A glycogen storage disease (GSD, also glycogenosis and dextrinosis) is a
metabolic disorder caused by an
enzyme deficiency
A deficiency is generally a lack of something. It may also refer to:
*A deficient number, in mathematics, a number ''n'' for which ''σ''(''n'') < 2''n''
* glycogen synthesis
Glycogenesis is the process of glycogen synthesis, in which glucose molecules are added to chains of glycogen for storage. This process is activated during rest periods following the Cori cycle, in the liver, and also activated by insulin in resp ...
,
glycogen breakdown
Glycogenolysis is the breakdown of glycogen (n) to glucose-1-phosphate and glycogen (n-1). Glycogen branches are catabolized by the sequential removal of glucose monomers via phosphorolysis, by the enzyme glycogen phosphorylase.
Mechanism
The ...
, or
glucose breakdown, typically in
muscle
Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...
s and/or
liver cells.
GSD has two classes of cause: genetic and acquired. Genetic GSD is caused by any
inborn error of metabolism (genetically defective
enzymes) involved in these processes. In livestock, acquired GSD is caused by
intoxication
Intoxication — or poisoning, especially by an alcoholic or narcotic substance — may refer to:
* Substance intoxication:
** Alcohol intoxication
** LSD intoxication
** Toxidrome
** Tobacco intoxication
** Cannabis intoxication
** Cocaine i ...
with the
alkaloid castanospermine.
Types
Remarks:
* Some GSDs have different forms, e.g. infantile, juvenile, adult (late-onset).
* Some GSDs have different subtypes, e.g. GSD1a / GSD1b, GSD9A1 / GSD9A2 / GSD9B / GSD9C / GSD9D.
* GSD type 0: Although
glycogen synthase
Glycogen synthase (UDP-glucose-glycogen glucosyltransferase) is a key enzyme in glycogenesis, the conversion of glucose into glycogen. It is a glycosyltransferase () that catalyses the reaction of UDP-glucose and (1,4--D-glucosyl)n to yield UD ...
deficiency does not result in storage of extra glycogen in the liver, it is often classified with the GSDs as type 0 because it is another defect of glycogen storage and can cause similar problems.
* GSD type VIII (GSD 8): In the past it was considered a distinct condition,
however it is now classified with GSD type VI
or GSD IXa1; it has been described as
X-linked recessive inherited.
[Definition: glycogen storage disease type VIII from Online Medical Dictionary](_blank)
* GSD type XI (GSD 11):
Fanconi-Bickel syndrome, hepatorenal glycogenosis with renal Fanconi syndrome, no longer considered a glycogen storage disease.
* GSD type XIV (GSD 14): Now classed as
Congenital disorder of glycosylation
A congenital disorder of glycosylation (previously called carbohydrate-deficient glycoprotein syndrome) is one of several rare inborn errors of metabolism in which glycosylation of a variety of tissue proteins and/or lipids is deficient or defecti ...
type 1 (CDG1T), affects the phosphoglucomutase enzyme (gene PGM1).
*
Lafora disease
Lafora disease is a rare, adult-onset and autosomal recessive genetic disorder which results in Myoclonus#Epilepsy forms, myoclonus epilepsy and usually results in death several years after the onset of symptoms. The disease is characterized by t ...
is considered a complex neurodegenerative disease and also a glycogen metabolism disorder.
* Polyglucosan Storage Myopathies are associated with defective glycogen metabolism
* (Not McArdle Disease) AMP-independent myophosphorylase deficiency: Autosomal dominant mutation on PYGM gene. AMP-independent myophosphorylase activity impaired, whereas the AMP-dependent activity was preserved. No exercise intolerance. Adult-onset muscle weakness. Accumulation of the intermediate filament desmin in the myofibers of the patients.
* Unknown glycogenosis related to dystrophy gene deletion: patient has a previously undescribed myopathy associated with both Becker muscular dystrophy and a glycogen storage disorder of unknown aetiology.
Diagnosis
Treatment
Treatment is dependent on the type of glycogen storage disease. GSD I is typically treated with frequent small meals of
carbohydrates
In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or may ...
and
cornstarch, called
modified cornstarch therapy Modified cornstarch therapy is a form of cornstarch used to treat glycogen storage disease. It is typically given at night to try to keep blood sugar levels from going low. Many children under one year of age, however, do not like uncooked cornstarc ...
, to prevent low blood sugar, while other treatments may include
allopurinol and
human granulocyte colony stimulating factor
Granulocyte colony-stimulating factor (G-CSF or GCSF), also known as colony-stimulating factor 3 (CSF 3), is a glycoprotein that stimulates the bone marrow to produce granulocytes and stem cells and release them into the bloodstream.
Functional ...
.
Epidemiology
Overall, according to a study in
British Columbia, approximately 2.3 children per 100,000 births (1 in 43,000) have some form of glycogen storage disease.
In the United States, they are estimated to occur in 1 per 20,000–25,000 births.
[eMedicine Specialties > Glycogen-Storage Disease Type I]
Author: Karl S Roth. Updated: Aug 31, 2009 Dutch incidence rate is estimated to be 1 per 40,000 births.
While a Mexican incidence showed 6.78:1000 male newborns.
See also
*
Metabolic Myopathies
References
External links
IamGSD- International Association for Muscle Glycogen Storage Disease. A non-profit, patient-led international group encouraging efforts by research and medical professionals, national support groups and individual patients worldwide.
IPA- International Pompe Association. (Pompe Disease is also known as GSD-II). A non-profit, federation of Pompe disease patient's groups world-wide. It seeks to coordinate activities and share experience and knowledge between different groups.
EUROMAC- EUROMAC is a European registry of patients affected by McArdle Disease and other rare neuromuscular glycogenoses.
CoRDS- Coordination of Rare Diseases at Sanford (CoRDS) is a centralized international patient registry for all rare diseases. They work with patient advocacy groups, including IamGSD, individuals and researchers.
CORD- Canadian Organization for Rare Disorders (CORD) is a Canadian national network for organizations representing all those with rare disorders. CORD provides a strong common voice to advocate for health policy and a healthcare system that works for those with rare disorders.
NORD- National Organization for Rare Disorders (NORD) is an American national non-profit patient advocacy organization that is dedicated to individuals with rare diseases and the organizations that serve them.
EURODIS- Rare Diseases Europe (EURODIS) is a unique, non-profit alliance of over 700 rare disease patient organizations across Europe that work together to improve the lives of the 30 million people living with a rare disease in Europe.
{{Authority control
Inborn errors of carbohydrate metabolism
Hepatology
Rare diseases
Diseases of liver