Pathogenesis of myasthenia gravis
- Shawn J Bird, MD
Shawn J Bird, MD
- Professor of Neurology
- University of Pennsylvania School of Medicine
- Section Editors
- Jeremy M Shefner, MD, PhD
Jeremy M Shefner, MD, PhD
- Section Editor — Neuromuscular Disease
- Professor and Chair of Neurology, Barrow Neurological Institute
- Professor of Neurology, University of Arizona, Phoenix
- Clinical Professor of Neurology, Creighton University
- Ira N Targoff, MD
Ira N Targoff, MD
- Section Editor — Muscle Disease
- Professor of Medicine, Section of Rheumatology
- University of Oklahoma Health Sciences Center
Myasthenia gravis is an autoimmune disorder characterized by weakness and fatigability of skeletal muscles. Muscle weakness due to dysfunction of the neuromuscular junction (myasthenia) may be an acquired disorder. The vast majority of patients who develop myasthenia in adolescence or adulthood have autoantibodies that play a pathogenetically important role by attacking the acetylcholine receptor (AChR), fixing complement, and reducing the number of AChRs over time. These autoantibodies are thought to originate in hyperplastic germinal centers in the thymus where myoid cells expressing AChR are clustered. Such antibody-mediated disease is referred to as myasthenia gravis.
Similar weakness can also result from mutation of components of the neuromuscular junction, resulting in a group of disorders collectively referred to as "congenital myasthenia." This type of myasthenia is often appreciated at birth. Congenital myasthenia and weakness in newborns that is due to transplacental passage of antibodies from a pregnant woman with myasthenia gravis are presented separately. (See "Neuromuscular junction disorders in newborns and infants".)
The pathogenesis of myasthenia gravis is discussed in this topic review. Other aspects of this disorder are discussed separately. (See "Clinical manifestations of myasthenia gravis" and "Diagnosis of myasthenia gravis" and "Treatment of myasthenia gravis".)
Myasthenia gravis is a condition that fulfills all the major criteria for a disorder mediated by autoantibodies against the acetylcholine receptor (AChR) [1,2]:
●The autoantibodies are present in 80 to 90 percent of affected patients
Subscribers log in hereLiterature review current through: Jun 2017. | This topic last updated: Sep 20, 2016.References
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