A rare, genetic disorder marked by a lack of tissue connecting the left and right halves of the brain, seizures, lesions on the back of the eye (retina), and other brain and eye abnormalities. Other problems may include unusual facial features, defects of the hands, spine, and ribs, and developmental and gastrointestinal problems. When Aicardi syndrome occurs, it is almost always in a newborn girl. People with Aicardi syndrome have an increased risk of certain tumors, such as hepatoblastoma (a type of liver cancer) and choroid plexus tumors (a rare tumor that forms in the brain).