Carbohydrate-deficient glycoprotein syndrome type Ib. Phosphomannose isomerase deficiency and mannose therapy

J Clin Invest. 1998 Apr 1;101(7):1414-20. doi: 10.1172/JCI2350.


Phosphomannose isomerase (PMI) deficiency is the cause of a new type of carbohydrate-deficient glycoprotein syndrome (CDGS). The disorder is caused by mutations in the PMI1 gene. The clinical phenotype is characterized by protein-losing enteropathy, while neurological manifestations prevailing in other types of CDGS are absent. Using standard diagnostic procedures, the disorder is indistinguishable from CDGS type Ia (phosphomannomutase deficiency). Daily oral mannose administration is a successful therapy for this new type of CDG syndrome classified as CDGS type Ib.

Publication types

  • Case Reports
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Cells, Cultured
  • Glycoproteins / metabolism*
  • Glycosylation
  • Humans
  • Infant
  • Male
  • Mannose / therapeutic use*
  • Mannose-6-Phosphate Isomerase / deficiency*
  • Mutation
  • Protein Processing, Post-Translational
  • Protein-Losing Enteropathies / enzymology
  • Protein-Losing Enteropathies / genetics*
  • Protein-Losing Enteropathies / therapy
  • Syndrome
  • Transferrin / metabolism


  • Glycoproteins
  • Transferrin
  • Mannose-6-Phosphate Isomerase
  • Mannose