Muscle Phosphofructokinase Deficiency, Tarui Disease
The phosphofructokinase enzyme is needed to facilitate the breakdown of glycogen into energy in muscle. Patients with this type of GSD have a deficient amount of this enzyme in their muscle tissue. With this deficiency, effective glycogen breakdown (glycolysis) during muscle stress cannot be accomplished, resulting in pain, weakness, and cramping in the exercising muscle.
The clinical features of Type VII Glycogen Storage Disease are similar to those of Type V GSD. Patients experience early onset of fatigue and muscle pain with exercise. The body breaks down muscle when trying to attain energy, which causes many symptoms such as muscle pain, muscle cramping, muscle fatigue, and muscle tenderness. With the breakdown of muscle (rhabdomyolysis) and the release of the red protein myoglobin, myoglobinuria may develop, as evidenced by dark-red or red-brown urine. However, exercise intolerance is evident in childhood and symptoms are more severe than in Type V GSD.
Diagnosis of Type VII Glycogen Storage Disease is done by muscle biopsy, with a deficiency of the muscle phosphofructokinase enzyme and a modest accumulation of glycogen found. Patients may also display a hemolytic anemia.
Tarui Disease from National Organization for Rare Disorders [NORD]
GSD Type VII from Online Mendelian Inheritance in Man searchable database [OMIM]
Glycogen Storage Disease Type VII from the AGSD-UK
Type VII GSD info from eMedicine/Medscape
Tarui disease from the Swedish Information Centre for Rare Diseases
About the association
The Association for Glycogen Storage Disease - AGSD - was established in 1979 in order to create an organization which would be a focus for parents of and individuals with glycogen storage disease (GSD) to communicate, share their successes and concerns, share useful findings, provide support, create an awareness of this condition for the public, and to stimulate research in the various forms of glycogen storage diseases.
This website provides basic information about the glycogen storage diseases. The information is intended to be of use to people affected by one of the glycogen storage diseases, their families, and other interested parties.
Some forms of GSD cause little in the way of illness, while others are life threatening. Included in this site is a description of the general symptoms, associated problems, current treatment, and long-term outcome for the most commonly diagnosed glycogen storage diseases. It does not do justice to the difficulty patients and their families' experience, and their deep desire for improved forms of treatment or ultimately total correction.
Association for Glycogen Storage Disease
1542 Flammang Dr. PMB 1004
Waterloo Iowa 50702