title: Episodic ataxia and channelopathies.
abstract: Clinical details are given of different types of episodic ataxia: type 1, with myokymia, and attacks which usually last a few minutes, and may occur several times a day, and treatment with acetazolamide can reduce the number of attacks; type 2, with interictal nystagmus, and attacks which last for several hours to a day or more, and treatment with acetazolamide is very effective; paroxysmal choreoathetosis with episodic ataxia, with attacks lasting for about 20 min and occurring at varying intervals; and familial hemiplegic migraine, with transient hemiplegia presenting during the aura of a migraine headache, the symptoms improving on treatment with acetazolamide. Their inheritance is of dominant type; and the gene for type 1 is mapped to chromosome 12p near to a cluster of potassium channel genes, and that for type 2 and for familial hemiplegic migraine to chromosome 19p near to calcium channel genes. The differential diagnosis from other conditions with a periodic symptomatology is discussed, especially from a number of metabolic disorders. Treatment is effective for many of these, and the treatment of the episodic ataxias with acetazolamide can sometimes have a dramatic effect. The possible role of the channelopathies in the causation of some periodic neurological disorders is considered; with the expectation that further research will improve the identification of specific diseases, and lead to more effective treatment.
authors.forename: N
authors.initials: N
authors.lastname: Gordon
mesh_terms: D000086:Acetazolamide / Q000627:therapeutic use; D001259:Ataxia / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology*; D001264:Athetosis / Q000150:complications / Q000235:genetics; D002524:Cerebellar Ataxia / Q000235:genetics / Q000503:physiopathology; D002819:Chorea / Q000150:complications / Q000235:genetics; D006429:Hemiplegia / Q000188:drug therapy / Q000235:genetics; D006801:Humans; D007473:Ion Channels / Q000235:genetics*; D008881:Migraine Disorders / Q000188:drug therapy / Q000235:genetics; D009422:Nervous System Diseases / Q000235:genetics*; D013997:Time Factors
chemical_list: D007473:Ion Channels; D000086:Acetazolamide