EFO_0700044 (ARX-related epileptic encephalopathy) can be described as follows. Developmental and epileptic encephalopathy-1 (DEE1) is a severe form of epilepsy characterized by frequent tonic seizures or spasms beginning in infancy. DEE1 is caused by mutation in the ARX gene. Also known as: Developmental and epileptic encephalopathy-1 (DEE1).