Ohtahara syndrome is an uncommon type of epilepsy characterized by hard to control seizures and developmental delays. The disorder affects infants, usually within the first three months of life (most often within the first 10 days) in the form of epileptic seizures. Infants have primarily tonic seizures (stiffening of the muscles, upward eye gaze, dilated pupils, and altered breathing), but may also experience focal seizures (involving only one area or side of the brain), and rarely, myoclonic seizures (involving sudden muscle jerks). Ohtahara syndrome is classically caused by very abnormal brain structure that may be due to damage or abnormal development. It also can be due to metabolic disorders or genetic epilepsy syndromes, although the cause or causes for many cases can’t be determined. Recent studies suggest that there is often an identifiable genetic cause of Ohtahara syndrome. Electroencephalography recordings of brain activity of infants with Ohtahara syndrome reveal a characteristic pattern of high voltage abnormal brain activity alternating with periods of very little activity. This pattern is known as “burst suppression.”
Antiseizure drugs are used to control seizures, but are unfortunately not usually very effective for this disorder. Corticosteroids (prednisolone or ACTH) are occasionally helpful and sometimes the ketogenic diet (high fat, low carbohydrate) is appropriate. In cases where there is a focal brain lesion (damage or abnormal development of one area/side of the brain), epilepsy surgery may be beneficial. Other therapies are symptomatic and supportive; these can include tratments for abnormal muscle tone, irritability, or stomach or lung problems. Physical, speech, and occupational therapies are usually offered. Consultation with a palliative care team is often helpful in order to define goals of care and ensure the infant's family and medical team are working toward the same set of goals.
The course of Ohtahara syndrome is severely progressive. If epilepsy surgery is not feasible, seizures become more frequent and are accompanied by delays in physical and cognitive development. Some children will die in infancy; others will survive but usually have severe handicaps. As they grow, some children will progress into other epilepsy syndromes such as West syndrome and Lennox-Gastaut syndrome.
Researchers are learning more about the fundamental processes that lead to the development of epilepsy. Genes associated with Ohtahara syndrome involve multiple pathways including gene regulation, mitochondrial function, and synaptic transmission (communication between nerve cells). Basic science studies contnue to investigate how alteration of these pathways in brain cells change nerve firing and contribute to seizures and abnormal development. The discovery of gene variants that cause early-life epilepsies raise the possibility of precision medicine and individualized treatment approaches. Information from the National Library of Medicine’s MedlinePlus Seizures