title: A critical update on the immunopathogenesis of Stiff Person Syndrome.
abstract: BACKGROUND
  Stiff Person Syndrome (SPS) is a relatively rare but often overlooked autoimmune neurological disorder that targets antigens within the brain's inhibitory pathways resulting in incapacitating stiffness and spasms that impact on the patients' quality of life. Although a number of immunomodulating therapies significantly improve the patients' symptoms, the exact pathogenic mechanisms remain unclear.
  
  
  METHODS
  The current literature on SPS was reviewed and combined with the authors' experience with many patients and various laboratory studies. The majority of the patients have high-titre anti-GAD (Glutamic Acid Decarboxylase) antibodies in the sera and CSF suggesting dysfunction of the GABAergic neurotransmission. These antibodies are excellent disease markers but their pathogenic role remains uncertain.
  
  
  CONCLUSIONS
  This review provides a critical assessment on the immunobiology of SPS, describes the identification of anti-GABARAP antibodies as a new antigenic target in the GABAergic synapse and identifies the areas for future research.
authors.affiliation: Neuroimmunology Unit, Department of Pathophysiology, Faculty of Medicine, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Harry
authors.initials: H
authors.lastname: Alexopoulos
authors.forename: Marinos C
authors.initials: MC
authors.lastname: Dalakas
mesh_terms: D001323:Autoantibodies / Q000276:immunology*; D015415:Biomarkers; D005260:Female; D005968:Glutamate Decarboxylase / Q000276:immunology*; D006801:Humans; D008297:Male; D012720:Severity of Illness Index; D016750:Stiff-Person Syndrome / Q000276:immunology* / Q000503:physiopathology
chemical_list: D001323:Autoantibodies; D015415:Biomarkers; D005968:Glutamate Decarboxylase