hypoglycosylated

Hypoglycosylated is a term used to describe a state in which a protein or lipid has fewer or shorter carbohydrate chains than is typical. Glycosylation is a major post-translational modification in which glycans are covalently attached to polypeptides or lipids, influencing folding, stability, trafficking, receptor function, and interactions. Hypoglycosylation indicates reduced occupancy or incomplete processing of glycan chains, often resulting from disruptions in the cellular glycosylation machinery.

Causes include genetic disorders of glycosylation, such as congenital disorders of glycosylation, due to mutations in enzymes of the endoplasmic reticulum or Golgi apparatus that build or transfer glycans. Acquired factors such as nutrient deficiency, hypoxia, or alcohol consumption can also shift glycosylation toward hypoglycosylated species. Enzymatic defects may affect N-linked glycosylation, O-linked glycosylation, or both, and can lead to altered protein folding and secretion, compromised stability, or changed cell signaling.

In clinical and research contexts, hypoglycosylation is observed in transferrin, where carbohydrate-deficient transferrin forms are used as biomarkers for certain congenital disorders of glycosylation or alcohol misuse. More broadly, hypoglycosylation of cell-surface proteins can affect adhesion, immune recognition, and receptor activity, contributing to disease pathogenesis in some cancers and inflammatory conditions.

Detection methods include electrophoretic glycoforms analysis, mass spectrometry, and high-performance liquid chromatography to assess glycan occupancy and structure.