Dandy-Walker syndrome results in abnormal brain formation. The NINDS states that the patient has an enlarged fourth ventricle, partial or complete lack of a cerebellar vermis (the area between the left and right hemsphere and a cyst close to the internal base of the skull. Due to the larger size of the ventricle, the patient has increased cranial pressure.
The symptoms of Dandy-Walker syndrome start as early as infancy, where the child has a slowed development of motor skills and a larger skull. As the child gets older, symptoms of intracranial pressure and cerebellar dysfunction start to show; the NINDS lists convulsions, vomiting, and irritability as symptoms of intracranial pressure; and jerky eye movements, unsteadiness, and lack of muscle coordination as symptoms of cerebellar dysfunction. Other symptoms of Dandy-Walker syndrome include abnormal breathing, nerve problems in the eye, face and neck, increased head circumference and bulging at the back of the head.
The NINDS adds that Dandy-Walker syndrome is often associated with other neurological disorders.