MALDI-MS profiling of serum O-glycosylation and N-glycosylation in COG5-CDG

A. Palmigiano, R. O. Bua, R. Barone, D. Rymen, L. Régal, N. Deconinck, C. Dionisi-Vici, C. W. Fung, D. Garozzo, J. Jaeken, L. Sturiale

Research output: Contribution to journalArticlepeer-review


Congenital disorders of glycosylation (CDG) are due to defective glycosylation of glycoconjugates. Conserved oligomeric Golgi (COG)-CDG are genetic diseases due to defects of the COG complex subunits 1–8 causing N-glycan and O-glycan processing abnormalities. In COG-CDG, isoelectric focusing separation of undersialylated glycoforms of serum transferrin and apolipoprotein C-III (apoC-III) allows to detect N-glycosylation and O-glycosylation defects, respectively. COG5-CDG (COG5 subunit deficiency) is a multisystem disease with dysmorphic features, intellectual disability of variable degree, seizures, acquired microcephaly, sensory defects and autistic behavior. We applied matrix-assisted laser desorption/ionization-MS for a high-throughput screening of differential serum O-glycoform and N-glycoform in five patients with COG5-CDG. When compared with age-matched controls, COG5-CDG showed a significant increase of apoC-III0a (aglycosylated glycoform), whereas apoC-III1 (mono-sialylated glycoform) decreased significantly. Serum N-glycome of COG5-CDG patients was characterized by the relative abundance of undersialylated and undergalactosylated biantennary and triantennary glycans as well as slight increase of high-mannose structures and hybrid glycans. Using advanced and well-established MS-based approaches, the present findings reveal novel aspects on O-glycan and N-glycan profiling in COG5-CDG patients, thus providing an increase of current knowledge on glycosylation defects caused by impairment of COG subunits, in support of clinical diagnosis.

Original languageEnglish
Pages (from-to)372-377
Number of pages6
JournalJournal of Mass Spectrometry
Issue number6
Publication statusPublished - Jun 1 2017


  • apoC-III IEF
  • COG5-CDG
  • N-glycosylation
  • O-glycosylation

ASJC Scopus subject areas

  • Spectroscopy


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