Disorders of neuromuscular junction ion channels

Ion channel defects produce a clinically diverse set of disorders that rang e from cystic fibrosis and some forms of migraine to renal tubular defects and episodic ataxias. This review discusses diseases related to impaired fu nction of the skeletal muscle acetylcholine receptor and calcium channels o f the motor nerve terminal. Myasthenia gravis is an autoimmune disease caus ed by antibodies directed toward the skeletal muscle acetylcholine receptor that compromise neuromuscular transmission. Congenital myasthenias are gen etic disorders, a subset of which are caused by mutations of the acetylchol ine receptor. Lambert-Eaton myasthenic syndrome is an immune disorder chara cterized by impaired synaptic vesicle release likely related to a defect of calcium influx. The disorders will illustrate new insights into synaptic t ransmission and ion channel structure that are relevant for all ion channel disorders. Am J Med. 1999;106:97-113. (C) 1999 by Excerpta Medica, Inc.