title: Myasthenia gravis and neuromyelitis optica spectrum disorder: a multicenter study of 16 patients.
abstract: OBJECTIVE
  To describe 16 patients with a coincidence of 2 rare diseases: aquaporin-4 antibody (AQP4-Ab)-mediated neuromyelitis optica spectrum disorder (AQP4-NMOSD) and acetylcholine receptor antibody (AChR-Ab)-mediated myasthenia gravis (AChR-MG).
  
  
  METHODS
  The clinical details and antibody results of 16 patients with AChR-MG and AQP4-NMOSD were analyzed retrospectively.
  
  
  RESULTS
  All had early-onset AChR-MG, the majority with mild generalized disease, and a high proportion achieved remission. Fifteen were female; 11 were Caucasian. In 14/16, the MG preceded NMOSD (median interval: 16 years) and 11 of these had had a thymectomy although 1 only after NMOSD onset. In 4/5 patients tested, AQP4-Abs were detectable between 4 and 16 years prior to disease onset, including 2 patients with detectable AQP4-Abs prior to thymectomy. AChR-Abs decreased and the AQP4-Ab levels increased over time in concordance with the relevant disease. AChR-Abs were detectable at NMOSD onset in the one sample available from 1 of the 2 patients with NMOSD before MG.
  
  
  CONCLUSIONS
  Although both conditions are rare, the association of MG and NMOSD occurs much more frequently than by chance and the MG appears to follow a benign course. AChR-Abs or AQP4-Abs may be present years before onset of the relevant disease and the antibody titers against AQP4 and AChR tend to change in opposite directions. Although most cases had MG prior to NMOSD onset, and had undergone thymectomy, NMOSD can occur first and in patients who have not had their thymus removed.
authors.affiliation: Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, UK.
authors.forename: M I
authors.initials: MI
authors.lastname: Leite
authors.forename: E
authors.initials: E
authors.lastname: Coutinho
authors.forename: M
authors.initials: M
authors.lastname: Lana-Peixoto
authors.forename: S
authors.initials: S
authors.lastname: Apostolos
authors.forename: P
authors.initials: P
authors.lastname: Waters
authors.forename: D
authors.initials: D
authors.lastname: Sato
authors.forename: L
authors.initials: L
authors.lastname: Melamud
authors.forename: M
authors.initials: M
authors.lastname: Marta
authors.forename: A
authors.initials: A
authors.lastname: Graham
authors.forename: J
authors.initials: J
authors.lastname: Spillane
authors.forename: A M
authors.initials: AM
authors.lastname: Villa
authors.forename: D
authors.initials: D
authors.lastname: Callegaro
authors.forename: E
authors.initials: E
authors.lastname: Santos
authors.forename: A Martins
authors.initials: AM
authors.lastname: da Silva
authors.forename: S
authors.initials: S
authors.lastname: Jarius
authors.forename: R
authors.initials: R
authors.lastname: Howard
authors.forename: I
authors.initials: I
authors.lastname: Nakashima
authors.forename: G
authors.initials: G
authors.lastname: Giovannoni
authors.forename: C
authors.initials: C
authors.lastname: Buckley
authors.forename: D
authors.initials: D
authors.lastname: Hilton-Jones
authors.forename: A
authors.initials: A
authors.lastname: Vincent
authors.forename: J
authors.initials: J
authors.lastname: Palace
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000906:Antibodies; D051401:Aquaporin 4 / Q000276:immunology; D001323:Autoantibodies; D001921:Brain / Q000473:pathology; D002648:Child; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000097:blood / Q000150:complications* / Q000276:immunology / Q000628:therapy*; D009471:Neuromyelitis Optica / Q000097:blood / Q000150:complications* / Q000276:immunology / Q000628:therapy*; D011950:Receptors, Cholinergic / Q000276:immunology; D012189:Retrospective Studies; D013934:Thymectomy; D055815:Young Adult
chemical_list: D000906:Antibodies; D051401:Aquaporin 4; D001323:Autoantibodies; D011950:Receptors, Cholinergic