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Glycogen storage disease due to hepatic glycogen synthase deficiency

Disease definition

A genetically inherited anomaly of glycogen metabolism and a form of glycogen storage disease (GSD) characterized by fasting hypoglycemia. This is not a glycogenosis, strictly speaking, as the enzyme deficiency decreases glycogen reserves.

ORPHA:2089

Classification level: Disorder
  • Synonym(s):
    • GSD due to hepatic glycogen synthase deficiency
    • GSD type 0a
    • Glycogen storage disease due to liver glycogen synthase deficiency
    • Glycogen storage disease type 0a
    • Glycogenosis type 0a
  • Prevalence: <1 / 1 000 000
  • Inheritance: Autosomal recessive 
  • Age of onset: Childhood
  • ICD-10: E74.0
  • ICD-11: 5C51.3
  • OMIM: 240600
  • UMLS: C4510753
  • MeSH: -
  • GARD: 2513
  • MedDRA: -

Summary

Epidemiology

It is an extremely rare disease; about 20 cases have been reported in the literature so far.

Clinical description

It commonly appears in infancy or in early childhood. Patients present with morning fatigue and fasting hypoglycemia (without hepatomegaly) associated with hyperketonemia but without hyperalaninemia or hyperlactacidemia. After meals, major hyperglycemia associated with lactate and alanine increase and hyperlipidemia is observed.

Etiology

Glycogen synthetase deficiency is caused by mutations in the GYS2 gene (12p12.2).

Diagnostic methods

Biological results after glucose loading test strongly suggest the diagnosis, but formal diagnosis requires a liver biopsy showing a slightly decreased glycogen concentration and evidence of the enzyme deficiency (it is not expressed in muscles, erythrocytes, leukocytes, or fibroblasts). Molecular analysis revealing a mutation in the GYS2 gene confirms the diagnosis. Mutation analysis is an alternative to liver biopsy.

Differential diagnosis

Differential diagnoses include fructose intolerance, GSD type 1 (see these terms), and hypoglycemia.

Genetic counseling

Transmission is autosomal recessive.

Management and treatment

The condition is treated with a specific diet that includes frequent meals with high protein intake during the day and addition of uncooked starch in the evening.

Prognosis

Prognosis is favorable when the disease is correctly managed.

Expert reviewer(s):  Dr Roseline FROISSART - Last update: September 2009

  A summary on this disease is available in Deutsch (2009) Español (2009) Français (2009) Italiano (2009) Nederlands (2009) Português (2009)

Detailed information

General public

Guidelines

ERN produced/endorsed by ERN(s)   FSMR produced/endorsed by FSMR(s)

Additional information

Further information on this disease

Patient-centred resources for this disease

Research activities on this disease

Specialised Social Services

The documents contained in this web site are presented for information purposes only. The material is in no way intended to replace professional medical care by a qualified specialist and should not be used as a basis for diagnosis or treatment.