What are the other Names for this Condition? (Also known as/Synonyms)

• Dandy-Walker Cyst
• Hydrocephalus, Non-Communicating, Dandy-Walker Type
• Luschka-Magendie Foramina Atresia

What is Dandy-Walker Malformation? (Definition/Background Information)

• Dandy-Walker Malformation (DWM) is a rare, congenital malformation of the brain that includes the cerebellum (an area present at the back side of the brain, which helps in controlling the body movements) and the fluid filled spaces around it
• The distinguishing features of Dandy-Walker Malformation include:
  • Enlarged fourth ventricle: The fourth ventricle is a channel that helps in the free flow of fluid between the upper and lower areas of the brain and spinal cord
  • Cyst formation in the fourth ventricle of the brain
  • Cerebellar vermis, an area of brain between the two cerebellar hemispheres, is partially or completely absent      
  • Increase in the size and pressure of fluid spaces surrounding the brain (hydrocephalus)
• Most cases of Dandy-Walker Malformations are caused by chromosomal abnormalities
• The treatment is directed towards managing the symptoms associated with the condition. The prognosis of Dandy-Walker Malformation is dependent upon the severity of the condition and the associated set of signs and symptoms

Who gets Dandy-Walker Malformation? (Age and Sex Distribution)

• Dandy-Walker Malformation is a congenital disorder that is present at birth. The symptoms can be seen in infants and older children
• Both men and women are affected by DWM
• No racial or ethnic group predominance is observed

What are the Risk Factors for Dandy-Walker Malformation? (Predisposing Factors)

Most cases of Dandy-Walker Malformation are sporadic, which means they occur in individuals with no previous family history of the condition. A few cases have been noticed to be running in families though.

Following are the possible risk factors associated with Dandy-Walker Malformation:

• Exposure of the fetus to viruses, such as rubella and toxoplasma, during brain development
• Exposure to substances that cause birth defects (teratogens)
• Pregnant women with uncontrolled diabetes

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Dandy-Walker Malformation? (Etiology)

Dandy-Walker Malformation is genetic disorder caused by chromosomal abnormalities.

• Most individuals have an extra copy of chromosome (3 copies instead of the normal 2 copies, called trisomy)
• In majority of the cases, there is an extra copy of chromosome 18 (trisomy 18); but, in some cases, there may be extra copies of chromosomes 13 (trisomy 13), 21 (trisomy 21), or 9 (trisomy 9)

What are the Signs and Symptoms of Dandy-Walker Malformation?

The signs and symptoms of Dandy-Walker Malformation may vary in infants and children. These may include:

• During early infancy:
  • Slow motor development
  • Skull keeps constantly increasing in size   
  • Breathing difficulties
  • Flat and widened veins are visibly seen in the skull
• In older children, increased intracranial pressure may cause:
  • Irritability
  • Vomiting
  • Convulsions
  • Developmental delays
  • Mental retardation
  • Abnormality in the functioning of the pituitary gland
  • Delayed puberty
• In older children, cerebellar dysfunctions may cause:
  • Unsteadiness
  • Abnormality in muscle coordination
  • Jerky eye movements     
• Other signs and symptoms of DWM may include:
  • Large circumference of the head
  • Swelling at the back portion of the skull
  • Abnormality in the nerves that control the eyes, face, and neck   
  • Irregular breathing patterns
  • Absence of corpus callosum - an area consisting of nerve fibers that connect the two cerebral hemispheres

  • Malformation of the heart, face, limbs, fingers, and toes

How is Dandy-Walker Malformation Diagnosed?

The diagnosis of Dandy-Walker Malformation may include:

• Ultrasound screening before birth can help diagnose the condition
• After birth, the baby’s head circumference is measured to check if it is increasing in size, due to any abnormal growths in the brain
• Imaging studies to be performed may include:
  • X-rays of the skull to check for skull enlargement
  • CT and MRI scan to measure the size and shape of the fourth ventricle      
  • Cranial ultrasound to monitor the development of hydrocephalus

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Dandy-Walker Malformation?

Complications associated with Dandy-Walker Malformation include:

• Slow motor development
• Muscle stiffness and paralysis of lower limbs
• Seizures
• Hearing and vision abnormalities
• Heart defects
• Extra fingers or toes, fused fingers or toes
• Malformations of the urinary and genital tracts

How is Dandy-Walker Malformation Treated?

The treatment of Dandy-Walker Malformation is directed towards treating the underlying symptoms.

• A surgical procedure, termed as shunt, may be performed to drain-off the excess fluid accumulated within the brain, in order to reduce the intracranial pressure. This method transfers some of the cerebrospinal fluid to other parts of the body, where it may be absorbed
• Anticonvulsant medications are given to control seizures
• Parents of children with DWM can be benefitted by genetic counseling, if they plan to have more children

How can Dandy-Walker Malformation be Prevented?

• Currently, there are no specific methods or guidelines to prevent Dandy-Walker Malformation, since it is a genetic condition
• Genetic testing of the expecting parents (and related family members) and prenatal diagnosis (molecular testing of the fetus during pregnancy) may help in understanding the risks better during pregnancy
• If there is a family history of the condition, then genetic counseling will help assess risks, before planning for a child
• Active research is currently being performed to explore the possibilities for treatment and prevention of inherited and acquired genetic disorders

What is the Prognosis of Dandy-Walker Malformation? (Outcomes/Resolutions)

• The prognosis for Dandy-Walker Malformation is generally guarded
• The presence of other congenital abnormalities along with DWM indicates a poor prognosis
• The intellectual development of the child affected by this disorder depends on the following parameters:
  • Severity of the disorder
  • Co-occurrence of other congenital abnormalities

Additional and Relevant Useful Information for Dandy-Walker Malformation:

Various studies are being conducted by the US National Institute of Neurological Disorders and Stroke (NINDS) for better understanding of abnormalities during the brain development. It hopes to discover new ways to prevent and treat brain malformations such as Dandy-Walker Malformations.