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Phosphomannomutase deficiency is a cause of carbohydrate‐deficient glycoprotein syndrome type I
Author(s) -
Emile Van Schaftingen,
Jaak Jaeken
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(95)01357-1
Subject(s) - phosphoglucomutase , glycoprotein , glycosylation , mannose , enzyme , biology , isozyme , endocrinology , biochemistry , medicine
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 (⩽ 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.