I Von Gierke

Glucose 6-phosphatase or transport system

Liver and kidney

Increased amount; normal structure.

Massive enlargement of the liver; failure to thrive; severe hypoglycemia, ketosis, hyperuricemia, hyperlipemia.

II Pompe

α-1,4-Glucosidase (lysosomal)

All organs

Massive increase in amount; normal structure.

Cardiorespiratory failure causes death, usually before age 2.

III Cori

α-1,6-Glucosidase (debranching enzyme)

Muscle and liver

Increased amount; short outer branches.

Like type I, but milder course.

IV Andersen

Branching enzyme (α-1,4 → α-1,6)

Liver and spleen

Normal amount; very long outer branches.

Progressive cirrhosis of the liver; liver failure causes death, usually before age 2.

V McArdle

Phosphorylase

Muscle

Moderately increased amount; normal structure.

Limited ability to perform strenuous exercise because of painful muscle cramps; otherwise patient is normal and well developed.

VI Hers

Phosphorylase

Liver

Increased amount.

Like type I, but milder course.

VII

Phosphofructokinase

Muscle

Increased amount; normal structure.

Like type V.

VIII

Phosphorylase kinase

Liver

Increased amount; normal structure.

Mild liver enlargement; mild hypoglycemia.

Note: Types I through VII are inherited as autosomal recessives. Type VIII is sex linked.