N-glycome analysis detects dysglycosylation missed by conventional methods in SLC39A8 deficiency

© 2020 The Authors. Journal of Inherited Metabolic Disease published by John Wiley & Sons Ltd on behalf of SSIEM..

Congenital disorders of glycosylation (CDG) are a growing group of inborn metabolic disorders with multiorgan presentation. SLC39A8-CDG is a severe subtype caused by biallelic mutations in the manganese transporter SLC39A8, reducing levels of this essential cofactor for many enzymes including glycosyltransferases. The current diagnostic standard for disorders of N-glycosylation is the analysis of serum transferrin. Exome and Sanger sequencing were performed in two patients with severe neurodevelopmental phenotypes suggestive of CDG. Transferrin glycosylation was analyzed by high-performance liquid chromatography (HPLC) and isoelectric focusing in addition to comprehensive N-glycome analysis using matrix-assisted laser desorption ionization time of flight (MALDI-TOF) mass spectrometry (MS). Atomic absorption spectroscopy was used to quantify whole blood manganese levels. Both patients presented with a severe, multisystem disorder, and a complex neurological phenotype. Magnetic resonance imaging (MRI) revealed a Leigh-like syndrome with bilateral T2 hyperintensities of the basal ganglia. In patient 1, exome sequencing identified the previously undescribed homozygous variant c.608T>C [p.F203S] in SLC39A8. Patient 2 was found to be homozygous for c.112G>C [p.G38R]. Both individuals showed a reduction of whole blood manganese, though transferrin glycosylation was normal. N-glycome using MALDI-TOF MS identified an increase of the asialo-agalactosylated precursor N-glycan A2G1S1 and a decrease in bisected structures. In addition, analysis of heterozygous CDG-allele carriers identified similar but less severe glycosylation changes. Despite its reliance as a clinical gold standard, analysis of transferrin glycosylation cannot be categorically used to rule out SLC39A8-CDG. These results emphasize that SLC39A8-CDG presents as a spectrum of dysregulated glycosylation, and MS is an important tool for identifying deficiencies not detected by conventional methods.

Medienart:

E-Artikel

Erscheinungsjahr:

2020

Erschienen:

2020

Enthalten in:

Zur Gesamtaufnahme - volume:43

Enthalten in:

Journal of inherited metabolic disease - 43(2020), 6 vom: 01. Nov., Seite 1370-1381

Sprache:

Englisch

Beteiligte Personen:

Park, Julien H [VerfasserIn]
Mealer, Robert G [VerfasserIn]
Elias, Abdallah F [VerfasserIn]
Hoffmann, Susanne [VerfasserIn]
Grüneberg, Marianne [VerfasserIn]
Biskup, Saskia [VerfasserIn]
Fobker, Manfred [VerfasserIn]
Haven, Jaclyn [VerfasserIn]
Mangels, Ute [VerfasserIn]
Reunert, Janine [VerfasserIn]
Rust, Stephan [VerfasserIn]
Schoof, Jonathan [VerfasserIn]
Schwanke, Corbin [VerfasserIn]
Smoller, Jordan W [VerfasserIn]
Cummings, Richard D [VerfasserIn]
Marquardt, Thorsten [VerfasserIn]

Links:

Volltext

Themen:

42Z2K6ZL8P
Cation Transport Proteins
Congenital disorders of glycosylation
Glycosylation
Journal Article
MALDI-TOF MS
Manganese
Multicenter Study
Research Support, Non-U.S. Gov't
SLC39A8
SLC39A8 protein, human
Transferrin

Anmerkungen:

Date Completed 07.10.2021

Date Revised 07.12.2022

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1002/jimd.12306

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM314261044