Congenital disorders of glycosylation type I leads to altered processing of N-linked glycans, as well as underglycosylation

The N-linked glycans on transferrin and α₁-antitrypsin from patients with congenital disorders of glycosylation type I have increased fucosylation and branching relative to normal controls. The elevated levels of monofucosylated biantennary glycans are probably due to increased α-(1 → 6) fucosylation. The presence of bi- and trifucosylated triantennary and tetra-antennary glycans indicated that peripheral α-(1 → 3), as well as core α-(1 → 6), fucosylation is increased. Altered processing was observed on both the fully and underglycosylated glycoforms.