Inheritance for glycogen storage diseases (GSDs) is autosomal recessive Autosomal Recessive Genetic disorders determined by a single gene (Mendelian disorders) are easiest to analyze and the most well understood. If expression of a trait requires only one copy of a gene (one allele)... read more except for GSD type VIII/IX, which is X-linked X-Linked Recessive Genetic disorders determined by a single gene (Mendelian disorders) are easiest to analyze and the most well understood. If expression of a trait requires only one copy of a gene (one allele)... read more . Incidence ranges from 1/20,000 to 1/43,000 births, depending on the population studied (1 Reference Glycogen storage diseases are carbohydrate metabolism disorders. There are many numbered and named types, all of which are caused by deficiencies of enzymes involved in glycogen synthesis or... read more ). For a more complete listing of glycogen storage diseases, see table .
Age of onset, clinical manifestations, and severity vary by type, but symptoms and signs are most commonly those of hypoglycemia and myopathy.
Diagnosis of glycogen storage diseases is suspected by history, examination, and detection of glycogen and intermediate metabolites in tissues by MRI or biopsy. Diagnosis is confirmed by DNA analysis or less commonly by detecting a significant decrease of enzyme activity in liver (types I, III, VI, and VIII/IX), muscle (types IIb, III, VII, and VIII/IX), skin fibroblasts (types IIa and IV), or red blood cells (type VII) or by lack of an increase in venous lactate with forearm activity/ischemia (types V and VII). GSD II (Pompe disease) is now part of the newborn screening panel in many states in the United States. (See also testing for suspected inherited disorders of metabolism Initial testing Most inherited disorders of metabolism (inborn errors of metabolism) are rare, and therefore their diagnosis requires a high index of suspicion. Timely diagnosis leads to early treatment and... read more .)
Treatment typically includes dietary supplementation with cornstarch to provide a sustained source of glucose for the hepatic forms of GSD and exercise avoidance for the muscle forms.
Prognosis for and treatment of glycogen storage diseases vary by type.
Defects in glycolysis (rare) may cause syndromes similar to GSDs. Deficiencies of phosphoglycerate kinase, phosphoglycerate mutase, and lactate dehydrogenase mimic the myopathies of GSD types V and VII; deficiencies of glucose transport protein 2 (Fanconi-Bickel syndrome) mimic the hepatopathy of other GSD types (eg, I, III, IV, VI).
Reference
1. Gümüş E, Özen H. Glycogen storage diseases: An update. World J Gastroenterol. 2023;29(25):3932-3963. doi:10.3748/wjg.v29.i25.3932
More Information
The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.
Online Mendelian Inheritance in Man (OMIM) database: Complete gene, molecular, and chromosomal location information