Glycogen storage disease type IX explained

Glycogen storage disease IX
Symptoms:	Enlarged liver
Causes:	Mutations in PHKA1, PHKA2, PHKB, or PHKG2 genes
Diagnosis:	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:

• 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.

Genetics

Glycogen storage disease type IX can be inherited via:^{[2] [3]}

• X-linked recessive inheritance due to mutations at either PHKA1 or the PHKA2 (most common^[4]) 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:^[5]

• 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.

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.^[7]

See also

• Glycogen storage disease

Further reading

• Johnson . Abiodun O. . Goldstein . Jennifer L. . Bali . Deeksha . July 2012 . Glycogen Storage Disease Type IX . Journal of Pediatric Gastroenterology and Nutrition . 55 . 1 . 90–92 . 10.1097/MPG.0b013e31823276ea . 21857251 . free.
• Özen . Hasan . 14 May 2007 . Glycogen storage diseases: New perspectives . World Journal of Gastroenterology . 13 . 18 . 2541–2553 . 10.3748/wjg.v13.i18.2541 . 1007-9327 . 4146814 . 17552001 . free.
• Albash . Buthainah . Imtiaz . Faiqa . Al-Zaidan . Hamad . Al-Manea . Hadeel . Banemai . Mohammed . Allam . R. . Al-Suheel . Ali . Al-Owain . Mohammed . 2014 . Novel PHKG2 mutation causing GSD IX with prominent liver disease: report of three cases and review of literature . European Journal of Pediatrics . 173 . 5 . 647–653 . 10.1007/s00431-013-2223-0 . 1432-1076 . 24326380 . 37564174.
• Book: Tubbs, Raymond R. . Cell and tissue based molecular pathology . Stoler . Mark H. . 2009 . Churchill Livingstone/Elsevier . 978-1437719482 . 1st . Philadelphia . en . 6 December 2017.

Notes and References

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