Glycogen Storage Diseases

Question 1

Severe Fasting Hypoglycemia

Increased Glycogen in the Liver (Hepatomegaly)

Increased Lactate

Increased Triglycerides

Increased Uric Acid

Answer 1

Von Gierke Disease

Deficient Enzyme: Glucose-6-Phosphatase

Treatment: Frequent oral glucose, avoidance of fructose and galactose

Question 2

Cardiomegaly

Hypertrophic Cardiomyopathy

Exercise Intolerance

Answer 2

Pompe Disease

Deficient Enzyme: Lysosomal Alpha-1-4-Glucosidase with Alpha-1-6-Glucosidase Activity

Question 3

Milder form of Von Gierke Disease

Normal Lactate Levels

Accumulation of limit dextrin-like structures in the cytosol

Answer 3

Cori Disease

Deficient Enzyme: Debranching Enzyme (Alpha-1-6-Glucosidase)

Question 4

Painful muscle cramps

Myoglobinuria with strenous exercise

Arrhythmias with electrolyte abnormalities

“Second-Wind” phenomenon noted during exercise due to increased muscular blood flow

Answer 4

McArdle Disease

Deficiency Enzyme: Myophosphorylase (skeletal muscle glycogen phosphorylase)

Blood glucose levels are usually unaffected