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Type 7 glycogenosis

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A metabolic disorder that is caused by a deficiency of muscle phosphofructokinase resulting in the extra glycogen storage in cells and the inability to break down glycogen in the muscle cells


Glycogenosis refers to a group of metabolic disorders due to the improper metabolism of glycogen. It involves certain enzymes that have become defective or deficient and therefore affected glycogen metabolism. The outcome is the excessive deposition of glycogen in cells. There are different types of glycogenosis. Type 7 glycogenosis is one of them.

Type 7 glycogenosis is a metabolic disorder caused by a deficiency in the muscle phosphofructokinase. This enzyme catalyzes the "committed" step of glycolysis, particularly the conversion of fructose 6-phosphate and ATP to fructose 1,6-bisphosphate and ADP. Deficiency of this enzyme leads to type 7 glycogenosis characterized by the symptoms such as exercise-induced muscle cramps and spasms, muscle weakness (myopathy), and myoglobinuria (i.e. the presence of myoglobin in urine). The deficiency of the muscle phosphofructokinase is associated with pathological mutations in the PKFM gene since it is the gene that codes for phosphofructokinase in the muscle cells. The condition is inherited in an autosomal recessive pattern.

The condition is also referred to as Tarui's disease. It is named after the first person (i.e. Seiichiro Tarui, a Japanese physician) to describe it in 1965.


  • glycogenosis 7
  • muscle phosphofructokinase deficiency
  • Tarui's disease
  • phosphofructokinase deficiency
  • glycogen storage disease type VII (GSD VII)

See also: