congenital disorder of glycosylation

Congenital disorders of glycosylation (CDG) are a group of rare diseases affecting multiple organs, particularly the brain. These disorders stem from defects in the N-glycosylation pathway, a crucial process within the cytoplasm and endoplasmic reticulum involved in protein and lipid synthesis.1

The most common form, CDG type I, is caused by a defect in the phosphomannomutase 2 enzyme. Classic CDG (type Ia) presents with low muscle tone, severe developmental delays, and brain abnormalities. Other symptoms can include hypoglycemia, seizures, stroke-like episodes, vision problems, heart issues, gastrointestinal problems, liver disease, diarrhea, and bleeding tendencies.1

Currently, there is no effective treatment for most CDG types. However, a rare subtype, CDG type Ib (phosphomannose isomerase deficiency), may show symptom reversal in some cases with oral mannose administration.1