Dandy-Walker syndrome is a congenital condition in which a part of a baby’s brain does not develop properly. This often results in issues with movement and balance.

Dandy-Walker syndrome is a rare condition that affects a child’s physical and intellectual development. It may also lead to a reduced life expectancy, depending on the severity of the condition.

This condition develops in about 1 in 25,000–35,000 live births and primarily affects females.

This article reviews the symptoms, causes, risk factors, diagnosis, treatment, and outlook for Dandy-Walker syndrome. We also look at some frequently asked questions (FAQs).

The effects of Dandy-Walker syndromeShare on Pinterest
Infographic by Bailey Mariner. Illustrated by Diego Sabogal.

When Dandy-Walker syndrome occurs, a baby’s cerebellum does not develop as expected. It may be smaller than usual or nonexistent. Fluid also tends to build up in spaces in the brain, which can lead to an increase in head size.

The severity will determine whether any noticeable symptoms develop. In some cases, the condition may go unnoticed for years. If doctors do not spot it at birth, symptoms may appear later in childhood, either gradually or suddenly.

Symptoms of the condition include:

Experts do not know the exact cause of Dandy-Walker syndrome.

The condition typically starts in the first month of pregnancy. As a baby’s brain develops, the cerebellum does not develop correctly, and fluid begins to build up in the brain.

Possible causes of Dandy-Walker syndrome include:

  • chromosomal defects, which often occur in people with:
    • trisomy 18 (an extra copy of chromosome 18)
    • trisomy 13
    • trisomy 21
    • trisomy 9
  • certain viral infections that may pass from the pregnant person to the fetus
  • diabetes during pregnancy — gestational diabetes occurs in 2–10% of pregnancies
  • exposure of the unborn baby to certain toxins or medications

Recessive genes may be responsible for the condition. These genes may cause cerebellar vermis hypoplasia, which is a small or underdeveloped cerebellum, and mega-cisterna manga, which is a large cerebrospinal space. Doctors refer to these conditions together as the Dandy-Walker complex.

The subtypes may be ordinary development variations that do not result in symptoms.

Genetic and environmental factors likely play a role in developing Dandy-Walker syndrome.

For example, pregnant people who have diabetes may have an increased risk of having children with the condition.

Non-Hispanic Black individuals and females with a history of infertility also have an increased risk.

Related disorders may help practitioners with differential diagnoses.

Related conditions include:

  • hydrocephalus, which causes unusually wide cerebral spaces that reduce fluid flow in the brain
  • Walker-Warburg syndrome, a rare multisystem condition that can cause muscle disease and brain and eye abnormalities

A doctor can diagnose Dandy-Walker syndrome through several testing methods, including:

At times, a neonatal doctor may be able to diagnose the condition in the developing fetus using ultrasound or MRI.

A doctor may order genetic testing to look for changes in the child’s DNA. This may include:

  • Cell-free fetal DNA testing: A blood draw from the pregnant person to look for problems with the developing baby’s DNA
  • Amniocentesis: Removal of some amniotic fluid to screen for genetic issues
  • Post-birth testing: a blood draw from the baby to check for genetic abnormalities

Treatment will often involve a combination of therapies to address the child’s needs. If hydrocephalus is present, a doctor may recommend surgery to remove the excess fluid.

The surgery typically involves inserting a tube or shunt to drain the excess fluid and reduce pressure on the brain. Surgery may help prevent further brain damage and help alleviate symptoms in some cases.

Specialists during pregnancy

Treatment can vary based on when doctors discover the condition. If they find it during pregnancy, a pregnant person will often receive additional monitoring and may have an expanded care team, which can include:

  • neurosurgeons — doctors who perform brain surgery
  • neonatologists — doctors who specialize in treating newborns
  • neurologists — doctors who specialize in the brain
  • nurse coordinators
  • nurses

Post-birth treatment

A baby born with Dandy-Walker syndrome will need additional, ongoing therapies. They may:

  • spend time in the neonatal intensive care unit
  • receive fluids through an IV line, directly into the bloodstream
  • undergo additional testing, including blood and image testing

After going home from the hospital, the baby will need regular checkups to monitor growth and development. They will generally receive a typical vaccination schedule.

Children may need additional therapies to help with mental or physical challenges resulting from the condition. Possible therapies include:

A child born with Dandy-Walker syndrome may need long-term care and interventions to help improve their quality of life.

Life expectancy can depend greatly on whether a child has hydrocephalus or pressure on the brain and whether doctors can successfully treat this. Various estimates suggest that a person has a 10–66% chance of dying due to Dandy-Walker syndrome. However, drainage surgery may reduce the chance of death by about 44%.

Parents should consider working closely with medical teams, who can provide better details on what may affect the overall outcome.

In some cases, after initial treatment, a baby may live an otherwise typical life with no complications.

The following sections provide answers to FAQs about Dandy-Walker syndrome.

Are there any complications associated with Dandy-Walker syndrome?

Dandy-Walker syndrome may occur alongside other developmental abnormalities. These can contribute to a worse prognosis and may lead to complications such as:

  • heart problems
  • limb and facial irregularities
  • hearing and vision issues

Other possible complications include:

  • delayed mental and physical development
  • seizures
  • paralysis
  • issues with learning and thinking

How else may doctors refer to this condition?

Dandy-Walker syndrome has several names:

  • Dandy-Walker malformation
  • Dandy-Walker
  • Dandy-Walker deformity
  • Dandy-Walker cyst
  • DWM
  • hydrocephalus, noncommunicating, Dandy-Walker type
  • hydrocephalus, internal, Dandy-Walker type
  • Luschka-Magendie foramina atresia

Can you prevent Dandy-Walker syndrome?

Environmental factors may lead to the development of Dandy-Walker syndrome.

A person may be able to reduce the risk for their baby by avoiding toxins and certain chemicals during pregnancy. People should consult a doctor about what is and is not safe for their developing fetus.

Dandy-Walker syndrome is a rare condition in which part of the brain does not develop correctly. This can lead to a buildup of fluid in the brain and potential complications, including physical and intellectual development issues.

Treatment can vary depending on the symptoms and severity of the condition. If fluid buildup occurs, a child will often need surgery to drain the fluid and prevent potential brain damage. Additional therapies typically help with physical and intellectual development concerns as the child ages.

With treatment, some children can have a typical life span. They may or may not need continued support throughout their life.