Congenital disorders of glycosylation | |
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Classification and external resources | |
Specialty | endocrinology |
ICD-10 | E77.8 |
ICD-9-CM | 271.8 |
OMIM | 212065 212066 |
DiseasesDB | 2012 31730 |
A congenital disorder of glycosylation (previously called carbohydrate-deficient glycoprotein syndrome) is one of several rare inborn errors of metabolism in which glycosylation of a variety of tissue proteins and/or lipids is deficient or defective. Congenital disorders of glycosylation are sometimes known as CDG syndromes. They often cause serious, sometimes fatal, malfunction of several different organ systems (especially the nervous system, muscles, and intestines) in affected infants. The most common subtype is CDG-Ia (also referred to as PMM2-CDG) where the genetic defect leads to the loss of phosphomannomutase 2, the enzyme responsible for the conversion of mannose-6-phosphate into mannose-1-phosphate.
The first CDG patients (twin sisters) were described in 1980 by Jaeken et al. Their main features were psychomotor retardation, cerebral and cerebellar atrophy and fluctuating hormone levels (e.g.prolactin, FSH and GH). During the next 15 years the underlying defect remained unknown but since the plasmaprotein transferrin was underglycosylated (as shown by e.g. isoelectric focusing), the new syndrome was named carbohydrate-deficient glycoprotein syndrome (CDGS) Its "classical" phenotype included psychomotor retardation, ataxia, strabismus, anomalies (fat pads and inverted nipples) and coagulopathy.