Congenital disorders of glycosylation and the pediatric liver

Congenital disorders of glycosylation (CDG) are caused by defects in protein N-glycosylation. These inherited disorders impact multiple organ systems, including the liver, its glycoprotein products, and the gastrointestinal system. Many patients have hypotonia, psychomotor retardation, developmental delay, and failure to thrive. Limited awareness of CDG and the diverse biological functions of glycosylation contribute to underdiagnosis of these disorders. Pediatric hepatologists and gastroenterologists arc likely to encounter CDG patients early on in their workups. This review will discuss the clinical pictures, biochemistry, molecular defects, diagnosis, and, for one type, an effective treatment. The broad and diverse CDG presentations within and between the various types indicate that it should be considered in any case of unexplained developmental delay, hepatopathology, especially hepatic fibrosis and/or steatosis, protein-losing enteropathy, coagulopathy, hypoglycemia, and failure to thrive.