Type IV glycogen-storage disease. Light-microscopic, electron-microscopic, and enzymatic study

Area of Science:

• Biochemistry
• Genetics
• Pediatrics

Background:

• Glycogen storage diseases (GSDs) are a group of inherited metabolic disorders affecting glycogen synthesis or degradation.
• Type IV glycogen-storage disease (Andersen disease) is a rare form characterized by deficiency of the glycogen branching enzyme.

Observation:

• A 14-month-old Latin American girl presented with clinical manifestations consistent with glycogen-storage disease.
• Diagnostic evaluation included light and electron microscopy of affected tissues.

Findings:

• The patient was diagnosed with Type IV glycogen-storage disease.
• Absence of the branching enzyme, alpha-1,4-glucan:alpha-1,4-glucan 6-glucosyl transferase, was confirmed in liver and cultured skin fibroblast samples.

Implications:

• This case highlights the diagnostic criteria for Type IV glycogen-storage disease.
• Understanding the enzymatic defect is crucial for potential therapeutic strategies and genetic counseling.