31 - Channelopathies of the nervous system

Abstract

Few neurological disorders can claim as long a passage of time between initial description and subsequent molecular characterization as the channelopathies, which are acquired or inherited disorders of membrane ion channel function. Mutations have now been identified for most channelopathies, and ongoing research suggests that these disorders are relatively common. This chapter focuses on the inherited disorders of ion channel function. However, acquired ion channel disorders due to autoimmune, paraneoplastic, and toxic causes are well described and the pathophysiology is well characterized. Ion channels facilitate rapid communication of electrical information in the central, peripheral, and autonomic nervous systems. So fundamental is the function that interference by channel-blocking toxins can have rapidly lethal effects. With the development of molecular techniques, channel structure is further elucidated through electrophysiological studies after cloning and expression in animal systems. Based on DNA sequence homology, channels initially thought to be electrophysiologically and pharmacologically distinct are now recognized as members of the same super family and may have evolved from a common ancestor.