infantile,severe myoclonic epilepsy meaning

[Medicine]
A clinically diverse group of epilepsy syndromes characterized either by myoclonic seizures or by myoclonus in association with other seizure types. Myoclonic epilepsy syndromes are divided into three subtypes based on etiology: familial,cryptogenic,and symptomatic (i.e.,occurring secondary to known disease processes such as infections,hypoxic-ischemic injuries,trauma,etc.).