title: Diagnostic and clinical classification of autoimmune myasthenia gravis.
abstract: Myasthenia gravis is characterized by muscle weakness and abnormal fatigability. It is an autoimmune disease caused by the presence of antibodies against components of the muscle membrane localized at the neuromuscular junction. In most cases, the autoantibodies are against the acetylcholine receptor (AChR). Recently, other targets have been described such as the MuSK protein (muscle-specific kinase) or the LRP4 (lipoprotein related protein 4). Myasthenia gravis can be classified according to the profile of the autoantibodies, the location of the affected muscles (ocular versus generalized), the age of onset of symptoms and thymic abnormalities. The disease generally begins with ocular symptoms (ptosis and/or diplopia) and extends to other muscles in 80% of cases. Other features that characterize MG include the following: variability, effort induced worsening, successive periods of exacerbation during the course of the disease, severity dependent on respiratory and swallowing impairment (if rapid worsening occurs, a myasthenic crisis is suspected), and an association with thymoma in 20% of patients and with other autoimmune diseases such as hyperthyroidism and Hashimoto's disease. The diagnosis is based on the clinical features, the benefit of the cholinesterase inhibitors, the detection of specific autoantibodies (anti-AChR, anti-MuSK or anti-LRP4), and significant decrement evidenced by electrophysiological tests. In this review, we briefly describe the history and epidemiology of the disease and the diagnostic and clinical classification. The neonatal form of myasthenia is explained, and finally we discuss the main difficulties of diagnosis.
authors: INSERM U974, Paris, France; CNRS FRE3617, Paris, France; Sorbonne Universités, UPMC Univ Paris 06, UM76, Paris, France; AIM, Institut de myologie, Paris, France. Electronic address: sonia.berrih-aknin@upmc.fr.
authors: Sonia
authors: S
authors: Berrih-Aknin
authors: INSERM U974, Paris, France; CNRS FRE3617, Paris, France; Sorbonne Universités, UPMC Univ Paris 06, UM76, Paris, France; AIM, Institut de myologie, Paris, France.
authors: Mélinée
authors: M
authors: Frenkian-Cuvelier
authors: Centre de référence de pathologie neuromusculaire Paris Est, Service de Neurologie 2, Institut de Myologie, Hôpital de la Pitié Salpêtrière, France.
authors: Bruno
authors: B
authors: Eymard
mesh_terms: D000818:Animals; D001323:Autoantibodies / Q000096:biosynthesis / Q000145:classification; D020274:Autoimmune Diseases of the Nervous System / Q000145:classification* / Q000175:diagnosis* / Q000453:epidemiology / Q000276:immunology; D005315:Fetal Diseases / Q000145:classification / Q000175:diagnosis / Q000276:immunology; D006801:Humans; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000145:classification / Q000175:diagnosis / Q000276:immunology; D026502:LDL-Receptor Related Proteins / Q000037:antagonists & inhibitors / Q000276:immunology; D009157:Myasthenia Gravis / Q000145:classification* / Q000175:diagnosis* / Q000453:epidemiology / Q000276:immunology; D009469:Neuromuscular Junction / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D020794:Receptor Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000276:immunology; D011950:Receptors, Cholinergic / Q000276:immunology
chemical_list: D001323:Autoantibodies; D026502:LDL-Receptor Related Proteins; C551781:LRP4 protein, human; D011950:Receptors, Cholinergic; C095714:MUSK protein, human; D020794:Receptor Protein-Tyrosine Kinases
keywords: Acetylcholine receptor; Diagnostic; LRP4; MuSK; Myasthenia gravis