Dandy-Walker malformation (DWM) is a condition in which there is abnormal development of parts of the brain.^1-3 DWM occurs before birth (congenital) and it mainly affects the cerebellum (a part of the brain which helps with balance and coordination) and the fourth ventricle (a space in the brain that contains cerebrospinal fluid).

In DWM, the cerebellar vermis (the structure that connects the two halves of the cerebellum) is under-developed or missing – this can range from subtle differences in the cerebellar vermis shape to complete absence of the cerebellar vermis. There is often cystic dilation of the fourth ventricle (where the ventricle becomes abnormally enlarged), which can lead to enlargement of the posterior fossa (a space at the back of the skull).

These changes can disrupt the normal flow of cerebrospinal fluid (CSF) and sometimes cause hydrocephalus, a build-up of CSF that increases pressure in the brain. Symptoms can vary widely between individuals depending on the structural differences.

Synonyms: Dandy-Walker syndrome, Dandy-Walker cyst, Dandy-Walker deformity, Dandy-Walker, Luschka-Magendie foramina atresia, Dandy-Walker spectrum disorder (DWSD), atresia of foramina of magendie and Luschka.^1,4,5

Two other conditions, cerebellar vermis hypoplasia (historically called Dandy-Walker variant) and mega-cisterna magna, have similar symptoms to Dandy-walker malformation and it can be hard to be distinguish between the three conditions.⁵ These three conditions are sometimes collectively referred to as the ‘Dandy-Walker complex’ or ‘Dandy-Walker syndrome’. However they are three distinct conditions with different causes, treatments and prognosis.

Universal rare disease classifications provide a common language for recording, reporting and monitoring diseases. Please visit the Rare Disease Classifications page for more information about these internationally recognised classifications.

ORPHA:269570 Genetic syndrome with a Dandy-Walker malformation as a major feature

ORPHA:217 Isolated Dandy-Walker malformation

ICD-11: LA06.0 Dandy-Walker malformation

DWM can cause different symptoms in different individuals.^1-4 In some people it can cause hydrocephalus, which is the build-up of cerebrospinal fluid causing pressure on the brain. The symptoms of DWM and their severity depend on the extent of the structural differences, and whether hydrocephalus also occurs. If hydrocephalus is present, then the symptoms are typically more severe.

Common symptoms include large head circumference, poor balance and coordination (ataxia), and low or high muscle tone. Some people with DWM also have developmental delays and intellectual disabilities, and some experience seizures or breathing issues. These symptoms are most common in individuals with hydrocephalus.

DWM commonly occurs at the same time as other conditions, which present additional symptoms. These can include additional brain malformations and malformations of the heart, limbs, fingers and toes.^{2, 7}

Please speak to your medical team to learn more about the symptoms and complications of DWM.

Rare diseases are often serious and progressive, exhibiting a high degree of symptom complexity, leading to significant disability. Majority of the estimated two million Australians living with a rare disease meet the Australian Government’s definition for disability (in accordance to the Australian Public Service Commission and Australian Bureau of Statistics), and many experience severe and permanent disability impacts. If you or someone you care for is experiencing disability-related impacts from a rare condition, please speak with a health or disability professional for advice. Information about relevant disability support can be found at the RARE Portal’s Disability Support Information page.

DWM occurs when the brain does not form correctly during embryonic development (before birth).^1,2

In many cases, the cause of the malformation is unknown. In some cases, it occurs due to chromosomal abnormalities, such as:^1-3,6

• deletion in chromosome 3q24.3 (which includes deletion of two genes ZIC1 and ZIC4)
• deletions or genetic changes in chromosomes 6p25 or 13q32.2-q33.2
• duplication of chromosome 9p

For more information on chromosome changes, see Centre for Genetics Education: Chromosome changes

If you would like to learn more about the inheritance and impact of this condition, please ask your doctor for a referral to a genetic counsellor. Genetic counsellors are qualified allied health professionals who can provide information and support regarding genetic conditions and testing. More information about genetic counselling can be found at:

• Information on Genetic Services
• The National and State Services pages underneath the ‘Genetic Counselling’ sections listed

DWM is diagnosed by medical imaging of the brain.^1-3 Sometimes perinatal ultrasound or foetal magnetic resonance imaging (MRI) can detect characteristic DWM features in the brain before a baby is born. In almost all cases, symptoms are present in a baby’s first year of life, and a computerised tomography (CT) scan or MRI of their brain can detect the malformation and confirm a diagnosis.

As part of the diagnostic process, doctors may do a differential diagnosis, where they rule out other conditions that have similar symptoms, such as cerebellar vermis hypoplasia (historically called Dandy-Walker variant), mega-cisterna magna, Blake’s pouch cyst, and Walker-Warburg syndrome.^{1, 3, 7}

Please speak to your medical team to learn more about the available diagnostic pathways for DWM.

There is currently no curative treatment for DWM. Treatment is targeted at managing symptoms (symptomatic management) and involves multidisciplinary care. Management strategies may include physiotherapy, occupational therapy, speech therapy and special education depending upon the individual child’s needs.^1,2

If hydrocephalus is present, surgery may be performed to reduce pressure in the brain and swelling.^1,2 This may involve a small hole being created in the ventricle to allow the fluids to flow properly (endoscopic third ventriculostomy) or a special tube, called a shunt, may be inserted into the skull which drains the excess fluid from the brain and directs the fluid to other parts of the body where it can be properly absorbed.

Please speak to your medical team to learn more about the possible treatment or management options for your condition. Treatment will depend on an individual’s specific condition and symptoms. It is also important to stay connected to your medical team so that you can be made aware of any upcoming clinical trial opportunities.

Healthcare professionals involved in the care of individuals with DWM may include general practitioners (GP), surgeons, paediatricians, occupational therapists, physiotherapists, genetic counsellors and neurologists. The need for different healthcare professionals may change over a person’s lifetime and extend beyond those listed here.

Clinical care for rare diseases often involves a multidisciplinary team of medical, care and support professionals. Please note that the information provided here is as a guide and that RVA does not necessarily monitor or endorse specific clinics or health experts.

For many rare diseases, palliative care services may be relevant and useful. Palliative care services are available for people (adults, children and their families) living with a life-limiting illness. Palliative care services provide assistance, support, resources and tools to help people manage their illness and the symptoms, ease pain, and improve comfort and quality of life. Palliative care is not only for end-of-life care. It can also help at any stage of illness from diagnosis onwards, and will look different for different people. For more information about palliative care and how it can help you, please visit:

• Australian Institute of Health and Welfare: Palliative care Overview
• Australian Government Department of Health, Disability and Ageing: Palliative care
• Palliative Care Australia

Healthcare professionals involved in the care of individuals with DWM may include general practitioners (GP), surgeons, paediatricians, occupational therapists, physiotherapists, genetic counsellors and neurologists. The need for different healthcare professionals may change over a person’s lifetime and extend beyond those listed here.

We are not aware of any clinical care guidelines for DWM in Australia or internationally. If you know of any relevant care guidelines, please let us know via the Contribute page.

Individuals living with rare diseases may have complex medical issues and disabilities, which are not always visible. It is often useful to refer to their medical history as well as personal information such as a medical card, doctor’s letter, or if available, a rare disease passport, for relevant information.

There are specific considerations around participating in rare disease research, including clinical trials. It is important to be mindful of issues such as data privacy, research ethics, consent and differences in research regulations between Australia and other countries.

If you are interested in finding clinical trials for your condition, please visit the following websites; however, there may not be any clinical trials available:

• Australian Clinical Trials
• ClinicalTrials.gov

It is best to discuss your interest in any clinical trials with your medical team to determine suitability and eligibility.

Australian Organisation:
We are not aware of any rare disease organisations for DWM in Australia. If you are aware of any relevant Australian organisations, please let us know via the Contribute page.

International Organisation:
Dandy-Walker Alliance (United States of America)
Website: https://dandy-walker.org/

Please note that RVA does not monitor or endorse each group/organisation’s operational governance and activities. When engaging with a group, please consider the information on the RARE Portal’s Finding Helpful Peer and Community Supports page.

DWM varies between individuals, and each person’s experience is unique.

If you would like to share your personal story with RVA, please visit the Rare Voices Australia: Share Your Story page. RVA will consider your story for publishing on our website and inclusion on the RARE Portal.

For information on available government and social services that provide support for individuals with a rare disease, please visit the National and State Services pages.

People living with a rare disease, including families and carers, often face unique challenges such as diagnostic delays, misdiagnoses, limited treatment options, and limited access to rare disease specialists and support. These challenges may impact people’s emotional wellbeing and quality of life. Many people find it helpful to seek mental health and wellbeing support to cope with ongoing stress and uncertainty. Connecting with people who have shared experiences through a support group may also be helpful. Information about relevant mental health and wellbeing support can be found at:

• Mental Health and Wellbeing Support for Australians Living with a Rare Disease
• The National and State Services pages underneath the ‘Mental Health’ sections listed

Further information on DWM can be found at:

• Genetic and Rare Diseases (GARD) Information Center: Dandy-walker syndrome
• National Organization for Rare Disorders (NORD): Dandy Walker Malformation

Online Mendelian Inheritance in Man, OMIM^®: 220200 Dandy-Walker Syndrome; DWS

Orphanet: Isolated Dandy Walker malformation

Orphanet: Genetic syndrome with a Dandy-Walker malformation as a major feature

Human Phenotype Ontology (HPO): Isolated Dandy-Walker malformation

This page has been developed by Rare Voices Australia (RVA)’s RARE Portal team.

If you are aware of any additional information that may benefit stakeholders with an interest in this page, or if you notice any broken links or inaccurate information, please let us know via the Contribute page.