STXBP1 encephalopathy with epilepsy

STXBP1 encephalopathy with epilepsy is a condition characterized by recurrent seizures (epilepsy), abnormal brain function (encephalopathy), and intellectual disability. The signs and symptoms of this condition typically begin in infancy. In most people with this disorder, seizures stop by age 1 but the other neurological problems continue throughout life.

The most common seizures in STXBP1 encephalopathy with epilepsy are infantile spasms, which occur before age 1 and consist of involuntary muscle contractions. Other seizure types that can occur in infants with this condition include involuntary muscle twitches (myoclonic seizures), sudden episodes of weak muscle tone (atonic seizures), partial or complete loss of consciousness (absence seizures), or loss of consciousness with muscle rigidity and convulsions (tonic-clonic seizures). Most people with STXBP1 encephalopathy with epilepsy have more than one type of seizure. In about one-quarter of individuals, the seizures are described as refractory because they do not respond to therapy with anti-epileptic medications.

Other signs and symptoms of STXBP1 encephalopathy with epilepsy include intellectual disability that is often moderate to profound. Affected individuals also have delayed development of speech and walking; in some, these skills never fully develop. Movement and behavior disorders may also occur. Many affected individuals have feeding difficulties. In some cases, areas of brain tissue loss (atrophy) have been found on medical imaging.