title: Novel variant in the PYGM gene causing late-onset limb-girdle myopathy, ptosis, and camptocormia.
abstract: BACKGROUND
  McArdle disease is a glycogen storage disease caused by mutations in the PYGM gene encoding myophosphorylase. It manifests classically with childhood-onset exercise-induced pain.
  
  
  METHODS
  We report the characteristics of 2 unrelated patients with a new homozygous mutation of the PYGM gene.
  
  
  RESULTS
  Two patients, aged 76 and 79 years, presented with severe upper and lower limb atrophy and weakness. Additionally, 1 patient presented with bilateral ptosis, and the other with camptocormia. In both patients, symptoms had developed progressively in the 2 preceding years, and there was no history of exercise intolerance. Both patients demonstrated myogenic abnormalities on electromyography, multiple glycogen-containing vacuoles and undetectable muscle myophosphorylase activity on muscle biopsy, and a novel homozygous frameshift p.Lys42Profs*48 PYGM mutation.
  
  
  CONCLUSIONS
  This report expands the phenotype and genotype of McArdle disease and suggests that PYGM mutations should be looked for in patients with very late-onset myopathy with no previous history of exercise intolerance. Muscle Nerve 57: 157-160, 2018.
authors.affiliation: Département de Neurologie, Hôpital de Hautepierre, Hôpitaux Universitaires de Strasbourg, 1 Avenue Molière, 67098, Strasbourg, France.|Centre de Référence Neuromusculaire du Grand Est (CERNEST), Hôpital de Hautepierre, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.
authors.forename: Chrystel
authors.initials: C
authors.lastname: Chéraud
authors.affiliation: Service des Maladies Héréditaires du Métabolisme, Centre de Biologie et de Pathologie Est, Hospices Civils de Lyon, Bron, France.
authors.forename: Roseline
authors.initials: R
authors.lastname: Froissart
authors.affiliation: Service de Pathologie, Hôpital de Hautepierre, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.
authors.forename: Béatrice
authors.initials: B
authors.lastname: Lannes
authors.affiliation: Département de Neurologie, Hôpital de Hautepierre, Hôpitaux Universitaires de Strasbourg, 1 Avenue Molière, 67098, Strasbourg, France.|Centre de Référence Neuromusculaire du Grand Est (CERNEST), Hôpital de Hautepierre, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.
authors.forename: Andoni
authors.initials: A
authors.lastname: Echaniz-Laguna
mesh_terms: D000368:Aged; D001763:Blepharoptosis / Q000150:complications / Q000235:genetics*; D003198:Computer Simulation; D004576:Electromyography; D005260:Female; D006012:Glycogen Storage Disease Type V / Q000235:genetics*; D006801:Humans; D008297:Male; D009134:Muscular Atrophy, Spinal / Q000150:complications / Q000235:genetics*; D049288:Muscular Dystrophies, Limb-Girdle / Q000150:complications / Q000235:genetics*; D009154:Mutation / Q000235:genetics; D013121:Spinal Curvatures / Q000150:complications / Q000235:genetics*
keywords: McArdle disease; PYGM; camptocormia; elderly; glycogen storage disease; myopathy