Clinical, biochemical and molecular phenotype of congenital disorders of glycosylation: long-term follow-up (original) (raw)
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Glycobiology, 2005
Defects in the biosynthesis of N- and core 1 O-glycans may be found by isoelectric focusing (IEF) of plasma transferrin and apolipoprotein C-III (apoC-III). We hypothesized that IEF of transferrin and apoC-III in combination with sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of apoC-III may provide a classification for congenital disorders of glycosylation (CDG) patients. We analyzed plasma from 22 patients with eight different and well-characterized CDG subtypes and 19 cases with unsolved CDG. Transferrin IEF (TIEF) has been used to distinguish between N-glycan assembly (type 1 profile) and processing (type 2 profile) defects. We differentiated two different CDG type 2 TIEF profiles: The "asialo profile" characterized by elevated levels of asialo- and monosialotransferrin and the "disialo profile" characterized by increased levels of disialo- and trisialotransferrin. ApoC-III IEF gave two abnormal profiles ("apoC-III(0)" and &qu...
Journal of Dr. Behcet Uz Children s Hospital, 2020
INTRODUCTION: Congenital disorders of glycosylation (CDG) is a group of genetic diseases that lead to impairment in protein and lipid glycosylation and glycosylphosphatidylinositol synthesis. More than 140 types of CDG have been identified and the number is increasing day by day. Glycosylation is very important in post-translational process and half of the proteins in human organism require glycosylation in order to exert an effect. Therefore, the disease causes an extremely wide clinical spectrum in affected patients. Our aim is to share the clinical features of our patients with CDG and contributing to increase the awareness of this highly heterogeneous clinical spectrum among paediatricians. METHODS: Nine patients from 9 families whose molecular and biochemical diagnosis was confirmed were included in the study. All patients were evaluated by a pediatric metabolism specialist. Laboratory analysis results and clinical features were obtained from hospital records. Clinical, biochem...
Congenital Disorders of Glycosylation: What Clinicians Need to Know?
Frontiers in Pediatrics, 2021
Congenital disorders of glycosylation (CDG) are a group of clinically heterogeneous disorders characterized by defects in the synthesis of glycans and their attachment to proteins and lipids. This manuscript aims to provide a classification of the clinical presentation, diagnostic methods, and treatment of CDG based on the literature review and our own experience (referral center in Poland). A diagnostic algorithm for CDG was also proposed. Isoelectric focusing (IEF) of serum transferrin (Tf) is still the method of choice for diagnosing N-glycosylation disorders associated with sialic acid deficiency. Nowadays, high-performance liquid chromatography, capillary zone electrophoresis, and mass spectrometry techniques are used, although they are not routinely available. Since next-generation sequencing became more widely available, an improvement in diagnostics has been observed, with more patients and novel CDG subtypes being reported. Early and accurate diagnosis of CDG is crucial for...
Clinical glycomics for the diagnosis of congenital disorders of glycosylation
Journal of inherited metabolic disease, 2018
Clinical glycomics comprises a spectrum of different analytical methodologies to analyze glycan structures, which provides insights into the mechanisms of glycosylation. Within clinical diagnostics, glycomics serves as a functional readout of genetic variants, and can form a basis for therapy development, as was described for PGM1-CDG. Integration of glycomics with genomics has resulted in the elucidation of previously unknown disorders of glycosylation, namely CCDC115-CDG, TMEM199-CDG, ATP6AP1-CDG, MAN1B1-CDG, and PGM1-CDG. This review provides an introduction into protein glycosylation and presents the different glycomics methodologies ranging from gel electrophoresis to mass spectrometry (MS) and from free glycans to intact glycoproteins. The role of glycomics in the diagnosis of congenital disorders of glycosylation (CDG) is presented, including a diagnostic flow chart and an overview of glycomics data of known CDG subtypes. The review ends with some future perspectives, showing...
Update and perspectives on congenital disorders of glycosylation
Glycobiology, 2001
Defects in nine genes of the N-linked glycosylation pathway cause congenital disorders of glycosylation (CDGs) and serious medical consequences. Although glycobiology is seldom featured in a general medical education, an increasing number of physicians are becoming acquainted with the field because it directly impacts patient diagnosis and care. Medical practice and attitudes will change in the postgenomic era, and glycobiology has an opportunity to be a cornerstone of part of that new perspective. This review of recent developments in the CDG field describes the biochemical and molecular basis of these disorders, describes successful experimental approaches, and points out a few perspectives on current problems. The broad, multisystemic presentations of these patients emphasize that glycobiology is very much a general medical science, cutting across many traditional medical specialties. The glycobiology community is well poised to provide novel perspectives for the dedicated clinicians treating both wellknown and emerging human diseases.
Epidemiology of congenital disorders of glycosylation (CDG)—overview and perspectives
Journal of Rare Diseases
Background and aim Congenital disorders of glycosylation (CDG) are a large heterogeneous group of about 170 rare inherited metabolic disorders due to defective protein and lipid glycosylation. This study aimed to assemble and summarise available data on the epidemiology of CDG. Methods A set of keywords related to epidemiology and CDG was defined. The keywords were combined through a custom Python script, search through the MEDLINE database, using PubMed as the search engine. The script retrieved the correspondent MEDLINE data from each article, and the relevant information was exported. Next, inclusion and exclusion criteria were set and applied during the selection phase. Finally, epidemiology-related information was extracted and compiled. Results One hundred sixty-five papers on CDG epidemiology were included in this literature review. Most of them reported on the frequency of symptoms in CDG patients followed in cohort studies, on pathogenic variant allelic frequency, and on th...
[Congenital disorders of glycosylation]
Annales pharmaceutiques françaises, 2003
Congenital disorders of glycosylation (CDG) is a fast growing group of autosomal recessive inherited diseases caused by defects in glycosylation. The biosynthesis of the glycans is a pathways which occurs in the endoplasmic reticulum and Golgi complex thanks to highly specific enzymes: glycosidases and glycosyltransferases. The sequential addition of monosaccharides needs precursors which are nucleotide sugars or dolichyl sugars. CDG are divided into two groups: CDG I composed of defects in enzymes involved in the assembly of dolicholpyrophosphate oligosaccharide and in the transfer of oligosaccharide from dolicholpyrophosphate to an Asn residue on nascent proteins; CDG II composed of defects in the processing of protein-bound glycans with alterations in enzymes or in the transporters of monosaccharides. Clinical symptoms are poorly specific and multisystemic, biochemistry provides the diagnosis: Isoelectrofocalisation and western blot of serum transferrin and some other glycoprotei...
Our experience with diagnostics of congenital disorders of glycosylation
Acta medica (Hradec Králové) / Universitas Carolina, Facultas Medica Hradec Králové, 2004
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 alpha1-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.
Clinical and biochemical characteristics of congenital glycosylation disorders
2007
We report on 8 patients with a recently described novel subtype of congenital disorder of glycosylation type Ic (CDG-Ic). Their clinical presentation was mainly neurological with developmental retardation, muscular hypotonia, and epilepsy. Several symptoms commonly seen in CDG-Ia such as inverted nipples, abnormal fat distribution, and cerebellar hypoplasia were not observed. The clinical course is milder overall, with a better neurological outcome, than in CDG-Ia. The isoelectric focusing pattern of serum transferrin in CDG-Ia and CDG-Ic is indistinguishable. Interestingly, -trace protein in cerebrospinal fluid derived from immunoblot analysis of the brain showed a less pronounced hypoglycosylation pattern in CDG-Ic patients than in CDG-Ia patients. Analysis of lipid-linked oligosaccharides revealed an accumulation of Man 9 GlcNAc 2 intermediates due to dolichol pyrophosphate-Man 9 GlcNAc 2 ␣-1,3 glucosyltransferase deficiency. All patients were homozygous for an A333V mutation.
Congenital disorders of glycosylation: Have you encountered them?
Genetics in Medicine, 2000
Protein glycosylation creates hundreds of sugar structures that serve a spectrum of functions. So it is not surprising that one percent of transcribed genes produce or recognize sugar chains. Given this substantial investment, it is also not surprising that defects in sugar chain biosynthesis have substantial consequences for development, growth, and survival. In the past few years, mutations in seven of these genes have been shown to cause congenital disorders of glycosylation (CDG). Their pathologies, like glycosylation itself, are diverse and affect multiple systems. The CDG are almost certainly underdiagnosed in the community, so increased clinical awareness of the many presentations of CDG is important. Simple diagnostic tests, and possible dietary therapy for some ofthese patients, make it important to consider and rule out altered glycosylation in unexplained cases of psychomotor retardation, hypotonia, coagulopathy, hepatic fibrosis, protein-losing enteropathy, feeding difficulties, and failure to thrive.