title: [Exercise-induced muscle pain due to phosphofrutokinase deficiency: Diagnostic contribution of metabolic explorations (exercise tests, 31P-nuclear magnetic resonance spectroscopy)].
abstract: BACKGROUND
  Muscle phosphofructokinase deficiency, the seventh member of the glycogen storage diseases family, is also called Tarui's disease (GSD VII).
  
  
  METHODS
  We studied two patients in two unrelated families with Tarui's disease, analyzing clinical features, CK level, EMG, muscle biopsy findings and molecular genetics features. Metabolic muscle explorations (forearm ischemic exercise test [FIET]; bicycle ergometer exercise test [EE]; 31P-nuclear magnetic resonance spectroscopy of calf muscle [31P-NMR-S]) are performed as appropriate.
  
  
  RESULTS
  Two patients, a 47-year-old man and a 38-year-old woman, complained of exercise-induced fatigue since childhood. The neurological examination was normal or showed light weakness. Laboratory studies showed increased CPK, serum uric acid and reticulocyte count without anemia. There was no increase in the blood lactate level during the FIET or the EE although there was a light increase in the respiratory exchange ratio during the EE. 31P-NMR-S revealed no intracellular acidification or accumulated intermediates such as phosphorylated monoesters (PME) known to be pathognomic for GSD VII. Two new mutations were identified.
  
  
  CONCLUSIONS
  FIET and EE were non-contributive to diagnosis, but 31P-NMR provided a characteristic spectra of Tarui's disease, in agreement with phosphofructokinase activity level in erythrocytes. Muscle biopsy does not always provide useful information for diagnosis. In these two cases, genetic studies failed to establish a genotype-phenotype correlation.
  
  
  CONCLUSIONS
  The search for phosphofructokinase deficiency should be continued throughout life in adults experiencing fatigability or weakness because of the severe disability for daily life activities caused by the late onset form.
authors.affiliation: Service de neurologie, HIA Desgenettes, 108, boulevard Pinel, 69275 Lyon cedex 3, France. Electronic address: drouetalain@yahoo.fr.
authors.forename: A
authors.initials: A
authors.lastname: Drouet
authors.forename: F
authors.initials: F
authors.lastname: Zagnoli
authors.forename: T
authors.initials: T
authors.lastname: Fassier
authors.forename: F
authors.initials: F
authors.lastname: Rannou
authors.forename: F
authors.initials: F
authors.lastname: Baverel
authors.forename: M
authors.initials: M
authors.lastname: Piraud
authors.forename: M
authors.initials: M
authors.lastname: Bahuau
authors.forename: F
authors.initials: F
authors.lastname: Petit
authors.forename: N
authors.initials: N
authors.lastname: Streichenberger
authors.forename: P
authors.initials: P
authors.lastname: Marcorelles
authors.forename: D
authors.initials: D
authors.lastname: Vital Durand
mesh_terms: D000328:Adult; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006014:Glycogen Storage Disease Type VII / Q000150:complications* / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism*; D063806:Myalgia / Q000175:diagnosis / Q000209:etiology* / Q000378:metabolism; D010759:Phosphorus Isotopes
chemical_list: D010759:Phosphorus Isotopes
keywords: Glycogenosis type VII; Glycogénose de type VII; Phosphofructokinase; Phosphofructokinase deficiency; RMN spectroscopy; Spectroscopie RMN; Tarui; Tarui disease