 Infantile spasms IIS, a characteristic epilepsy syndrome of infancy with often catastrophic developmental consequences, is known in some patients to have many different genetic, metabolic and structural etiologies. However, for most patients IIS is the only presenting clinical feature and the specific cause is unknown. Only two FDA approved pharmacologic treatments for IIS exist, Adrenocorticotropic hormone ACTH and vigabatrin. While vigabatrin may be the treatment of choice for Tuberous Sclerosis as a cause for IS, ACTH is the treatment of choice for all others. Unfortunately, a substantial number of patients may still not respond to ACTH and there is no a priori way that suggests which patients may be responders. This has led to the following key questions: 