MCardle's syndrome is due to
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
Deficiency of glucose-6-phosphatase
Absence of muscle phosphorylase
Deficiency of liver phosphorylase
Deficiency of liver phosphorylase kinase
Genetics