GLYCOGEN storage diseases are a group of inborn error of metabolism and characterized by accumulation of GLYCOGEN in various tissues. The overall incidence of GLYCOGEN storage diseases is estimated 1 per 20, 000-43, 000 live births. There are twelve distinct diseases that are commonly considered to be GLYCOGEN storage diseases and classified based on enzyme deficiency and affected tissue.3TWe searched all review articles and books in the national and international databases which considered as inherited metabolic disorders and the genetic associations of these disorders.3TA large number of enzymes intervene in the synthesis and degradation of GLYCOGEN which is regulated by hormones. Several hormones, including insulin, glucagon and cortisol regulate the relationship between glycolysis, GLYCOGENosis, and GLYCOGEN synthesis.3TThese diseases are divided into three major groups: disorders that affected liver, disorders that affected muscle and those which are generalized. GLYCOGEN storage diseases are called by a Roman numerical that reflects the historical sequence of their discovery by an enzyme defect or by the author's name of the first description.