National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Dandy-Walker complex


Other Names:
DW complex; Dandy-Walker syndrome or malformation (type of DW complex); Dandy-Walker variant (type of DW complex); DW complex; Dandy-Walker syndrome or malformation (type of DW complex); Dandy-Walker variant (type of DW complex); Mega cisterna magna (type of DW complex) See More
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Dandy-Walker complex is a group of disorders that affect the development of the brain. The changes in brain development are present from birth (congenital). Dandy-Walker complex affects the formation of the area of the brain known as the cerebellum, which is responsible for coordinating movement, and the fluid-filled spaces around it. People with Dandy-Walker complex may have a portion of the brain called the cerebellar vermis that is smaller than expected (hypoplastic) or completely absent (aplastic). The cerebellar vermis is the area of the brain between the two halves of the cerebellum.  People with Dandy-Walker complex have a larger than expected fourth ventricle of the brain. This ventricle allows fluid to flow between the upper and lower areas of the brain and spinal cord. People with Dandy-Walker complex may have an enlarged portion of the base of the skull (posterior fossa).[1][2] Dandy-Walker complex may be more common in females than in males.[2]

Dandy-Walker complex is a group of disorders that have overlapping symptoms. These disorders include:[2][3]
  • Dandy-Walker malformation (also known as Dandy-Walker syndrome): having a small cerebellar vermis, large fourth ventricle, and enlarged posterior fossa
  • Isolated cerebellar vermis hypoplasia (sometimes known as Dandy-Walker variant): having a small cerebellar vermis without other features of Dandy-Walker complex
  • Mega-cisterna magna: having an enlarged posterior fossa with a typically developed cerebellum. This may be a normal variant and may not cause any health problems.
  • Posterior fossa arachnoid cyst: the development of a cyst on the posterior fossa without any other features of Dandy-Walker complex
Each of these disorders can have separate causes and different long-term outlooks. In order to provide families with more information about the specific developmental differences in the brain and the long-term outlook, a person with Dandy-Walker complex may be given a more specific diagnosis.[2]

In some cases, Dandy-Walker complex is caused by an underlying genetic change. These genetic changes may cause Dandy-Walker complex alone, or they may cause Dandy-Walker complex as well as other health problems. In these situations, the complex can run in families. However, in most situations, Dandy-Walker complex is caused by a combination of genetic and environmental factors.[2] Dandy-Walker complex can be diagnosed by imaging of the brain such as ultrasound, CT scan, or MRI scan.[2][3] Treatment options may include a surgery to place a ventriculoperitoneal shunt that relieves excess fluid from the brain, as well as physical and occupational therapies.[1][2]
Last updated: 4/30/2018
The signs and symptoms of Dandy-Walker complex may depend on the age of the person who has the complex. In some cases, Dandy-Walker complex can be detected with an ultrasound before a baby is born. In other cases, the first symptoms of the complex begin in infancy. Symptoms of Dandy-Walker complex that begin in infancy may include a head circumference that is becoming larger faster than expected, low muscle tone (hypotonia) or very stiff muscles (spasticity). Children with Dandy-Walker complex might meet developmental milestones such as sitting up or walking later than expected (developmental delay).[1][2] In older children who have Dandy-Walker complex, signs and symptoms may include irritability, vomiting, jerky movements of the eyes (nystagmus), and trouble coordinating movements (ataxia). These symptoms may develop slowly or appear suddenly.[1] Most people with Dandy-Walker complex develop symptoms within the first year of life.[4]

Other signs and symptoms of Dandy-Walker complex may include an increase in the size and pressure of fluid spaces surrounding the brain (hydrocephalus) and bulging at the back of the skull. In some cases, the increased pressure on the brain can cause breathing problems, seizures, and difficulty controlling the movements of the eyes, face, and neck. About half of people with Dandy-Walker complex have intellectual disability.[2]

In some cases, Dandy-Walker complex can be a sign of a separate underlying genetic syndrome. Therefore, some people with Dandy-Walker complex have other health problems or differences from birth that can affect other parts of the brain as well as the heart, face, limbs, fingers, and toes.[1][2]
Last updated: 4/30/2018

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Showing of 19 |
Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Dandy-Walker malformation 0001305
Platybasia 0002691
Prominent occiput
Prominent back of the skull
Prominent posterior skull
[ more ] 		0000269
30%-79% of people have these symptoms
Frontal bossing 0002007
5%-29% of people have these symptoms
Aplasia/Hypoplasia of the corpus callosum 0007370
Cleft palate
Cleft roof of mouth
0000175
Encephalocele 0002084
Tetralogy of Fallot 0001636
Percent of people who have these symptoms is not available through HPO
Agenesis of cerebellar vermis 0002335
Cranial nerve paralysis 0006824
Dilated fourth ventricle 0002198
Elevated imprint of the transverse sinuses 0000930
Hydrocephalus
Too much cerebrospinal fluid in the brain
0000238
Nystagmus
Involuntary, rapid, rhythmic eye movements
0000639
Partial absence of cerebellar vermis 0002951
Posterior fossa cyst at the fourth ventricle 0000933
Sporadic
No previous family history
0003745
Thinning and bulging of the posterior fossa bones 0000931
Truncal ataxia
Instability or lack of coordination of central trunk muscles
0002078
Showing of 19 |
Last updated: 7/1/2020
In most cases, the exact cause of Dandy-Walker complex is unknown. It is thought that most cases are caused by a combination of genetic and environmental factors that affect early development before birth. In some cases, exposures that occur during pregnancy, such as a pregnant woman having diabetes or an infection such as rubella, are thought to cause an increased risk for the developing baby to have Dandy-Walker complex.[1][2] 

In some cases, Dandy-Walker complex is caused by an underlying genetic change. For example, some people with Dandy-Walker complex have extra or missing pieces of chromosomes in each cell of the body (chromosome abnormalities). Dandy-Walker complex can also occur as a symptom of another genetic syndrome. For example, people with Dandy-Walker complex may have a change in a gene that causes them to develop Dandy-Walker complex as well as other health problems.[2] Researchers are currently learning more about genes in which changes (pathogenic variants or mutations) can cause Dandy-Walker complex.[1]
Last updated: 4/30/2018
Most cases of Dandy-Walker complex are sporadic, meaning they occur in people with no history of the complex in their family. The cause of most cases of Dandy-Walker complex remains unknown. A small percentage of people with Dandy-Walker complex may have other family members with the complex, but it is not clear how the complex is inherited.[4] When the complex is not thought to be caused by a single genetic change (pathogenic variant or mutation), the risk for a sibling to have the complex is between 1-5%.[2][5]  

When Dandy-Walker complex is caused by an underlying genetic syndrome, the chance for family members to have the complex as well depends on the inheritance pattern of the underlying syndrome.[4] 
Last updated: 4/30/2018
Dandy-Walker complex may be suspected when a doctor observes signs and symptoms of the complex including an increased head size and developmental delay. A doctor may order tests to evaluate the cause of these symptoms, including imaging of the brain. Most typically, a brain ultrasound, CT scan, or brain MRI is used to diagnose Dandy-Walker complex.[2][3] In some cases, the doctor may order genetic testing to determine if there is an underlying genetic cause for the complex.[3]
Last updated: 4/30/2018
Treatment for Dandy-Walker complex is focused on relieving any pressure on the brain that is caused by the brain malformations. If there is excess fluid in the brain, a doctor may perform a surgery to place a ventriculoperitoneal shunt in the brain, which allows for the excess fluid to be drained. This can relieve the pressure in the brain and reduce some symptoms of Dandy-Walker complex. Medications can be used to help control seizures. Other symptoms of Dandy-Walker complex such as developmental delay or trouble coordinating movements may be treated with occupational therapy or physical therapy. Some children with Dandy-Walker complex may require additional help in school such as special education classes.[1]
Last updated: 4/30/2018
The long-term outlook for people with Dandy-Walker complex depends on the symptoms that are caused by the changes in the structures of the brain. The long-term outlook also depends on whether Dandy-Walker complex occurs alone (isolated) or whether there is an underlying genetic syndrome that may cause other health problems. Because the differences in brain structure and the presence of an underlying genetic syndrome may affect the signs and symptoms or life expectancy that a person has, it may be difficult to predict the long-term outlook for people who have Dandy-Walker complex.[1][6]

Some people with Dandy-Walker complex may have physical disabilities or intellectual disabilities. In most cases, infants who have isolated Dandy-Walker variant are more likely to have normal outcomes in the newborn period.[7] 
Last updated: 4/30/2018

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • The Centers for Mendelian Genomics program is working to discover the causes of rare genetic disorders. For more information about applying to the research study, please visit their website.
  • ClinicalTrials.gov lists trials that are related to Dandy-Walker complex. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

    Please note: Studies listed on the ClinicalTrials.gov website are listed for informational purposes only; being listed does not reflect an endorsement by GARD or the NIH. We strongly recommend that you talk with a trusted healthcare provider before choosing to participate in any clinical study.
  • The Research Portfolio Online Reporting Tool (RePORT) provides access to reports, data, and analyses of research activities at the National Institutes of Health (NIH), including information on NIH expenditures and the results of NIH-supported research. Although these projects may not conduct studies on humans, you may want to contact the investigators to learn more. To search for studies, enter the disease name in the "Text Search" box. Then click "Submit Query".

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

In-Depth Information

  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Dandy-Walker complex. Click on the link to view a sample search on this topic.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know. Submit a new question

  • My wife is 17 weeks pregnant. During a level 2 ultrasound scan, the doctor told us there is a problem with the development of the cerebellar vermis. Can the vermis develop after 17 weeks? If a child is born with this, what problems could the child face? What are other tests we can do to confirm the condition? See answer

  • Can a child have Dandy-Walker variant and have other extracranial malformations, such as kidney and foot issues? Or does the presence of other issues point toward the more serious Dandy-Walker malformation? See answer

  • My husband was diagnosed with Dandy Walker variant at the age of 50. His brain surgeon placed a shunt. We have three children of adult age. Should they be concerned that this can be passed on? He went his whole life not knowing he had Dandy Walker till problems neurologically started happening and was in critical condition. How long can a person live with this once shunted and can our children be concerned that this is passed on? See answer

  • What is the life expectancy of someone with Dandy-Walker complex? See answer


  1. Dandy-Walker Syndrome Information Page. National Institute of Neurological Disorders and Stroke (NINDS). December 20, 2017; https://www.ninds.nih.gov/Disorders/All-Disorders/Dandy-Walker-Syndrome-Information-Page.
  2. Dobyns WB. Dandy Walker Malformation. National Organization for Rare Disorders (NORD). 2008; http://rarediseases.org/rare-diseases/dandy-walker-malformation/.
  3. Incesu L and Khosla A. Imaging in Dandy-Walker Malformation. Medscape Reference. March 27, 2018; http://emedicine.medscape.com/article/408059-overview.
  4. Dandy-Walker malformation. Genetics Home Reference. October 2015; https://ghr.nlm.nih.gov/condition/dandy-walker-malformation.
  5. Dandy-Walker Syndrome; DWS. Online Mendelian Inheritance in Man (OMIM). May 22, 2013; http://omim.org/entry/220200.
  6. Salihu HM, Kornosky JL, and Druschel CM. Dandy-Walker syndrome, associated anomalies and survival through infancy: a population-based study. Fetal Diagn Ther. 2008; 24(2):155-60. http://www.ncbi.nlm.nih.gov/pubmed/18648217.
  7. Harper T, Fordham LA, and Wolfe HM. The fetal Dandy Walker complex: associated anomalies, perinatal outcome and postnatal imaging.. Fetal Diagn Ther. 2007; 22(4):277-281. https://www.ncbi.nlm.nih.gov/pubmed/17369695.