Glycogen Storage Disease Ixd, also known as glycogen storage disease due to muscle phosphorylase kinase deficiency, is related to glycogen storage disease ixb and glycogen storage disease, and has symptoms including muscle weakness and exercise-induced myalgia. An important gene associated with Glycogen Storage Disease Ixd is PHKA1 (Phosphorylase Kinase Regulatory Subunit Alpha 1), and among its related pathways/superpathways are Metabolism and Activation of cAMP-Dependent PKA. Affiliated tissues include skeletal muscle and liver, and related phenotypes are hypoglycemia and increased muscle glycogen content