Glycogen Storage Diseases

Question 1

Von Gierke disease (Type I)

Answer 1

Deficient Glucose-6-phosphatase (final step in gluconeogenesis/glycogenolysis)
- Fasting hypoglycemia
- Hyperlipidemia
- Hyperurecemia
- Increased hepatic glycogen
- Increased blood lactate
- Hepatomegaly
Tx: Avoid fructose and galactose

Question 2

Pompe disease (Type II)

Answer 2

Deficient Lysosomal a-1,4-glucosidase (acid maltase)

- Cardiomyopathy and systemic findings leading to early death

Question 3

Cori disease (Type III)

Answer 3

Deficient Debranching enzyme (a-1,6-glucosidase)

• Milder form than Type I
• Elevated LFTs
• FTT
• Hypoglycemia
• Normal lactate
• Gluconeogenesis is intact

Question 4

McArdle disease (Type V)

Answer 4

Deficient Skeletal muscle glycogen phosphorylase (myophosphorylase)

• Painful muscle cramps
• Myoglobinuria
• Arrhythmia from electrolyte abnormalities