within the group of Congenital Disorders of Glycosylation (CDG). We here describe the clinical symptoms of two new and unrelated ALG9-CDG patients, both carrying the novel homozygous missense variant c.1460 T > C (p.L487P) in the ALG9 gene which led to global developmental delay, psychomotor disability, facial dysmorphisms, brain and heart defects, hearing loss, hypotonia, as well as feeding problems. New clinical symptoms comprised West syndrome with hypsarrhythmia. Quantitative RT-PCR analysis revealed a significantly enhanced ALG9 mRNA transcript level, whereas the protein amount in fibroblasts was significantly reduced. This could be ascribed to a stronger degradation of the mutated ALG9 protein in patient fibroblasts. Lipid-linked oligosaccharide analysis showed an ALG9-CDG characteristic accumulation of Man6GlcNAc2-PP-dolichol and Man8GlcNAc2-PP-dolichol in patient cells. The clinical findings of our patients and of all previously published ALG9-CDG patients are brought together to further expand the knowledge about this rare N-glycosylation disorder. SYNOPSIS: Homozygosity for p.L487P in ALG9 causes protein degradation and leads to West syndrome.
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Affiliation(s)
- Nastassja Himmelreich
- Center for Child and Adolescent Medicine, Pediatrics I, University of Heidelberg, Analysezentrum 3, Im Neuenheimer Feld 669, 69120 Heidelberg, Germany
| | - Bianca Dimitrov
- Center for Child and Adolescent Medicine, Pediatrics I, University of Heidelberg, Analysezentrum 3, Im Neuenheimer Feld 669, 69120 Heidelberg, Germany
| | - Matthias Zielonka
- Center for Child and Adolescent Medicine, Pediatrics I, University of Heidelberg, Analysezentrum 3, Im Neuenheimer Feld 669, 69120 Heidelberg, Germany
| | - Andreas Hüllen
- Center for Child and Adolescent Medicine, Pediatrics I, University of Heidelberg, Analysezentrum 3, Im Neuenheimer Feld 669, 69120 Heidelberg, Germany
| | - Georg Friedrich Hoffmann
- Center for Child and Adolescent Medicine, Pediatrics I, University of Heidelberg, Analysezentrum 3, Im Neuenheimer Feld 669, 69120 Heidelberg, Germany
| | - Hendrik Juenger
- Klinik für Kinderheilkunde und Jugendmedizin, Neonatologie, Klinikum Kempten, Robert-Weixler-Straße 50, 87439 Kempten, Germany
| | - Herbert Müller
- Klinik für Kinderheilkunde und Jugendmedizin, Neonatologie, Klinikum Kempten, Robert-Weixler-Straße 50, 87439 Kempten, Germany
| | - Imke Lorenz
- Klinik für Kinder und Jugendliche der Universität Erlangen, Abteilung für Neuropädiatrie und Sozialpädiatrie, Loschgestraße 15, 91054 Erlangen, Germany
| | - Birgit Busse
- MVZ Martinsried, Lochhamer Str.29, 82152 Martinsried, Germany
| | | | - Gregor Schlüter
- Pränatalmedizin, Gynäkologie und Genetik (MVZ), Bankgasse 3, 90402 Nürnberg, Germany
| | - Christian Thiel
- Center for Child and Adolescent Medicine, Pediatrics I, University of Heidelberg, Analysezentrum 3, Im Neuenheimer Feld 669, 69120 Heidelberg, Germany.
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9
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Boyer SW, Johnsen C, Morava E. Nutrition interventions in congenital disorders of glycosylation. Trends Mol Med 2022; 28:463-481. [PMID: 35562242 DOI: 10.1016/j.molmed.2022.04.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 03/30/2022] [Accepted: 04/04/2022] [Indexed: 12/13/2022]
Abstract
Congenital disorders of glycosylation (CDG) are a group of more than 160 inborn errors of metabolism affecting multiple pathways of protein and lipid glycosylation. Patients present with a wide range of symptoms and therapies are only available for very few subtypes. Specific nutritional treatment options for certain CDG types include oral supplementation of monosaccharide sugars, manganese, uridine, or pyridoxine. Additional management includes specific diets (i.e., complex carbohydrate or ketogenic diet), iron supplementation, and albumin infusions. We review the dietary management in CDG with a focus on two subgroups: N-linked glycosylation defects and GPI-anchor disorders.
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Affiliation(s)
- Suzanne W Boyer
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA
| | - Christin Johnsen
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA
| | - Eva Morava
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA.
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10
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Freeze HH, Jaeken J, Matthijs G. CDG or not CDG. J Inherit Metab Dis 2022; 45:383-385. [PMID: 35338706 PMCID: PMC9121739 DOI: 10.1002/jimd.12498] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 03/16/2022] [Accepted: 03/24/2022] [Indexed: 11/09/2022]
Affiliation(s)
- Hudson H. Freeze
- Human Genetics Program, Sanford Burnham Prebys, La Jolla, CA 92037, USA
| | - Jaak Jaeken
- Center of Metabolic Diseases, KU Leuven, Leuven, Belgium
| | - Gert Matthijs
- Department of Human Genetics, KU Leuven, Leuven, Belgium
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