Glycogen Storage Diseases EC

Question 1

Child with fat cheeks, severe fasting hypoglycemia, dramatically increased glycogen in liver, increased blood lactate, and hepatomegaly. (Disease, Enzyme and function, Treatment)

Answer 1

Von Gierke’s (type 1)

Deficient Glucose-6-Phosphatase
Cannot convert G-6-P to Glucose

Supplement with cornstarch
Restrict galactose/fructose intake because they cannot be converted to glucose

Question 2

Fasting hypoglycemia, increased glycogen in liver, hepatomegaly, but normal blood lactate. (Disease, Enzyme, and function, Treatment)

Answer 2

Cori’s (type III)

Deficient Debranching enzyme (a-1-6-glucosidase)
Cannot break down limit dextrins

Supplement with cornstarch

Question 3

Cardiomegaly, large tongue, hypotonic, systemic disease, early death. Labs show elevated creatine kinase and aspartate transaminase., Vacuoles stain + for glycogen. (Disease, Enzyme and function)

Answer 3

Pompe’s disease (Type II)

Lysosomal a-1-4-glucosidase (acid maltase)
Cannot break down glycogen to glucose in lysosomes
(leads to accumulation in muscle > myopathies)

Question 4

Increased glycogen in muscle but cannot be broken down. Painful muscle cramps, myoglobinuria with strenuous exercise (Disease, Enzyme and function)

Answer 4

McArdle’s disease (type V)

Glycogen phosphorylase deficiency
Cannot break down glycogen in muscle