Phosphomannomutase deficiency is a cause of carbohydrate-deficient glycoprotein syndrome type I

FEBS Lett. 1995 Dec 27;377(3):318-20. doi: 10.1016/0014-5793(95)01357-1.


Carbohydrate-deficient glycoprotein (CDG) syndromes are genetic multisystemic disorders characterized by defective N-glycosylation of serum and cellular proteins. The activity of phosphomannomutase was markedly deficient (< or = 10% of the control activity) in fibroblasts, liver and/or leucocytes of 6 patients with CDG syndrome type I. Other enzymes involved in the conversion of glucose to mannose 1-phosphate, as well as phosphoglucomutase, had normal activities. Phosphomannomutase activity was normal in fibroblasts of 2 patients with CDG syndrome type II. Since this enzyme provides the mannose 1-phosphate required for the initial steps of protein glycosylation, it is concluded that phosphomannomutase deficiency, which is first reported here for higher organisms, is a cause, and most likely the major one, of CDG syndrome type I.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Child, Preschool
  • Congenital Disorders of Glycosylation / classification
  • Congenital Disorders of Glycosylation / enzymology
  • Congenital Disorders of Glycosylation / etiology*
  • Female
  • Glucose / metabolism
  • Glycosylation
  • Humans
  • Infant
  • Liver / enzymology
  • Mannose-6-Phosphate Isomerase / analysis
  • Mannosephosphates / biosynthesis
  • Phosphoglucomutase / analysis
  • Phosphotransferases (Phosphomutases) / analysis
  • Phosphotransferases (Phosphomutases) / deficiency*
  • Protein Processing, Post-Translational


  • Mannosephosphates
  • mannose 1-phosphate
  • Mannose-6-Phosphate Isomerase
  • Phosphotransferases (Phosphomutases)
  • Phosphoglucomutase
  • phosphomannomutase
  • Glucose