Early infantile epileptic encephalopathy 4 (EIEE4) is a form of early infantile epileptic encephalopathy, which refers to a group of neurological conditions characterized by severe seizures beginning in infancy. EIEE4, specifically, is often associated with partial complex or tonic-clonic seizures, although other seizure types have been reported. Other signs and symptoms mayinclude intellectual disability, reduced muscle tone (hypotonia), hypsarrhythmia (an irregular pattern seen on EEG), dyskinesia (involuntary movement of the body), and spastic di- or quadriplegia. EIEE4 is caused by changes (mutations) in the STXBP1 gene and is inherited in an autosomal dominant manner. Treatment is based on the signs and symptoms present in each person. For example, certain medications are often prescribed to help control seizures, although they are not always effective in all people with the condition. The disease is developmental and epileptic encephalopathy, 4 (MONDO_0012812). Also known as: DEE4, EIEE4, STXBP1 early infantile epileptic encephalopathy, STXBP1-related encephalopathy, developmental and epileptic encephalopathy 4, early infantile epileptic encephalopathy 4, early infantile epileptic encephalopathy caused by mutation in STXBP1, epileptic encephalopathy, early infantile, 4.