A new type of congenital disorders of glycosylation (CDG-Ii) provides new insights into the early steps of dolichol-linked oligosaccharide biosynthesis.

Deficiency of GDP-Man:Man1GlcNAc2-PP-dolichol mannosyltransferase (hALG2), is the cause of a new type of congenital disorders of glycosylation (CDG) designated CDG-Ii. The patient presented normal at birth but developed in the 1st year of life a multisystemic disorder with mental retardation, seizures, coloboma of the iris, hypomyelination, hepatomegaly, and coagulation abnormalities. An accumulation of Man1GlcNAc2-PP-dolichol and Man2GlcNAc2-PP-dolichol was observed in skin fibroblasts of the patient.

Deficiency of dolichyl-P-Man:Man7GlcNAc2-PP-dolichyl mannosyltransferase causes congenital disorder of glycosylation type Ig.

Deficiency of the endoplasmic reticulum enzyme dolichyl-phosphate mannose (Dol-P-Man):Man(7)GlcNAc(2)-PP-dolichyl mannosyltransferase leads to a new type of congenital disorder of glycosylation, designated type Ig. The patient 1 presented with a multisystemic disorder with microcephaly, developmental retardation, convulsions and dysmorphic signs. The isoelectric focusing pattern of the patient's serum transferrin showed the partial loss of complete N-glycan side chains.

Deficiency of UDP-galactose:N-acetylglucosamine beta-1,4-galactosyltransferase I causes the congenital disorder of glycosylation type IId.

Deficiency of the Golgi enzyme UDP-Gal:N-acetylglucosamine beta-1,4-galactosyltransferase I (beta4GalT I) (E.C.2.

[Carbohydrate-deficient glycoprotein syndrome (CDGS) type Ib. A hereditary metabolic disease and its therapy].

Underlying the carbohydrate-deficient glycoprotein syndrome (CDGS) type 1b is a defect in phosphomannose isomerase (PMI), an enzyme of mannose metabolism. The clinical manifestations include exudative gastroenteropathy, thromboses and hemorrhages. In contrast to other forms of the CDGS syndrome, neurological symptoms are completely lacking.