title: COG5-CDG: expanding the clinical spectrum.
abstract: BACKGROUND
  The Conserved Oligomeric Golgi (COG) complex is involved in the retrograde trafficking of Golgi components, thereby affecting the localization of Golgi glycosyltransferases. Deficiency of a COG-subunit leads to defective protein glycosylation, and thus Congenital Disorders of Glycosylation (CDG). Mutations in subunits 1, 4, 5, 6, 7 and 8 have been associated with CDG-II. The first patient with COG5-CDG was recently described (Paesold-Burda et al. Hum Mol Genet 2009; 18:4350-6). Contrary to most other COG-CDG cases, the patient presented a mild/moderate phenotype, i.e. moderate psychomotor retardation with language delay, truncal ataxia and slight hypotonia.
  
  
  METHODS
  CDG-IIx patients from our database were screened for mutations in COG5. Clinical data were compared. Brefeldin A treatment of fibroblasts and immunoblotting experiments were performed to support the diagnosis.
  
  
  CONCLUSIONS
  We identified five new patients with proven COG5 deficiency. We conclude that the clinical picture is not always as mild as previously described. It rather comprises a broad spectrum with phenotypes ranging from mild to very severe. Interestingly, on a clinical basis some of the patients present a significant overlap with COG7-CDG, a finding which can probably be explained by subunit interactions at the protein level.
authors.affiliation: Centre for Metabolic Diseases, University Hospital Gasthuisberg, Leuven, Belgium.
authors.forename: Daisy
authors.initials: D
authors.lastname: Rymen
authors.forename: Liesbeth
authors.initials: L
authors.lastname: Keldermans
authors.forename: Valérie
authors.initials: V
authors.lastname: Race
authors.forename: Luc
authors.initials: L
authors.lastname: Régal
authors.forename: Nicolas
authors.initials: N
authors.lastname: Deconinck
authors.forename: Carlo
authors.initials: C
authors.lastname: Dionisi-Vici
authors.forename: Cheuk-Wing
authors.initials: CW
authors.lastname: Fung
authors.forename: Luisa
authors.initials: L
authors.lastname: Sturiale
authors.forename: Claire
authors.initials: C
authors.lastname: Rosnoblet
authors.forename: François
authors.initials: F
authors.lastname: Foulquier
authors.forename: Gert
authors.initials: G
authors.lastname: Matthijs
authors.forename: Jaak
authors.initials: J
authors.lastname: Jaeken
mesh_terms: D033942:Adaptor Proteins, Vesicular Transport / Q000235:genetics* / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D018981:Congenital Disorders of Glycosylation / Q000175:diagnosis / Q000235:genetics* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D009154:Mutation; D010641:Phenotype; D012720:Severity of Illness Index; D055815:Young Adult
chemical_list: D033942:Adaptor Proteins, Vesicular Transport; C115632:COG5 protein, human