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Disease Profile

Dandy-Walker complex

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.

1-9 / 100 000

US Estimated

Europe Estimated

Age of onset





Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)

DW complex; Dandy-Walker syndrome or malformation (type of DW complex); Dandy-Walker variant (type of DW complex);


Congenital and Genetic Diseases


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]


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]

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.

Medical Terms Other Names
Learn More:
80%-99% of people have these symptoms
Dandy-Walker malformation
Prominent occiput
Prominent back of the skull
Prominent posterior skull

[ more ]

30%-79% of people have these symptoms
Frontal bossing
5%-29% of people have these symptoms
Aplasia/Hypoplasia of the corpus callosum
Cleft palate
Cleft roof of mouth
Tetralogy of Fallot
Percent of people who have these symptoms is not available through HPO
Agenesis of cerebellar vermis
Cranial nerve paralysis
Dilated fourth ventricle
Elevated imprint of the transverse sinuses
Too much cerebrospinal fluid in the brain
Involuntary, rapid, rhythmic eye movements
Partial absence of cerebellar vermis
Posterior fossa cyst at the fourth ventricle
No previous family history
Thinning and bulging of the posterior fossa bones
Truncal ataxia
Instability or lack of coordination of central trunk muscles


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]


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]


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]


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

    Learn more

    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.


        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; https://rarediseases.org/rare-diseases/dandy-walker-malformation/.
        3. Incesu L and Khosla A. Imaging in Dandy-Walker Malformation. Medscape Reference. March 27, 2018; https://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; https://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. https://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.

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