<prompt> Antibodies to calcium channel are seen inEaton lambe syndromeDermatomyositisMyaesthenia gravisPolymyositis  <response>: Lambe-Eaton syndrome presents with proximal muscle weakness that improves with exercise is caused by the development of antibodies to presynaptic calcium channels. Myasthenia gravis is autoimmune disease caused by the development of antibodies to postsynaptic acetylcholine receptors.Polymyositis Dermatomyositis are related disorders that are characterised by an inflammatory process affecting skeletal muscle. In dermatomyositis,characteristic skin changes also occur. Davidsons Medicine-22nd edition,page no:272,1114,1226,1227 