Alternating hemiplegia of childhood: insights into its pathophysiology.

Alternating hemiplegia of childhood is a rare disorder characterized by episodic paroxysmal attacks of neurologic dysfunction and has historically been thought to represent a migraine equivalent, an unusual form of epilepsy, or a movement disorder. Medical treatment with a variety of anticonvulsants and migraine agents is largely unsuccessful, and progressive mental deterioration is universally expected. Despite extensive laboratory studies, the pathophysiologic basis of this condition has thus far eluded identification. Recently, an international workshop was held to generate testable hypotheses regarding the pathophysiology of alternating hemiplegia of childhood. This paper summarizes the major proceedings of that workshop, and hopes to stimulate further interest in elucidating the molecular and cellular mechanisms underlying this unusual disorder.