title: Clinical characteristics and molecular genetic analysis of Korean patients with GNE myopathy.
abstract: OBJECTIVE
  Glucosamine (UDP-N-acetyl)-2-epimerase/N-acetylmannosamine kinase (GNE) myopathy is an autosomal recessive neuromuscular disorder characterized by early adult-onset weakness of the distal muscles of the lower limbs. The clinical spectrum of GNE myopathy varies, and it is not clear how the same GNE gene mutations can result in different phenotypes. Here, we present clinical, pathological and genetic characteristics of twenty-one Korean patients with GNE myopathy.
  
  
  METHODS
  Twenty-one GNE myopathy patients were included in this study, conducted from 2004 to 2011. Based on medical records, patients' gender, onset age, family history, clinical history, serum creatine kinase (CK) level, neurologic examination, findings of muscle biopsy, muscle imaging findings and electrophysiologic features were extensively reviewed. Mutation of the GNE gene (9p13.3) was confirmed by DNA direct sequencing analysis in all patients.
  
  
  RESULTS
  The mean onset age was 23.8±8.8 years (mean±SD). Patient serum CK levels were slightly to moderately elevated, ranging from 41 to 2610 IU. Among the patients, twelve patients were female and nine patients were male. Except for eight patients, all of the patients presented initially with only distal muscle weakness in the lower extremities. The most common mutation was V572L, followed by C13S.
  
  
  CONCLUSIONS
  The clinical manifestations of our patients with GNE mutations varied. Among twenty-one patients, thirteen patients showed the typical GNE myopathy phenotype. There was no relationship between clinical features and site of mutation. Therefore, we suggest that neither homozygous nor compound heterozygous models are correlated with disease phenotype or disease severity.
authors.affiliation: Department of Neurology, Brain Korea 21 Project for Medical Science, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonju-ro, Gangnam-gu, Seoul 135-720, Korea.
authors.forename: Jae Eun
authors.initials: JE
authors.lastname: Sim
authors.forename: Hyung-Jun
authors.initials: HJ
authors.lastname: Park
authors.forename: Ha Young
authors.initials: HY
authors.lastname: Shin
authors.forename: Tai-Seung
authors.initials: TS
authors.lastname: Nam
authors.forename: Seung Min
authors.initials: SM
authors.lastname: Kim
authors.forename: Young-Chul
authors.initials: YC
authors.lastname: Choi
mesh_terms: D000293:Adolescent; D000328:Adult; D003402:Creatine Kinase / Q000097:blood; D049310:Distal Myopathies / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D009097:Multienzyme Complexes / Q000235:genetics*; D056910:Republic of Korea; D017422:Sequence Analysis, DNA
chemical_list: D009097:Multienzyme Complexes; C482901:UDP-N-acetylglucosamine 2-epimerase - N-acetylmannosamine kinase; D003402:Creatine Kinase
keywords: GNE; genotype; phenotype
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