Chapter 9 - Channelopathies

Summary

This chapter provides a clinicians' guide to the key clinical, genetic, and treatment aspects of the main single-gene neurological channelopathies. It considers the major skeletal muscle channelopathies followed by the main CNS channelopathies. The periodic paralyses (PP) are disorders in which patients experience focal or generalized episodes of muscle weakness of variable duration. Hypokalemic periodic paralysis can also be caused by missense mutations in the voltage sensor of domain 2 of SCN4A. Expression studies indicate that the SCN4A mutations associated with hypo-PP cause loss of function of the channel. Many studies indicate a strong genetic contribution to the risk of developing idiopathic generalized epilepsy, as well as febrile seizures. Inherited variability in the coding sequence of the GABRD gene, encoding the subunit of GABAA receptors, has also been suggested to act as a susceptibility factor for generalized epilepsy.