Severe hypoglycemia as a presenting symptom of carbohydrate-deficient glycoprotein syndrome

We describe clinical, biochemical, and molecular findings in a 2(1/2)-year-old girl with a phosphomannose isomerase deficiency who presented with severe and persistent hypoglycemia and subsequently developed protein-losing enteropathy, liver disease, and coagulopathy. Six months of therapy with mannose supplementation resulted in clinical improvement and partial correction of biochemical abnormalities.