scholarly journals Dissecting Total Plasma and Protein-Specific Glycosylation Profiles in Congenital Disorders of Glycosylation

2020 ◽  
Vol 21 (20) ◽  
pp. 7635 ◽  
Author(s):  
Agnes L. Hipgrave Ederveen ◽  
Noortje de Haan ◽  
Melissa Baerenfaenger ◽  
Dirk J. Lefeber ◽  
Manfred Wuhrer
Keyword(s):  
Sialic Acid ◽  
Plasma Proteins ◽  
Protein Glycosylation ◽  
Congenital Disorders ◽  
Congenital Disorders Of Glycosylation ◽  
Healthy Controls ◽  
Total Plasma ◽  
Intact Proteins ◽  
Linkage Isomers ◽  
Specific Effects

Protein N-glycosylation is a multifactorial process involved in many biological processes. A broad range of congenital disorders of glycosylation (CDGs) have been described that feature defects in protein N-glycan biosynthesis. Here, we present insights into the disrupted N-glycosylation of various CDG patients exhibiting defects in the transport of nucleotide sugars, Golgi glycosylation or Golgi trafficking. We studied enzymatically released N-glycans of total plasma proteins and affinity purified immunoglobulin G (IgG) from patients and healthy controls using mass spectrometry (MS). The applied method allowed the differentiation of sialic acid linkage isomers via their derivatization. Furthermore, protein-specific glycan profiles were quantified for transferrin and IgG Fc using electrospray ionization MS of intact proteins and glycopeptides, respectively. Next to the previously described glycomic effects, we report unprecedented sialic linkage-specific effects. Defects in proteins involved in Golgi trafficking (COG5-CDG) and CMP-sialic acid transport (SLC35A1-CDG) resulted in lower levels of sialylated structures on plasma proteins as compared to healthy controls. Findings for these specific CDGs include a more pronounced effect for α2,3-sialylation than for α2,6-sialylation. The diverse abnormalities in glycomic features described in this study reflect the broad range of biological mechanisms that influence protein glycosylation.

scholarly journals Congenital disorders of glycosylation. Part II. Defects of protein O-glycosylation.

2013 ◽  
Vol 60 (3) ◽  
Author(s):  
Bogdan Cylwik ◽  
Karina Lipartowska ◽  
Lech Chrostek ◽  
Ewa Gruszewska
Keyword(s):  
Gene Mutations ◽  
Protein Glycosylation ◽  
Congenital Disorders ◽  
Congenital Disorders Of Glycosylation ◽  
Post Translational Modification ◽  
Specific Expression ◽  
Laboratory Findings ◽  
Ehlers Danlos Syndrome ◽  
Core Proteins ◽  
Organ Specific

Glycosylation is a form of post-translational modification of proteins and occurs in every living cell. The carbohydrate chains attached to the proteins serve various functions. There are two main types of protein glycosylation: N-glycosylation and O-glycosylation. In this paper, we describe the O-glycosylation process and currently known congenital disorders of glycosylation associated with defects of protein O-glycosylation. This process takes place in the cis Golgi apparatus after N-glycosylation and folding of the proteins. The O-glycosylation is essential in the biosynthesis of mucins, the formation of proteoglycan core proteins and blood group proteins. Most common forms of O-glycans are the mucin-type glycans. There are more than 20 known disorders related to O-glycosylation disturbances. We review 8 of the following diseases linked to defects in the synthesis of O-xylosylglycans, O-N acetylgalactosaminylglycans, O-xylosyl/N-acetylglycans, O-mannosylglycans, and O-fucosylglycans: multiple exostoses, progeroid variant of Ehlers-Danlos syndrome, progeria, familial tumoral calcinosis, Schneckenbecken dysplasia, Walker-Warburg syndrome, spondylocostal dysostosis type 3, and Peter's plus syndrome. Causes of these diseases include gene mutations and deficiency of proteins (enzymes). Their diagnosis includes syndromic presentation, organ-specific expression and laboratory findings.

scholarly journals Our Experience with Diagnostics of Congenital Disorders of Glycosylation

2004 ◽  
Vol 47 (4) ◽  
pp. 267-272 ◽  
Author(s):  
Ziad Albahri ◽  
Eliška Marklová ◽  
Hubert Vaníček ◽  
Lenka Minxová ◽  
Petr Dědek ◽  
...  
Keyword(s):  
Metabolic Disease ◽  
Isoelectric Focusing ◽  
Congenital Disorders ◽  
Serum Transferrin ◽  
Congenital Disorders Of Glycosylation ◽  
Healthy Controls ◽  
Protein Variants

The aim of this study is to report our 3years experience with the screening of congenital disorders of glycosylation. A common isoelectric focusing method with immunofixation was used for analysis of serum transferrin and α1-antitrypsin, apart from several other procedures. A group of about 1000 individuals, both healthy controls and patients, mostly with signs of a metabolic disease were examined. Here we present an overview of 1) hypoglycosylation findings, 2) distribution of protein variants, 3) misguiding rare Tf variants found in our set, and 4) association of some phenotypes with various diseases.

scholarly journals Congenital Disorders of Glycosylation from a Neurological Perspective

2021 ◽  
Vol 11 (1) ◽  
pp. 88
Author(s):  
Justyna Paprocka ◽  
Aleksandra Jezela-Stanek ◽  
Anna Tylki-Szymańska ◽  
Stephanie Grunewald
Keyword(s):  
Neurological Symptoms ◽  
Protein Glycosylation ◽  
Screening Tests ◽  
Main Element ◽  
Congenital Disorders ◽  
Congenital Disorders Of Glycosylation ◽  
Brain Malformations ◽  
Cell Membrane Proteins ◽  
Human Proteins ◽  
Sugar Chains

Most plasma proteins, cell membrane proteins and other proteins are glycoproteins with sugar chains attached to the polypeptide-glycans. Glycosylation is the main element of the post-translational transformation of most human proteins. Since glycosylation processes are necessary for many different biological processes, patients present a diverse spectrum of phenotypes and severity of symptoms. The most frequently observed neurological symptoms in congenital disorders of glycosylation (CDG) are: epilepsy, intellectual disability, myopathies, neuropathies and stroke-like episodes. Epilepsy is seen in many CDG subtypes and particularly present in the case of mutations in the following genes: ALG13, DOLK, DPAGT1, SLC35A2, ST3GAL3, PIGA, PIGW, ST3GAL5. On brain neuroimaging, atrophic changes of the cerebellum and cerebrum are frequently seen. Brain malformations particularly in the group of dystroglycanopathies are reported. Despite the growing number of CDG patients in the world and often neurological symptoms dominating in the clinical picture, the number of performed screening tests eg transferrin isoforms is systematically decreasing as broadened genetic testing is recently more favored. The aim of the review is the summary of selected neurological symptoms in CDG described in the literature in one paper. It is especially important for pediatric neurologists not experienced in the field of metabolic medicine. It may help to facilitate the diagnosis of this expanding group of disorders. Biochemically, this paper focuses on protein glycosylation abnormalities.

scholarly journals Congenital disorders of glycosylation. Part I. Defects of protein N-glycosylation.

2013 ◽  
Vol 60 (2) ◽  
Author(s):  
Bogdan Cylwik ◽  
Marcin Naklicki ◽  
Lech Chrostek ◽  
Ewa Gruszewska
Keyword(s):  
Protein Modification ◽  
Unknown Origin ◽  
Protein Glycosylation ◽  
Congenital Disorders ◽  
Type I ◽  
Congenital Disorders Of Glycosylation ◽  
Multisystem Disorder ◽  
Clinical Description ◽  
Glycosylation Pathway ◽  
Disease Family

Glycosylation is the most common chemical process of protein modification and occurs in every living cell. Disturbances of this process may be either congenital or acquired. Congenital disorders of glycosylation (CDG) are a rapidly growing disease family, with about 50 disorders reported since its first clinical description in 1980. Most of the human diseases have been discovered recently. CDG result from defects in the synthesis of the N- and O-glycans moiety of glycoproteins, and in the attachment to the polypeptide chain of proteins. These defects have been found in the activation, presentation, and transport of sugar precursors, in the enzymes responsible for glycosylation, and in proteins that control the traffic of component. There are two main types of protein glycosylation: N-glycosylation and O-glycosylation. Most diseases are due to defects in the N-glycosylation pathway. For the sake of convenience, CDG were divided into 2 types, type I and II. CDG can affect nearly all organs and systems. The considerable variability of clinical features makes it difficult to recognize patients with CDG. Diagnosis can be made on the basis of abnormal glycosylation display. In this paper, an overview of CDG with a new nomenclature limited to the group of protein N-glycosylation disorders, clinical phenotype and diagnostic approach, have been presented. The location, reasons for defects, and the number of cases have been also described. This publication aims to draw attention to the possibility of occurrence of CDG in each multisystem disorder with an unknown origin.

scholarly journals The Estimated Prevalence of N-Linked Congenital Disorders of Glycosylation Across Various Populations Based on Allele Frequencies in General Population Databases

2021 ◽  
Vol 12 ◽  
Author(s):  
Sander Pajusalu ◽  
Mari-Anne Vals ◽  
Laura Mihkla ◽  
Ustina Šamarina ◽  
Tiina Kahre ◽  
...  
Keyword(s):  
Metabolic Diseases ◽  
Clinical Care ◽  
Protein Glycosylation ◽  
Allele Frequencies ◽  
European Ancestry ◽  
Congenital Disorders ◽  
Congenital Disorders Of Glycosylation ◽  
Diverse Populations ◽  
Loss Of Function ◽  
Birth Prevalence

Congenital disorders of glycosylation (CDG) are a widely acknowledged group of metabolic diseases. PMM2-CDG is the most frequently diagnosed CDG with a prevalence as high as one in 20,000. In contrast, the prevalence of other CDG types remains unknown. This study aimed to analyze the estimated prevalence of different N-linked protein glycosylation disorders. We extracted allele frequencies for diverse populations from The Genome Aggregation Database (gnomAD), encompassing variant frequency information from 141,456 individuals. To identify pathogenic variants, we used the ClinVar database as a primary source. High confidence loss-of-function variants as defined by the LOFTEE algorithm were also classified as pathogenic. After summing up population frequencies for pathogenic alleles, estimated disease birth prevalence values with confidence intervals were calculated using the Bayesian method. We first validated our approach using two more common recessive disorders (cystic fibrosis and phenylketonuria) by showing that the estimated prevalences calculated from population allele frequencies were in accordance with previously published epidemiological studies. Among assessed 27 autosomal recessive N-glycosylation disorders, the only disease with estimated birth prevalence higher than one in 100,000 was PMM2-CDG (in both, all gnomAD individuals and those with European ancestry). The combined prevalence of 27 different N-glycosylation disorders was around one in 22,000 Europeans but varied considerably across populations. We will show estimated prevalence data from diverse populations and explain the possible pitfalls of this analysis. Still, we are confident that these data will guide CDG research and clinical care to identify CDG across populations.

scholarly journals Targeted Proteomics Reveals Quantitative Differences in Low Abundance Glycosyltransferases of Patients with Congenital Disorders of Glycosylation

2020 ◽  
Author(s):  
Roman Sakson ◽  
Lars Beedgen ◽  
Patrick Bernhard ◽  
Keziban M. Alp ◽  
Nicole Lübbehusen ◽  
...  
Keyword(s):  
Multiple Reaction Monitoring ◽  
Gene Mutations ◽  
Internal Standard ◽  
Fibroblast Cell ◽  
Protein Glycosylation ◽  
Stable Complex ◽  
Congenital Disorders ◽  
Type I ◽  
Congenital Disorders Of Glycosylation ◽  
Domains Of Life

AbstractProtein glycosylation is essential in all domains of life and its mutational impairment in humans can result in severe diseases named Congenital Disorders of Glycosylation (CDGs). Studies on molecular level are however challenging, because many glycosyltransferases in the endoplasmic reticulum (ER) are low abundance membrane proteins. We established a comprehensive multiple reaction monitoring (MRM) assay to quantify most human glycosyltransferases involved in the processes of N-glycosylation,O- and C-mannosylation in the ER. To increase reproducibility, a membrane protein fraction of isotopically labeled HEK 293T cells was used as an internal standard. With this internal standard the MRM assay is easily transferable between laboratories. 22 glycosyltransferases could be reliably quantified from whole cell lysates of HEK 293T cells, HeLa cells and skin fibroblast cell lines. We then analyzed fibroblasts derived from CDG type I patients with mutations in the ALG1,ALG2 or ALG11 gene. Mutations in ALG1 or ALG2 gene strongly reduced the levels of the ALG1 and ALG2 protein, respectively. In contrast, the levels of all other glycosyltransferases remained unchanged, which was unexpected given evidence that the ALG1, ALG2 and ALG11 proteins form a stable complex. This study describes an efficient workflow for the development of MRM assays for low abundance proteins, establishes a ready-to-use tool for the comprehensive quantification of ER-localized glycosyltransferases and provides new insight into the organization of disease-relevant glycosylation processes.

scholarly journals Congenital disorders of glycosylation in children - histopathological and ultrastructural changes in the liver

2021 ◽  
Author(s):  
Patryk Lipiński ◽  
Joanna Cielecka-Kuszyk ◽  
Elżbieta Czarnowska ◽  
Anna Bogdańska ◽  
Piotr Socha ◽  
...  
Keyword(s):  
Ultrastructural Changes ◽  
Congenital Disorders ◽  
Congenital Disorders Of Glycosylation

scholarly journals The Importance of Platelet Glycoside Residues in the Haemostasis of Patients with Immune Thrombocytopaenia

2021 ◽  
Vol 10 (8) ◽  
pp. 1661
Author(s):  
Andrés Ramírez-López ◽  
María Teresa Álvarez Román ◽  
Elena Monzón Manzano ◽  
Paula Acuña ◽  
Elena G. Arias-Salgado ◽  
...  
Keyword(s):  
Platelet Count ◽  
Sialic Acid ◽  
Healthy Controls ◽  
Caspase Activity ◽  
Antibody Dependent Cellular Cytotoxicity ◽  
Activation Markers ◽  
Platelet Surface ◽  
Mannose Binding ◽  
Transversal Study ◽  
Binding Lectin

Loss of sialic acid from the carbohydrate side chains of platelet glycoproteins can affect platelet clearance, a proposed mechanism involved in the etiopathogenesis of immune thrombocytopaenia (ITP). We aimed to assess whether changes in platelet glycosylation in patients with ITP affected platelet counts, function, and apoptosis. This observational, prospective, and transversal study included 82 patients with chronic primary ITP and 115 healthy controls. We measured platelet activation markers and assayed platelet glycosylation and caspase activity, analysing samples using flow cytometry. Platelets from patients with ITP with a platelet count <30 × 103/µL presented less sialic acid. Levels of α1,6-fucose (a glycan residue that can directly regulate antibody-dependent cellular cytotoxicity) and α-mannose (which can be recognised by mannose-binding-lectin and activate the complement pathway) were increased in the platelets from these patients. Platelet surface exposure of other glycoside residues due to sialic acid loss inversely correlated with platelet count and the ability to be activated. Moreover, loss of sialic acid induced the ingestion of platelets by human hepatome HepG2 cells. Changes in glycoside composition of glycoproteins on the platelets’ surface impaired their functional capacity and increased their apoptosis. These changes in platelet glycoside residues appeared to be related to ITP severity.

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