This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Inborn Errors of Metabolism, Subject name: Pediatrics
Which glycogen storage disease does not affect muscles? 
Select and explain. 
A. Type 1, B. Type 2, C. Type 3, D. Type 4
A: Type 1
Answer: A: Type 1 
Explanation: a. Type 1(Ref: Nelson's 20/e p 715-725, Ghai 8/e p 655-657)Type 2 Pompe disease predominantly involves muscles, while type I GSD involves liver.Although type 2 and type 3 GSD are predominantly liver glycogenoses, skeletal muscle involvement may also be seen.