There are a number of disorders which disrupt normal functioning of ion channels and have disastrous consequences for the organism. Genetic and autoimmune disorders of ion channels and their modifiers are known as channelopathies. See :Category:Channelopathies for a full list.
* Shaker gene mutations cause a defect in the voltage gated ion channels, slowing down the repolarization of the cell.
* Equine hyperkalaemic periodic paralysis as well as human hyperkalaemic periodic paralysis (HyperPP) are caused by a defect in voltage-dependent sodium channels.
* Paramyotonia congenita (PC) and potassium-aggravated myotonias (PAM)
* Generalized epilepsy with febrile seizures plus (GEFS+)
* Episodic ataxia (EA), characterized by sporadic bouts of severe discoordination with or without myokymia, and can be provoked by stress, startle, or heavy exertion such as exercise.
* Familial hemiplegic migraine (FHM)
* Spinocerebellar ataxia type 13
* Long QT syndrome is a ventricular arrhythmia syndrome caused by mutations in one or more of presently ten different genes, most of which are potassium channels and all of which affect cardiac repolarization.
* Brugada syndrome is another ventricular arrhythmia caused by voltage-gated sodium channel gene mutations.
* Polymicrogyria is a developmental brain malformation caused by voltage-gated sodium channel and NMDA receptor gene mutations.
* Cystic fibrosis is caused by mutations in the CFTR gene, which is a chloride channel.
* Mucolipidosis type IV is caused by mutations in the gene encoding the TRPML1 channel
* Mutations in and overexpression of ion channels are important events in cancer cells. In Glioblastoma multiforme, upregulation of gBK potassium channels and ClC-3 chloride channels enables glioblastoma cells to migrate within the brain, which may lead to the diffuse growth patterns of these tumors.