Megalencephaly

Megalencephaly, also called macrencephaly, is a condition in which there is an abnormally large, heavy, and usually malfunctioning brain.

By definition, the brain weight is greater than average for the age and gender of the individual. Head enlargement may be evident at birth or the head may become abnormally large in the early years of life. Megalencephaly is thought to be related to a disturbance in the regulation of cell reproduction or proliferation. In normal development, neuron proliferation the process in which nerve cells divide to form new generations of cells is regulated so that the correct number of cells is formed in the proper place at the appropriate time.

Symptoms of megalencephaly may include delayed development, convulsive disorders, corticospinal (brain cortex and spinal cord) dysfunction, and seizures.

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.

Information provided by the
National Institute of Neurological Disorders and Stroke,
National Institutes of Health

Each year, Medical College of Wisconsin physicians care for more than 180,000 patients, representing nearly 500,000 patient visits. Medical College physicians practice at Children's Hospital of Wisconsin, Froedtert Memorial Lutheran Hospital, the Milwaukee VA Medical Center, and many other hospitals and clinics in Milwaukee and southeastern Wisconsin.