title: Novel mutation in the PYGM gene resulting in McArdle disease.
abstract: BACKGROUND
  McArdle disease is a common metabolic disorder characterized by marked exercise intolerance, premature fatigue during exertion, myalgia, and cramps. Despite the wide knowledge of the molecular basis of McArdle disease, few studies have used a physiological approach or explored the possibility of improving the exercise capacity of these patients.
  
  
  OBJECTIVE
  To describe 3 unrelated patients with McArdle disease with a novel mutation in the PYGM gene and to assess the physical capacity in 1 of them.
  
  
  METHODS
  Using molecular genetic approaches, we identified the underlying molecular defect in 3 patients with McArdle disease. Physical performance was evaluated in 1 patient by means of an exercise tolerance test on a bicycle ergometer.
  
  
  METHODS
  Two university hospitals. Exercise physiology studies were performed in a university department. Patients The 3 patients showed common features of McArdle disease. They were definitively diagnosed by histochemistry, biochemistry, or molecular genetic analysis.
  
  
  RESULTS
  All of the 3 patients were genetic compounds for the common Arg50Stop mutation and a novel c.13_14delCT mutation in the PYGM gene. The peak oxygen uptake (VO(2peak)) of the patient who performed the exercise test was only 20.2 mL x kg(-1) x min(-1).
  
  
  CONCLUSIONS
  Together with the novel mutation, there is a markedly decreased exercise capacity in a patient with McArdle disease, which could account for the profound alteration in the capacity for performing normal activities of daily living in this subpopulation.
authors.affiliation: Centro de Investigación and Servicio de Neuropatología, Hospital Universitario 12 de Octubre, Madrid, Spain.
authors.forename: Juan C
authors.initials: JC
authors.lastname: Rubio
authors.forename: Alejandro
authors.initials: A
authors.lastname: Lucia
authors.forename: Israel
authors.initials: I
authors.lastname: Fernández-Cadenas
authors.forename: Ana
authors.initials: A
authors.lastname: Cabello
authors.forename: Alberto
authors.initials: A
authors.lastname: Blázquez
authors.forename: Josep
authors.initials: J
authors.lastname: Gámez
authors.forename: Antoni L
authors.initials: AL
authors.lastname: Andreu
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Martín
authors.forename: Joaquin
authors.initials: J
authors.lastname: Arenas
mesh_terms: D000328:Adult; D015308:Anaerobic Threshold / Q000502:physiology; D004562:Electrocardiography; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology; D005260:Female; D024981:Glycogen Phosphorylase / Q000235:genetics*; D006012:Glycogen Storage Disease Type V / Q000235:genetics*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D009154:Mutation / Q000502:physiology; D010101:Oxygen Consumption / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D024981:Glycogen Phosphorylase