MCardle's syndrome is due to: (A) Deficiency of glucose-6-phosphatase, (B) Absence of muscle phosphorylase, (C) Deficiency of liver phosphorylase, (D) Deficiency of liver phosphorylase kinase
Answer is A. McArdle disease (also known as glycogen storage disease type V) is a disorder affecting muscle metabolism. The condition is caused by the lack of an enzyme called muscle phosphorylase. This results in an inability to break down glycogen 'fuel' stores. McArdle disease leads to pain and fatigue with strenuous exercise. Ref Robbins 9/e pg 153