Inherited ion channel disorders.

Abstract

The inherited ion channel disorders (channelopathies) are a group of disorders caused by mutations in genes encoding ion channels. Ion channel disorders can affect any tissue, but the majority affect skeletal muscle or the central nervous system. These disorders include skeletal muscle sodium channelopathies causing hyperkalaemic periodic paralysis, paramyotonia congenita and potassium-aggravated myotonia. Skeletal muscle calcium channelopathies can cause hypokalaemic periodic paralysis, malignant hyperthermia and central core disease. Skeletal muscle chloride channelopathies can cause Thomsen and Becker myotonia. A neuronal sodium channelopathy causes the generalised epilepsy febrile seizures plus syndrome. Neuronal potassium channelopathies can cause familial benign neonatal convulsions and episodic ataxia type 1. Finally, neuronal calcium channelopathies can cause episodic ataxia type 2, familial hemiplegic migraine and spinocerebellar ataxia type 6. The clinical features, aetiology and pathogenesis of inherited voltage-gated ion channel disorders affecting muscle and the central nervous system are reviewed here.