Glycogen storage disease type V

Glycogen storage disease type V (GSD-V) is a metabolic disorder, more specifically a glycogen storage disease, caused by a deficiency of myophosphorylase. Its incidence is reported as 1 in 100,000, approximately the same as glycogen storage disease type I. GSD type V is also known as McArdle's disease or muscle phosphorylase (myophosphorylase) deficiency. The disease was first reported in 1951 by Dr. Brian McArdle of Guy's Hospital, London. The deficiency was the first metabolic myopathy to be recognized, when Dr. McArdle described the first case in a 30-year-old man who always experienced pain and weakness after exercise. Dr. McArdle noticed this patient’s cramps were electrically silent and his venous lactate levels failed to increase...