A novel disorder of N-glycosylation due to phosphomannose isomerase deficiency

Biochem Biophys Res Commun. 1998 Apr 7;245(1):38-42. doi: 10.1006/bbrc.1998.8385.


Three siblings suffered from an unusual disorder of cyclic vomiting and congenital hepatic fibrosis. Serum transferrin isoelectric focusing showed increased asialo- and disialotransferrin isoforms as seen in the carbohydrate-deficient glycoprotein (CDG) syndrome type I. Phosphomannomutase, which is deficient in most patients with type I CDG syndrome, was found to be normal in all three patients. Structural analysis of serum transferrin revealed nonglycosylated, hypoglycosylated, and normoglycosylated transferrin molecules. These findings suggested a defect in the early glycosylation pathway. Phosphomannose isomerase was found to be deficient and the defect was present in leucocytes, fibroblasts, and liver tissue. Phosphomannose isomerase deficiency appears to be a novel glycosylation disorder, which is biochemically indistinguishable from CDG syndrome type I. However, the clinical presentation is entirely different.

Publication types

  • Case Reports

MeSH terms

  • Adolescent
  • Child
  • Congenital Disorders of Glycosylation / classification
  • Congenital Disorders of Glycosylation / genetics
  • Female
  • Fructose / metabolism
  • Genetic Diseases, Inborn / genetics
  • Glucose / metabolism
  • Glycosylation
  • Humans
  • Male
  • Mannose / metabolism
  • Mannose-6-Phosphate Isomerase / deficiency*
  • Mannose-6-Phosphate Isomerase / genetics
  • Phosphotransferases (Phosphomutases) / analysis
  • Transferrin / analysis


  • Transferrin
  • Fructose
  • Mannose-6-Phosphate Isomerase
  • Phosphotransferases (Phosphomutases)
  • phosphomannomutase
  • Glucose
  • Mannose