Sign Up for a Free Account
  • Updated 01.19.2024
  • Released 08.13.1998
  • Expires For CME 01.19.2027

Dandy-Walker syndrome



Dandy-Walker syndrome involves a constellation of posterior fossa malformations, including cerebellar vermian hypoplasia, elevation, and rotation of the cerebellar vermis and cyst-like dilatation of the fourth ventricle. Posterior fossa enlargement and hydrocephalus are variably present. Associated symptoms include learning and motor disabilities. Although the pathogenesis of Dandy-Walker syndrome is poorly understood and multifactorial, several genes implicate abnormal mesenchymal development. MRI diagnostic signs include the unpaired caudal lobule, or “tail-sign,” and increased tegmentovermian angle and fastigial recess. The differential diagnosis includes acquired cerebellar lesions as a complication of extreme prematurity and other posterior fossa abnormalities.

Key points

• Dandy-Walker syndrome is a posterior fossa malformation involving hypoplasia of the cerebellar vermis, which is elevated and upwardly rotated, and cyst-like dilatation of the fourth ventricle. Other malformations are variably associated.

• Dandy-Walker syndrome can be associated with normal intellect and development.

• Developmental prognosis hinges on associated malformations, extent of vermian abnormalities, and the presence of an underlying genetic condition.

• The pathogenesis of Dandy-Walker syndrome is thought to be related to abnormal mesenchymal development due to genetic abnormalities. Several loci have been investigated, but a specific genetic cause is often not found.

Historical note and terminology

Sutton was the first to describe the association of hydrocephalus, hypoplasia of the cerebellar vermis, and posterior fossa cyst (73). The triad was later confirmed by Dandy and Blackfan, who added four cases (20). The primary defect was thought to be atresia of the foramina of Luschka and Magendie. In 1942 Taggart and Walker added three case reports (74). Benda introduced the eponym "Dandy-Walker syndrome" (07). He considered it a developmental anomaly not necessarily due to foraminal atresia, because some autopsy cases had patent foramina. In 1959 based on a murine model of hydrocephalus, Brodal and Hauglie-Hanssen postulated that an abnormal distension of the fourth ventricle leads to maldevelopment of the cerebellar vermis. The definition of the syndrome, the diagnostic criteria, and the nomenclature remain a perpetual subject of debate between authors. In light of the variability of developmental posterior fossa abnormalities, some authors consider these to be part of a spectrum, "lumping" diverse conditions into a Dandy-Walker complex or Dandy-Walker continuum. In the neuroradiological literature a distinction is often made between Dandy-Walker malformation and Dandy-Walker variant; the latter term is applied if the posterior fossa is not enlarged, the hypoplasia of the cerebellar vermis is less pronounced, or both (75; 04). In view of its variable definition and lack of specificity the terms Dandy-Walker variant and Dandy-Walker complex are best avoided.

This view has been explicitly supported by experts in the field (05). Many cases of Dandy Walker variant correspond to inferior vermian hypoplasia.

In this article, the term Dandy-Walker syndrome is used in reference to Dandy-Walker malformation, which consists of cerebellar vermian hypoplasia, elevation, and rotation of the cerebellar vermis and cyst-like dilatation of the fourth ventricle (52). From a didactic point of view, one can distinguish between the following:

• Dandy-Walker syndrome proper (isolated)
• Dandy-Walker syndrome as part of another defined syndrome (see Table 1).

Table 1. Defined Syndromes that Include Dandy-Walker Syndrome

• Aase-Smith
• Coffin-Siris
• Ellis-van Creveld
• Fraser cryptophthalmus
• Goldenhar
• Hydrolethalus
• Meckel-Gruber
• Marden-Walker
• Mohr (oro-facio-digital II)
• Ritscher-Schinzel (3C)
• Walker-Warburg
• Wyburn-Mason

Note: Syndromes with vermian agenesis but without posterior fossa cyst are not included.

Modified from: (46; 12; 52; 50; 45; 37).

Neurocutaneous melanosis has been repeatedly found associated with cystic posterior fossa lesions including Dandy-Walker syndrome (41).

This is an article preview.
Start a Free Account
to access the full version.

  • Nearly 3,000 illustrations, including video clips of neurologic disorders.

  • Every article is reviewed by our esteemed Editorial Board for accuracy and currency.

  • Full spectrum of neurology in 1,200 comprehensive articles.

  • Listen to MedLink on the go with Audio versions of each article.

Questions or Comment?

MedLink®, LLC

3525 Del Mar Heights Rd, Ste 304
San Diego, CA 92130-2122

Toll Free (U.S. + Canada): 800-452-2400

US Number: +1-619-640-4660



ISSN: 2831-9125