Named after Japanese child neurologist Shunsuke Ohtahara, who first described its characteristics in 1976, Ohtahara syndrome (OS) is a rare form of early infantile developmental epileptic encephalopathy. A majority of cases of OS are associated with underlying structural brain abnormalities such as hemimegalencephaly, porencephaly, cortical dysplasias, and neuronal migration disorders. Several genetic mutations have also been associated with OS, most common being STXBP1, followed by KCNQ2. Many primary metabolic disorders are also associated with OS, such as nonketotic hyperglycinemia and other amino and organic acid disorders. Ohtahara syndrome affects males and females equally.