Dandy Walker Malformation

Question 1

What is a Dandy Walker malformation?

Answer 1

Enlargement of the posterior fossa with dilated 4th ventricle, malformed cerebellar vermis. 70-80% ventriculomegaly and hydrocephaly

Question 2

if a Dandy Walker malformation is identified, how will you counsel the patient?

Answer 2

Antenatal:

• 60% with other anomalies
• Holoprosencephaly
• Dysgenesis of corpus callosum
• Cardiac disease
• Cranial facial disease
• CDH
• Ambiguous genitalia

Postnatal:

• Ataxia
• Motor Deficits
• Hypotonia
• MR

Question 3

What are the associated genetic or karyotypic abnormalities with Dandy Walker malformation?

Answer 3

Trisomy 9
T13
T18
T21
Triploidy 
3q22-24 deletion 
Cornelia de lange

Question 4

If Dandy Walker malformation is identified, what is your differential diagnosis?

Answer 4

• Vermian dysgenesis
• Blake’s pouch
• Mega Cisterna Magna
• Arachnoid cyst

Question 5

If a Dandy Walker malformation is identified what workup do you recommend?

Answer 5

• Detailed fetal anatomy
• Fetal echocardiogram
• Amniocentesis
• Neurosonography
• MRI
• Fetal growth
• Antenatal testing

Question 6

In the setting of a Dandy Walker malformation and if an amniocentesis is performed, what testing will you send on the fluid?

Answer 6

FISH with karyotype reflex to CMA if normal

Question 7

How do you counsel the patient about prognosis for an isolated Dandy Walker malformation?

Answer 7

• Motor deficits (hypotonia, ataxia)
• Mental retardation
• Uncontrolled hydrocephalus and shunt complications which is the major cause of death