title: A new method for the rapid diagnosis of protein N-linked congenital disorders of glycosylation.
abstract: The Congenital Disorders of Glycosylation (CDG) are a devastating group of genetic disorders that encompass a spectrum of glycosylation defects and are characterized by the underglycosylation of or the presence of abnormal glycans on glycoproteins. The N-linked CDG disorders (Type I and II) are usually diagnosed in chemical pathology laboratories by an abnormal serum transferrin isoelectric focusing (IEF) pattern. Transferrin has been the protein of choice for CDG analysis because it is well characterized, highly abundant, and easily detected in plasma. However, IEF provides limited information on the glycosylation defect and requires a separate and extensive glycan analysis to diagnose CDG Type II. We have therefore developed a simple bead-based immunoaffinity and mass spectrometry-based assay to address these issues. Our method uses immuno-purified transferrin and proteolytic digestion followed by a rapid 30 min mass spectral analysis and allows us to identify both micro- and macroheterogeneity of transferrin by sequencing of peptides and glycopeptides. In summary, we have developed a simple, rapid test for N-linked glycosylation disorders that is a significant improvement on existing laboratory tests currently used for investigating defective N-linked glycosylation.
authors.affiliation: Biochemistry Research Group, Clinical and Molecular Genetics Unit, Institute of Child Health & Great Ormond Street Hospital, University College London, United Kingdom. w.heywood@ich.ucl.ac.uk
authors.forename: Wendy E
authors.initials: WE
authors.lastname: Heywood
authors.forename: Philippa
authors.initials: P
authors.lastname: Mills
authors.forename: Stephanie
authors.initials: S
authors.lastname: Grunewald
authors.forename: Viki
authors.initials: V
authors.lastname: Worthington
authors.forename: Jaak
authors.initials: J
authors.lastname: Jaeken
authors.forename: Gabriela
authors.initials: G
authors.lastname: Carreno
authors.forename: Hugh
authors.initials: H
authors.lastname: Lemonde
authors.forename: Peter T
authors.initials: PT
authors.lastname: Clayton
authors.forename: Kevin
authors.initials: K
authors.lastname: Mills
mesh_terms: D002846:Chromatography, Affinity; D018981:Congenital Disorders of Glycosylation / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D006023:Glycoproteins / Q000097:blood* / Q000302:isolation & purification; D006031:Glycosylation; D006801:Humans; D013058:Mass Spectrometry; D010455:Peptides / Q000737:chemistry / Q000145:classification; D011134:Polysaccharides / Q000097:blood / Q000737:chemistry / Q000145:classification; D014168:Transferrin / Q000737:chemistry* / Q000145:classification / Q000302:isolation & purification*
chemical_list: D006023:Glycoproteins; D010455:Peptides; D011134:Polysaccharides; D014168:Transferrin