| Main clinical features
|
severe neurologic disorder characterized by global developmental delay with intellectual disability and absent speech, poor, if any, motor development, and onset of seizures in the first year of life
seizures, interictal epileptiform activity with a disorganized electroencephalography background, developmental regression or retardation, and onset before 1 year of age
affected individuals have poor eye contact with optic atrophy, and postnatal microcephaly and abnormal movements |