Type 5 glycogen storage disorder
Biochemical defect
Muscle phosphorylase defect
Lack of this enzyme limits muscle ATP generation by glycogenolysis, resulting in muscle glycogen accumulation.
Clinical manifestations
Exercise intolerance
A characteristic second wind phenomenon( if they slow down or pause briefly at the 1st appearance of muscle pain, they can resume exercise with more ease.
Burgundy colored urine after exercise, due to myoglobinuria secondary to rhabdomyolysis.