ABSTRACT
Glycogen storage disease (GSD) is a heterogeneous group of genetic disorders characterized by defective glycogen utilization or synthesis. There are 13 distinct types of GSD affecting liver, muscle, and other tissues. This chapter will describe those types of GSD that involve the liver as shown in Table 42.1 . Deficient enzyme and typical features of glycogen storage diseases (GSDs) that involve the liver
Type
Deficiency
Features
GSD 0
Glycogen synthase
No hepatomegaly; ketotic hypoglycemia; postprandial hyperlactatemia
GSD I
Glucose-6-phosphatase
Hepatomegaly; most severe hypoglycemia; elevated lactate, uric acid, and triglycerides; no response to glucagon
GSD III
Debranching enzyme
Firm hepatomegaly; AST/ALT often >1000 I/U; may have elevated CK
GSD IV
Branching enzyme
Hepatomegaly; amylopectin accumulation in liver and heart; cirrhosis may develop in infancy
GSD VI/IX
Phosphorylase/phosphorylase kinase
Hepatomegaly with fasting ketosis
GSD XI
GLUT-2 transpoter
Hepatomegaly; ketotic hypoglycemia; postprandial hyperlactatemia; chronic glucosuria and diarrhea
ALT; alanine aminotransferase; AST: aspartate aminotransferase; CK: creatine kinase.