title: DAG1 mutations associated with asymptomatic hyperCKemia and hypoglycosylation of α-dystroglycan.
abstract: OBJECTIVE
  To identify gene mutations in patients with dystroglycanopathy and prove pathogenicity of those mutations using an in vitro cell assay.
  
  
  METHODS
  We performed whole-exome sequencing on 20 patients, who were previously diagnosed with dystroglycanopathy by immunohistochemistry and/or Western blot analysis. We also evaluated pathogenicity of identified mutations for phenotypic recovery in a DAG1-knockout haploid human cell line transfected with mutated DAG1 complementary DNA.
  
  
  RESULTS
  Using exome sequencing, we identified compound heterozygous missense mutations in DAG1 in a patient with asymptomatic hyperCKemia and pathologically mild muscular dystrophy. Both mutations were in the N-terminal region of α-dystroglycan and affected its glycosylation. Mutated DAG1 complementary DNAs failed to rescue the phenotype in DAG1-knockout cells, suggesting that these are pathogenic mutations.
  
  
  CONCLUSIONS
  Novel mutations in DAG1 are associated with asymptomatic hyperCKemia with hypoglycosylation of α-dystroglycan. The combination of exome sequencing and a phenotype-rescue experiment on a gene-knockout haploid cell line represents a powerful tool for evaluation of these pathogenic mutations.
authors.affiliation: From the Department of Neuromuscular Research, National Institute of Neuroscience (M.D., S.N., Y.E., Y.K.H., I. Nonaka, I. Nishino) and Department of Clinical Development, Translational Medical Center (S.N., Y.E., Y.K.H., I. Nishino), NCNP, Tokyo, Japan; Department of Neurology (M.D.), China-Japan Friendship Hospital, Beijing, China; Department of Neurophysiology (Y.K.H.), Tokyo Medical University; and Department of Pediatrics (S.Y.), Omihachiman Community Medical Center, Shiga, Japan.
authors.forename: Mingrui
authors.initials: M
authors.lastname: Dong
authors.affiliation: From the Department of Neuromuscular Research, National Institute of Neuroscience (M.D., S.N., Y.E., Y.K.H., I. Nonaka, I. Nishino) and Department of Clinical Development, Translational Medical Center (S.N., Y.E., Y.K.H., I. Nishino), NCNP, Tokyo, Japan; Department of Neurology (M.D.), China-Japan Friendship Hospital, Beijing, China; Department of Neurophysiology (Y.K.H.), Tokyo Medical University; and Department of Pediatrics (S.Y.), Omihachiman Community Medical Center, Shiga, Japan. noguchi@ncnp.go.jp.
authors.forename: Satoru
authors.initials: S
authors.lastname: Noguchi
authors.affiliation: From the Department of Neuromuscular Research, National Institute of Neuroscience (M.D., S.N., Y.E., Y.K.H., I. Nonaka, I. Nishino) and Department of Clinical Development, Translational Medical Center (S.N., Y.E., Y.K.H., I. Nishino), NCNP, Tokyo, Japan; Department of Neurology (M.D.), China-Japan Friendship Hospital, Beijing, China; Department of Neurophysiology (Y.K.H.), Tokyo Medical University; and Department of Pediatrics (S.Y.), Omihachiman Community Medical Center, Shiga, Japan.
authors.forename: Yukari
authors.initials: Y
authors.lastname: Endo
authors.affiliation: From the Department of Neuromuscular Research, National Institute of Neuroscience (M.D., S.N., Y.E., Y.K.H., I. Nonaka, I. Nishino) and Department of Clinical Development, Translational Medical Center (S.N., Y.E., Y.K.H., I. Nishino), NCNP, Tokyo, Japan; Department of Neurology (M.D.), China-Japan Friendship Hospital, Beijing, China; Department of Neurophysiology (Y.K.H.), Tokyo Medical University; and Department of Pediatrics (S.Y.), Omihachiman Community Medical Center, Shiga, Japan.
authors.forename: Yukiko K
authors.initials: YK
authors.lastname: Hayashi
authors.affiliation: From the Department of Neuromuscular Research, National Institute of Neuroscience (M.D., S.N., Y.E., Y.K.H., I. Nonaka, I. Nishino) and Department of Clinical Development, Translational Medical Center (S.N., Y.E., Y.K.H., I. Nishino), NCNP, Tokyo, Japan; Department of Neurology (M.D.), China-Japan Friendship Hospital, Beijing, China; Department of Neurophysiology (Y.K.H.), Tokyo Medical University; and Department of Pediatrics (S.Y.), Omihachiman Community Medical Center, Shiga, Japan.
authors.forename: Shinobu
authors.initials: S
authors.lastname: Yoshida
authors.affiliation: From the Department of Neuromuscular Research, National Institute of Neuroscience (M.D., S.N., Y.E., Y.K.H., I. Nonaka, I. Nishino) and Department of Clinical Development, Translational Medical Center (S.N., Y.E., Y.K.H., I. Nishino), NCNP, Tokyo, Japan; Department of Neurology (M.D.), China-Japan Friendship Hospital, Beijing, China; Department of Neurophysiology (Y.K.H.), Tokyo Medical University; and Department of Pediatrics (S.Y.), Omihachiman Community Medical Center, Shiga, Japan.
authors.forename: Ikuya
authors.initials: I
authors.lastname: Nonaka
authors.affiliation: From the Department of Neuromuscular Research, National Institute of Neuroscience (M.D., S.N., Y.E., Y.K.H., I. Nonaka, I. Nishino) and Department of Clinical Development, Translational Medical Center (S.N., Y.E., Y.K.H., I. Nishino), NCNP, Tokyo, Japan; Department of Neurology (M.D.), China-Japan Friendship Hospital, Beijing, China; Department of Neurophysiology (Y.K.H.), Tokyo Medical University; and Department of Pediatrics (S.Y.), Omihachiman Community Medical Center, Shiga, Japan.
authors.forename: Ichizo
authors.initials: I
authors.lastname: Nishino
mesh_terms: D000328:Adult; D002461:Cell Line, Transformed; D015331:Cohort Studies; D003402:Creatine Kinase / Q000378:metabolism*; D049030:Dystroglycans / Q000235:genetics* / Q000378:metabolism*; D016189:Dystrophin / Q000378:metabolism; D005260:Female; D056726:Genetic Association Studies; D006031:Glycosylation; D006801:Humans; D007797:Laminin / Q000378:metabolism; D008297:Male; D008659:Metabolic Diseases / Q000150:complications / Q000235:genetics*; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000473:pathology; D009136:Muscular Dystrophies / Q000150:complications / Q000175:diagnosis / Q000235:genetics*; D009154:Mutation / Q000235:genetics*; D010641:Phenotype; D021381:Protein Transport / Q000235:genetics; D014162:Transfection
chemical_list: C483081:DAG1 protein, human; D016189:Dystrophin; D007797:Laminin; D049030:Dystroglycans; D003402:Creatine Kinase