Glycogen storage diseases

Question 1

GSD 0

Answer 1

• Deficiency in glycogen synthase
• Patients cannot synthesize glycogen
-rely on glucose

Question 2

GSD III/Cori Disease:

Answer 2

• deficiency in a-1,6,-glucosidase (debranching enzyme).
• hypoglycemia/hepatomegaly
• glycogen molecules with large number of short branches

Question 3

GSD IV/Andersen Disease:

Answer 3

-Deficiency in glucosyl (4:6) transferase
(branching enzyme)
-Patients have long chain glycogen with fewer
branches
• Causes enlargement of liver and spleen,
scarring of liver tissue (cirrhosis)

Question 4

GSD V/McArdle Disease:

Answer 4

• Deficiency in muscle glycogen phosphorylase
• Rate limiting step of glycogen breakdown
• Patients unable to supply muscles with enough glucose

Question 5

GSD VI/Hers Disease: Deficiency in liver glycogen phosphorylase

Answer 5

• Prevents glycogen breakdown in liver, hence it
accumulates in liver causing hepatomegaly
• Low blood glucose levels

Question 6

Pompe Disease (GSD III)

Answer 6

-Defect in acid maltase (aka α-glucosidase) – used in lysosomal glycogen
degradation pathway.
-• Accumulation of glycogen in lysosomes

ERT – recombinant human α-glucosidase delivered via intravenous
infusion in babies/young children