Episodic ataxia type 1

Episodic ataxia type 1 (EA1) is a potassium channelopathy characterized by constant myokymia and dramatic episodes of spastic contractions of the skeletal muscles of the head, arms, and legs with loss of both motor coordination and balance. During attacks individuals may experience a number of variable symptoms including vertigo, blurred vision, diplopia, nausea, headache, diaphoresis, clumsiness, stiffening of the body, dysarthric speech, and difficulty in breathing, among others. EA1 may be associated with epilepsy. Other possible associations include delayed motor development, cognitive disability, choreoathetosis, and carpal spasm. Usually, onset is in childhood or early adolescence.

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