Résumé :
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The McArdle s disease (GSD V, MIM#232600) is the most common autosomal recessive disorder of glycogen metabolism. There are several mutations in the myophosphorylase gene (PYGM, MIM#608455). There is a clinical heterogeneity, with a wide clinical spectrum of severity. The most common mutation in Caucasian patients is a nonsense mutation at codon 50 in exon 1 (p.R50X, Andreu et al. 1998 and others), the frequency of different mutations varies in ethnic groups. There are no phenotype genotype correlations. Bruno, Andreu and cols published in 2006, the novel c.2380-1G A, identified in 4 patients and in 4 alleles seems to be the most frequent Italian specific mutation.OBJECTIVE: The aim of this study is to describe the mutation in an Argentinean patient with McArdle disease.MATERIAL AND METHODS: A 17-years old- male was hospitalized extreme fatigue, associated with myalgia and muscle cramps. He complained of exercise intolerance with premature fatigue since he was 12 years old without diagnosis. In his lab test he had severe myoblubinuria, increased levels of serum creatine kinase and renal failure. In muscle biopsy there was histochemical and biochemical deficiency of myophosphorylase. The diagnosed was GSD V and the molecular studies (A. Andreu,Spain) showed that the mutation was p.K 754NfsX49 and c.2380-1G>A. Conclusions: it is appropriate to think about glycogenosis in a patients that has painful cramps during exercise in infancy and adolescence. Histochemically and biochemically tests are important for diagnosis, and a test for detection of asymptomatic heterozygotes. We present the adapted flow chart for diagnosis of McArdle disease (Rubio.Consuegra et al.).Acknowledgments: Dr. Andreu Antoni , Arumi Elena, Taratuto Analia, Domuez .
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