abnormal glycan occupancy An increase or decrease in the number of glycan chains conjugated to an aglycone target. "Occupancy" is used here to describe the extent of conjugation of a glycan chain to glycosylation sites on an aglycone target. Abnormal occupancy does not speak to the structure or composition of the glycan chain, just the relative abundance of glycan chains on some protein or lipid target. abnormal glycosylation