1. Von Gierke disease (type I)- Glucose-6-phosphatase deficiency- severe fasting hypoglycemia- ↑ glycogen in liver, ↑ blood lactate, ↑ triglycerides, ↑ uric acid

2. Pompe disease (type II)- Lysosomal α-glucosidase deficiency- Cardiomegaly, exercise intolerance

3. Cori disease (type III)- Debranching enzyme (α-1-6-glucosidase) deficiency - mild form of von Gierke- gluconeogenesis is intact

4. McArdle disease (type V)- skeletal muscle glycogen phosphorylase deficiency- blood glucose levels unaffected- muscle cramps, myoglobinuria (red urine)- second-wind phenomenon due to ↑ muscular blood flow