Unique Exercise Lactate Profile in Muscle Phosphofructokinase Deficiency (Tarui Disease); Difference Compared with McArdle Disease.

Päivi Piirilä,Petri Haapalahti,Minna E Similä,Satu Sandell,Bjarne Udd,Mari Auranen,Henna Tyynismaa,Lasse Uotila,Emil Ylikallio,Johanna Palmio,Tomi Wuorimaa

doi:10.3389/fneur.2016.00082

Abstract

Glycogen storage disease V (GSDV, McArdle disease) and GSDVII (Tarui disease) are the most common of the rare disorders of glycogen metabolism. Both are associated with low lactate levels on exercise. Our aim was to find out whether lactate response associated with exercise testing could distinguish between these disorders. Two siblings with Tarui disease, two patients with McArdle disease and eight healthy controls were tested on spiroergometric exercise tests with follow-up of venous lactate and ammonia. A late increase of lactate about three times the basal level was seen 10-30 min after exercise in patients with Tarui disease being higher than in McArdle disease and lower than in the controls. Ammonia was increased in Tarui disease. Our results suggest that follow-up of lactate associated with exercise testing can be utilized in diagnostics to distinguish between different GSD diseases.

Highlights

Tarui disease or glycogen storage disease VII (GSDVII) and McArdle disease (GSDV) are char acterized by exercise intolerance, cramps and myoglobinuria or rhabdomyolysis, and very low lactate levels during exercise [1,2,3,4,5]
We studied the lactate and ammonia profiles in two siblings with Tarui disease associated with symptom-limited maximal spiroergometric exercise testing
In Tarui disease, the utilization of glycogen during anaerobic exercise is interrupted by the lack of PFKM leading to very low levels of lactate during exercise

Summary

Introduction

Tarui disease or glycogen storage disease VII (GSDVII) and McArdle disease (GSDV) are char acterized by exercise intolerance, cramps and myoglobinuria or rhabdomyolysis, and very low lactate levels during exercise [1,2,3,4,5]. In Tarui disease, reduced enzyme activity of muscle phospho fructokinase (PFKM) is detected resulting in impaired phosphorylation of fructose 6-phosphate to Exercise Lactate Response in Tarui Disease fructose 1,6-bisphosphate. In McArdle disease, a more proximal defect in the glycolysis chain is present based on the defect of glycolytic enzyme myophosphorylase. We studied the lactate and ammonia profiles in two siblings with Tarui disease associated with symptom-limited maximal spiroergometric exercise testing. In defects of muscle metabolism, the level of lactate and/or ammonia asso ciated with exercise may be altered depending on the character and location of the metabolic defect in the energy chain [5, 6]. We report here the differences found in exercise-induced metabolites in these different study groups

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Conclusion