title: Different characteristic phenotypes according to antibody in myasthenia gravis.
abstract: OBJECTIVE
  To find the characteristic phenotypes of 3 different types of myasthenia gravis (MG).
  
  
  METHODS
  The clinical and electrophysiological features among 15 cases of muscle-specific kinase antibody positive (MuSK Ab+) MG, 59 cases of double seronegative (DSN) MG, and 161 cases of acetylcholine receptor antibody (AChR Ab)+ MG in the University of Alabama at Birmingham were compared.
  
  
  RESULTS
  AChR Ab was positive in 69% of cases and MuSK Ab in 6% of cases. MuSK Ab+ MG was more common (14%) in African Americans compared with whites (4%). AChR Ab+ MG is characterized by male predominance, later onset, a fewer cases of ocular MG, and a higher association with thymoma. DSN-MG is characterized by a greater prevalence of ocular MG, milder forms of MG with less number of crisis, and fewer abnormalities in the repetitive nerve stimulation test. MuSK Ab+ MG is characterized by younger age at onset, severe and bulbar forms of MG, predominant faciobulbar neck weakness, and a poor response to edrophonium, anticholinesterase, and intravenous immunoglobulin. Long-term outcome showed no difference among 3 types of MG.
  
  
  CONCLUSIONS
  AChR Ab+ MG and DSN-MG are similar, with the exception of less severity in the latter. MuSK Ab+ MG has distinct clinical and electrophysiological features.
authors.affiliation: Department of Neurology, University of Alabama at Birmingham, Veterans Affairs Medical Center, USA. shinjoh@uab.edu
authors.forename: Shin J
authors.initials: SJ
authors.lastname: Oh
authors.forename: Marla B
authors.initials: MB
authors.lastname: Morgan
authors.forename: Liang
authors.initials: L
authors.lastname: Lu
authors.forename: Yuki
authors.initials: Y
authors.lastname: Hatanaka
authors.forename: Shoji
authors.initials: S
authors.lastname: Hemmi
authors.forename: Angela
authors.initials: A
authors.lastname: Young
authors.forename: Gwendolyn C
authors.initials: GC
authors.lastname: Claussen
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000368:Aged; D001323:Autoantibodies / Q000378:metabolism*; D016009:Chi-Square Distribution; D002800:Cholinesterase Inhibitors / Q000627:therapeutic use; D004558:Electric Stimulation; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D006801:Humans; D016756:Immunoglobulins, Intravenous / Q000627:therapeutic use; D007155:Immunologic Factors / Q000627:therapeutic use; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000145:classification* / Q000276:immunology* / Q000628:therapy; D009431:Neural Conduction / Q000502:physiology; D010641:Phenotype; D011729:Pyridostigmine Bromide / Q000627:therapeutic use; D020794:Receptor Protein-Tyrosine Kinases / Q000276:immunology; D011950:Receptors, Cholinergic / Q000276:immunology; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D001323:Autoantibodies; D002800:Cholinesterase Inhibitors; D016756:Immunoglobulins, Intravenous; D007155:Immunologic Factors; D011950:Receptors, Cholinergic; C095714:MUSK protein, human; D020794:Receptor Protein-Tyrosine Kinases; D011729:Pyridostigmine Bromide