RT Journal Article SR Electronic T1 Clinical heterogeneity and phenotype/genotype findings in 5 families with GYG1 deficiency JF Neurology Genetics JO Neurol Genet FD Lippincott Williams & Wilkins SP e208 DO 10.1212/NXG.0000000000000208 VO 3 IS 6 A1 Ben Yaou, Rabah A1 Hubert, Aurélie A1 Nelson, Isabelle A1 Dahlqvist, Julia R. A1 Gaist, David A1 Streichenberger, Nathalie A1 Beuvin, Maud A1 Krahn, Martin A1 Petiot, Philippe A1 Parisot, Frédéric A1 Michel, Fabrice A1 Malfatti, Edoardo A1 Romero, Norma A1 Carlier, Robert Yves A1 Eymard, Bruno A1 Labrune, Philippe A1 Duno, Morten A1 Krag, Thomas A1 Cerino, Mathieu A1 Bartoli, Marc A1 Bonne, Gisèle A1 Vissing, John A1 Laforet, Pascal A1 Petit, François M. YR 2017 UL http://ng.neurology.org/content/3/6/e208.abstract AB Objective: To describe the variability of muscle symptoms in patients carrying mutations in the GYG1 gene, encoding glycogenin-1, an enzyme involved in the biosynthesis of glycogen, and to discuss genotype-phenotype relations.Methods: We describe 9 patients from 5 families in whom muscle biopsies showed vacuoles with an abnormal accumulation of glycogen in muscle fibers, partially α-amylase resistant suggesting polyglucosan bodies. The patients had either progressive early-onset limb-girdle weakness or late-onset distal or scapuloperoneal muscle affection as shown by muscle imaging. No clear definite cardiac disease was found. Histologic and protein analysis investigations were performed on muscle.Results: Genetic analyses by direct or exome sequencing of the GYG1 gene revealed 6 different GYG1 mutations. Four of the mutations were novel. They were compound heterozygous in 3 families and homozygous in 2. Protein analysis revealed either the absence of glycogenin-1 or reduced glycogenin-1 expression with impaired glucosylation.Conclusions: Our report extends the genetic and clinical spectrum of glycogenin-1–related myopathies to include scapuloperoneal and distal affection with glycogen accumulation.FSHD=facioscapulohumeral dystrophy; mRNA=messenger RNA; PAS=periodic acid–Schiff