Glycogen storage disease

Question 1

Type I: Von Gierke’s disease:

Very poor carbohydrate metabolism

Answer 1

AR, glucose-6-phosphatase (Liver)

Severe fasting hypoglycemia, increased glycogen in liver and increased blood lactate, hepatomegaly

Question 2

Type II: Pompe’s disease

Very poor carbohydrate metabolism

Answer 2

AR, lysosmal alpha-1,4-glucosidase (acid maltase)

Pompe’s trashes the pump (heart, liver, muscle)

Cardiomegaly, and systemic finding leading to early death

Question 3

Type III: Cori’s disease

Very poor carbohydrate metabolism

Answer 3

AR, debranching enzyme (alpha-1,6-glucosidase)
Gluconeogenesis is intact

Milder form of type I with normal blood lactate.

Question 4

Type IV: McArdle’s disease

Very poor carbohydrate metabolism

Answer 4

AR, skeletal muscle glycogen phosphorylase
McArdle=Muscle

Increased glycogen in muscle, but cannot break it down, leading to painful muscle cramps, myoglobinuria with strenuous exercise.