Dandy-Walker Malformation Health Article

Diagnosis

About 80% of children with Dandy-Walker malformation are diagnosed before the end of the first year, usually as a result of the signs of hydrocephalus. Following birth, the newborn's head circumference is measured to determine whether it has been enlarged by the development of cysts. As has already been mentioned, ultrasound screening before birth can detect some signs of hydrocephalus. Ultrasound screening is recommended if the family has a history of congenital neurologic abnormalities. Genetic counseling is recommended for parents who have already had a child with Dandy-Walker malformation as there is an increased risk that the malformation will reoccur in later pregnancies.

Imaging studies used to diagnose and monitor Dandy-Walker include:

• x rays of the skull to determine that the posterior fossa has been enlarged;
• CT scan or magnetic resonance imaging (MRI) tests to evaluate the size and shape of the fourth ventricle, the presence and size of the vermis, and the displacement of other parts of the brain by fluid pressure;
• cranial ultrasound to evaluate the size of the ventricle or to assess the progression of hydrocephalus; or
• transillumination, a technique that shines a strong light through an organ or body part to assist in diagnosis. The posterior fossa may be transilluminated as part of the differential diagnosis of Dandy-Walker.

Treatment and management

Treatment of Dandy-Walker malformation is usually focused on managing hydrocephalus when it is present. Hydrocephalus cannot be cured, but it can be treated surgically by placing a shunt in the ventricles of the brain to reduce fluid pressure. The shunt carries some of the CSF into another part of the body where it can be reabsorbed.

Another important part of managing Dandy-Walker is treatment of conditions or abnormalities associated with it—such as giving anticonvulsant medications for seizures or hormones to bring on puberty that has been delayed.

Prognosis

The prognosis for children with Dandy-Walker malformation is usually not encouraging because of the associated multiple abnormalities. Children with other congenital abnormalities occurring together with Dandy-Walker often do not survive. The affected person's chances of normal intellectual development depend on the severity of the malformation and the presence of other abnormalities.

BOOKS

Martin, John H., PhD. Neuroanatomy: Text and Atlas, 2nd ed. Norwalk, CT: Appleton & Lange, 1996.

"Neurologic Abnormalities." The Merck Manual of Diagnosis and Therapy, edited by Mark H. Beers, MD, and Robert Berkow, MD. Whitehouse Station, NJ: Merck Research Laboratories, 1999.

PERIODICALS

Cavalcanti, D. P., and M. A. Salomao. "Dandy-Walker malformation with postaxial polydactyly: further evidence for autosomal recessive inheritance." American Journal of Medical Genetics 16 (July 1999): 183-184.

Kawame, H., et al. "Syndrome of microcephaly, Dandy-Walker malformation, and Wilms tumor caused by mosaic variegated aneuploidy with premature centromere division (PCD): report of a new case and review of the literature. Journal of Human Genetics 44, no. 4 (1999): 219-224.

Macmillin, M. D., et al. "Prenatal diagnosis of inverted duplicated 8p." American Journal of Medical Genetics 17 (July 2000): 94-98.

Marszal, E., et al. "Agenesis of corpus callosum: clinical description and etiology." Journal of Child Neurology 15, no. 6 (June 2000): 401-405.

Rittler, M., and E. E. Castilla. "Postaxial polydactyly and Dandy-Walker malformation. Further nosological comments." Clinical Genetics 56 (1999): 462-463.

Ulm, B., et al. "Isolated Dandy-Walker malformation: prenatal diagnosis in two consecutive pregnancies." American Journal of Perinatology 16, no. 2 (1999): 61-63.

von Kaisenberg, C. S., et al. "Absence of 9q22-9qter in trisomy 9 does not prevent a Dandy-Walker phenotype." American Journal of Medical Genetics 18 (December 2000): 425-428.

ORGANIZATIONS

Dandy-Walker Syndrome Network. 5030 142nd Path West, Apple Valley, MN 55124. (612) 423-4008.

Guardians of Hydrocephalus Research Foundation. 2618 Avenue Z, Brooklyn, NY 11235-2023. (718) 743-4473 or (800) 458-865. Fax: (718) 743-1171. ghrf2618@aol.com.

Hydrocephalus Association. 870 Market St. Suite 705, San Francisco, CA 94102. (415) 732-7040 or (888) 598-3789. (415) 732-7044. hydroassoc@aol.com. <http://neurosurgery.mgh.harvard.edu/ha>.

National Institute of Neurological Disorders and Stroke. 31 Center Drive, MSC 2540, Bldg. 31, Room 8806, Bethesda, MD 20814. (301) 496-5751 or (800) 352-9424. <http://www.ninds.nih.gov>.

National Organization for Rare Disorders (NORD). PO Box 8923, New Fairfield, CT 06812-8923. (203) 746-6518 or (800) 999-6673. Fax: (203) 746-6481. <http://www.rarediseases.org>.

WEBSITES

Hydrocephalus Association. <http://www.HydroAssoc.org> or <http://www.neurosurgery.mgh.harvard.edu/ha>.

Rebecca J. Frey, PhD