Megalencephaly affects males more often than females. Unilateral megalencephaly or hemimegalencephaly is a rare condition and is characterized by the enlargement of one-half of the brain. Children with this disorder may have a large, sometimes asymmetrical head. Often they suffer from intractable seizures and mental retardation. There is no definitive treatment for megalencephaly.
Treatment is symptomatic and supportive.
The prognosis for individuals with megalencephaly largely depends on the underlying cause and the associated neurological disorders. The prognosis for those with hemimegalencephaly is poor. The knowledge gained from these fundamental studies provides the foundation for understanding how this process can go awry and, thus, may eventually give clues to understanding disorders such as megalencephaly. The Neurological Disorders. Merritt's Textbook of Neurology.