Glycogen storage disease type IV

Glycogen storage disease type IV
Glycogen
Classification and external resources
Specialty
ICD-10	E74.0
ICD-9-CM	271.0
OMIM	232500 263570 607839
DiseasesDB	5303
eMedicine	med/910 ped/97
Patient UK	Glycogen storage disease type IV
MeSH	D006011
GeneReviews	Glycogen storage disease type IV Adult polyglucosan body disease

Glycogen storage disease type IV is a rare hereditary metabolic disorder. It is the result of a mutation in GBE1 gene, which causes a defect in the glycogen branching enzyme. Therefore, glycogen is not made properly and abnormal glycogen molecules accumulate in cells; most severely in cardiac and muscle cells. The severity of this disease varies on the amount of enzyme produced. Glycogen Storage Disease Type IV is autosomal recessive, which means each parent has a mutant copy of the gene but show no symptoms of the disease. It affects 1 in 800,000 individuals worldwide, with 3% of all Glycogen Storage Diseases being type IV.

Synonyms

It is also known as:

• Glycogenosis type IV
• Glycogen branching enzyme deficiency
• Polyglucosan body disease
• Amylopectinosis

Eponym

The eponym "Andersen's disease" is sometimes used, for Dorothy Hansine Andersen.

Human pathology

It is a result of the absence of the glycogen branching enzyme amylo-1,4-1,6 transglucosidase, which is critical in the production of glycogen. This leads to very long unbranched glucose chains being stored in glycogen. The long unbranched molecules have a low solubility which leads to glycogen precipitation in the liver. These deposits subsequently build up in the body tissue, especially the heart and liver. The inability to breakdown glycogen in muscle cells causes muscle weakness. The probable end result is cirrhosis and death within 5 years. In adults, the activity of the enzyme is higher and symptoms do not appear until later in life.

Variant types

Fatal perinatal neuromuscular type

• Excess fluid builds up around fetus and in the fetus’ body
• Fetus have condition called akinesia deformation sequence
• Causes decrease in fetal movement and stiffness of joints after birth
• Infants have low muscle tone and muscle wasting
• Do not survive past newborn stage due to weakened heart and lungs

Congenital muscular type

• Develops in early infancy
• Babies have dilated cardiomyopathy, preventing heart from pumping efficiently
• Only survive a few months

Progressive hepatic type

• Infants have difficulty gaining weight
• Develop enlarged liver and cirrhosis, that is irreversible
• High BP in hepatic portal vein and buildup of fluid in abdominal cavity
• Die of liver failure in early childhood

Non-progressive hepatic type

• Same as progressive, but liver disease is not as severe
• Do not usually develop cirrhosis
• Usually show muscle weakness and hypotonia
• Survive into adulthood
• Life expectancy varies on severity of symptoms

Childhood neuromuscular type

• Develops in late childhood
• Has myopathy and dilated cardiomyopathy
• Varies greatly
• Some have mild muscle weakness
• Some have severe cardiomyopathy and die in early adulthood

In animals

In horses: it has been reported in American Quarter Horses and related breeds.

Main article: Glycogen branching enzyme deficiency

In cats: the disease has been reported in the Norwegian Forest Cat, where it causes skeletal muscle, heart, and CNS degeneration in animals greater than 5 months old. It has not been associated with cirrhosis or liver failure.

External links

• Glycogen storage disease type IV at GPnotebook
• Asociación Española de Enfermos de Glucogenosis