Introduction
Glycogen Storage Diseases (GSDs) refer to metabolic disorders that affect glycogen metabolism. The condition is genetic and passed down to children by their parents, who can carry the flawed gene without having any symptoms. GSD primarily affects the liver and muscles since glycogen is mostly stored in the muscle tissue and the liver.
Background
GSD is an uncommon genetic condition resulting from enzyme problems. According to Cleveland Clinic (2019), this disease occurs in “one in 20,000 to 25,000 babies” (para. 7). The most common types among the 13 known types of this disorder include:
- type I (von Gierke’s disease);
- type II (Pompe’s disease);
- type III (Forbes-Cori disease);
- type IV (Andersen’s disease) (Cleveland Clinic, 2019).
Cause and Symptoms
GSDs occurs when the body lacks an enzyme required for the proper use and storage of glycogen or when such an enzyme is flawed. The most common type of GSD, von Gierke disease, is a result of G6PC gene mutations (Nyhan & Hoffmann, 2020).
The common signs of the disease include hypoglycemia (low blood glucose level), an enlarged liver, slow growth, weak muscles, and abnormal blood test results (Hannigan & Field, 2018). However, the symptoms vary based on different GSD types and body parts affected.
Description of the Biochemistry Behind GSD
Glycogen metabolism includes two metabolic pathways: glycogen synthesis and breakdown, essential to maintain the required blood glucose levels in the body. In people with GSDs, these pathways are affected due to the abnormalities or deficiency of enzymes controlling the synthesis and degradation of glycogen (Ellingwood & Cheng, 2018). Figure 1 demonstrates glycogen metabolism pathways and illustrates that glycogen breakdown results in the production of glucose-1-phosphate and glucose.
Treatment
Similar to other genetic diseases, GSDs are incurable, and the treatment includes maintaining the appropriate glucose levels to prevent hypoglycemia. Patients take uncooked cornstarch and nutrition supplements and are advised to take small frequent meals (Szymańska et al., 2021). A liver transplant might be needed in case of Andersen’s disease (type IV), resulting in liver failure or cirrhosis.
References
GSD Cleveland Clinic. (2019). Glycogen storage disease (GSD). Web.
Ellingwood, S. S., & Cheng, A. (2018). Biochemical and clinical aspects of glycogen storage diseases. Journal of Endocrinology, 238(3), R131-R141. Web.
Hannigan, S., & Field, S. (2018). Inherited Metabolic Diseases: Research, Epidemiology and Statistics, Research, Epidemiology and Statistics. CRC Press.
Nyhan, W. L., & Hoffmann, G. F. (2020). Atlas of inherited metabolic diseases (4th ed.). CRC Press.
Szymańska, E., Jóźwiak-Dzięcielewska, D. A., Gronek, J., Niewczas, M., Czarny, W., Rokicki, D., & Gronek, P. (2021). Hepatic glycogen storage diseases: Pathogenesis, clinical symptoms and therapeutic management. Archives of Medical Science: AMS, 17(2), 304-313. Web.