Dandy-Walker Syndrome

What is Dandy-Walker syndrome?

Dandy-Walker syndrome is sometimes called Dandy-Walker malformation or just Dandy-Walker. It’s a congenital brain malformation that causes an issue with how the brain forms. It is congenital meaning a baby is born with the condition, and it occurs as the baby develops during pregnancy.

Dandy-Walker involves the cerebellum and the spaces around it. The cerebellum is in the back of the brain, near the brainstem. It's part of the central nervous system. The cerebellum coordinates movements. It also helps control:

• Balance, coordination and posture.
• Vision.
• Cognition (thinking ability).
• Motor skills.
• Behavior.

Dandy-Walker syndrome is named after the two neurosurgeons (brain surgeons) who described it in the 1900s, Walter Dandy, MD, and Arthur Walker, MD.

What happens to the brain in people with Dandy-Walker?

In Dandy-Walker syndrome, several conditions may occur:

• The fourth ventricle becomes enlarged. This space around the cerebellum helps cerebrospinal fluid (CSF) flow between the upper and lower brain and the spinal cord.
• The cerebellar vermis (area between the two hemispheres, or halves, of the cerebellum) is partially or completely absent.
• A cyst (fluid-filled sac) forms near the fourth ventricle.
• The base of the skull (posterior fossa) becomes enlarged.
• Hydrocephalus may occur if CSF builds up, leading to high pressure and swelling in the skull.

How common is Dandy-Walker syndrome?

In the United States, Dandy-Walker malformation affects about 1 in 25,000 to 35,000 babies. It affects more female babies than male babies.

What causes Dandy-Walker syndrome?

Dandy-Walker happens when there’s an issue with the development of the baby’s cerebellum in the uterus. In some cases, a genetic mutation (change) may cause the condition.

Some people with Dandy-Walker have chromosomal conditions, such as extra or missing pieces of chromosomes. Chromosomes are packages of DNA that carry genes. Dandy-Walker syndrome may also happen as part of a genetic disorder that includes several birth defects (congenital conditions).

Other potential causes of Dandy-Walker may include:

• Certain viruses that pass from the birthing parent to baby during pregnancy.
• Exposure to certain toxins or medications during pregnancy.
• The birthing parent had diabetes.

When do symptoms of Dandy-Walker begin?

Sometimes, the symptoms appear suddenly and dramatically. Other times, symptoms may occur without parents noticing anything is wrong.

Symptoms tend to develop in the baby’s first few months of life, but some children don’t receive a diagnosis until age 3 or 4.

What are the symptoms of Dandy-Walker syndrome?

Symptoms in infants include:

• Meeting motor milestones later than expected (developmental delays).
• Disproportionately large skull.
• Low muscle tone (hypotonia).
• Stiff muscles (spasticity).

Symptoms in older children include:

• Vomiting, convulsions and irritability — signs of increased pressure on the brain.
• Uncoordinated movements, unsteadiness or jerky eye movements — signs of conditions with the cerebellum.

Other signs include:

• Bulge or swelling at the back of the skull.
• Conditions with the nerves that control the neck, face and eyes.
• Unusual breathing rhythm.
• Seizures.
• Intellectual disabilities.
• Symptoms of hydrocephalus.

What is the difference between Dandy-Walker complex and Dandy-Walker syndrome?

Dandy-Walker complex is a group of disorders with similar symptoms. Dandy-Walker syndrome is one of the disorders included in Dandy-Walker complex.

Other disorders included in Dandy-Walker complex are:

• Isolated cerebellar vermis hypoplasia or Dandy-Walker variant: The cerebellar vermis is small or underdeveloped. Children’s brains don’t have other structural issues associated Dandy-Walker syndrome. Many children with this diagnosis develop normally.
• Mega cisterna magna: The posterior fossa is large, but the cerebellum is typical. Mega cisterna magna often doesn’t cause any health issues.
• Posterior fossa arachnoid cyst: A cyst develops on the posterior fossa. It's not common for children to have symptoms due to the presence of a cyst.

What other disorders are associated with Dandy-Walker syndrome?

Children with Dandy-Walker may have disorders of other parts of the central nervous system, including:

• Absence of the corpus callosum (ACC), a rare congenital condition where a baby is missing part of the brain.
• Issues with how the limbs, face, heart, fingers and toes form.

Will my child have an intellectual disability?

Fewer than half of children with Dandy-Walker have an intellectual disability. Intellectual disability most often occurs in children with Dandy-Walker who also have:

• Severe hydrocephalus.
• Chromosomal conditions.
• Other congenital conditions.

How is Dandy-Walker syndrome diagnosed?

Healthcare providers or parents may notice that a child has increased head size. A child may also not meet developmental milestones. Providers order brain imaging to diagnose Dandy-Walker. Tests may include:

• Ultrasound.
• CT.
• MRI.

Occasionally, providers diagnose this condition before a baby is born during a prenatal ultrasound or fetal MRI.

Should my family get genetic testing if a child has Dandy-Walker?

If you have a child with Dandy-Walker malformation, talk to your healthcare provider about genetic counseling. A small percentage of people with this condition have family members who also have it. Because there may be a genetic component, many providers recommend genetic testing.

What are treatment options for Dandy-Walker syndrome?

Treatment is based on the symptoms resulting from Dandy-Walker syndrome. A careful evaluation by a healthcare provider is essential before initiating treatment. For example, healthcare providers may recommend:

• Ventriculoperitoneal (VP) shunt: Surgeons place a VP shunt, a small device, to drain excess fluid from the brain. The shunt can reduce pressure on the brain and improve symptoms.
• Medications: Your child’s provider may prescribe medications to control seizures.
• Therapy: Physical and occupational therapy can help children maintain muscle strength. Therapists can also teach children new methods of doing their regular activities. Speech therapy can help with language and speech development.
• Special education: The right learning environment can help children reach educational and social goals.

Can Dandy-Walker syndrome be prevented?

There is no known way to prevent Dandy-Walker syndrome. Consistent prenatal care provides your best likelihood of a healthy pregnancy. Follow your provider’s recommendations for healthy living while you’re pregnant.

What’s the outlook for children with Dandy-Walker syndrome?

Your child’s outlook and life expectancy depend on how severe their condition is. Other congenital conditions also affect their prognosis.

People with the condition have a wide range of experiences. Some have minor symptoms. Others have profound disabilities. Some children can achieve typical cognitive abilities with the right treatment plan. Others do not, even when their care team diagnoses and treats the condition early.

How can I care for my child with Dandy-Walker?

Early intervention can help your child have the best chance at successful treatment. If you notice your child is not reaching their developmental milestones on time, such as not sitting, walking or talking, see your healthcare provider. They can provide an accurate diagnosis so your child can get the most effective treatment plan.

Your child’s Dandy-Walker care team may include:

• Pediatrician.
• Development specialists.
• Speech, occupational and physical therapists.
• Special education professionals.

What should I ask my healthcare provider about Dandy-Walker syndrome?

If your child receives a diagnosis of Dandy-Walker, ask your provider:

• Will my child need a shunt?
• What other conditions does my child have?
• What’s the outlook for my child?
• How can we improve my child’s symptoms?
• Should we get genetic testing?

A note from Cleveland Clinic

Dandy-Walker syndrome, or Dandy-Walker malformation, is a brain condition that develops before a baby is born. Babies with Dandy-Walker often don’t meet their developmental milestones. Some children need a shunt to drain excess fluid from the brain. Therapies can help children manage daily tasks, succeed in school and live a fulfilling life. If you notice your child has a large head size or does not seem to be sitting, walking or talking as expected, talk to your provider.