Disorders in protein glycosylation and potential therapy: Tip of an iceberg?

Genetic defects in glycoprotein metabolism usually result in neurologic symptoms, but newly discovered defects in glycoprotein biosynthesis (the carbohydrate-deficient glycoprotein syndromes) also present as severe gastrointestinal disorders with hypoglycemia, protein-losing enteropathy, and hepatic pathology. Glycosylation disorders may be more widespread than previously thought and can be detected by using a simple, but underutilized, serum test. Some patients may benefit from promising dietary therapies now in clinical trials.