Dandy-Walker Syndrome

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 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.

• Incidence is approximately 1 in 30,000 live births.
• Occurs more frequently in females than males.
• Marked variation has been shown in the genetics and aetiology.²
• 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.
• 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%.³

• 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, 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.
• There may also be jerky movements of the face and neck and abnormal breathing patterns.

• The diagnosis of Dandy-Walker malformation can be made by antenatal ultrasound.^4,5
• 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 gain more detailed information.⁶

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.

• Treatment generally consists of treating the associated problems, if needed, and usually consists of a shunt to treat associated hydrocephalus. 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.

• 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 life span.