Disease Information for Phosphofructokinase def/GSD VII (Tarui)

Serum creatine kinase (CK) values usually are increased;

Lactic acid does not increase following exercise;

Bilirubin may be elevated; Reticulocytosis may be increased;

Phosphorous 31-nuclear magnetic resonance (31P-NMR) spectroscopy reveals a distinct peak of phosphorylated monoesters, which represents the glycolytic intermediates that accumulate as a result of the enzymatic block;

Electromyography (EMG) may show small motor potentials of short duration consistent with myopathic changes;

Histologic Findings: Glycogen accumulates between myofibrils under the sarcolemma, as in McArdle disease; Muscle glycogen content typically is greater than 1_5 g per 100 gms wet muscle weight; An abnormal polysaccharide, unique to Tarui disease, also may be found, especially in older patients; This polysaccharide is periodic acid-Schiff (PAS) positive but is not digested by diastase; Nonspecific myopathic changes also may be observed;

Renal failure may complicate myoglobinuria; The small number of patients with the infantile variant have all died during early childhood;

The classic and late-onset types are relatively mild disorders with minor lifestyle restrictions.

Failure to limit exercise in a patient with myoglobinuria may lead to renal failure;

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Tarui"s disease; Type VII glycogenosis, Tarui"s syndrome;

Glycogen storage defect type VII, Glycogen storage disease VII, glycogenosis VII, glycogenosis type VII, muscle phosphofructokinase deficiency, phosphofructokinase (PFK) deficiency; An inborn error of glycogen metabolism characterized by phosphofructokinase deficiency in the muscles, associated with abnormal deposition of glycogen in muscle tissues; Occasionally, myoglobinuria; The symptoms are similar to those seen in McArdle"s disease (Type V glycogenosis); Occurs in three variants: Classic Tarui disease typically presents in childhood with exercise intolerance and anemia; The fatal infantile variant presents in the first year of life; All patients of reported cases died by age 4 years; The late-onset variant manifests itself during later adulthood with progressive limb weakness without myoglobinuria or cramps; Autosomal recessive inheritance; Males are slightly more often affected than females; Very rare, only about 40 cases reported; The report of Tarui et al in 1965 was based on 3 adult siblings with exercise intolerance and easy fatigability

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