Autoantibodies in the Lambert-Eaton myasthenic syndrome (LEMS) and amyotrophic lateral sclerosis (ALS)
Voltage-gated calcium channels (VGCC) are a family of multimeric transmembrane proteins involved in calcium homeostasis, gene expression, and neurotransmitter release. Multiple types of VGCCs have been described in both the central nervous system and peripheral tissue. Antibodies to various subtypes of VGCC have been implicated in a number of different neurological disorders, including the Lambert-Eaton myasthenic syndrome (LEMS), amyotrophic lateral sclerosis (ALS), and certain forms of cerebellar ataxia (CA). Although antibodies to the P-/Q-, N- and L-type VGCC have been described in LEMS, only the P-/Q-type antibodies have been shown experimentally to be pathogenic. These antibodies have also been described in the serum and CSF of some patients with CA and lung cancer, and therefore are diagnostic for LEMS and, at least, markers for paraneoplastic CA. Although antibodies to VGCC have been suggested as a possible cause in sporadic cases of ALS, evidence no longer supports this hypothesis, and the detection of anti-VGCC antibodies is not used diagnostically in ALS. Standard radioimmunoassay procedures can be used for the detection of VGCC antibodies. © 2007 Elsevier Inc. All rights reserved.