Dandy-Walker Syndrome is a congenital brain malformation involving the cerebellum (an area at the back of the brain that controls movement) and the fluid-filled spaces around it.

The Dandy-Walker complex is a genetically sporadic disorder that occurs one in every 25,000 births, mostly in females. Symptoms often occur in early infancy.

The key features of this syndrome are:

• An enlargement of the fourth ventricle (a small channel that allows fluid to flow freely between the upper and lower areas of the brain and spinal cord)
• A partial or complete absence of the area of the brain between the two cerebellar hemispheres
• Cyst formation near the internal base of the skull

An increase in the size of the fluid spaces surrounding the brain as well as an increase in pressure may also be present.

The syndrome can appear dramatically or develop unnoticed. Symptoms in infants include slow motor development and progressive enlargement of the skull.

In older children, symptoms of increased intracranial pressure such as irritability, vomiting, and convulsions, and signs of cerebellar dysfunction such as unsteadiness, lack of muscle coordination, or jerky movements of the eyes may occur. Other symptoms include increased head circumference, bulging at the back of the skull, problems with the nerves that control the eyes, face and neck, and abnormal breathing patterns.

Dandy-Walker Syndrome is frequently associated with disorders of other areas of the central nervous system, including absence of the area made up of nerve fibers connecting the two cerebral hemispheres (corpus callosum) and malformations of the heart, face, limbs, fingers and toes.

The effect of Dandy-Walker Syndrome on intellectual development is variable, with some children having normal cognition and others never achieving normal intellectual development even when the excess fluid buildup is treated early and correctly. Longevity depends on the severity of the syndrome and associated malformations. The presence of multiple congenital defects may shorten life span.

Treatment for individuals with Dandy-Walker Syndrome generally consists of treating the associated problems, if needed. A special tube to drain off excess fluid may be placed inside the skull. This will reduce intracranial pressure and help control swelling. Parents of children with Dandy-Walker Syndrome may benefit from genetic counseling if they intend to have more children.