Dandy-Walker malformation is a rare congenital brain malformation characterised by hypoplasia and upward rotation of the cerebellar vermis, cystic dilation of the fourth ventricle and enlargement of the posterior fossa.¹ It may also form part of the PHACES syndrome (= Posterior fossa anomalies as Dandy-Walker malformation; Haemangioma; Arterial lesions of the head and neck; Cardiac abnormalities as aortic coarctation; Eye abnormalities and Sternal defect).²

A large number of associated problems may also be present, such as hydrocephalus (often develops postnatally), atresia of the foramen of Magendie and atresia of the foramen of Luschka.

Epidemiology

• Incidence is approximately 1 in 25-35,000 live births.³
• It occurs slightly more frequently in females than in males.
• Marked variation has been shown in the genetics and aetiology.⁴
• Recurrence risk for siblings may be high when there is an association with a single gene disorder.
• Dandy-Walker syndrome may result from chromosomal anomalies or environmental factors.⁵
• Associated environmental factors include first trimester exposure to rubella, cytomegalovirus, toxoplasmosis or warfarin.
• When the evidence suggests that there is no association with a Mendelian or chromosomal disorder then the recurrence risk is relatively low at between 1 and 5%.⁶

Presentation

• The syndrome can appear dramatically or develop unnoticed.
• Symptoms often occur in early infancy and include slow motor development and abnormally rapid increase in head circumference with bulging at the back of the skull.
• In older children there may be signs of increased intracranial pressure, such as irritability, vomiting, and convulsions. There may also be signs of cerebellar dysfunction, such as unsteadiness, lack of muscle co-ordination, or jerky movements of the eyes. One case report describes conduct disorder, hyperactivity, stereotypical movements and nocturnal enuresis in a 14 year-old.⁷
• There may also be jerky movements of the face and neck and abnormal breathing patterns.

Investigations

• The diagnosis of Dandy-Walker malformation can be made by antenatal ultrasound.^8,9
• MRI scan allows a detailed evaluation of Dandy-Walker malformation lesions and complications. MRI evaluation can then be used antenatally to confirm the diagnosis and to gain more detailed information.¹⁰

Associated diseases

Dandy-Walker syndrome is frequently associated with disorders of other areas of the central nervous system, including absence of the corpus callosum, and malformations of the heart, face, limbs, fingers and toes.

Management

• Treatment involves managing the associated problems, e.g. seizure management.
• A shunt to treat associated hydrocephalus can be inserted. This may be to shunt the cyst (cystoperitoneal), the ventricles (ventriculoperitoneal), or both.
• Parents of children with Dandy Walker syndrome will benefit from genetic counselling if they intend to have more children.

Prognosis

• Children with Dandy-Walker syndrome may never have normal intellectual development, even when the hydrocephalus is treated early.
• Prognosis otherwise depends on the severity of the syndrome and associated malformations.
• The presence of multiple congenital defects may shorten lifespan.

Document references

1. Incesu L et al; Imaging in Dandy-Walker Malformation, eMedicine, Sep 2009
2. Lopez Gutierrez JC; PHACES syndrome and ectopia cordis. Interact Cardiovasc Thorac Surg. 2011 Jan 19. [abstract]
3. Lavanya T, Cohen M, Gandhi SV, et al; A case of a Dandy-Walker variant: the importance of a multidisciplinary team Br J Radiol. 2008 Oct;81(970):e242-5. [abstract]
4. Dandy-Walker Syndrome, Online Mendelian Inheritance in Man (OMIM)
5. Imataka G, Yamanouchi H, Arisaka O; Dandy-Walker syndrome and chromosomal abnormalities. Congenit Anom (Kyoto). 2007 Dec;47(4):113-8. [abstract]
6. Murray JC, Johnson JA, Bird TD; Dandy-Walker malformation: etiologic heterogeneity and empiric recurrence risks. Clin Genet. 1985 Oct;28(4):272-83. [abstract]
7. Prakash R, Singh LK, Kour J, et al; Psychiatric comorbidities in Dandy-Walker variant disorder. J Neuropsychiatry Clin Neurosci. 2009 Fall;21(4):477-9.
8. Has R, Ermis H, Yuksel A, et al; Dandy-Walker malformation: a review of 78 cases diagnosed by prenatal sonography. Fetal Diagn Ther. 2004 Jul-Aug;19(4):342-7. [abstract]
9. Klein O, Pierre-Kahn A, Boddaert N, et al; Dandy-Walker malformation: prenatal diagnosis and prognosis. Childs Nerv Syst. 2003 Aug;19(7-8):484-9. Epub 2003 Jul 16. [abstract]
10. Zimmerman RA, Bilaniuk LT; Magnetic resonance evaluation of fetal ventriculomegaly-associated congenital malformations and lesions. Semin Fetal Neonatal Med. 2005 Oct;10(5):429-43. [abstract]

Acknowledgements