title: Molecular characterization of myophosphorylase deficiency (McArdle disease) in 34 patients from Southern France: identification of 10 new mutations. Absence of genotype-phenotype correlation.
abstract: We report on 31 patients and 3 affected siblings (17 males and 17 females) from Southern France with McArdle disease (two from Spanish and three from Portuguese background). Molecular analysis revealed the presence of five previously described mutations: the common p.R50X nonsense mutation, the p.R94W and p.V456M missense mutations, the p.K609K conservative mutation which generates an aberrant splicing, and the p.K754fs frameshift mutation; and 10 new molecular defects: eight missense mutations at homozygous (p.G136D) or heterozygous state (p.T379M, p.G449R, p.T488I, p.R490Q, p.R570Q, p.R590H, and p.R715W), one nonsense mutation p.R650X and one deletion (p.delK170). Our results confirm that the p.R50X nonsense mutation is also the most common associated with myophosphorylase deficiency in the Southern French population: 21 of 25 French unrelated patients (15 homozygous and six heterozygous, i.e., 72% of the mutated alleles). Two patients, one from Algeria and one from Tunisia, were homozygous for a previously identified missense mutation p.V456M in a Moroccan subject. Our findings further demonstrate molecular heterogeneity of myophosphorylase deficiency, absence of genotype-phenotype correlation and expand the already crowded map of mutations within the myophosphorylase gene. Our study also provides evidence for increased medical interest of malignant hyperthermia susceptibility (MHS) because of 34 McArdle disease patients, three and two affected siblings were contracture-tested and found to be positive.
authors.affiliation: Université de la Méditerranée, Laboratoire de Biochimie et Biologie Moléculaire, Faculté de Médecine, Marseille, France. robert.aquaron@medecine.univ-mrs.fr
authors.forename: Robert
authors.initials: R
authors.lastname: Aquaron
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Bergé-Lefranc
authors.forename: Jean-Francois
authors.initials: JF
authors.lastname: Pellissier
authors.forename: Marie-France
authors.initials: MF
authors.lastname: Montfort
authors.forename: Michèle
authors.initials: M
authors.lastname: Mayan
authors.forename: Dominique
authors.initials: D
authors.lastname: Figarella-Branger
authors.forename: Michelle
authors.initials: M
authors.lastname: Coquet
authors.forename: Georges
authors.initials: G
authors.lastname: Serratrice
authors.forename: Jean
authors.initials: J
authors.lastname: Pouget
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D004252:DNA Mutational Analysis / Q000379:methods; D005260:Female; D005602:France / Q000453:epidemiology; D018740:Genetic Heterogeneity; D005838:Genotype; D024982:Glycogen Phosphorylase, Muscle Form / Q000235:genetics*; D006012:Glycogen Storage Disease Type V / Q000453:epidemiology / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010375:Pedigree; D010641:Phenotype; D012189:Retrospective Studies
chemical_list: D024982:Glycogen Phosphorylase, Muscle Form