Glycogen storage disease type IX

Glycogen storage disease IX
Glycogen storage disease IX
	Glycogen structure
Symptoms	Enlarged liver
Causes	Mutations in PHKA1, PHKA2, PHKB, or PHKG2 genes
Diagnostic method	CBC, Urinalysis
Treatment	Physical therapy, follow metabolic nutritionist

Glycogen storage disease type IX is a hereditary deficiency of glycogen phosphorylase kinase B that affects the liver and skeletal muscle tissue. It is inherited in an X-linked or autosomal recessive manner.^[1]

Signs and symptoms

The signs and symptoms in glycogen storage disease type IX include:^[1]

Enlarged liver
Slowed growth
Motor development delay (mild)
Low blood sugar accompanied by ketosis
Lack of muscle tone

Most of these signs and symptoms diminish as adulthood sets in.^[1]

Genetics

Glycogen storage disease type IX can be inherited via:^[2]^[4]

X-linked recessive inheritance due to mutations at either PHKA1 or the PHKA2 (most common^[5]) gene
Autosomal recessive could be the inheritance pattern for an affected individual when the genes PHKB or PHKG2 have a mutation.

Diagnosis

The diagnosis of glycogen storage disease IX consists of the following:^[1]^[3]

Complete blood count
Urinalysis
Histological study of the liver (via biopsy)
Genetic testing
Physical exam

Types

There are two types of this inherited condition, glycogen storage disease IXa1 and glycogen storage disease IXa2 that affect the liver of an individual.^[6] Mutations in PHKA2 have been seen in individuals with glycogen storage disease IXa2.^{[medical citation needed]}

Management

The management of Glycogen storage disease IX requires treatment of symptoms by frequent intake of complex carbohydrates and protein to combat the low blood sugar. A nutritionist will advise on suitable diets. Liver function is regularly monitored and problems managed as they arise. However, liver problems have only been successfully treated by a transplant. Routine checks of metabolism are needed to ensure blood sugar (glucose) and ketones are managed. Regular moderate exercise is beneficial, although over-vigorous exercise is to be avoided, especially in those with enlarged livers.^[1]^[7]

References

^ ^a ^b ^c ^d ^e ^f ^g ^h Goldstein, Jennifer; Austin, Stephanie; Kishnani, Priya; Bali, Deeksha (1993). Pagon, Roberta A; Adam, Margaret P; Ardinger, Holly H; Wallace, Stephanie E; Amemiya, Ann; Bean, Lora JH; Bird, Thomas D; Fong, Chin-To; Mefford, Heather C (eds.). Phosphorylase Kinase Deficiency. Seattle (WA): University of Washington. PMID 21634085. update 2011
^ ^a ^b "Glycogen storage disease type IX". Genetics Home Reference. Retrieved 2016-08-06.
^ ^a ^b Tidy, Colin (21 August 2014). "Glycogen Storage Disorders. GSD information and treatment". Patient Platform. Retrieved 6 August 2016.
^ "Glycogen storage disease due to phosphorylase kinase deficiency". Orphanet. Retrieved 2016-08-06.
^ Bernstein, Laurie E; Rohr, Fran; Helm, Joanna R (2015-06-03). Nutrition Management of Inherited Metabolic Diseases: Lessons from Metabolic University. Springer. p. 303. ISBN 9783319146218. Retrieved 6 August 2016.
^ "Glycogen storage disease IX". OMIM. Johns Hopkins University. Retrieved 2016-08-06.
^ Fernandes, John; Saudubray, Jean-Marie; van den Berghe, Georges (2013-03-14). Inborn Metabolic Diseases: Diagnosis and Treatment. Springer Science & Business Media. p. 80. ISBN 9783662031476. Retrieved 6 August 2016.