Clinical Immunology (Sixth Edition) - Chapter 65: Myasthenia Gravis

Myasthenia gravis (MG) is an autoimmune disorder characterized by weakness of the skeletal muscles. Weakness is caused by autoantibodies that target proteins at the neuromuscular junction (NMJ), primarily to the acetylcholine receptor (AChR), but to a lesser degree muscle-specific kinase (MuSK) and LDL receptor-related protein 4 (Lrp4). This chapter describes the function of these targeted proteins at the neuromuscular junction and the pathogenic mechanisms of autoantibodies that impair neuromuscular transmission, which includes the reduction in the number of AChRs, as well as altered structure and destruction of the postsynaptic membrane. A review of clinical diagnosis and current therapies for MG highlights the complexity of the disease. Advances in understanding of MG pathophysiology will improve current therapies and contribute to the development of novel, MG-specific therapeutics.