Phenotype abnormal glycosylation An abnormality in the structure or composition of glycans, or their attachment to aglycone conjugation targets. Abnormal glycosylation phenotypes cover altered glycan composition, including altered sugar residue content, chain length, linkage, or branching patterns, as well as altered occupancy, characterized by abnormal degree or pattens or conjugation of glycan chains to aglycone targets. Abnormal glycosylation phenotypes typically result from defects in the machinery that directly (glycosyltransferase, glycosidase, oligosaccharyltransferase enzymes) or indierctly (isomerasaes, transport proteins, chaperones, glycan residue synthesis/activation pathways, etc.) contribute to the building/remodeling of glycan chains, or their attachement to aglycone targets. glycosylation phenotype abnormal glycosylation