Glycogen storage disease type IX

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.

Signs and symptoms
The signs and symptoms in glycogen storage disease type IX include: Most of these signs and symptoms diminish as adulthood sets in.
 * Enlarged liver
 * Slowed growth
 * Motor development delay (mild)
 * Low blood sugar accompanied by ketosis
 * Lack of muscle tone

Genetics
Glycogen storage disease type IX can be inherited via:
 * X-linked recessive inheritance due to mutations at either PHKA1 or the PHKA2 (most common ) 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:
 * 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. 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.